Academic literature on the topic 'Economic aspects of Gypsum as soil amendment'

This study analyzes the economic feasibility of gypsum amendment as a means to reduce particulate and dissolved phosphorus loads from arable areas. To this end, an optimization model is developed that includes gypsum amendment as well as matching phosphorus fertilization to crop need and the level of soil phosphorus reserves as phosphorus load mitigation measures, with soil phosphorus reserves measured by soil test phosphorus (STP). The optimal extent of gypsum amendment is then determined simultaneously with optimal fertilization use as a function of field STP level. The results indicate that whether or not gypsum amendment is economically feasible depends on field erosion susceptibility and STP level. When accounting for the costs and benefits to the society on the whole, gypsum treatment suits best to mitigation of phosphorus losses from soils with excessively high phosphorus reserves; once a threshold STP level is reached, gypsum amendment is optimally given up. This threshold level depends on field slope and on society’s willingness to pay for water quality.

Highly alkaline soils (pH >9) may adversely affect agricultural crop productivity. At pH >9.2, aluminium (Al) phytotoxicity may further retard plant development. Most alkaline soils have little alkaline buffering capacity, making it feasible to use acid to lower soil pH to <9.2. Many methods of lowering soil pH have been trialled; however, little research has been done on their relative effectiveness and longevity. Methods trialled in this study as means of lowering soil pH were chemical additives (gypsum), organic additives (glucose, molasses, horse manure, green manure, humus) and leguminous plants. Gypsum was also used in conjunction with plants to determine any synergistic effects of combining treatments. All ameliorants trialled except humus and horse manure proved effective at lowering soil pH to <9.2. The reduction achieved with biological amendments was temporary, with pH returning to pre-amendment levels over the course of the study. Gypsum was most effective amendment for lowering soil pH and sustaining the lowered pH level. The use of plants to lower soil pH, in conjunction with gypsum to sustain the lowered pH, may be an effective and economic method of remediating Al phytotoxicity in alkaline soils.

As efforts to close crop production yield gaps increase, the need has emerged to identify cost-effective strategies to reduce yield losses through soil improvement. Maize (Zea mays L.) production in coastal saline soil is limited by high salinity and high pH, and a limited number of soil amendment options are available. We performed a field experiment in 2015 and 2016 to evaluate the ability of combined flue gas desulfurization gypsum and furfural residue application (CA) to reduce the maize yield gap and improve soil properties. We carried out the same amendment treatments (CA and no amendment as a control) under moderate (electrical conductivity (EC1:1) ≈ 4 dS m−1) and high (EC1:1 ≈ 6 dS m−1) salinity levels. Averaged over all salinity levels and years, maize yields increased from 32.6% of yield potential in the control to 44.2% with the CA treatments. Post-harvest CA treatment increased the calcium (Ca2+) and soil organic carbon (SOC) contents while decreasing the sodium (Na+) content and pH in the upper soil layer. Corresponding nitrogen, phosphorus, potassium, calcium, and magnesium accumulations in maize were significantly increased, and Na accumulation was decreased in the CA group compared with the control. The economic return associated with CA treatment increased by 215 $ ha−1 at the high salinity level compared with the control, but decreased at the moderate salinity level because of the minor increase in yield. The results of this study provide insight into the reduction of yield gaps by addressing soil constraints.

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.

The Baltic Sea is considered the marine water body most severely affected by eutrophication within Europe. Due to its limited water exchange nutrients have a particularly long residence time in the sea. While several studies have analysed the costs of reducing current nutrient emissions, the costs for remediating legacy nutrient loads of past emissions remain unknown. Although the Baltic Sea is a comparatively well-monitored region, current data and knowledge is insufficient to provide a sound quantification of legacy nutrient loads and much less their abatement costs. A first rough estimation of agricultural legacy nutrient loads yields an accumulation of 0.5–4.0 Mt N and 0.3–1.2 Mt P in the Baltic Sea and 0.4–0.5 Mt P in agricultural soils within the catchment. The costs for removing or immobilising this amount of nutrients via deep water oxygenation, mussel farming and soil gypsum amendment are in the range of few tens to over 100 billion €. These preliminary results are meant as a basis for future studies and show that while requiring serious commitment to funding and implementation, remediating agricultural legacy loads is not infeasible and may even provide economic benefits to local communities in the long run.

The aim of the research was determination the efficiency of application 50 t ha-1 digestate from the process of anaerobic digestion on the productivity of sorghum (Sorghum bicolor L.) on moderately degraded (calcic gleysol) and fertile (chernozem) agricultural land, in southern Banat, Republic of Serbia. In the field experiment during three years digestate amendment led to an increase in the number of leaves by 28.56% and plant height by 5.34%, which led to an increase in yield by 3.40%. The maximum yield was 2018 (41.74 DM t ha-1) on chernozem. The yield of sorghum was lower on calcic gleysol compared to chernozem by 5.43% and was in positive, medium and very significant dependence on precipitation (0.61) and in positive significant correlation with digestate (0.53) and plant height (0.59). Biogas yield reach 157.05 Nm3 t-1 (9582 Nm3 ha-1) on chernozem with digestate. Digestate had a statistically significant positive effect on all tested characteristics of sorghum as well as biogas yield during all three experimental years. The use of digestate as a by-product in the process of producing biogas based on silage of sorghum, allows the substitution of mineral fertilizers and remediation of damaged soil, which contributes to sustainability from the bio-economic and environmental aspects.

<p>Insufficient supply of P for initial growth of crops does not only limit N uptake but it also leads to poor yield of crops. In acidic soils of the tropics, sorption of P occurs mainly on surfaces of Fe and Al oxides and hydroxides. Most of the P added through mineral fertilizers is fixed by high Al and Fe oxide concentrations and transformed into insoluble P compounds. Reduction of Al and Fe is important so as to ensure adequate supply and readily available P for crops uptake. A number of studies using zeolites as an amendment in the fertilization programs of crops have improved crops production, nutrients uptake, and nutrients use efficiency. However, there is dearth of information on the use of clinoptilolite zeolite (CZ) to reduce P fixation not to mention reduction of N, P, and K fertilizers use in agriculture. This study was conducted to: (i) determine dry matter production, nutrients concentration, nutrients uptake, and use efficiency of <em>Zea mays</em> (Hibrimas variety) by including CZ in the fertilization program of <em>Zea mays</em> planted on an acidic soil, and (ii) determine the effect of including CZ in the fertilization program of <em>Zea mays</em> on selected chemical properties of an acidic soil. Egypt rock phosphate (ERP), urea, and muriate of potash were used in this study. Seventy five percent (w/w) of the recommended N, P, and K fertilizers for <em>Zea mays</em> were combined with CZ. Standard procedures were used to determine soil pH, inorganic nitrogen, available phosphorus, exchangeable aluminium, iron, potassium, calcium, magnesium, and organic matter before and after planting. <em>Zea mays</em> were harvested at tasselling stage and measured for dry matter production, nutrients uptake and use efficiency. The effect of CZ application with 75% of fertilizers (E2) and 100% fertilizers (E1) were statistically similar for selected soil chemical properties, dry matter production, nutrients concentration, uptake of nutrients, and nutrients use efficiency except for N. Nitrogen use efficiency for E2 was better than that of E1. These findings suggest that adoption of CZ with 25% reduction of N, P, and K fertilizers are useful. Further field trials and economic analysis are recommended to confirm the findings of this study. These aspects are being investigated in our on-going field experiments.</p>

Agriculture plays a central role within the Ethiopian economy. In our country, concerning 85% of total population depends on agriculture and its product. This implies agriculture provides a good portion of national product growth. In spite of the importance of this sector, production and productivity area units restricted by varied biophysical, social and economic aspects. Soil fertility decline is one of the central issues that scale back Ethiopian agriculture and at last, it ends up in poverty and starvation. The main causes of those entrenched challenges are the land degradation showed in type of soil fertility decline, as introduced by varied hindrances as deforestation, overgrazing and through a consequence of wearing away, deposit, pollution, etc. Hence, the core objectives of this review are to evaluate the soil fertility status in Ethiopia, the sources of soil fertility decline and find improved resolutions to soil fertility in Ethiopia. As the physiological factors of the country are rugged with dynamical sorts of soils, preponderantly the upland wherever regarding 90% of the tillable land is concentrated, difficulties such as soil erosion, meager and incessant cultivation are the chief reasons of soil fertility loss. Thus, the application of combined soil fertility management approach with presence and mixture of manure, compost, crop rotation, soil protection practices provides improved production and saves the soil fertility standing to an improved level. The apply undertaken by the government of Ethiopia, is that the application of optimum rate of fertilizers, but it's not thriving as a results of various factors like amendment of agroecology, edaphic factors, the social and economic state of affairs of the farmer, repair to property combined soil fertility management to get high yield while not compromising the soil fertility position within the future, this can be broad and needed to be followed.