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1
Scott, B. J., I. G. Fenton, A. G. Fanning, W. G. Schumann, and L. J. C. Castleman. "Surface soil acidity and fertility in the eastern Riverina and Western Slopes of southern New South Wales." Australian Journal of Experimental Agriculture 47, no. 8 (2007): 949. http://dx.doi.org/10.1071/ea05155x.
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This study, in southern New South Wales (NSW), examined the chemical properties of ~4700 surface soils in agricultural paddocks and recorded lime and gypsum inputs. The area was bounded approximately by Cootamundra in the north, the NSW/Victorian border in the south, extending to Tumbarumba in the east and to near Berrigan in the west. The long-term average annual rainfall ranged from ~420 mm in the west to a maximum of 1175 mm in the east. The data, collected between 1997 and 2003, were for the surface 20 cm of soil, in two 10-cm layers. The data were generated from a soil testing program conducted with farmers in the region. We grouped the soils into three zones based on a GPS location taken at the time of sampling. These zones were 1 (lower rainfall mixed farming), 2 (higher rainfall mixed farming) and 3 (long-term pasture). Acidic soils occurred across all three zones; however, the soils in zone 1 appeared to be less acidic than soils in the other two zones. We found that surface soils (0–10 cm) with soil pH in 1 : 5 soil : 0.01 mol/L calcium chloride (pHCa) ≤4.5 represented 27%, 57% and 54% for zones 1, 2 and 3, respectively. In addition, zone 1 had 74% of surface soils with a pHCa ≤ 5.0, and this was more acidic than previously reported. However, the surface soils in zone 1 had relatively low exchangeable aluminium (Alex) and had less acidic subsurface soils (10–20 cm), so that responses to lime application by pastures and crops may be less frequent or smaller than the surface soil pHCa alone may indicate. There was a higher frequency of acidic soils (pHCa ≤ 4.5) in the subsurface soils than in the surface soils in zones 2 (62 cf. 57%) and 3 (64 cf. 54%), suggesting that the acidity problem at this depth was a major problem. Low pHCa in the subsurface soil is known to be a constraint on crop yield. We found no evidence of the amendment of this soil depth when lime was applied and incorporated into the 0–10 cm depth, and economic amendment of acidity in the 10–20 cm depth remains unresolved. Increased adoption of liming occurred in the late 1990s, and by 1997 the percentage of paddocks limed was 14.3%, 21.3% and 13.6% in zones 1 to 3, respectively. Soil pH buffering and long-term pHCa decline after liming were similar to rates reported in field experiments. The total quantities of lime applied were insufficient for soil amendment and maintenance of soil pHCa, particularly in the long-term pasture areas. The rate of soil acidification in the 0–20 cm depth in the average annual rainfall range of 525–625 mm was estimated to be 1.52 kmol H+/ha.year. This would require 76 kg lime/ha.year to neutralise. Sodic and saline soils occurred mainly in the lower rainfall cropping areas, and were more frequent in an area around the township of Lockhart. Half the gypsum applications were at low rates (≤0.5 t/ha), and were probably for sulfur application to canola. Some of the sodic soils were acidic (34% ≤ pHCa 4.5) so that the application of lime/gypsum mixes could be appropriate in the amendment of these soils. Soils in the pasture system had mean organic carbon content (OC%) of 2.42, compared to the cropping zones at 1.65 and 1.75%. OC% was related to annual average rainfall; the increase in OC% was 0.19% and 0.08% for each 100 mm of average annual rainfall for the surface and subsurface soil, respectively. A group of soils in the cropping areas had surface OC% ≤ 1.25% OC (zone 1, 12%; zone 2, 20%) and this could be the result of intensive cropping. Most soils (55–63%) were of moderate P status (P(Colwell), 21–60 µg/g). However, there was still a substantial group of soils (31–43%) of low P status (P ≤ 20 µg/g). Most surface soils in all zones (72–80%) were low to marginal in sulfur status (KCl 40, ≤10 mg S/kg). Sulfur deficiency has been identified in canola, and current practice in the cropping areas is for inputs of gypsum at low rates.
2
Mullen, C. L., B. J. Scott, C. M. Evans, and M. K. Conyers. "Effect of soil acidity and liming on lucerne and following crops in central-western New South Wales." Australian Journal of Experimental Agriculture 46, no. 10 (2006): 1291. http://dx.doi.org/10.1071/ea04042.
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On some of the lighter textured soils in the wheatbelt of central-western New South Wales near Dubbo, soil acidity is a major problem, and lucerne (Medicago sativa) often establishes and grows poorly. We selected a site with a surface soil pHCa of 4.4 and an exchangeable aluminium of 0.4 cmol(+)/kg, which was also acidic down the soil profile. Experimental plots of 4 application rates of lime (nil, 1, 2 and 3 t/ha) in 4 replications were established. The site was limed in 1990 and lucerne sown in May 1991. Over the next 6 years the trial was periodically grazed with sheep, and lucerne regrowth and stand density were monitored. In October 1997, the lucerne was removed and 3 crops of varying acid tolerance (wheat, barley and canola) were sown as split plots in both 1998 and 1999. Lucerne density was higher in the limed plots compared with the unlimed treatment, and this difference persisted for 6 years. Dry matter production of lucerne was increased by lime applied at rates up to 2 t/ha. All 3 crops sown after the lucerne phase responded to lime applied 8 and/or 9 years earlier. The responses were attributed to the strong residual effect of the lime in the 0–10 cm soil layer, to smaller improvements in the 10–20 cm zone (possibly due to the movement of lime down the soil profile over the 7 years before the date of measurement) and to carry over effects of nitrogen fixation by the lucerne into the cropping phase. The protein content of the wheat grain was increased concurrently with grain yield due to the previous liming and resultant legume nitrogen effects. The results support the application of lime to improve the productivity of lucerne and subsequent crops, even when the soil is acidic to depths below the cultivation layer.
3
Horsnell, LJ. "The growth of improved pastures on acid soils. 2. The effect of soil incorporation of lime and phosphorus on the growth of subterranean clover and lucerne pastures and on their response to topdressing." Australian Journal of Experimental Agriculture 25, no. 1 (1985): 157. http://dx.doi.org/10.1071/ea9850157.
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Subterranean clover responds poorly to superphosphate application on some acid soils of the Southern Tablelands of New South Wales. A field experiment was undertaken, for two years, to examine the effects of incorporating large additional amounts of superphosphate or rock phosphate in the soil, with and without lime, on the growth of subterranean clover, lucerne and phalaris sown with recommended rates of lime superphosphate. Dry matter responses of subterranean clover and lucerne to superphosphate topdressing in the second year were also recorded. In the first year, subterranean clover growth was increased by the additional lime and by lime plus superphosphate. Lucerne growth was increased by additional lime. In the second year, the growth of subterranean clover was increased by the lime treatments and the superphosphate treatments applied in the previous year and by the deep incorporation into the soil of lime and superphosphate together. Subterranean clover growth also responded to the application of rock phosphate without lime. Lucerne dry matter production in the second year was increased by the lime, superphosphate and rock phosphate treatments applied in the first year. Lime application increased the yield responses of subterranean clover and lucerne to superphosphate topdressed in the second year. Lime application had no effect on the nitrogen content of the clover but increased that of lucerne. Lime application reduced the aluminium levels in the tops of all three species. The data suggest that the responsiveness of pastures to superphosphate on these soils is increased by the application of lime and rock phosphate and is related to low nitrogen fixation and high aluminium levels in the plant.
4
Leech, Fiona J., Alan E. Richardson, Michael A. Kertesz, Beverley A. Orchard, Samiran Banerjee, and Phillip Graham. "Comparative effect of alternative fertilisers on pasture production, soil properties and soil microbial community structure." Crop and Pasture Science 70, no. 12 (2019): 1110. http://dx.doi.org/10.1071/cp19018.
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Different fertiliser products are commonly promoted for use on pastures in order to improve pasture productivity and support a more ‘healthy’ soil microbial environment. However, minimal field research has been conducted to validate such claims. A 6-year study (2009–14) was conducted on phosphorus (P)-deficient soils at three sites near Yass, New South Wales, to investigate the effect of topdressing perennial native-based pastures with a range of alternative fertilisers compared with single superphosphate and an unfertilised control treatment. The alternative fertiliser products included manures, composts, crushed rock, rock-phosphate-derived products, concentrated ash and microbial products. Annual measurements were made of soil chemical properties, botanical composition and pasture yield during spring and/or winter + spring, as well as the relative effectiveness of products per unit of pasture grown. Soil microbial community structure under each fertiliser treatment was also analysed in the sixth year of the study. Fertiliser products with substantial quantities of P increased extractable soil P and resulted in significantly higher pasture growth and clover content compared with the unfertilised control. Superphosphate was found to be the most P-effective fertiliser for increasing pasture growth, along with a range of other products that showed differential responses. However, the cost and P-effectiveness of the products in relation to pasture growth varied considerably and was a function of rate and frequency of application as well as amount and solubility of the P applied. Despite large differences in pasture growth across the various fertiliser treatments, there was no significant effect of the alternative fertiliser products on microbial community structure compared with either the superphosphate or unfertilised control treatments. The observed variation in bacterial, fungal and archaeal community structures across all fertiliser treatments was best explained by soil pH or aluminium (Al) concentration, which was influenced differentially by the fertiliser products. Fungal community structure was also correlated with pasture-productivity parameters (i.e. spring pasture yield, clover content and soil-available P). Our findings reveal a highly resilient soil microbial community that was influenced minimally by use of the alternative fertiliser products, thus highlighting that on-farm management decisions regarding fertiliser product choice should primarily focus on pasture response and cost-effectiveness.
5
Knowles, T. A., and B. Singh. "Carbon storage in cotton soils of northern New South Wales." Soil Research 41, no. 5 (2003): 889. http://dx.doi.org/10.1071/sr02023.
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Soil carbon is an important component of the global carbon cycle with an estimated pool of soil organic carbon of about 1500 Gt. There are few estimates of the pool of inorganic carbon, but it is thought to be approximately 50% of the organic carbon pool. There is no detailed study on the estimation of the soil carbon pool for Australian soils.In order to quantify the carbon pools and to determine the extent of spatial variability in the organic and inorganic carbon pools, 120 soil cores were taken down to a depth of 0.90 m from a typical cotton field in northern NSW. Three cores were also taken from nearby virgin bushland and these samples were used as paired samples. Each soil core was separated into 4 samples, i.e. 0–0.15, 0.15–0.30, 0.30–0.60, and 0.60–0.90 m. Soil organic carbon was determined by wet oxidation and inorganic carbon content was determined using the difference between total carbon and organic carbon, and confirmed by the acid dissolution method. Total carbon was measured using a LECO CHN analyser. Soil organic carbon of the field constituted 62% (0–0.15 m), 58% (0.15–0.30 m), 60% (0.30–0.60 m), and 67% (0.60–0.90 m) of the total soil carbon. The proportion of inorganic carbon in total carbon is higher than the global average of 32%. Organic carbon content was relatively higher in the deeper layers (>0.30�m) of the studied soils (Vertosols) compared with other soil types of Australia. The carbon content varied across the field, however, there was little correlation between the soil types (grey, red, or intergrade colour) and carbon content. The total soil carbon pool of the studied field was estimated to be about 78 t/ha for 0–0.90 m layer, which was approximately 58% of the total soil carbon in the soil under nearby remnant bushland (136 t/ha). The total pool of carbon in the cotton soils of NSW was estimated to be 44.8 Mt C, where organic carbon and inorganic carbon constitute 34.9 Mt C and 9.9 Mt C, respectively. Based on the results of a limited number of paired sites under remnant vegetation, it was estimated that about 18.9 Mt of C has been lost from Vertosols by cotton cropping in NSW. With more sustainable management practices such as conservation tillage and green manuring, some of the lost carbon can be resequestered, which will help to mitigate the greenhouse effect, improve soil quality and may increase crop yield.
6
Holland, Jonathan E., and Asim Biswas. "Predicting the mobile water content of vineyard soils in New South Wales, Australia." Agricultural Water Management 148 (January 2015): 34–42. http://dx.doi.org/10.1016/j.agwat.2014.09.018.
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7
Banu, Nargis A., Balwant Singh, and Les Copeland. "Microbial biomass and microbial biodiversity in some soils from New South Wales, Australia." Soil Research 42, no. 7 (2004): 777. http://dx.doi.org/10.1071/sr03132.
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Eight surface soils (0–15 cm) including 1 Ferrosol, 2 Tenosols, 2 Kurosols, 1 Sodosol, 1 Chromosol, and 1 Kandosol were collected from mainly pasture sites in New South Wales. The soils had different physico-chemical properties and there were some differences between the sites in climatic conditions. Soil microbial biomass carbon (MBC) was estimated by the chloroform-fumigation extraction method, and substrate utilisation patterns determined by the Biolog method were used to assess the amount, functional diversity, substrate richness and evenness, and community structure of the microorganisms in these soils. The amount of MBC (585 µg C/g) and the microbial diversity (H´ = 3.24) were high in soils that had high clay (33%), organic C (5.96%), total N (0.45%), free iron (7.06%), moisture content (50%), and cation exchange capacitiy (133.5 mmolc/kg). These soil properties, e.g. soil moisture (r2 = 0.72), organic C (r2 = 0.58), total N (r2 = 0.63), free iron (r2 = 0.44), and EC (r2 = 0.53), were positively correlated with MBC and microbial diversity index, whereas pH and sand and silt content showed negative correlations. The climatic factors (temperature and rainfall) had no significant influence on either MBC or diversity.
8
Mckenzie, DC, TS Abbott, KY Chan, PG Slavich, and DJM Hall. "The nature, distribution and management of sodic soils in New-South-Wales." Soil Research 31, no. 6 (1993): 839. http://dx.doi.org/10.1071/sr9930839.
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Accurate data on the distribution of the various types of sodic soils in New South Wales are not available. However, general observations suggest that large areas are affected by structural instability as a result of sodicity, particularly on grey clays and red-brown earths of the Murray-Darling Basin. There is a strong need for new sodicity surveys because the production of crops and pasture often is well below potential on these lands. Exchangeable sodium data on their own do not adequately describe sodic soil behaviour, so information is also required about related factors such as electrical conductivity, exchangeable magnesium, clay mineralogy, pH, calcium carbonate content, degree of remoulding, and the frequency of continuous stable macropores. Critical limits for sodicity that are used by soil management advisory services need to be redefined. Considerable research into the reclamation and management of sodic soils has occurred in the irrigation areas and rainfed cropping districts of the Murray-Darling Basin in New South Wales. Mined and by-product gypsum, and to a lesser extent lime, have been shown to greatly improve the physical condition and profitability of production from soils with a dispersive surface. However, the responses to these treatments are less likely to be economical when sodicity is confined to the subsoil. Adequate supplies of gypsum and lime are available in New South Wales, but further research is required to determine economically optimal and environmentally acceptable rates and frequencies of application, particle sizes and chemical compositions for different farming systems that utilize the various types of sodic soil.
9
Crocker, GJ, and ICR Holford. "Effects of pasture improvement with superphosphate on soil pH, nitrogen and carbon in a summer rainfall environment." Australian Journal of Experimental Agriculture 31, no. 2 (1991): 221. http://dx.doi.org/10.1071/ea9910221.
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The effects of pasture improvement on soil pH, total nitrogen, organic carbon and extractable phosphorus (P) were determined by analysing adjacent soils from improved and unimproved pastures at 67 sites on the Northern Tablelands of New South Wales. Pasture improved sites contained at least 1 clover species, predominantly white clover, and had received at least 125 kg P/ha over periods of 15-45 years. The majority of pasture improved sites contained more soil nitrogen, carbon and phosphorus and were of lower soil pH than adjacent unimproved sites. However, the decreases in pH were not statistically significant and not usually related to the magnitude of the increases in other soil fertility parameters nor to the amounts of superphosphate applied or duration of fertiliser history. The largest decline in soil pH and largest increase in organic carbon were on granitic soils which had received more than 250 kg P/ha. The relatively small decreases in soil pH and lack of relationship with fertiliser history, compared with soils from southern New South Wales, were attributed to: (i) re-cycling of legume-fixed nitrogen by summer-growing grasses; (ii) the naturally lower pH, higher nitrogen content and higher buffering capacity of many northern soils. Soil acidification therefore seems to be much slower and less frequent in the perennial pasture systems of the Northern Tablelands of New South Wales.
10
Leys, J., T. Koen, and G. McTainsh. "The effect of dry aggregation and percentage clay on sediment flux as measured by a portable field wind tunnel." Soil Research 34, no. 6 (1996): 849. http://dx.doi.org/10.1071/sr9960849.
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The effect of dry aggregation levels >0.85 mm and the percentage clay content of 9 soils from south-western New South Wales on erosion rate is evaluated using a portable field wind tunnel. Standard soil preparations and wind velocities are used based on conventions established in the North American wind erosion literature. For the prediction of erosion rate on both cultivated and uncultivated soils, 2 highly significant empirical relationships for percentage soil clay content and percentage mass dry aggregation >0.85 mm are presented. These spatial and temporal variations in erosion rates have significance for our understanding of soil erodibility. The concept of erodibility continuum is introduced.
11
Graham, S., B. R. Wilson, N. Reid, and H. Jones. "Scattered paddock trees, litter chemistry, and surface soil properties in pastures of the New England Tablelands, New South Wales." Soil Research 42, no. 8 (2004): 905. http://dx.doi.org/10.1071/sr03065.
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Scattered paddock trees are widespread throughout rural Australia but their effect on soil conditions has received only limited research attention. This study investigated the influence of 3 Eucalyptus species on surface soil properties on different parent materials at both stocked and unstocked sites on the Northern Tablelands of New South Wales. Mineral soil samples to a depth of 5 cm were collected at intervals up to twice the canopy radius away from tree trunks and litter samples were collected at corresponding points. Mineral soils were analysed for pH (CaCl2), organic carbon (C), and extractable phosphorus (P) concentration, while for the litter samples, P, sulfur, cations, and ash alkalinity were determined. Stocking with sheep and cattle increased surface soil acidity and C and P concentrations at each location. However, soils under E. melliodora and E. viminalis showed higher pH and increased C and P concentrations close to the tree stem irrespective of grazing. Soils under E. caliginosa, while having similar patterns of C and P, showed variable acidity patterns with instances of lower pH close to the tree stem. Spatial patterns in soil acidity were associated with the ash alkalinity of litter, indicating litter as a source of alkalinity addition to the soil surface, although different patterns of soil pH could not be fully explained by litter ash alkalinity alone. The close correlation of litter Ca content with ash alkalinity suggests that this element might be a suitable indicator of the acid amelioration capacity of different tree species.
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Holland, Jonathan, Mark Conyers, Beverley Orchard, and Graeme Poile. "Soil potassium relationships, uptake efficiency and availability for six distinctive soils in central and southern New South Wales, Australia." Soil Research 52, no. 2 (2014): 129. http://dx.doi.org/10.1071/sr13171.
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Most soils in eastern Australian contain abundant soil potassium (K) reserves, and it is often assumed that there are no problems with soil K status. However, soil K deficiency has been reported in selected locations, and for viticulture, there are potential problems with high soil K concentrations due to the application of winery wastewater. This study investigated different soil K variables and plant variables for six soils with distinctive properties from across central and southern New South Wales to determine the presence of soil K deficiency and to understand the effect of adding K on the dynamics of soil K availability. A glasshouse experiment compared the selected soils under three fertiliser K rates with forage kale as the test species. Highly significant differences (P < 0.001) were found for soil and fertiliser K rate effects for three measures of soil K (solution K, soln K; exchangeable K, exch. K; tetraphenyl borate K; TBK). Significant soil and fertiliser rate effects were detected (P < 0.001 and P = 0.04 respectively) for the plant shoot (stem and leaf) biomass and nutrient uptake efficiency (UPE) index, but no plant K deficiency was detected; in fact, luxury K consumption was likely. Quantification of K efficiency indices (UPE and utilisation efficiency, UTE) demonstrated significant differences between the soils in the ease with which K was removed. This was illustrated by the negative correlation between both UPE and UTE with final exch. K. From soil properties potentially related to soil K variables, a significant linear regression relationship (P = 0.05) was found for TBK with illite and clay content. By contrast, a linear regression relationship between exch. K and illite content only was weaker (P = 0.09). These relationships show how soil properties (especially mineralogy) can predict soil K variables. A significant positive log–log relationship was found between exch. K or TBK for 37 Queensland soils and the same soil K measures from this study, consistent with this relationship. This relationship indicates that TBK can be effectively predicted from measuring exch. K for a wide range of soils across eastern Australia, but more research is required to understand the value of TBK to predict soil K availability.
13
Mclaughlin, MJ, TG Baker, TR James, and JA Rundle. "Distribution and forms of phosphorus and aluminum in acidic topsoils under pastures in south-eastern Australia." Soil Research 28, no. 3 (1990): 371. http://dx.doi.org/10.1071/sr9900371.
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The vertical distributions of pH, and forms of phosphorus (P) and aluminium (Al) in acidic topsoils (0-100 mm depth) under pastures were examined at 15 sites in New South Wales and Victoria. The soils were characterized by shallow surface strata of moderate pH, high P and low Al concentrations overlying more acidic, P-deficient and Al-rich subsurface strata. Significant amounts (35-65%) of the total P in acidic pasture topsoils were present in organic forms (Po). Some 20-40% of this Po was extractable using 0.5 M NaHCO3, and is regarded as easily mineralizable and a potential source of P for plant uptake. Substantial amounts of Al were present in crystalline and non-crystalline oxides (2000- 6000 mg kg-1) and complexed to organic matter (up to 400 mg kg-1). The amount of aluminium extracted using reagents commonly accepted to indicate Al toxicity in soils (1 M KCl and 0.01 M CaCl2) was not related to the amounts of those Al forms (extracted by ammonium oxalate, sodium citrate-dithionite) typically identified in pedological and mineralogical studies. Sampling and analysis of soils for determining P fertilizer requirements and diagnosing acidity and related problems (e.g. Al toxicity, Ca deficiency) should take into account the vertical heterogeneity in soil properties in the top 100 mm of the profile.
14
Little, IP, AJ Ringrose-Voase, and WT Ward. "Surface structure in gray clays of northwestern New South Wales in relation to micromorphology, cation suite and particle size attributes." Soil Research 30, no. 1 (1992): 1. http://dx.doi.org/10.1071/sr9920001.
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Considerable differences in surface structure (0-100 mm) were observed in the field in two adjacent areas of grey clays near Narrabri, N.S.W. The absence of any differences in clay mineralogy and granulometry of the sand fraction supported the field assessment that both types of soil were similar in provenance. A transect of soil profiles including seven with poor structure and five with well-structured surface horizons was examined. The field observations of structure were supported by photographs of the surface, and water entry after rain. Micromorphological examination showed that closely spaced porphyric to adporphyric fabric in the poorly structured soils contributed to poor structure, highlighting the importance of textural attributes. The well-structured soils had a more widely spaced porphyric fabric. A measure of dispersibility depending on clay content and exchangeable plus soluble Na, Ca and Mg tallied very well with the field assessment of soil structure. Five groups were obtained from a euclidean distance/flexible sort strategy on the basis of cation suite, carbon content and particle size attributes. The groups identified areas of poor structure very well and the groups appear to be discriminated mainly on the basis of differences in Na, Ca and clay content. Treating the transect as a continuum of soils of very poor structure at site 1 grading to very good at site 12 showed that greater values for Ca, K, and clay were associated with good structure and greater values for Mg, C and silt were associated with poor structure. The sodium adsorption ratio and ionic strength of the soil solution were not on their own good predictors of structural behaviour possibly due to the independent contribution of Ca and Mg in this respect.
15
McKenzie, DC, and HB So. "Effect of gypsum on vertisols of the Gwydir Valley, New South Wales. 2. Ease of tillage." Australian Journal of Experimental Agriculture 29, no. 1 (1989): 63. http://dx.doi.org/10.1071/ea9890063.
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An experiment was carried out to deter- mine the effect of applied gypsum on the ease of tillage in 3 vertisols of the Gwydir Valley, New South Wales. The soils were classified as 'poor' and 'good' on the basis of past dryland wheat yields and structural of their surface aggregates.Where gypsum had been applied 22 months earlier at a rate of 7.5 t ha-1, tractor fuel consumption per centimetre of soil tilled was reduced by as much as 37% (0.85 v. 0.54 L ha-1 cm-1). The effect was most marked on the more sodic clays. The reduction in fuel consumption due to gypsum was associated with instability creased soil water content (0.127 v. 0.224 kg kg-1) and lower soil strength (330 v. 140 kPa).
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Willis, TM, and AS Black. "Irrigation increases groundwater recharge in the Macquarie Valley." Soil Research 34, no. 6 (1996): 837. http://dx.doi.org/10.1071/sr9960837.
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Rising groundwater, and the potential for development of shallow watertables, were recognised in the Lower Macquarie Valley of New South Wales in the late 1980s. Irrigated agriculture was proposed as a possible source of the recharge causing the problem. This paper reports the increase in deep percolation rates resulting from cotton irrigation on 4 soils in the Lower Macquarie Valley, New South Wales. Changes in deep percolation rates were measured on these soils over the long-term, using temporally separated chloride profiles and mass balance modelling. These changes in long-term deep percolation rates were integrated over all years since irrigation commenced. Irrigation affected deep percolation on all soils, with an increase in long-term mean rates ranging from 17 to 202 mm/year. This equated to increased leaching rates ranging from 3 to 25%. Deep percolation appeared to be related to the clay content of the B horizon. The potential groundwater rise varied from 37 to 524 mm/year. The largest increases in deep percolation rates corresponded to sites where the watertable was closest to the soil surface. This suggests that the development of shallow watertables is related to recharge resulting from irrigated agriculture. Detailed studies of deep percolation under irrigated agriculture are required in the Macquarie Valley.
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Murphy, S. R., G. M. Lodge, and S. Harden. "Surface soil water dynamics in pastures in northern New South Wales. 3. Evapotranspiration." Australian Journal of Experimental Agriculture 44, no. 6 (2004): 571. http://dx.doi.org/10.1071/ea03041.
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Evapotranspiration is the major component of the hydrological balance of grazed pastures on the North-West Slopes of New South Wales, representing up to 93% of annual rainfall. Nearly 80% of evapotranspiration may occur as bare soil evaporation, however, representing water not available for plant growth. Few studies have reported daily values of actual evapotranspiration for pastures, particularly in northern New South Wales. The studies reported here were conducted to measure actual evapotranspiration using an evaporation dome technique, for plots with a range of pasture, litter and ground cover. Measurements were taken in each season between autumn 2000 and autumn 2001, with both wet and dry soil surface conditions, to document the range of values that might be expected. Similar measurements were conducted in areas of natural pasture, to quantify values under grazed conditions. A range of other variables were also quantified in association with each evapotranspiration measurement; these included components of net radiant energy, atmospheric conditions, pasture physical characteristics, ground cover and soil water content. These data were used to identify the most important variables, which may be influenced by or interact with grazing management, that account for variation in daily evapotranspiration values.Hourly evapotranspiration ranged from 0.02 to 0.82 mm/h and daily values ranged from 0.2 to 7.6 mm/day, in winter to summer, respectively. Linear regression models that included variables of solar radiation, herbage mass, vapour pressure deficit and soil water content accounted for up to 93% of the variation in daily evapotranspiration values. These models predicted that high litter mass (3000 kg DM/ha) may reduce evaporation by up to 1 mm/day for wet soils, making a substantial contribution to the annual hydrological balance. A simulation study of a grazed pasture, using the Sustainable Grazing Systems Pasture Model, indicated that grazing management may influence the partitioning of transpiration and evaporation from canopy, litter and bare soil. With rotational grazing, predicted soil evaporation was lower and transpiration and canopy evaporation were higher than with continuous grazing. Hence, pastures may require different management between summer and winter, so that bare soil evaporation and canopy interception losses are minimised, to maximise stored soil water available for pasture use. Pastures with lower evaporative losses are likely to have higher productivity and sustainability.
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Martin, RJ, MG McMillan, and JB Cook. "Survey of farm management practices of the northern wheat belt of New South Wales." Australian Journal of Experimental Agriculture 28, no. 4 (1988): 499. http://dx.doi.org/10.1071/ea9880499.
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A survey of management practices on wheat farms in northern New South Wales was carried out on 50 farms between 1983 and 1985 and was supplemented by a questionnaire mailed to 750 growers in 1985. Information was collected on crop rotation, tillage practice, fertiliser use and weed control practices. Data were collected from 1 paddock on each farm and included: wheat grain yield and quality, available soil water and nutrients at sowing, wild oat density, and incidence of soil-borne diseases. The 3-year average grain yield in survey paddocks was 2.2 t/ha. Multiple regression analysis was used to identify factors affecting grain yield and protein in 1985. Of the variation in wheat grain yield, 74% was explained by variation in available soil water at sowing, available soil nitrate at sowing, sowing date and wild oat density. Grain protein content declined with increasing available soil water and phosphate at sowing and with earlier sowing, but increased with available nitrate at sowing. Agronomic practices aimed at maximising wheat grain yield, in the presence of a deficiency ofavailable soil nitrate, are likely to result in a reduction of grain protein content. Likewise, responses to application of nitrogenous fertiliser are likely to be inversely related to available soil water at sowing. The mean gross margin for 1984 and 1985, based on $100/t of wheat grain, was $128. The mean gross margin for the least profitable 20% of paddocks was $37, and $253 for the top 20%. New varieties of wheat and herbicides were readily adopted by farmers. On the other hand, adoption of nitrogenous fertiliser use was slow, considering the widespread and long-standing deficiencies of nitrogen in cropping soils of the region. Crop rotation and tillage practices have changed only marginally since the late 1940s. The results of this survey indicate that the usefulness of soil testing for predicting fertiliser requirements could be improved by taking into account levels of available soil water, weed competition and sowing date and by using multiple regression analysis.
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Bedrossian, Sevag, and Balwant Singh. "Potassium adsorption characteristics and potassium forms in some New South Wales soils in relation to early senescence in cotton." Soil Research 42, no. 7 (2004): 747. http://dx.doi.org/10.1071/sr03143.
Full textAbstract:
The occurrence of premature senescence (PS) in cotton in Australia has been related to decreased potassium (K) concentration in the affected plants. Soil samples (0–120 cm) were taken from paired cotton fields, i.e. PS fields and similar soils not affected by PS (Non-PS fields), in northern New South Wales. The samples were analysed for different forms of K in soil, mineralogy of various size fractions, and K adsorption characteristics to evaluate differences in their K availability. Smectite was the dominant clay mineral in the studied soils. The K-bearing mineral illite was present in the clay fraction of all samples and its content was generally higher in soils from the Non-PS sites than the PS sites from Moree, Pilliga, and Warren. Water-soluble K (H2O-K) ranged from 0.03 to 2.64 mg/kg (median 0.35 mg/kg), exchangeable K (Exch-K) from 43 to 687 mg/kg (median 107 mg/kg), non-exchangeable K (Nonexch-K) from 164 to 1981 mg/kg (median 819 mg/kg), and total K (Total-K) from 16 811 to 23 207 mg/kg (median 14 740 mg/kg). The values of various K forms were generally higher in samples from the Non-PS fields than the PS fields from Pilliga and Warren sites and the reverse trend occurred for the samples from Trangie. Similar H2O-K and Exch-K values were found for the PS and Non-PS samples from Moree, whereas Nonexch-K and Total-K contents were higher in the top 60 cm soil depth from the Non-PS field than the PS field. The equilibrium activity ratio (ARKe) values were significantly higher for surface samples from the Non-PS sites than the PS sites from Pilliga and Warren and the reverse was true for the Trangie site. There was a sharp decrease in ARKe with depth for the studied samples. The potential buffering capacity (PBCK) for both surface and subsurface samples from the Non-PS site (mean 31.5 (mmol/kg)/(mol/L)1/2) from Trangie was substantially higher than the corresponding samples from the PS sites (mean 14.7 (mmol/kg)/(mol/L)1/2). There was a significant increase in K adsorption for the subsurface samples than the surface samples for all sites, as indicated by the higher values of Freundlich adsorption coefficient, k. At the Pilliga and Warren sites, the occurrence of premature senescence in cotton plants can be explained on the basis of differences in the levels of different forms of K, mineralogy, and K adsorption characteristics of soils from the PS and Non-PS fields. At the Moree site, higher illite content in the Non-PS than the PS soil may explain the difference in their K availability. For the paired Trangie samples, greater PBCK of the Non-PS soil than the PS soil may be responsible for increased K availability in the Non-PS soil. The occurrence of PS symptoms in cotton at Narrabri site cannot be directly contributed to K supplying parameters analysed in the study. The results also show that Exch-K alone may not be adequate to measure K availability to cotton in these soils.
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Yang, Xihua, Jonathan Gray, Greg Chapman, Qinggaozi Zhu, Mitch Tulau, and Sally McInnes-Clarke. "Digital mapping of soil erodibility for water erosion in New South Wales, Australia." Soil Research 56, no. 2 (2018): 158. http://dx.doi.org/10.1071/sr17058.
Full textAbstract:
Soil erodibility represents the soil’s response to rainfall and run-off erosivity and is related to soil properties such as organic matter content, texture, structure, permeability and aggregate stability. Soil erodibility is an important factor in soil erosion modelling, such as the Revised Universal Soil Loss Equation (RUSLE), in which it is represented by the soil erodibility factor (K-factor). However, determination of soil erodibility at larger spatial scales is often problematic because of the lack of spatial data on soil properties and field measurements for model validation. Recently, a major national project has resulted in the release of digital soil maps (DSMs) for a wide range of key soil properties over the entire Australian continent at approximately 90-m spatial resolution. In the present study we used the DSMs and New South Wales (NSW) Soil and Land Information System to map and validate soil erodibility for soil depths up to 100 cm. We assessed eight empirical methods or existing maps on erodibility estimation and produced a harmonised high-resolution soil erodibility map for the entire state of NSW with improvements based on studies in NSW. The modelled erodibility values were compared with those from field measurements at soil plots for NSW soils and revealed good agreement. The erodibility map shows similar patterns as that of the parent material lithology classes, but no obvious trend with any single soil property. Most of the modelled erodibility values range from 0.02 to 0.07 t ha h ha–1 MJ–1 mm–1 with a mean (± s.d.) of 0.035 ± 0.007 t ha h ha–1 MJ–1 mm–1. The validated K-factor map was further used along with other RUSLE factors to assess soil loss across NSW for preventing and managing soil erosion.
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Lambert, Marcia, and John Turner. "Nutrient distribution and cycling in a subtropical rainforest in New South Wales." Australian Journal of Botany 64, no. 2 (2016): 100. http://dx.doi.org/10.1071/bt14342.
Full textAbstract:
Subtropical rainforests in New South Wales (NSW) are distributed on the more fertile forest soils and are nutritionally distinct from the Eucalyptus forests in the same areas. The distribution, cycling of organic matter and nutrients and nutrient use efficiency in an Australian subtropical rainforest were studied and aspects were compared with reported Eucalyptus studies. The available nutrients were greatly in excess of the stand uptake or requirement. A single undisturbed plot within a research trial in mature forest was selected for the study. At the beginning of the study, the aboveground forest biomass was ~334 t ha–1 of organic matter and, 22 years later, there was 357 t ha–1, giving a net accumulation rate of 1.03 t ha–1 year–1, and net primary productivity of 13.0–14.6 t ha–1 year–1. Litterfall and forest-floor analyses indicated a very rapid turnover of organic matter, with an estimated half-life of ~0.5 years. The quantity of nutrients in the stand was high relative to other forest types in the area, with 1109.2 kg N ha–1, 62 kg P ha–1, 1999 kg Ca ha–1, 591 kg Mg ha–1 and 901 kg K ha–1. Nutrient requirement estimated as nutrient content of the current tissue was estimated to be 107, 5.3, 99, 26 and 61 kg ha–1 year–1 for N, P, Ca, Mg and K, respectively, and uptake defined as removal from the soil was estimated to be 112, 4.7, 128, 37 and 49 kg ha–1 year–1 for the same nutrients, the difference between these being net nutrient redistribution. Nutrient use efficiency (NUE), defined as net primary productivity (NPP) per requirement (t kg–1), was calculated to be 0.12, 2.43, 0.13, 0.50 and 0.21 for N, P, Ca, Mg and K, respectively; these values were low, for example, compared with mature E. pilularis, for which NPP was 0.20, 6.5, 0.43, 1.04 and 0.52 t kg–1 for N, P, Ca, Mg and K, respectively. Using NUE defined as NPP per uptake provided comparable estimates. The rainforest represents a forest growing with basically no nutrient limitations, and, as such, is a benchmark for forest nutrient distribution, cycling and NUE.
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Kelly, B., C. Allan, and B. P. Wilson. "Soil indicators and their use by farmers in the Billabong Catchment, southern New South Wales." Soil Research 47, no. 2 (2009): 234. http://dx.doi.org/10.1071/sr08033.
Full textAbstract:
‘Soil health’ programs and projects in Australia’s agricultural districts are designed to influence farmers’ management behaviours, usually to produce better outcomes for production, conservation, and sustainability. These programs usually examine soil management practices from a soil science perspective, but how soils are understood by farmers, and how that understanding informs their farm management decisions, is poorly documented. The research presented in this paper sought to better understand how dryland farmers in the Billabong catchment of southern New South Wales use soil indicators to inform their management decisions. Thematic content analysis of transcripts of semi-structured, face-to-face interviews with farmers suggest several themes that have implications for soil scientists and other professionals wishing to promote soil health in the dryland farming regions of south-eastern Australia. In particular, all soil indicators, including those related to soil ‘health’, need to relate to some clear, practical use to farmers if they are to be used in farm decision making. This research highlights a reliance of the participants of this research on agronomists. Reliance on agronomists for soil management decisions may result in increasing loss of connectivity between farmers and their land. If this reflects a wider trend, soil health projects may need to consider where best to direct their capacity-building activities, and/or how to re-empower individual farmers.
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Kelly, B., C. Allan, and B. P. Wilson. "Corrigendum to: Soil indicators and their use by farmers in the Billabong Catchment, southern New South Wales." Soil Research 47, no. 3 (2009): 340. http://dx.doi.org/10.1071/sr08033_co.
Full textAbstract:
'Soil health' programs and projects in Australia's agricultural districts are designed to influence farmers' management behaviours, usually to produce better outcomes for production, conservation, and sustainability. These programs usually examine soil management practices from a soil science perspective, but how soils are understood by farmers, and how that understanding informs their farm management decisions, is poorly documented. The research presented in this paper sought to better understand how dryland farmers in the Billabong catchment of southern New South Wales use soil indicators to inform their management decisions. Thematic content analysis of transcripts of semi-structured, face-to-face interviews with farmers suggest several themes that have implications for soil scientists and other professionals wishing to promote soil health in the dryland farming regions of south-eastern Australia. In particular, all soil indicators, including those related to soil 'health', need to relate to some clear, practical use to farmers if they are to be used in farm decision making. This research highlights a reliance of the participants of this research on agronomists. Reliance on agronomists for soil management decisions may result in increasing loss of connectivity between farmers and their land. If this reflects a wider trend, soil health projects may need to consider where best to direct their capacity-building activities, and/or how to re-empower individual farmers.
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Dear, B. S., G. A. Sandral, M. B. Peoples, B. C. D. Wilson, J. N. Taylor, and C. A. Rodham. "Growth, seed set and nitrogen fixation of 28 annual legume species on 3 Vertosol soils in southern New South Wales." Australian Journal of Experimental Agriculture 43, no. 9 (2003): 1101. http://dx.doi.org/10.1071/ea02141.
Full textAbstract:
The adaptation of 28 annual legume species to heavy clay cracking soils prone to waterlogging during winter was evaluated at 3 sites ranging in pH (CaCl2) from 4.6 to 5.4 in the wheatbelt of southern NSW. The 32 accessions and cultivars included Medicago arabica, M. polymorpha, Melilotus albus (syn. M. alba), Trigonella balansae, and 24 Trifolium species. Species identified as potentially valuable new plants for these environments included Trifolium hirtum, T. echinatum, T. glanduliferum and M. arabica for winter production, and M. albus, T. echinatum, T. glanduliferum, T. isthmocarpum, T. pauciflorum, and T. purpureum for spring production. Current cultivars of T. subterraneum subsp. brachycalycinum cv. Clare, and subsp. yanninicum, cv. Riverina, T. resupinatum cvv. Kyambro, Nitro and Prolific, and T. michelianum cvv. Bolta and Paradana, and M. polymorpha cv. Santiago, also proved well adapted. Average seed mass (size) of the legume species varied from 0.3 mg to 8.9 mg/seed with a negative curvilinear relationship between individual seed mass of a species and the number of seed set at all 3 sites (r2 = 0.59–0.89). Seed mass of a species did not influence winter productivity or seed yield. The percentage of nitrogen biologically fixed by the individual species in the first year averaged over the 3 sites varied from 30 to 75%. Species which fixed the highest proportion of their nitrogen requirement were T. subterraneum, M. arabica, T. isthmocarpum and T. resupinatum cv. Kyambro, all fixing >62% of their shoot nitrogen and having a nitrogen content >3.0%. In contrast, T. sylvaticum, T. cherleri, T. spumosum, T. stellatum and T. glomeratum performed poorly at most sites, and fixed <42% of their nitrogen requirements (averaged over 3 sites) with <2.5% nitrogen in their tissue in spring.
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Rosicky, Mark A., Leigh A. Sullivan, Peter G. Slavich, and Mike Hughes. "Soil properties in and around acid sulfate soil scalds in the coastal floodplains of New South Wales, Australia." Soil Research 42, no. 6 (2004): 595. http://dx.doi.org/10.1071/sr03078.
Full textAbstract:
Soil profiles in 10 persistently bare areas (i.e. scalds), mainly located in coastal backswamps of New South Wales, Australia, were examined for chromium-reducible sulfur content and selected chemical properties. At 5 of the sites, the adjacent paddocks with vegetation cover were also examined. All of the tested sites had been affected by the extensive drainage of the surrounding acid sulfate soil (ASS) landscapes and the consequent oxidation of pyrite. All sites had low pH values in the surface soil layers and these low pH values extended for up to 150 cm into the underlying unoxidised blue/grey pyritic estuarine gels. This can be attributed to the downward diffusion of acidity, either produced in the overlying oxidised zones of these soils or transported laterally across the landscape to these low-lying areas. Acidified unoxidised pyritic zones 120 cm thick can evidently form within several decades after drainage disturbance. At the scalded sites the depth from the soil surface to the main pyritic zone varied from the surface to >200 cm depth, indicating that this variable is not critical to ASS scald formation. For most of the sites examined, the chromium-reducible sulfur contents in the surface soil layers were appreciably higher than those in the immediately underlying soil layers. In most of the vegetated sites the chromium-reducible sulfur content in the surface layers was considerably higher than for the adjacent scalded site. The conditions necessary for pyrite formation (i.e. adequate supplies of organic matter, soluble iron, sulfate, and waterlogging) were found to exist at all sites, and the pyrite accumulations in these surface soil layers are considered to be neo-formed. The vegetated soil-profile pyrite and pH results were very similar to their scalded counterparts except that they had an extra 20–40 cm layer of vegetation and mulch that was missing from the scalded profiles. This indicates that there is considerable potential for more extensive scalding in these ASS areas.
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Roper, MM, and DM Halsall. "Use of products of straw decomposition by N2-fixing (C2H2-reducing) populations of bacteria in three soils from wheat-growing areas." Australian Journal of Agricultural Research 37, no. 1 (1986): 1. http://dx.doi.org/10.1071/ar9860001.
Full textAbstract:
The potential for N2 fixation by free-living bacteria using straw as a source of energy was evaluated in three soils (one from Gunnedah and two from Cowra) representative of the wheat belt in New South Wales. All three soils had a history of straw incorporation. The abilities of the respective microbial populations to use a range of carbon sources, including potential products of decomposition of straw, was determined and compared with the size and composition of each population. Neutral to alkaline (pH 7.4) soil of high (51%) clay content from Gunnedah produced higher rates of nitrogenase activity with straw than more acid (pH 5.6) lower (17%) clay containing soil from Cowra (site B). Gunnedah soil also contained a larger population of N2-fixing bacteria which used a broader range of energy sources than soil from either Cowra site B or Cowra site W (pH 5.8, clay content 34%). There was little difference in the composition of the N2-fixing populations in each of the soils except that Azotobacter spp. were absent from the acid Cowra soils. It was concluded that the difference in behaviour of the respective N2-fixing populations was primarily due to the physical characteristics of the soil affecting the numbers and activities of diazotrophic microorganisms. In addition some soil environments failed to support specific organisms.
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Acworth, R. I., R. R. Young, and A. L. Bernadi. "Monitoring soil moisture status in a Black Vertosol on the Liverpool Plains, NSW, using a combination of neutron scattering and electrical image methods." Soil Research 43, no. 2 (2005): 105. http://dx.doi.org/10.1071/sr04064.
Full textAbstract:
Electrical image data were used to estimate soil moisture content beneath smectite-dominated black Vertosol in the Liverpool Plains catchment in northern New South Wales. Measurements carried out over a range of soil moisture conditions included: water use by lucerne sown into a full profile, recharge of profiles after lucerne and long fallow after a cereal crop. Measurements were repeated approximately every 2 months between September 2000 and August 2001. Estimates of bulk electrical conductivity (EC), determined from inversion of apparent conductivity electrical images, were compared to soil moisture measurements made using neutron access tubes. A correlation of 0.77 (n = 228, P < 0.0001) between the 2 datasets indicates that electrical imaging can be used to satisfactorily predict bulk moisture content in soils of this type. Interpretation of the bulk EC images indicates drying of the soil profile to 6 m depth beneath lucerne.
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McKenzie, DC, KW Hucker, LJ Morthorpe, and PJ Baker. "Field calibration of a neutron-gamma probe in three agriculturally important soils of the Lower Macquarie Valley." Australian Journal of Experimental Agriculture 30, no. 1 (1990): 115. http://dx.doi.org/10.1071/ea9900115.
Full textAbstract:
A neutron-gamma probe was field calibrated in a grey clay, a grey-brown clay and a red-brown earth near Trangie, New South Wales. These are the main soils used for irrigated agriculture in this region. Accurate but simple calibrations and sampling procedure\ are required by commercial irrigators and researchers. Bias in the estimation of soil water content was minimised by using separate calibrations for each soil and depth where equations were significantly different. Precision tended to be higher where an equation combining all depths and soils was used. but the introduction of large bias at some depths suggests that soil-specific equations should be used where possible. Calibration error generally was a smaller component of total error than location error, particularly where the combination equation was used. The errors associated with commercial sampling methods are discussed. The relationship between gamma count rate ratio and soil wet bulk density was poor, particularly in the grey and grey-brown clays, and this technique was considered to be inadequate for the measurement of bulk density in the field.
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CHEN, G., G. D. LI, M. K. CONYERS, and B. R. CULLIS. "LONG-TERM LIMING REGIME INCREASES PRIME LAMB PRODUCTION ON ACID SOILS." Experimental Agriculture 45, no. 2 (April 2009): 221–34. http://dx.doi.org/10.1017/s0014479708007497.
Full textAbstract:
SUMMARYPrime lamb live weight response to lime application on pasture was measured in a grazing experiment in the high rainfall zone of the southwestern slopes of New South Wales, Australia. The pastures were limed every 6 years over 15 years. First cross South African Meat Merino lambs were used as test animals. Pre- and post-grazing pasture dry matter (DM) yield, botanical composition, feed quality and lamb live weight were monitored over 12 weeks in 2007. Results showed that liming significantly increased pasture DM yield of high quality species and improved overall pasture quality due to increased digestibility and metabolic energy content. As a result, the limed perennial and annual pastures carried 24.0% (3.6 lambs ha−1) and 29.0% (4.4 lambs ha−1) more stock than the unlimed perennial and annual pastures, respectively. Averaged across pasture types, the limed pastures produced 30.6% (131 kg ha−1) more lamb live weight gain than the unlimed pastures over 12 weeks. The live weight gain varied between grazing cycles depending on the availability of feed-on-offer and feed quality, which were closely related to the rainfall pattern. The perennial pastures did not show any advantage in animal production over annual pastures during the experimental period due to lack of moisture in the deep soil profile because of severe drought in the previous year. More seasons with normal or above average rainfall are needed to compare animal production on perennial pastures and annual pastures to investigate the advantage of perennial pastures in animal production.
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Rosicky, Mark A., Peter Slavich, Leigh A. Sullivan, and Mike Hughes. "Surface and sub-surface salinity in and around acid sulfate soil scalds in the coastal floodplains of New South Wales, Australia." Soil Research 44, no. 1 (2006): 17. http://dx.doi.org/10.1071/sr05027.
Full textAbstract:
Two-metre-deep soil profiles at 10 acid sulfate soil (ASS) scalds along the coast of New South Wales (NSW), Australia, were examined for salinity indicators. At 5 of the sites, permanently vegetated areas adjacent to the ASS-scalded land were also tested. Throughout the profiles, most sites had high soluble chloride (Cl−) concentrations (≤17 mg/g soil) and high soluble sulfate (SO42−) concentrations (≤17 mg/g soil). Very low Cl− : SO42− ratios (≤3) indicated active pyrite oxidation. Soil salinity (measured as electrical conductivity, EC) was extremely high in the top 2 m of most of the ASS scalds when related to the growth requirements of the typical introduced pasture species that were planted in these areas following drainage. This allows salinity, in addition to the extremely low pH of the surface soils, to contribute to land denudation, which can instigate or perpetuate pyrite oxidation and ASS-related land scalding. Although the sites had shallow watertables and soil-moisture content was high, the surface soil (top 0.10 m) of the scalds had consistently higher soluble Cl− and SO42− concentrations and EC than adjacent vegetated areas. All coastal ASS areas investigated, typically freshwater backswamps used for cattle grazing, were underlain by estuarine-derived sediments containing saline ground water. The results demonstrate that revegetation of ASS scalds must include investigation and management of salinity, in addition to acidity, within the soil profile and at the soil surface.
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Wilson, Brian R., Phoebe Barnes, Terry B. Koen, Subhadip Ghosh, and Dacre King. "Measurement and estimation of land-use effects on soil carbon and related properties for soil monitoring: a study on a basalt landscape of northern New South Wales, Australia." Soil Research 48, no. 5 (2010): 421. http://dx.doi.org/10.1071/sr09146.
Full textAbstract:
There is a growing need for information relating to soil condition, its current status, and the nature and direction of change in response to management pressures. Monitoring is therefore being promoted regionally, nationally, and internationally to assess and evaluate soil condition for the purposes of reporting and prioritisation of funding for natural resource management. Several technical and methodological obstacles remain that impede the broad-scale implementation of measurement and monitoring schemes, and we present a dataset designed to (i) assess the optimum size of sample site for soil monitoring, (ii) determine optimum sample numbers required across a site to estimate soil properties to known levels of precision and confidence, and (iii) assess differences in the selected soil properties between a range of land-use types across a basalt landscape of northern NSW. Sample site size was found to be arbitrary and a sample area 25 by 25 m provided a suitable estimate of soil properties at each site. Calculated optimum sample numbers differed between soil property, depth, and land use. Soil pH had a relatively low variability across the sites studied, whereas carbon, nitrogen, and bulk density had large variability. Variability was particularly high for woodland soils and in the deeper soil layers. A sampling intensity of 10 samples across a sampling area 25 by 25 m was found to yield adequate precision and confidence in the soil data generated. Clear and significant differences were detected between land-use types for the various soil properties determined but these effects were restricted to the near-surface soil layers (0–50 and 50–100 mm). Land use has a profound impact on soil properties near to the soil surface, and woodland soils at these depths had significantly higher carbon, nitrogen, and pH and lower bulk density than the other land uses. Soil properties between the other non-woodland land-use types were largely similar, apart from a modestly higher carbon content and higher soil acidity under improved pasture. Data for soil carbon assessment should account for equivalent mass, since this significantly modified carbon densities, particularly for the lighter woodland soils. Woodland soils had larger quantities of carbon (T/ha corrected for equivalent mass) than any other land-use type, and in order to maintain the largest quantity of carbon in this landscape, retaining trees and woodland is the most effective option. Results from this work are being used to inform further development the NSW Statewide Soil Monitoring Program.
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Farquharson, R. J., G. D. Schwenke, and J. D. Mullen. "Should we manage soil organic carbon in Vertosols in the northern grains region of Australia?" Australian Journal of Experimental Agriculture 43, no. 3 (2003): 261. http://dx.doi.org/10.1071/ea00163.
Full textAbstract:
Two issues prompted this paper. The first was the measured soil organic carbon decline in fertile northern Australian soils under continual cropping using traditional management practices. We wanted to see whether it was theoretically possible to maintain or improve soil organic carbon concentrations with modern management recommendations. The second was the debate about use of sustainability indicators for on-farm management, so we looked at soil organic carbon as a potential indicator of soil health and investigated whether it was useful in making on-farm crop decisions. The analytical results indicated first that theoretically the observed decline in soil organic carbon concentrations in some northern cracking clay soils can be halted and reversed under continuous cropping sequences by using best practice management. Second, the results and associated discussion give some support to the use of soil organic carbon as a sustainability indicator for soil health. There was a consistent correlation between crop input decisions (fertilisation, stubble management, tillage), outputs (yield and profits) and outcomes (change in soil organic carbon content) in the short and longer term. And this relationship depended to some extent on whether the existing soil organic carbon status was low, medium or high. A stock dynamics relationship is one where the change in a stock (such as soil organic carbon) through time is related not only to the management decisions made and other random influences (such as climatic effects), but also to the concentration or level of the stock itself in a previous time period. Against such a requirement, soil organic carbon was found to be a reasonable measure. However, the inaccuracy in measuring soil organic carbon in the paddock mitigates the potential benefit shown in this analysis of using soil organic carbon as a sustainability indicator.These results are based on a simulation model (APSIM) calibrated for a cracking clay (Vertosol) soil typical of much of the intensively-cropped slopes and plains region of northern New South Wales and southern Queensland, and need to be interpreted in this light. There are large areas of such soils in north-western New South Wales; however, many of these experience lower rainfalls and plant-available soil water capacities than in this case, and the importance of these characteristics must also be considered.
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Vervoort, R. W., S. R. Cattle, and B. Minasny. "The hydrology of Vertosols used for cotton production: I. Hydraulic, structural and fundamental soil properties." Soil Research 41, no. 7 (2003): 1255. http://dx.doi.org/10.1071/sr02154.
Full textAbstract:
This paper describes the hydraulic, structural and fundamental soil properties for 23 Vertosol horizons from 18 sampling sites in New South Wales and southern Queensland. At each site a combination of infiltration measurements and soil sampling was conducted. Samples were collected for determination of the soil water characteristic, shrink–swell relationships, and fundamental soil properties such as particle size distributions, pH, electrical conductivity (EC), exchangeable cations (Ca2+, Mg2+, K+, Na+), extractable P contents, extractable sulfate and Fe contents, and CaCO3 and total C contents. Large cores were sampled, impregnated with resin, and sectioned for image analysis. The program SOLICON v2.1 was used to calculate structural form parameters from the images. Measured hydraulic conductivities of the surface soils were large compared with earlier reported research for Vertosols. However, a sharp decrease in hydraulic conductivity occurred with depth in the profiles, which is assumed to be due to increased bulk densities and exchangeable sodium percentages (ESP). The data also indicated a general north–south trend in the structural development of these Vertosols. Surface soils from the northern areas, such as the Gwydir and Namoi valleys, exhibited more porous structural forms, and as a result, greater average hydraulic conductivities. This appears to be due to differences in ESP, clay content and the mineralogical suite of the clay; surface samples with smaller ESPs and larger proportions of smectitic clay tended to have the greatest values of hydraulic conductivity. Other fundamental soil properties such as extractable Fe and P contents, and CaCO3 content, were found to have little or no correlation to the hydraulic or structural properties of these Vertosols, while differences in measured shrink-swell and water retention properties were largely a function of soil depth. The database developed has given an overview of the hydraulic properties of Vertosols used for cotton production in south-eastern Australia.
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Paul, K. I., M. K. Conyers, and A. S. Black. "Influence of moist - dry cycles on pH changes in surface soils." Soil Research 37, no. 6 (1999): 1057. http://dx.doi.org/10.1071/sr98105.
Full textAbstract:
It is well established that in the moderately acidic soils of southern Australia, the 0–2 cm layer commonly has a higher pH than soil layers between 2 and 10 cm depth. The surface 2 cm of soil is also exposed to much greater fluctuations of moisture content than deeper soil layers. There are contradictory or speculative reports in the literature on how soil moisture fluctuation affects pH and processes which influence pH. Therefore, the aim of this study was to determine the effect of moist–dry cycles on pH, and on processes involving H+ transformations, in 3 surface soils (0–2 cm) sampled from southern New South Wales. Following a pre-incubation, the 3 surface soils were incubated for 28 days at 30°C and were: (i) maintained continuously dry, (ii) subjected to short (2 days dry, 5 days moist) or long (7 days dry, 7 days moist) moist–dry cycles, or (iii) maintained continuously moist. During the incubation, the pH of continuously dry soil slightly increased by 0.03–0.10 units, while the pH of continuously moist soil decreased by 0.16–0.39 units. In soils subject to both short and long moist–dry cycles, the pH decreased by 0.06–0.34 units. However, relative to soils maintained moist, exposure to moist–dry cycles suppressed acidification by 0.05–0.26 pH units. In dry soils the pH increased, since some of the NH4+-N produced by net N mineralisation was not subsequently nitrified, and there was a net reduction of Mn. In soils which received water, acidification was predominately attributed to nitrification. Relative to soils maintained moist, acidification was suppressed by 1.6–6.5 mmol H+/kg due to the 11–35% decrease of nitrification on exposure to moist–dry cycles. In acidic surface soils (pH <5.5), acidification rates were further suppressed by 0.1–1.0 mmol H+/kg due to the 1.06–2.06 times greater net Mn reduction in moist–dry soils than in continuously moist soils.
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Murphy, S. R., and G. M. Lodge. "Root depth of native and sown perennial grass-based pastures, North-West Slopes, New South Wales. 2. Estimates from changes in soil water content." Australian Journal of Experimental Agriculture 46, no. 3 (2006): 347. http://dx.doi.org/10.1071/ea04277.
Full textAbstract:
Root depth of pasture is an important hydrological parameter that has substantial implications for the use of rainfall by plants and in estimating deep drainage using biophysical modelling. Studies were undertaken for native and sown perennial grass-based pastures on the North-West Slopes of New South Wales to investigate 4 approaches that may identify the depth of plant roots based on objective assessments of change in soil water content (SWC). The 4 approaches were to examine traces of SWC measured with a neutron moisture meter (NMM) at about 4-week intervals (0–210 cm profile at 20-cm increments) for defined periods with root depth interpreted as, (i) the maximum depth at which there was a distinct decrease in SWC, (ii) the maximum depth at which there was a >0.01 m3/m3 decrease in SWC, (iii) the uppermost depth at which the change in SWC was significant using t0.05, and (iv) the uppermost depth at which the daily rate of change in SWC was significant using t0.05. For each of these approaches, 4 preliminary criteria were applied as filters to the SWC data before they were used in these analyses, (i) the depth of NMM tubes and maximum depth of measurement of SWC was greater than the anticipated pasture root depth, (ii) the depth of initial profile wetting was greater than the anticipated pasture root depth, (iii) there was a drying period of >3 months duration in the major pasture growth phase to allow pastures to extract soil water to the maximum extent, and (iv) the SWC was measured at a sufficient frequency to determine extraction of soil water by roots. SWC data were available from spring 1997 to spring 2001 for Barraba (45 access tubes, native pasture), Manilla (45 tubes, native pasture) and Nundle (36 tubes, sown pasture). Analyses of monthly rainfall compared with mean values identified 3 times where substantial rainfall was followed by an extended drying period. These periods occurred in 1998, 1999 and 2000. SWC data for the 1998 drying period best met all the preliminary filters, particularly criteria (ii) and (iii). Root depth values estimated from these data using the 4 approaches were not significantly different for Barraba (188 ± 4 to 190 ± 3 cm, n = 45), Nundle (142 ± 5 to 143 ± 7 cm, n = 13) and Manilla Red Chromosol (164 ± 7 to 176 ± 7 cm, n = 14), but were significantly different for Manilla Brown Vertosol (98 ± 7 to 121 ± 7 cm, n = 23). It was concluded that reliable estimates of root depth may be readily obtained for a range of soils and environments by firstly applying the 4 simple criteria used in these studies to the SWC data and by determining the depth of significant drying using t0.05. The depth of significant drying approach was the most objective, providing consistent results among sites and accounting for variance among NMM counts and tubes in these studies.
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Haddad, KS, and RG Weir. "Influence of soil properties on the use of soil and plant zinc to predict zinc response in maize." Australian Journal of Experimental Agriculture 25, no. 4 (1985): 856. http://dx.doi.org/10.1071/ea9850856.
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The value of using the diethylenetriaminepentaacetic acid (DTPA) soil zinc and/or the zinc concentration in young maize tops to predict the response, to zinc application, of maize growth on soils from the Liverpool Plains of New South Wales was assessed in a glasshouse experiment. Forty-eight composite soil samples, 23 medium clays (MC) and 25 heavy clays (HC), were collected from the study area and two rates of zinc (0 and 10 �g/g air-dried soil), were applied to each soil in a triplicated randomized block design. Maize was grown for 30 days and the growth response to zinc application was calculated as Bray's percentage yield (%y). Although zinc application generally increased the yield of maize grown on all soils tested (P<0.001), the correlations between %y and soil zinc, plant zinc and soil zinc, and %y and plant zinc of all soils tested, as one group, were not significant. When the soils were treated as two textural groups and the influence of other soil properties on the growth response of maize to zinc application were tested statistically, the %y differed between the MC and HC groups (P<0.05) and between the soils in each group (P<0.001). The multiple regression of %y on soil properties, within each soil group, revealed that, for the MC soils, the phosphorus content, DTPA extractable iron, manganese and zinc, percentage organic carbon and phosphorus sorption capacity were consistently and significantly related to %y and accounted for 93% of variation in %y. For the HC soils, only pH, DTPA-extractable manganese and percentage organic carbon were significantly related to %y and these accounted for 75% of the variation in %y. Zinc concentration in maize tops grown on the untreated soils was 12-40 �g/g. The %y was significantly (P<t0.05) related to zinc concentration in the tops of maize grown on the MC soils (r= 0.63), but not in those grown on the HC soils. These results suggest that, for maize grown in these soils, it is not possible to predict the response to zinc application by considering only zinc levels in soil or in young maize tops.
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Stanley, John N., David W. Lamb, Gregory Falzon, and Derek A. Schneider. "Apparent electrical conductivity (ECa) as a surrogate for neutron probe counts to measure soil moisture content in heavy clay soils (Vertosols)." Soil Research 52, no. 4 (2014): 373. http://dx.doi.org/10.1071/sr13142.
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Site-specific measurements of the apparent electrical conductivity (ECa) of soil using the EM38 were correlated with near-simultaneous neutron probe readings over periods of moisture extraction by an irrigated cotton crop. Thirty sites were monitored from three ECa zones within a 96-ha field of grey Vertosol soil 30 km west of Moree, New South Wales, Australia. This study differs from previous approaches by reporting the effect on ECa of a wetting front (irrigation) reaching a single ECa measurement point in a field and by using polyethylene neutron probe access tubes so that the EM38 could be operated directly over the same site measured by a neutron probe. We report strong correlations (r = 0.94) between neutron probe counts (CRR) averaged to a depth of 40 or 60 cm and ECa from an EM38 held in the vertical mode 20 cm above the soil surface. All combinations of EM sensor height (0–1.2 m) to neutron probe measurement depth (0.2–1.4 m) returned correlations >0.85. The relationship between CCR and ECa was linear for the purposes of estimating water content over a range of background ECa levels. More critical modelling suggested a slight curve (logarithmic model) fitted best. The range of surface-surveyed ECa from the start of irrigation (refill point) to fully irrigated (full point) was ~27 mS m–1 for this Vertosol, where surface ECa readings typically ranged from 50 to 200 mS m–1. We suggest that the calibration of ECa to CRR might be effected by a two-point measurement of the soil, namely at both upper (field capacity) and lower (wilting point) ECa values, and a site-specific calibration template generated by extending these point measures to whole-field surveys.
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Hulugalle, N. R., and L. A. Finlay. "EC1:5/exchangeable Na, a sodicity index for cotton farming systems in irrigated and rainfed Vertosols." Soil Research 41, no. 4 (2003): 761. http://dx.doi.org/10.1071/sr02058.
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Sodic soils are characterised by their poor structural stability. This is thought to be caused mainly by high levels of exchangeable sodium and low electrolyte concentrations. Historically, soil sodicity has been reported as the exchangeable sodium percentage, ESP [(exchangeable Na/∑ exchangeable cations)�×�100]. However, some authors believe that exchangeable sodium content alone is a better indicator of sodicity, whereas others suggest that an effective sodicity index is one which includes both the exchangeable sodium levels and electrolyte concentration (EC1:5). Some examples are the electrochemical stability index (EC 1:5/ESP) and EC1:5/exchangeable Na. The objective of this study was to evaluate which of 3 empirical sodicity indices (ESP, EC1:5/ESP, EC1:5/exchangeable Na) was best related to soil dispersion in Vertosols sown to cotton farming systems.Soil was sampled between 1995 and 2001 from 4 irrigated and dryland sites in New South Wales and Queensland, where the cropping systems included continuous cotton (Gossypium hirsutum L.), cotton–rotation crop sequences, and 2- and 1-m beds. Tillage systems ranged from zero to minimum tillage. Soils from all sites were analysed for EC1:5, exchangeable Ca, Mg, K, and Na, and dispersion index, and ESP, EC1:5/ESP and EC1:5/exchangeable Na derived. Long-term dispersion was best predicted by EC1:5/exchangeable Na, except where zero tillage was practised when none of the sodicity indices were related to dispersion. Aggregate stabilisation under zero tillage was speculated to be determined largely by labile soil organic matter and microbial activity rather than sodicity.
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Lusk, C. H., K. M. Sendall, and P. J. Clarke. "Seedling growth rates and light requirements of subtropical rainforest trees associated with basaltic and rhyolitic soils." Australian Journal of Botany 62, no. 1 (2014): 48. http://dx.doi.org/10.1071/bt13262.
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A trade-off between shade tolerance and growth in open conditions is widely believed to underlie the dynamics of humid forests. Little is known about how the growth versus shade tolerance trade-off interacts with other major trade-offs associated with differential adaptation to major environmental factors besides light. We asked whether the growth versus shade tolerance trade-off differed between subtropical rainforest tree assemblages native to basaltic (fertile) and rhyolitic (infertile) soils in northern New South Wales, because of the allocational costs of adaptation to low nutrient availability. Seedling relative growth rates of six basalt specialists and five rhyolite specialists were measured in a glasshouse and the minimum light requirements of each species were quantified in the field by determining the 10th percentile of juvenile tree distributions in relation to understorey light availability. A similar range of light requirements was observed in the two assemblages, and although the two fastest growing species were basalt specialists, seedling growth rates did not differ significantly between the two substrates. The overall relationship between light requirements and growth rate was weak, and there was no compelling evidence that the slope or elevation of this relationship differed between the two assemblages. Growth rates were significantly correlated, overall, with specific leaf area, and marginally with leaf area ratio. The apparent similarity of the growth versus shade tolerance trade-off in the two suites of species could reflect effects of leaf nutrient content on respiration rates; basalt specialists tended to have a smaller root mass fraction, but this may have been offset by the effects of leaf nitrogen status on respiration rates, with higher respiration rates expected on fertile basaltic soils. However, the results might also partly reflect impairment of the field performance of two basalt specialists that were heavily attacked by natural enemies.
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Lodge, G. M., S. R. Murphy, and S. Harden. "Effects of grazing and management on herbage mass, persistence, animal production and soil water content of native pastures. 2. A mixed native pasture, Manilla, North West Slopes, New South Wales." Australian Journal of Experimental Agriculture 43, no. 8 (2003): 891. http://dx.doi.org/10.1071/ea02189.
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As part of the Sustainable Grazing Systems (SGS) National Experiment a study was conducted on a native pasture in the Manilla district of northern New South Wales to examine the effects of 5 grazing treatments on total herbage mass, litter mass, basal cover, ground cover, sheep liveweight, wool production and soil water content (SWC, mm) at different depths. The pasture was a mixture of native perennial grasses, with redgrass (Bothriochloa macra) and wiregrass (Aristida ramosa) dominant on a red Chromosol soil type and bluegrass (Dichanthium sericeum) on a brown Vertosol. Wallaby grasses (Austrodanthonia richardsonii and A. bipartita) were common on both soils. Plots were grazed with Merino wethers and data collected from spring 1997 to spring 2001 were analysed to determine the effect of treatments on both production and sustainability. Five grazing treatments were applied in a randomised 3 replicate design. Grazing treatments were: continuous grazing at 3.1 and 6.2�sheep/ha (C3 and C6), continuous grazing at 9.2 sheep/ha, with subterranean clover (Trifolium subterraneum) oversown and fertiliser applied (C9+sub) and rotational grazing at an annual stocking rate of 3.1 sheep/ha with pasture grazed for 4 weeks and rested for 4 weeks (R4/4), or rested for 12 weeks (R4/12). Over time, treatments had no significant effect on either total pasture herbage mass (compared with the C3�control) or the basal cover of the major perennial grasses. Treatments had inconsistent significant effects on ground cover, litter mass, sheep liveweight and wool production (kg/head) over time. Compared with all other treatments ground cover was less (P<0.05) in the C6 treatment in only May and September 2000 and litter mass less (P<0.05) in only December 1998 and March 1999. Treatment sheep liveweights were not significantly different from the C3 treatment from September 1997 to 1999. However, from October 1999 to October 2001 sheep liveweight in the C6 treatment was significantly less than in the C3 treatment, while in the C9+sub and R4/12 treatments it was significantly greater than the control. In 1999, wool production per head was higher (P<0.05) in the C9+sub and R4/12 treatments compared with all other treatments but treatment differences were not significant in all other years. Significant differences in SWC only occurred at the 0–30 cm depth between the C3 and the C6 and R4/12 treatments, but were predicted to be <1.5 mm/year. A sustainability index derived from economic [equivalent annual net return ($/ha) for a 10-year period], animal production, pasture, soil health and soil water data indicated that the overall indices were lowest for the C3, C6 and C9+sub treatments and highest for the R4/4 and R4/12 treatments.
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O'Connell, D. A., and P. J. Ryan. "Prediction of three key hydraulic properties in a soil survey of a small forested catchment." Soil Research 40, no. 2 (2002): 191. http://dx.doi.org/10.1071/sr01036.
Full textAbstract:
Direct measurement of ψ(θ) and K(θ) relationships at all observation sites in soil survey is not feasible. Three key hydraulic properties — water content at field capacity (θ–5 kPa), water content at wilting point (θ–1.5 MPa), and saturated hydraulic conductivity (Ks) — can be used to derive K(θ) and ψ(θ) when combined with bulk density. These properties were measured in 'calibration' horizons in a soil survey in Yambulla State Forest in south-east New South Wales. Pedotransfer functions (PTFs) for predicting θ-5 kPa, θ–1.5 MPa, and Ks from the physical and morphologic soil attributes are presented and evaluated here. Models for predicting θ–5 kPa and θ–1.5 MPa relied on per cent clay. An R2 of 0.64 (for θ–5 kPa) to 0.67 (for θ–1.5 MPa) was obtained for linear regressions using only morphologic explanatory variables. An R2 of 0.73 (for θ–5 kPa) to 0.90 (for θ–1.5 MPa) was obtained if laboratory-measured clay content was included as an explanatory variable. Ks was measured in situ using well permeameters, and used for developing PTFs. Large cores were taken from a small subsample of horizons and measurements of Ks, K–0.1 kPa, K–0.2 kPa, and K–0.5 kPa were made in the laboratory. Ks measurements from well permeameters were similar to K-0.5 kPa from laboratory measurements. Regression and tree models were used to predict Ks. The linear regression had an R2 of 0.55, while the tree models accounted for approximately 40% reduction in deviance. Bulk density was the most useful predictor in all Ks models. The inclusion of per cent rock fragments, bulk density, and estimated percentage clay as useful explanatory variables demonstrated the utility of functional descriptors not routinely measured in soil survey. The models are empirical and were locally calibrated for use in a soil survey. They may be applicable in target domains similar to the source domain (i.e. coarse-grained adamellite soils in similar climatic regimes). surrogates, saturated hydraulic conductivity, K(θ), ψ(θ), Ks, pedotransfer functions, soil survey, soil morphology, PTF.
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Chen, Wen, Graeme Blair, Jim Scott, and Rod Lefroy. "Nitrogen and sulfur dynamics of contrasting grazed pastures." Australian Journal of Agricultural Research 50, no. 8 (1999): 1381. http://dx.doi.org/10.1071/ar98104.
Full textAbstract:
The experimental area was located at the Big Ridge 2 site, CSIRO, Chiswick (30°31′S, 151°39′E), 20 km south of Armidale, New South Wales, Australia. The site was established in 1955. In March 1966, phalaris and white clover were sown and pastures were fertilised annually with superphosphate until 1993. There were 3 pasture treatments, each with 2 replicates: degraded pasture (low phalaris content), phalaris dominant, and phalaris–white clover. Each of 6 experimental plots was divided into 3 strata. Two representative areas 1 m by 0.5 m were selected in each stratum of each treatment. The selected areas were labelled with 34S-enriched (90%) elemental sulfur and 15N-enriched (99%) NH4Cl solution. All plots were grazed continuously by sheep. No effect of pasture type on N leaching was apparent in this experiment. Seasonal variation of total soil mineral N in different soil layers, low 15N recovery down to 60 cm soil depth, and low nitrate-N concentrations in drainage water obtained in this experiment suggest that synchronisation of pasture growth with mineralisation and nitrification, together with ammonium domination of the soil N system, is the key ecological feature in preventing N leaching in this environment. Unlike N, potential S leaching was found with evidence of a large amount of sulfate stored deeper in the soil profile and high S concentrations in drainage water. High KCl-40 extractable S concentration in the top 20 cm soil layers was associated with the long history of superphosphate application. Long-term applications of superphosphate (1967–93), together with an increase in sulfate sorption capacity at lower soil depths, resulted in a large amount of sulfate stored at greater depth. However, retention of the 34S applied in 1995 in the top 10 cm soils suggests that sulfate-S movement down the soil profile is slow.
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Hobley, E. U., A. J. L. E. Gay Brereton, and B. Wilson. "Soil charcoal prediction using attenuated total reflectance mid-infrared spectroscopy." Soil Research 55, no. 1 (2017): 86. http://dx.doi.org/10.1071/sr16068.
Full textAbstract:
Despite strong evidence for the importance of charcoal as a long-term carbon sink in soils, simple methods to quantify charcoal in soil are still lacking. In this study, we tested the application of attenuated total reflectance mid-infrared spectroscopy (ATR-MIR) for quantification of charcoal in soil. To do this, we created calibration samples from defined quantities of pulverised rock, charcoal and litter sampled from a forest floor in Guy Fawkes National Park, New South Wales, Australia, and analysed them via ATR-MIR and dry combustion. The organic carbon concentration (mass proportion) of the samples ranged from 0.1 to 15% and the charcoal mass proportion from 0.02–11% (10–50% of soil organic matter). We then trained randomForest models to the spectral data and assessed the predictive performance of the models for both the quantity of charcoal and litter in the samples. The models were excellent at predicting both charcoal and litter contents of the samples, explaining 94% of variance in the mass proportion of charcoal and 93% of the variance in the litter content of the validation dataset (i.e. out-of-bag estimates of the models). Extracting the variable importance from the models showed that the spectral regions important to charcoal prediction differed from those important to litter prediction, highlighting the capacity of the models to distinguish between charcoal and litter components based upon ATR-MIR spectra. Our method enables a simple, cheap and efficient prediction of litter and charcoal without the need for complex chemical extraction or analyses.
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Sarooshi, R. A., G. C. Cresswell, L. Tesoriero, P. J. Milham, I. Barchia, and A. M. Harris. "Effect of biosolids compost on two NSW coastal soils used to grow vegetables." Soil Research 40, no. 5 (2002): 761. http://dx.doi.org/10.1071/sr00107.
Full textAbstract:
The study compares the effects of biosolids compost (BC) and inorganic fertiliser (IF) on the nutrient status of a clay loam at Rydalmere in Western Sydney, and an earthy sand at Somersby, 85 km north of Sydney. The soils represent the textural range used for vegetable production in the Sydney Basin of New South Wales. The soils had been under permanent sod (Rydalmere) or native vegetation (Somersby) for at 40 years prior to the experiment. There were 3 treatments during February 1994: IF, fallow (F), and BC. The same plots were treated again during September 1994 to give the combinations: IF followed by IF (IF + IF); F by BC (F + BC); BC by BC (BC + BC). The 4 replicates of each treatment were randomised in blocks. Treatments were incorporated into raised beds to a depth of 15 cm and vegetables were planted in March and again in October 1994. The total amounts of C and N initially present in the soil in the beds (0-15 cm) at Rydalmere were at least 3 times greater than at Somersby and the ratio was greater for S, P, Ca, Mg, K, and Na. By April 1995, the quantities of the 8 monitored nutrients had decreased at both sites for the IF + IF treatment; increased at Somersby, but not at Rydalmere for F + BC; and increased at both sites for the BC + BC treatment. The changes caused by the BC + BC treatment were greater in relative terms at Somersby, because of the initial difference in fertility between the 2 soils. For example, the C and N content increased by an approximate factor of 2 at Somersby, and by greater factors for the other elements. BC + BC was also the only treatment to increase other indices of fertility, such as effective cation exchange capacity (ECEC) and Bray-P, in the surface 15 cm. The treatments did not affect pH in the soil profile (0-50 cm) and increases in EC were ephemeral. The nutrient composition of the 20-30 cm zone was affected at both sites. By the end of the experiment the concentration of C, N, P, Ca, and Bray-P increased and Mg decreased. For C and N between-treatment differences were small, indicating that the observed effects were mostly caused by leaching of the products of mineralisation of soil organic matter. Treatment effects were larger for P, Ca, Mg, and Bray-P, and the final concentrations for the F + BC and BC + BC treatments exceeded those for the IF + IF treatment. At Somersby, both BC treatments increased ECEC, consistent with the importance of leaching as a process of nutrient loss at this site. Consequently, intensive vegetable cropping may pose serious environmental risks particularly on sandy sites.
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Anderson, G. C., G. J. Blair, and R. D. B. Lefroy. "Soil-extractable sulfur and pasture response to applied sulfur." Australian Journal of Experimental Agriculture 38, no. 6 (1998): 575. http://dx.doi.org/10.1071/ea97136.
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Summary. Attempts to measure the sulfur (S) requirements of pastures using existing soil test procedures have largely been unsuccessful due to the extractants either under- or over-estimating the availability of S from soil organic matter. A range of extractants was used to assess the availability of S at 2 field sites on Kentucky yellow podzolic and Walcha krasnozem soils located on the Northern Tablelands of New South Wales. The experiments were conducted over a 2-year period on improved perennial pastures. The 7 extraction techniques used were: 0.1 mol Ca(H2PO4)2/L (MCPt); 0.1 mol Ca(H2PO4)2/L, treated with activated charcoal (MCPi); water (H2O); 0.25 mol KCl/L, heated at 40˚C for 3 h (KCl-40); 0.25 mol KCl/L, heated at 100˚C for 4 h (KCl-100); 0.5 mol NaHCO3/L, (NaHCO3); and an acid digestion of the soil (total). In both soils, the MCPi technique extracted the least amount of S. The amount of S extracted by the MCPt, H2O and KCl-40 techniques was intermediate. The KCl-100 technique extracted greater amounts of S than these techniques. For the Kentucky yellow podzolic soil, the KCl-100 technique extracted the same amount as the NaHCO3 technique but extracted less for the Walcha krasnozem soil. The extraction techniques which varied least throughout the year were total and NaHCO3 for both soils. The KCl-40 technique was as stable as these techniques for the Kentucky yellow podzolic soil but was less stable for the Walcha krasnozem soil. Nevertheless, the KCl-40 technique had a higher stability than the KCl-100, H2O and MCPt techniques, while the MCPi technique was the least stable. Pasture S content response to applied S fertilisers was related to dry matter production of each site, which was largely determined by the environmental factors (soil moisture, temperature and solar radiation). Seasonal changes in the level of soil S only modified this relationship for the Walcha krasnozem site when environmental conditions promoted mineralisation of soil organic S which was retained within the soil profile due to sulfate adsorption and resulted in an increase in inorganic soil sulfur. These findings suggest future research is required into field measurements of the ability of soil to supply S as determined by the rate of mineralisation and leaching in relation to the plant‘s demand for soil S.
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Badgery, W. B., and D. L. Michalk. "Synthesis of system outcomes for a grazing-management experiment in temperate native pastures." Animal Production Science 57, no. 9 (2017): 1869. http://dx.doi.org/10.1071/an16599.
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Increasing the intensity of grazing management from continuous grazing or set-stocking to intensive rotational grazing has been proposed as a way of improving the profitability and environmental outcomes for native pasture-based grazing systems in the high-rainfall zone (HRZ) of southern Australia. The present paper synthesised the results and outcomes of eight papers covering different aspects of a grazing-system study investigating the intensity of grazing management at Panuara (33°27ʹS, 148°56ʹE), 25 km south-west of Orange, New South Wales. The systems analysis covered soils and soil water, pastures, animal production, profitability and business risk by using a combination of field experiments and biophysical modelling. The experimental approach, engagement with stakeholders and the potential impact of the research outcomes are discussed; as are the future directions for grazing system research. Increasing the intensity of grazing management from a 1- to a 20-paddock system resulted in a 21% higher pasture growth, 22% higher stocking rate and 20% higher lamb production per hectare. However, modelling demonstrated that seasonal variability had a greater impact on profitability than did the management system, and whole-farm profitability of the 20-paddock system was lower than that of the 1- and 4-paddock systems due to higher infrastructure costs. Pasture stability was associated with a high perennial grass content (>70%), and a stocking rate of 4.2 ewes/ha for continuous grazing or 5.3 ewes/ha for intensive rotational grazing limited the potential for degradation events. Advantages were identified in fencing and managing production zones, with different production potential within a farm, to improve utilisation across the landscape and efficiency of fertiliser use. The farming-system approach successfully integrated field research with pre- and post-experimental modelling, and with strategic input from an advisory group containing farmers, researchers and advisors, to develop a full understanding of the impact, at a system level, of increasing the intensity of grazing management in the HRZ.
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Sadras, Víctor, David Roget, and Garry O'Leary. "On-farm assessment of environmental and management constraints to wheat yield and efficiency in the use of rainfall in the Mallee." Australian Journal of Agricultural Research 53, no. 5 (2002): 587. http://dx.doi.org/10.1071/ar01150.
Full textAbstract:
The responses of wheat grain yield to soil properties, weather, root diseases, and management practices were investigated in 75 grower-managed crops in the Mallee region of South Australia, Victoria, and New South Wales during 3 growing seasons. Fourteen cultivars were represented in the sampled crops, with Frame being the most common (56%). The most widespread crop sequence was wheat after pasture (43% of wheat crops), followed by wheat after fallow or cereal (both about 20%); 12% of the wheat was sown after legumes. Wheat after cereal was more common in drier sites, and wheat after fallow in wetter sites. Wheat yield was proportional to Fischer’s photothermal coefficient around flowering, and ranged from nil to 4.7 t/ha. On average, wheat crops sown after cereals yielded 0.4 t/ha less than their counterparts sown after fallow, and 0.7 t/ha less than those after legumes. Sowing date ranged from 24 April to 21 July; yield declined with delayed sowing at an average rate of 17 kg/ha.day. Growing season rainfall (April–October) ranged from 111 to 266 mm, and accounted for 27% of the variation in grain yield. Soil water content at sowing (0–1 m) ranged from 32 to 330 mm; yield increased with initial soil water at an average rate of 6 kg/ha.mm. Grain yield per unit growing season rainfall was generally low, with 75% of crops producing <12 kg grain/ha.mm; the maximum ratio was 21 kg/ha.mm. Soil constraints, including sodicity, alkalinity, salinity, and boron toxicity, reduced yield in part by reducing availability of stored soil water. Owing to severity of chemical constraints increasing with soil depth, grain yield and yield per unit growing season rainfall were both inversely related to the proportion of water stored deeper in the soil (0.5–1 m). Yield was unrelated to nitrogen, both initial and applied. Larger amounts of nitrogen accumulated in soils with more severe constraints partially accounted for the lack of association between yield and nitrogen.
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Dear, B. S., G. D. Li, R. C. Hayes, S. J. Hughes, N. Charman, and R. A. Ballard. "Cullen australasicum (syn. Psoralea australasica): a review and some preliminary studies related to its potential as a low rainfall perennial pasture legume." Rangeland Journal 29, no. 2 (2007): 121. http://dx.doi.org/10.1071/rj06039.
Full textAbstract:
This paper reviews the morphology, establishment, herbage quality, grazing tolerance, palatability, anti-nutritional compounds and rhizobial symbiosis of Cullen australasicum (Schltdl.) J.W. Grimes (syn. Psoralea australasica Schltdl.), a deep-rooted Australian native legume commonly known as tall verbine or native scurf-pea. Its natural distribution and the edaphic and climatic characteristics of germplasm collection sites within Australia are described. It also reports the results of three preliminary studies; two field studies on the establishment, persistence and herbage quality, and a glasshouse study to identify an effective Rhizobium strain for C. australasicum. In the field studies, C. australasicum established readily from seed and demonstrated similar persistence to Medicago sativa L. over a 3-year period in the medium rainfall wheat belt of southern New South Wales. The productivity of C. australasicum in year 3 was similar to M. sativa at one site but inferior at the second site. C. australasicum demonstrated superior persistence and higher herbage yields than Lotus corniculatus L. in year 3 at both sites. The mineral content of the leaves and stems of C. australasicum in these studies were similar to M. sativa and L. corniculatus for most elements except for Mo and Zn, which were significantly higher, and Na which was lower in C. australasicum. Organic matter digestibility of the leaves and stems of C. australasicum ranged from 79 to 89% and 62 to 72%, respectively, compared with 73–79% and 59–73% in M. sativa. Crude protein levels of C. australasicum leaves and stems were 22–28% and 15–27%, respectively, compared with 26–33% and 13–33% in M. sativa. The study of Rhizobium strains isolated from four South Australian soils identified a superior strain (SRDI 483) capable of establishing an effective symbiosis with C. australasicum. The potential of C. australasicum as a drought hardy perennial legume for extensive grazing systems where M. sativa fails to persist because of selective grazing is discussed. Its low palatability to sheep was seen as an advantage in assisting its survival in extensive low-input grazing systems.
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Zare, E., M. F. Ahmed, R. S. Malik, R. Subasinghe, J. Huang, and J. Triantafilis. "Comparing traditional and digital soil mapping at a district scale using residual maximum likelihood analysis." Soil Research 56, no. 5 (2018): 535. http://dx.doi.org/10.1071/sr17220.
Full textAbstract:
Conventional soil mapping uses field morphological observations to classify soil profiles into predefined classification systems and extrapolates the classified soils to make a map based on aerial photographs and the experience of the surveyor. A criticism of this approach is that the subjectivity of the surveyor leads to non-reproducible maps. Advances in computing and statistical analysis, and an increased availability of ancillary data have cumulatively led to an alternative, referred to as digital soil mapping (DSM). In this research, two agriculturally productive areas (i.e. Warren and Trangie) located in central New South Wales, Australia, were considered to evaluate whether pedoderms and soil profile classes defined according to the traditional approach can also be recognised and mapped using a DSM approach. First, we performed a fuzzy k-means analysis to look for clusters in the ancillary data, which include data from remote-sensed gamma-ray (γ-ray) spectrometry and proximal-sensed electromagnetic (EM) induction. We used the residual maximum likelihood method to evaluate the maps for various numbers of classes (k = 2–10) to minimise the mean square prediction error (σ2p,C) of soil physical (i.e. clay content, field capacity (FC), permanent wilting point (PWP) and available water content (AWC)) and chemical (pH, EC of 1 : 5 soil water extract (EC1:5) and cation exchange capacity (CEC)) properties of topsoil (0–0.3 m) and subsoil (0.6–0.9 m). In terms of prediction, the calculated σ2p,C was locally minimised for k = 8 when accounting for topsoil clay, FC, PWP, pH and CEC, and subsoil FC, EC1:5 and CEC. A comparison of σ2p,C of the traditional (seven pedoderm components) and DSM approach (k = 8) indicated that only topsoil EC1:5 and subsoil pH was better accounted for by the traditional approach, whereas topsoil clay content, and CEC and subsoil clay, EC1:5 and CEC were better resolved using the DSM approach. The produced DSM maps (e.g. k = 3, 6 and 8) also reflected the pedoderm components identified using the traditional approach. We concluded that the DSM maps with k = 8 classes reflected the soil profile classes identified within the pedoderms and that soil maps of similar accuracy could be developed from the EM data independently.
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Holford, I. C. R., and G. J. Crocker. "A comparison of chickpeas and pasture legumes for sustaining yields and nitrogen status of subsequent wheat." Australian Journal of Agricultural Research 48, no. 3 (1997): 305. http://dx.doi.org/10.1071/a96072.
Full textAbstract:
Six treatments were compared for their effects on wheat yields, nitrogen (N) uptake, protein content, and fertiliser N requirements in a long-term rotation study on a black earth and a red clay in northern New South Wales. Three of the treatments were lucerne, subterranean clover, and snail medic, all grown simultaneously from 1988 to 1990 and all followed by 3 years of wheat. The other 3 treatments were biennial rotations of chickpea–wheat and long-fallow–wheat as well as a continuous wheat monoculture, all lasting 6 years. With the exception of the first wheat crop, which experienced very low growing-season rainfall, lucerne was more beneficial than other legumes to following wheat crops in terms of yield, protein content, and fertiliser N requirement. Clover closely followed lucerne in the magnitude of its positive effects, whereas medic and chickpea produced much smaller effects. Because of the amount of N removed in the chickpea grain, it appeared that the small positive effects of chickpea were due to soil N sparing or rapid mineralisation from crop residues rather than any net contribution of N fixation to soil N accretion. Average yields of the 3 wheat crops following lucerne and clover were much higher than average yields 20 years previously following lucerne, even though average yields of continuously grown wheat have declined over the past 20 years. However, lucerne eliminated the need for N fertiliser for no more than 2 following wheat crops, and clover for only the first wheat crop. It appears that the longer duration of lucerne benefits reported in earlier studies was due to the higher background soil N levels as well as the lower yield potential in the earlier years. Nevertheless, lucerne lowered the fertiliser requirement of the third wheat crop by more than 50%. In contrast to lucerne, annual legumes are probably most beneficial if grown in alternate years with wheat. The large benefits of long fallowing particularly on the black earth were apparently caused by its enhancement of soil moisture and mineral N accumulation. However, these N effects were surprisingly large considering the degree of depletion of organic matter in long-fallowed soils.