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1

Watanabe, Kunio, Tetsuya Kito, Tomomi Wake, and Masaru Sakai. "Freezing experiments on unsaturated sand, loam and silt loam." Annals of Glaciology 52, no. 58 (2011): 37–43. http://dx.doi.org/10.3189/172756411797252220.

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AbstarctEstimating soil-water flow during ground freezing is important for understanding factors affecting spring farming, soil microbial activity below the frozen soil, and permafrost thawing behavior. In this study, we performed a column freezing experiment using three different unsaturated soils (sand, loam and silt loam) to obtain a detailed dataset of temperature, water-content and pressure-head change under freezing conditions. The liquid water content and pressure head in the three soils decreased with decreasing temperature. Three soil temperature stages were found: unfrozen, stagnating near 0˚C and frozen. The temperature and duration of the stagnation stage differed among the soil types. The changes in liquid water content and pressure head during the freezing process were highly dependent on the soil-water retention curve. Water flowed through the frozen area in silt loam and sand, but no water flux was observed in the frozen loam. The freezing soil columns tended to contain more liquid water than estimated from retention curves measured at room temperature, especially at the early stage of freezing.
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2

Jalota, SK, and SS Prihar. "Effects of atmospheric evaporativity, soil type and redistribution time on evaporation from bare soil." Soil Research 24, no. 3 (1986): 357. http://dx.doi.org/10.1071/sr9860357.

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Several reports in the literature show that atmospheric evaporativity (Eo), water transmission characteristics of soil and distribution of water in the profile influence the pattern of evaporation losses from soil, but few relate to their interactive effects. Experiments were conducted with silt loam, sandy loam and loamy sand soils with zero and 2 days' redistribution time before commencement of evaporation under high (15.1 � 0.50 mm day-1), medium (10.1 � 0.50 mm day-1) and low (6.3 � 0.52 mm day-1) Eo to ascertain if cumulative evaporation (CE) was always greater under higher Eo irrespective of experimental conditions, and if the evaporation rates during falling rate stage were insensitive to changes in Eo in all soils. Where evaporation commenced immediately after wetting, CE up till 30 days was always higher under higher than lower Eo values in the silt loam and sandy loam soils. In the loamy sand, however, CE under medium Eo conditions exceeded that under high Eo conditions after 2 days. When evaporation commenced after 2 days of redistribution CE under medium and low Eo values exceeded that under high Eo values after 8 and 12 days in the sandy loam, and 2 and 6 days in loamy sand, respectively. Where evaporation was commenced after the 2-day redistribution, CE at 30 days in the silt loam and sandy loam was 12% less than where evaporation commenced immediately after infiltration under all the Eo values. In loamy sand these differences were 17% and 40% under low and high Eo values, respectively. CE as well as evaporation rate (ER) were sensitive to Eo in the initial period of falling rate stage in the silt loam and the sandy loam but not in the loamy sand.
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3

Mueller, Thomas C., and Philip A. Banks. "Flurtamone Adsorption and Mobility in Three Georgia Soils." Weed Science 39, no. 2 (June 1991): 275–79. http://dx.doi.org/10.1017/s0043174500071605.

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Flurtamone and atrazine adsorption to soil was examined using a batch equilibrium method. Flurtamone mobility in packed soil columns under saturated flow conditions was also evaluated. Adsorption was greater for flurtamone than atrazine in the three soils, and the order of adsorption to soil for both herbicides was Greenville sandy clay loam > Cecil loam > Dothan loamy sand. Greater adsorption of each herbicide corresponded to soils with greater organic matter and clay content. The14C–flurtamone movement under saturated flow conditions in 28–cm soil–packed columns was limited to 16 cm, with no flurtamone leaching from any soil column after the addition of two pore volumes of water. Seventy–five percent of the applied14C–flurtamone remained in the 0– to 4–cm soil depth in the Greenville sandy clay loam, with less than 5 percent moving to a depth > 4 cm. Flurtamone movement was greater in the Cecil loam and the Dothan loamy sand, with movement in each soil to a depth of 16 and 12 cm, respectively.
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4

Barnes, Clyde J., Andrew J. Goetz, and Terry L. Lavy. "Effects of Imazaquin Residues on Cotton (Gossypium hirsutum)." Weed Science 37, no. 6 (November 1989): 820–24. http://dx.doi.org/10.1017/s0043174500072908.

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Field and laboratory studies were conducted in 1987 and 1988 on several Arkansas soils to determine the effects of residual levels of imazaquin on cotton. Imazaquin concentrations ranging from 0.007 to 0.024 μg/g and 0.00 to 0.015 μg/g were found in soil samples taken 12 and 24 months, respectively, following preplant-incorporated applications at rates of 140 g/ha. Cotton yields were reduced from 7 to 42% in 1987 as the soil concentration of imazaquin increased from 0.007 to 0.024 μg/g. Imazaquin persistence was greater in clay soils than loams or sandy loams. Imazaquin was weakly adsorbed to a clay, loam, and sandy loam soil in laboratory studies; the adsorption isotherms did not differ significantly by soil texture. A bioassay utilizing cotton as the indicator species was developed to determine imazaquin concentrations in soils ranging from 0 to 0.06 μg/g. Imazaquin concentrations determined by the bioassay method were found to be 75, 77, and 80% of those determined by chemical extractions for a clay, loam, and sandy loam soil, respectively.
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5

Li, Danfeng, and Ming'an Shao. "Simulating the vertical transition of soil textural layers in north-western China with a Markov chain model." Soil Research 51, no. 3 (2013): 182. http://dx.doi.org/10.1071/sr12332.

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The heterogeneity of textures in soil profiles is important for quantifying the movement of water and solutes through soil. Soil-profile textures to a depth of 300 cm were investigated at 100 sites in a 100-km2 area in the central region of the Heihe River system, where oases coexist with widespread deserts and wetland. The probability distribution of textural-layer thickness was quantified. The vertical transition of the soil textural layers was characterised by a Markov chain–log-normal distribution (MC-LN) model based on the probability of one textural type transitioning to another. Nine types of textural layers were observed: sand, loamy sand, sandy loam, silt loam, loam, clay loam, silty clay loam, silty clay, and clay. Sand was the most frequent in the profiles, whereas silt loam and clay were rare. The layers of sand and silty clay were relatively thick, and the layers of loam and clay were relatively thin. The coefficients of variation ranged from 36–87%, indicating moderate variation in the layer thickness of each textural type. The soil profile was characterised as a log-normal distribution. A χ2 test verified the Markov characteristic and the stability of the vertical change of soil textural layers. Realisations of the soil textural profiles were generated by the MC-LN model. A Monte Carlo simulation indicated that the simulated mean layer thickness of each textural type agreed well with the corresponding field observations. Element values of the transition probability matrix of the textural layers simulated by the MC-LN model deviated <12.6% from the measured values, excluding the data from the layers of clay and silt loam. The main combinations of upper to lower textural layers in the study area were loamy sand and sand (or sandy loam), sandy loam and sand (or loamy sand and loam), loam and clay loam, clay loam (or silty clay) and silty clay loam, and silty clay loam and silty clay. The MC-LN model was able to accurately quantify the vertical changes of textures in the soil profiles. This study will aid in quantification of water and solute transport in soils with vertical heterogeneity of soil textural layers.
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6

Yazdanpanah, N. "CO<sub>2</sub> emission and structural characteristics of two calcareous soils amended with municipal solid waste and plant residue." Solid Earth 7, no. 1 (January 26, 2016): 105–14. http://dx.doi.org/10.5194/se-7-105-2016.

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Abstract. This investigation examines the effect of different amendments on selected soil physical and biological properties over a 24-month period in two cropland fields. Urban municipal solid waste (MSW) compost and alfalfa residue (AR) were used as different organic amendments at the rates of 0 (control), 10 and 30 Mg ha−1 to a clay loam soil and a loamy sand soil in a semiarid region. Results showed that the soil improvement was controlled by the application rate and decomposability of amendments and soil type. The addition of organic amendments to the soils improved aggregate stability and consequently enhanced total porosity, especially macropore fraction. The increased soil organic carbon (SOC) and total porosity values as compared to the control treatment were greater in the loamy sand soil than in the clay loam soil. Moreover, compared to the microbial respiration of control plots, the application of MSW resulted in higher values of microbial respiration in the clay loam soil than in the loamy sand soil, whereas the reverse was found for AR. Linear and power functions were provided for the relationships between microbial respiration and SOC in the loamy sand and clay loam soils, respectively. Also, CO2 emission was stimulated significantly as power functions of the total porosity and the ratio of macroporosity to microporosity. However, the soil microbial respiration and carbon storage improved aggregate stability and pore size distribution, and as a response, soil porosity, especially the macropore fraction, controlled CO2 flux.
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7

Yazdanpanah, N. "CO<sub>2</sub> emission and structural characteristics of two calcareous soils amended with municipal solid waste and plant residue." Solid Earth Discussions 7, no. 4 (November 9, 2015): 3151–77. http://dx.doi.org/10.5194/sed-7-3151-2015.

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Abstract. This investigation examines the effect of different amendments on selected soil physical and biological properties over a twenty four month period in two cropland fields. Urban municipal solid waste (MSW) compost and alfalfa residue (AR) were used as different organic amendments at the rates of 0 (control), 10 and 30 Mg ha−1 to a clay loam soil and a loamy sand soil in a semiarid region. Result showed that the soil improvement was controlled by the application rate and decomposability of amendments and soil type. The addition of organic amendments to the soils improved aggregate stability and consequently enhanced total porosity, especially macro pores fraction. The increased soil organic carbon (SOC) and total porosity values as compared to the control treatment were greater in the loamy sand soil than in the clay loam soil. Moreover, compared to the microbial respiration of control plots, the application of MSW resulted in higher values of microbial respiration in the clay loam soil than in the loamy sand soil, whereas the reverse order was found for AR. Linear and power functions were provided for the relationships between microbial respiration and SOC in the loamy sand and clay loam soils, respectively. Also, CO2 emission was stimulated significantly as power functions of the total porosity and the ratio of macro to micro pores. However, the soil microbial respiration and carbon storage improved aggregate stability and pore size distribution, as a response, soil porosity especially macro pores fraction controlled CO2 flux.
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8

Wilson, John S., and Chester L. Foy. "Influence of Various Soil Properties on the Adsorption and Desorption of ICIA-0051 in Five Soils." Weed Technology 6, no. 3 (September 1992): 583–86. http://dx.doi.org/10.1017/s0890037x00035831.

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The soil organic matter and/or humic matter fraction was highly correlated with the adsorption of ICIA-0051 herbicide onto five soils; clay content and other soil factors were less correlated. The Freundlich equation was used to describe the adsorption of ICIA-0051 by the various soils. Based on the K constants, the general order for adsorption for each soil was Hyde silty clay loam > Frederick silt loam > Davidson clay = Bojac sandy loam > Appling loamy sand. Across all soils, 25 to 50% of the amount adsorbed was removed by two desorptions. Appling, Bojac, and Davidson soils retained less herbicide after two desorptions than did Frederick and Hyde.
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9

Akhter, J., K. Mahmood, K. A. Malik, A. Mardan, M. Ahmad, and M. M. Iqbal. "Effects of hydrogel amendment on water storage of sandy loam and loam soils and seedling growth of barley, wheat and chickpea." Plant, Soil and Environment 50, No. 10 (December 10, 2011): 463–69. http://dx.doi.org/10.17221/4059-pse.

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The hydrogel amendments may improve seedling growth and establishment by increasing water retention capacity of soils and regulating the plants available water supplies, particularly under arid environments. The effects of different levels of a locally prepared hydrogel were studied on the moisture properties of sandy loam and loam soils (fine-loamy, mixed, hyperthermic Typic Haplargids, USDA, Luvic Yermosol, FAO) and on growth response of three plant species, viz. barley (Hordeum vulgare L.), wheat (Triticum aestivum L.) and chickpea (Cicer arietinum L.). Water absorption by gel was rapid and highest in distilled water and was inhibited by an increase in water salinity. The addition of 0.1, 0.2 and 0.3% hydrogel increased the moisture retention (&theta;r) at field capacity linearly (r = 0.988) and thus the amount of plant available water significantly in both sandy loam and loam soils compared to the untreated soils. Seed germination of wheat and barley was not affected but seedling growth of both species was improved by the gel amendment. In loam soil, seed germination of chickpea was higher with 0.2% gel and seedling growth increased with increase in gel level compared with control conditions. The hydrogel amendment caused a delay by 4&ndash;5 days in wilting of seedlings grown in both soils compared with control conditions. The hydrogel amendment was effective in improving soil moisture availability and thus increased plant establishment. However, the varied responses of plant species in sandy loam and loam soils warrant further studies on the behaviour of different soil types with gel amendments.
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10

Rosen, Carl J., and David E. Birong. "Soil Quality Factors Affecting Garlic Production." HortScience 32, no. 3 (June 1997): 445D—445. http://dx.doi.org/10.21273/hortsci.32.3.445d.

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Recent demand for high-quality garlic (Allium sativum L.) has prompted an interest in growing garlic as an alternative crop in the Upper Midwest. The overall objective of this study was to determine the effects of various amendments on garlic growth and selected soil quality indices in two contrasting soils. Garlic (Rocambole type) was planted in the fall of 1995 on a Kandota sandy loam (5% organic matter) and a Spartan loamy sand (1.5% organic matter). Three treatments replicated three times were tested: 1) a nonamended control, 2) manure compost, and 3) fertilizer application based on a soil test. Scapes were removed on half the plants in each plot and allowed to grow until harvest on the other half. Soil microbial biomass nitrogen (N) and carbon (C) were determined before planting and about 4 weeks after emergence. Within each site, the effect of soil amendments on garlic yield depended on scape removal. Garlic yield in nonamended soil was lowest when scapes were not removed. The effect of scape removal tended to diminish when compost or fertilizer was applied. Overall yields were 35% higher in the sandy loam soil compared to the loamy sand soil. Drought stress occurred during bulbing at both locations. Higher yields in the sandy loam soil were likely due to its higher water-holding capacity. Soil amendments did not consistently affect microbial biomass N and C; however, the sandy loam soil had 2 to 6 times higher biomass N and 3 to 4 times higher biomass C than the loamy sand soil and reflected the higher organic matter content of the sandy loam.
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11

Toleikiene, Monika, Ausra Arlauskiene, Andreas Fliesbach, Rashid Iqbal, Lina Sarunaite, and Zydre Kadziuliene. "The decomposition of standardised organic materials in loam and clay loam arable soils during a non-vegetation period." Soil and Water Research 15, No. 3 (June 17, 2020): 181–90. http://dx.doi.org/10.17221/31/2019-swr.

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The decomposition of plant organic materials in the soil during the non-vegetation period in a cool temperate climate is associated with nutrient loss and asynchrony in nutrient supply for subsequent crops. Therefore, it is important to select sustainable management tools to regulate the decomposition rate of organic material during the non-vegetation period. The aim of the present study was to assess the influence of soil type (loam vs. clay loam), green manuring (wheat straw vs. wheat straw + red clover), and incorporation depth of organic materials (4–7 vs. 14–17 cm) on mass loss, decomposition rate and stabilization of standardised organic material in the organically managed arable soils. A Tea Bag Index method was used in the field experiments with standardised organic plant materials of green and rooibos tea. In addition, litter-bags of locally grown red clover were investigated. The findings of this study suggested that of the three management factors investigated soil type had a significant and longest effect. The mass loss and decomposition rate of the standardised organic materials were significantly (P &lt; 0.5) higher and stabilization significantly lower in the loam soil than in the clay loam soil. During the non-vegetation period, green tea lost 46.3% of its initial mass, rooibos tea lost 19.7% and red clover lost 66%. The study showed that decomposition of fast-decomposing materials could be slowed down during the non-vegetation period by choosing soils with a higher clay content, shallow organic material incorporation depth and manuring soil with N-rich plant residues.
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12

Telesiński, Arkadiusz, Teresa Krzyśko-Łupicka, Krystyna Cybulska, Barbara Pawłowska, Robert Biczak, Marek Śnieg, and Jacek Wróbel. "Comparison of oxidoreductive enzyme activities in three coal tar creosote-contaminated soils." Soil Research 57, no. 8 (2019): 814. http://dx.doi.org/10.1071/sr19040.

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This study used laboratory experiments to compare the effects of coal tar creosote on the activity of oxidoreductive enzymes in sandy loam, loamy sand and sandy clay loam soils. Different amounts of coal tar creosote were added to soil samples as follows: 0 (control), 2, 10 or 50 g kg–1 dry matter. The activity of soil dehydrogenases (DHAs), o-diphenol oxidase (o-DPO), catalase (CAT), nitrate reductase (NR) and peroxidases (POX) was determined. Contamination of soil with coal tar creosote affected oxidoreductase activity. Oxidoreductive enzyme activity following soil contamination with coal tar creosote was in the following order: DHAs &gt; CAT &gt; NR &gt; POX &gt; o-DPO in loamy sand and in sandy loam; and DHAs &gt; POX &gt; CAT &gt; NR &gt; o-DPO in sandy clay loam. The index of soil oxidoreductive activity (IOx) introduced in this study confirms the negative effect of coal tar creosote on oxidoreductase activity in soil. DHAs were the most sensitive to the contamination of soil with coal tar creosote. Moreover, the greatest changes in oxidoreductase activities were observed in loamy sand. Knowledge of the mechanism underlying the effects of coal tar creosote on oxidoreductive processes may enable development of a method for the bioremediation of polycyclic aromatic hydrocarbon-contaminated soils.
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13

Cruz, D. R., L. F. S. Leandro, D. A. Mayfield, Y. Meng, and G. P. Munkvold. "Effects of Soil Conditions on Root Rot of Soybean Caused by Fusarium graminearum." Phytopathology® 110, no. 10 (October 2020): 1693–703. http://dx.doi.org/10.1094/phyto-02-20-0052-r.

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Fusarium graminearum is an important soybean pathogen that causes seedling disease, root rot, and pre- and postemergence damping-off. However, effects of soil conditions on the disease are not well understood. The objective of this greenhouse study was to determine the impacts of soil texture, pH, and soil moisture on seedling root rot symptoms and detrimental effects on seedling development caused by F. graminearum. F. graminearum-infested millet was added (10%, vol/vol) to soil with four different textures (sand, loamy sand, sandy loam, and loam). Soil moisture was maintained at saturation, field capacity or permanent wilting point at soil pH levels of 6 or 8. Seedlings were evaluated 4 weeks after planting for root rot, root length, root and shoot dry weights, leaf area, and F. graminearum colonization (by qPCR). There was a significant interaction between soil moisture and soil texture for root rot assessed visually (P < 0.0001). Highest severity (67%) and amount of F. graminearum DNA were observed at pH 6 and permanent wilting point in sandy loam soils. Pot saturation resulted in the lowest levels of disease in sandy loam and loam soils (11.6 and 10.8%, respectively). Reductions in seedling growth parameters, including root length, foliar area, shoot and root dry weights, and root tips, relative to the noninfested control, were significantly greater in sandy loam soils. In contrast, there were no significant growth reductions in sand. This study showed that levels of root rot increased under moisture-limiting conditions, producing detrimental effects on plant development.
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14

Fernández, P. L., C. R. Alvarez, and M. A. Taboada. "Assessment of topsoil properties in integrated crop - livestock and continuous cropping systems under zero tillage." Soil Research 49, no. 2 (2011): 143. http://dx.doi.org/10.1071/sr10086.

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A regional study was conducted in the northern Pampas of Argentina in order to compare soil quality at proximal cropland sites that are managed under either continuous cropping (CC) (n = 11) or integrated crop–livestock (ICL) (n = 11) systems under zero tillage. In the ICL system, samples were taken in the middle of the agricultural period. Although soil total and resistant organic carbon (TOC, ROC) were significantly higher in silt loam soils than in loam/sandy loam soils, variations in carbon concentration were not associated with differences in soil management. Soil relative compaction was the only property that was significantly (P < 0.05) affected by the soil type × management interaction. Soil relative compaction values were significantly lower with ICL in loam/sandy loam soils, but there were no significant differences in silt loam soils. Structural instability index showed little change from CC to ICL sites, indicating that there was no soil structural damage. Soil penetration resistance was significantly higher in ICL soils within the first 0.075 m of soil depth, slightly exceeding the critical threshold (2000 kPa). However, firmer topsoil under ICL was not due to shallow compaction, as evidenced by no increase in soil bulk density.
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15

Ćwieląg-Piasecka, Irmina, Magdalena Debicka, and Agnieszka Medyńska-Juraszek. "Effectiveness of Carbaryl, Carbofuran and Metolachlor Retention in Soils under the Influence of Different Colloid." Minerals 11, no. 9 (August 26, 2021): 924. http://dx.doi.org/10.3390/min11090924.

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The affinity of different soil colloids to retain carbaryl, carbofuran and metolachlor in sandy loam and loam soil from mineral, surface horizons was investigated. The undisturbed soil samples and soils amended with colloids—kaolinite (K), montmorillonite (Mt), illite (Il), goethite (G), humic acid (HA)—were mixed with the pesticides for sorption–desorption studies. Their sorption magnitude in pristine soils followed the sequence metolachlor > carbaryl > carbofuran, with loam soil being a better pesticides retarder than sandy soil. The biggest magnitude of carbaryl sorption in light soil was observed in samples with the addition of HA (92.7%), Il (92.3%) and Ge (87.5%), whereas for carbofuran it was goethite (52.3%). Metolachlor uptake was significantly enhanced by 2:1 clays (Mt-85.0%, Il-69.4%), goethite (73.3%) and humic acids (75.4%). The loamy soil sorption capacity of the studied pesticides was blocked by the natural organic matter potentially due to the formation of organo-mineral complexes. HA (66.8%) was the most effective sorbent for carbaryl in the loamy soil, whereas Mt (55.1%) and HA (40.3%) for carbofuran. Metolachlor was retained to the same extent in all loamy soil variants (75.8–83.6%) and its desorption values were the lowest. Carbofuran demonstrated the greatest ability to leach among the studied chemicals.
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16

Massey, Jeffrey D., W. James Steenburgh, Sebastian W. Hoch, and Jason C. Knievel. "Sensitivity of Near-Surface Temperature Forecasts to Soil Properties over a Sparsely Vegetated Dryland Region." Journal of Applied Meteorology and Climatology 53, no. 8 (August 2014): 1976–95. http://dx.doi.org/10.1175/jamc-d-13-0362.1.

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AbstractWeather Research and Forecasting Model forecasts over the Great Salt Lake Desert erroneously underpredict nocturnal cooling over the sparsely vegetated silt loam soil area of Dugway Proving Ground in northern Utah, with a mean positive bias error in temperature at 2 m AGL of 3.4°C in the early morning [1200 UTC (0500 LST)]. Positive early-morning bias errors also exist in nearby sandy loam soil areas. These biases are related to the improper initialization of soil moisture and parameterization of soil thermal conductivity in silt loam and sandy loam soils. Forecasts of 2-m temperature can be improved by initializing with observed soil moisture and by replacing Johansen's 1975 parameterization of soil thermal conductivity in the Noah land surface model with that proposed by McCumber and Pielke in 1981 for silt loam and sandy loam soils. Case studies illustrate that this change can dramatically reduce nighttime warm biases in 2-m temperature over silt loam and sandy loam soils, with the greatest improvement during periods of low soil moisture. Predicted ground heat flux, soil thermal conductivity, near-surface radiative fluxes, and low-level thermal profiles also more closely match observations. Similar results are anticipated in other dryland regions with analogous soil types, sparse vegetation, and low soil moisture.
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17

Al-Ameri, Baydaa H. A., Suad A. Al-Saedi, and Ibrahim B. Razaq. "Effect of Boron Supplement on Yield of Wheat Grown in Calcareous Soils of Different Textural Classes under Arid Conditions." Journal of Agricultural Science 11, no. 1 (December 15, 2018): 112. http://dx.doi.org/10.5539/jas.v11n1p112.

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Boron sufficiency supply to plant in calcareous soils of arid regions is severely reduced under arid climatic conditions. Therefore, this study was conducted to determine the effect of Boron (B) fertilization on yield of Wheat grown in calcareous soils of arid regions. Boron was added at two rates namely 0 and 0.5 mg B kg-1 soil to three most common textured class&rsquo;s soils. Straw and grain yield was determined on oven dried basis. B content of plants was determined as well. Straw and grain yield of wheat was significantly increased by (67.0 and 87.1%), (24.5 and 82%) and (64.5 and 48%) under the addition of 0.5 mg B Kg-1 soil over that of no B addition to clay, loam and sandy loam soil, respectively. Results also showed that wheat grown on the coarse-textured soil had the least B uptake per pot compared to loam and clay textured soils. B content in straw and grain was increased by (77.4 and 121%), (81.2 and 157%) and (184 and 96.9%) under B addition compared to those of zero B addition to clay soil, loam soil and sandy loamy soil, respectively. Response to B addition, significantly, increased in all soils due to increase of available B content in soils which may suggest the importance of adding adequate rate of B application under cropping system of arid regions.
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18

Gomboš, Milan. "Soil water regime in clay-loam soils." Cereal Research Communications 35, no. 2 (June 2007): 417–20. http://dx.doi.org/10.1556/crc.35.2007.2.63.

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19

Lu, Jian, Baoyang Sun, Feipeng Ren, Hao Li, and Xiyun Jiao. "Effect of Freeze-Thaw Cycles on Soil Detachment Capacities of Three Loamy Soils on the Loess Plateau of China." Water 13, no. 3 (January 29, 2021): 342. http://dx.doi.org/10.3390/w13030342.

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Soil detachment is the initial phase of soil erosion and is of great significance to study in seasonal freeze-thaw regions. In order to elucidate the effects mechanism of freeze-thaw cycles on soil detachment capacity of different soils, a sandy loam, a silt loam, and a clay loam were subjected to 0, 1, 5, 10, 15, and 20 freeze-thaw cycles before they were scoured. The results revealed that with increased freeze-thaw cycles, soil bulk density and water-stable aggregates content decreased after the first few times and then kept nearly stable after about 10 cycles, especially for sandy loam. The shear strength of all soils gradually decreased as freeze-thaw cycles increased, except the values of clay loam increased subsequent to the 5th and 15th cycles. After the 20th cycle, the degree of decline of silt loam was the greatest (77.72%), followed by sandy loam (63.18%) and clay loam (39.77%). The soil organic matter of clay loam was much greater than silt loam and sandy loam and all significantly increased after freeze-thaw. Soil detachment capacity of silt loam and sandy loam was positively correlated with freeze-thaw cycle, which was contrary to findings for clay loam. The values of clay loam increased at first and then decreased during the cycles, reaching minimum values at about the 15–20th cycle. After the 20th cycle, the values of sandy loam and silt loam significantly increased 1.62 and 4.74 times over unfrozen, respectively, which was greater than clay loam (0.53 times). A nonlinear regression analysis indicated that the soil detachment capacity of silt loam could be estimated well by soil properties (R2 = 0.87, p < 0.05). This study can provide references for the study of the soil erosion mechanism in seasonal freeze-thaw regions.
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20

Bagarello, Vincenzo, Vito Ferro, and Giuseppe Giordano. "ESTIMATING SOIL PARTICLE-SIZE DISTRIBUTION FOR SICILIAN SOILS." Journal of Agricultural Engineering 40, no. 3 (September 30, 2009): 33. http://dx.doi.org/10.4081/jae.2009.3.33.

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The soil particle-size distribution (PSD) is commonly used for soil classification and for estimating soil behavior. An accurate mathematical representation of the PSD is required to estimate soil hydraulic properties and to compare texture measurements from different classification systems. The objective of this study was to evaluate the ability of the Haverkamp and Parlange (HP) and Fredlund et al. (F) PSD models to fit 243 measured PSDs from a wide range of 38 005_Bagarello(547)_33 18-11-2009 11:55 Pagina 38 soil textures in Sicily and to test the effect of the number of measured particle diameters on the fitting of the theoretical PSD. For each soil textural class, the best fitting performance, established using three statistical indices (MXE, ME, RMSE), was obtained for the F model with three fitting parameters. In particular, this model performed better in the fine-textured soils than the coarse-textured ones but a good performance (i.e., RMSE &lt; 0.03) was detected for the majority of the investigated soil textural classes, i.e. clay, silty-clay, silty-clay-loam, silt-loam, clay-loam, loamy-sand, and loam classes. Decreasing the number of measured data pairs from 14 to eight determined a worse fitting of the theoretical distribution to the measured one. It was concluded that the F model with three fitting parameters has a wide applicability for Sicilian soils and that the comparison of different PSD investigations can be affected by the number of measured data pairs.
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21

Nikooee, Ehsan, Rasoul Mirghafari, Ghassem Habibagahi, Alireza Ghadamgahi Khorassani, and Amir Mohammad Nouri. "Determination of soil-water retention curve: an artificial intelligence-based approach." E3S Web of Conferences 195 (2020): 02010. http://dx.doi.org/10.1051/e3sconf/202019502010.

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Soil Water Retention Curve (SWRC) is a fundamental relationship in unsaturated soil mechanics, knowledge of which is essential for determining major mechanical and hydraulic properties of unsaturated soils. There are several empirical, semi-empirical and physically-based models which have been proposed to date for estimating SWRC. While the physically-based models which employ the basic soil characteristics such as grain-size and pore-size distributions are regarded superior to purely empirical models, their Achilles’ heel is the several simplifying assumptions based on which these models are constructed, thereby, restricting their applications and influencing their accuracy. Given the complexity of the soil porous structure, one may resort to the new inference techniques rather than mechanistic modelling to find the relationship among soil physical characteristics and the retention properties. Therefore, an alternative approach to purely empirical relationships as well as physically-based and conceptual models for determining SWRC is the use of Artificial Intelligence (AI) based techniques to acquire a relationship for SWRC based on the soil basic properties, especially grain size distribution and porosity. Among AI-based methods, Multi-Gene Genetic Programming (MGGP), often used to establish a close form equation for a complex physical system, offers a suitable alternative to the current approaches. In this study, a database compromising of 437 soils (containing various soil types, namely, sand, clay, silt, loam, silt loam, clay loam, sandy loam, sandy clay loam, silty clay loam, silty clay, and loamy sand soils) was used along with MGGP to establish a relationship among suction, saturation, porosity and grain size distribution. The proposed equation had a reasonable agreement with the experimental data compared to the other grain-based and physically-based models.
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22

Mueller, Thomas C., Philip A. Banks, and William C. Steen. "Microbial Degradation of Flurtamone in Three Georgia Soils." Weed Science 39, no. 2 (June 1991): 270–74. http://dx.doi.org/10.1017/s0043174500071599.

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Degradation of flurtamone in a Greenville sandy clay loam, a Cecil loam, and a Dothan loamy sand with 0, 1, or 2 yr of previous flurtamone field use was evaluated under controlled conditions. Soil sterilization by autoclaving significantly reduced flurtamone dissipation rate in all soils. Enhanced degradation of flurtamone was observed in a Greenville sandy clay loam after 1 yr of previous flurtamone field use and in a Cecil loam after 2 yr of previous flurtamone field use. No enhancement of flurtamone degradation was observed in a Dothan loamy sand. Flurtamone degradation kinetics in these studies was described as a first-order process. Microbial populations in each soil showed no major changes in total bacterial numbers due to preexposure to flurtamone in the field.
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23

Elsas, J. D. Van, J. T. Trevors, L. S. Van Overbeek, and M. E. Starodub. "Survival of Pseudomonas fluorescens containing plasmids RP4 or pRK2501 and plasmid stability after introduction into two soils of different texture." Canadian Journal of Microbiology 35, no. 10 (October 1, 1989): 951–59. http://dx.doi.org/10.1139/m89-157.

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Survival of Pseudomonas fluorescens R2f containing either the conjugative plasmid RP4 or the nonconjugative plasmid pRK2501, and stability of the plasmids were studied in two soils, Ede loamy sand and Guelph loam, and in extracts prepared from these soils. In sterile soils, the introduced bacterial populations initially increased and then remained stable over a 47-day period. The presence of wheat roots did not significantly influence bacterial numbers in Guelph loam, whereas a slight increase occurred in Ede loamy sand. In Guelph loam, both plasmids were stably maintained in the introduced populations, but in Ede loamy sand substantial plasmid loss was observed. The presence of added phosphate in Ede loamy sand enhanced plasmid maintenance in the introduced R2f population. In nonsterile Guelph loam, a slow decline in the introduced populations was noted, regardless of plasmid type, whereas in Ede loamy sand the decline was more rapid. There was no detectable effect of plasmid type on host survival. Both plasmids RP4 and pRK2501 remained present in the R2f populations in these soils. The results obtained with sterile soil extracts substantiated the data on plasmid loss in both soils; both plasmids were rather unstable during starvation in minimal medium. The results indicated the absence of an effect of plasmid type on host survival. Soil type significantly affected host survival and plasmid maintenance, and higher survival and stability were observed in the heavier-textured Guelph loam.Key words: survival, plasmid stability, Pseudomonas spp., soil, microcosms.
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24

Hamza, M. A., and W. K. Anderson. "Responses of soil properties and grain yields to deep ripping and gypsum application in a compacted loamy sand soil contrasted with a sandy clay loam soil in Western Australia." Australian Journal of Agricultural Research 54, no. 3 (2003): 273. http://dx.doi.org/10.1071/ar02102.

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In the low rainfall, cropping area of Western Australia, massive soil structure due to machinery traffic is common on a range of soil types and is a major obstacle to crop yield improvement. Yield increases on compacted soils have been poor in the last decade compared with those on other soils. An experiment was conducted over 4 years (1997–2000) on a loamy sand soil with massive subsoil structure using a factorial combination of soil ripping to 0.4 m (DR), and application of commercial grade gypsum at 2.5 t/ha (G) to address the soil compaction problem. Complete nutrients, based on soil test each year, were applied to all treatments and regarded as the control treatment. All crop residues were retained after harvest and returned to the soil. The experiment was conducted in a wheat–grain legume (chickpea in 1998, field pea in 2000) rotation at Tammin in Western Australia. The purpose of the experiment was to assess possible improvements in soil properties and grain yields that may result from deep soil disturbance and application of an aggregating agent such as gypsum on a loamy sand soil in a low rainfall cropping system. Soil water infiltration rate, soil strength, porosity, water-stable aggregates, exchangeable Ca and Mg, cation exchange capacity, and grain yields were measured. The results of this experiment on a loamy sand soil are compared and contrasted with those from a similar experiment on another common soil type in the low rainfall zone, a sandy clay loam soil (reported earlier by MA Hamza and WK Anderson). Grain yields were increased slightly more on the loamy sand soil at Tammin than on the sandy clay loam soil at Merredin due to deep ripping and gypsum application, even though the corresponding improvements in soil parameters were not as great on the loamy sand soil. The yield increases of wheat and legumes due to gypsum treatment were significantly lower on both soil types than those due to the combination of gypsum and ripping, whereas ripping alone without gypsum produced a yield decrease in the third and subsequent years after treatment. The main treatment effects on yield were additive, as significant interactions between the treatments on yield were seldom found. Deep ripping and gypsum application (DRG) resulted in the greatest improvement in the soil physical properties as indicated by crop growth on both soil types. The DRG treatment increased soil water infiltration rate by about 90% on the loamy sand soil but by more than 130% on the sandy clay loam soil 4 years after the application of the treatments. Strength and porosity of the topsoil were decreased much more on the sandy clay loam soil. Summer rain stored in the soil prior to seeding was increased almost 3 times in both soils. The increase in water-stable aggregates was only 8% in the loamy sand soil but 46% on the sandy clay loam soil. Cation exchange capacity and exchangeable calcium were also increased more on the clayey than on the sandy soil by the use of DRG. Economic analysis of the yield improvements showed that the DRG treatment produced significantly higher profit than the G or DR treatments alone on both soil types, but was slightly greater on the loamy sand soil type. The combination of soil ripping and gypsum application in the presence of complete nutrients and annual return of crop residues to the soil had somewhat different effects on the soil physical properties and grain yields at a loamy sand soil site compared with the sandy clay loam soil site. However, the effect in both cases was favourable and is suggested to improve crop grain yield and soil physical fertility on both commonly occurring soil types in the low rainfall, cropping zone of Western Australia.
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25

Schroeder, Jill, and Philip A. Banks. "Persistence and Activity of Norflurazon and Fluridone in Five Georgia Soils Under Controlled Conditions." Weed Science 34, no. 4 (July 1986): 599–606. http://dx.doi.org/10.1017/s0043174500067515.

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Response of grain sorghum [Sorghum bicolor(L.) Moench. ‘BR 64’] to norflurazon [4-chloro-5-(methylamino)-2-(3-(trifluoromethyl)phenyl)-3(2H)-pyridazinone] and fluridone {1-methyl-3-phenyl-5-[3-(trifluoromethyl) phenyl]-4(1H)pyridinone} and the effect of previous treatment on the persistence of herbicide activity in five soils were determined in the greenhouse. Relative phytotoxicity of fluridone in the soils was ordered as Greenville sandy clay loam > Appling coarse sandy loam > Dothan loamy sand = Rome gravelly clay loam > Bradson clay loam. Phytotoxicity of norflurazon was ordered as Greenville = Appling = Dothan > Rome > Bradson. Fluridone was more phytotoxic than norflurazon. Field soil that has been previously treated with norflurazon or fluridone (500 days earlier at 1.7 kg ai/ha) still had low concentrations of each herbicide present at the time of retreatment in the greenhouse. Previous treatment of norflurazon did not affect the rate of decline in activity in any of the soils compared to previously nontreated soils except for Appling. Significantly higher concentrations of norflurazon remained in all previously treated soils 297 days after treatment (DAT) compared to previously nontreated soil. Residual carryover of norflurazon was greater in the Bradson soil (2.8% O.M.) than soils having less than 2% O.M. Fluridone dissipation was significantly faster in previously treated soil than in previously nontreated soil, indicating enhanced microbial degradation of the herbicide.
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26

Wang, Haiyan, Ran Chen, Yuefan Sheng, Weitao Jiang, Rong Zhang, Xuesen Chen, Xiang Shen, Chengmiao Yin, and Zhiquan Mao. "Impact of Three Soil Textures on the Fungal Community Structure in Rhizosphere Soils of Malus hupehensis Rehd. Seedlings." HortScience 56, no. 5 (May 2021): 572–78. http://dx.doi.org/10.21273/hortsci15688-21.

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The relationship between soil texture and the degree of apple replant disease (ARD) was analyzed from the perspective of the microbial community structure and diversity within the rhizosphere soil of Malus hupehensis Rehd. seedlings. Three different textured soils were taken from different apple orchards in Laizhou, Yantai. The soils were divided into two parts, one was kept in replanted conditions, and the other was fumigated with methyl bromide to act as a high standard control. The strength of ARD occurrence was examined by measuring fresh and dry weight suppression (%) of the M. hupehensis seedlings. Differences in the fungal community structure (especially in Fusarium) among the three soil texture types were analyzed using high-throughput sequencing. The results showed that replanted loam clay soil had the highest fungal diversity, followed by sandy loam soil and finally loam soil. The richness of fungi between soil textures, however, was not significantly different. At the genus level, the relative abundance of Fusarium was 1.96%, 0.78%, and 10.89% in replanted sandy loam, replanted loam soil, and replanted loam clay soil, respectively. Moreover, the gene copy number of Fusarium oxysporum, Fusarium solani, and the inhibition rate of fresh weight of M. hupehensis seedlings were the same in the three soil textures. The plant height, photosynthesis (net) (Pn), and stomatal conductance (gS) of the M. hupehensis seedlings were significantly less in the replanted soil compared with the control treatments, with the overall difference being greatest in replanted loam clay soil, followed by replanted sandy loam and then replanted loam soil.
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27

Zhao, Litong, D. M. Gray, and B. Toth. "Influence of soil texture on snowmelt infiltration into frozen soils." Canadian Journal of Soil Science 82, no. 1 (February 1, 2002): 75–83. http://dx.doi.org/10.4141/s00-093.

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This paper describes the influence of soil texture on snowmelt infiltration into frozen soils. Field data collected on frozen, unsaturated agricultural soils of the Canadian Prairies during snow ablation demonstrate: (a) poor association between the amount of infiltration of meltwater released by the seasonal snowcover and soil texture, and (b) small differences in cumulative amounts among soils of widely different textures. A physics-based numerical simulation of heat and mass transfers with phase changes in frozen soils is used to study the mechanics of the infiltration process in representative clay, silty clay loam, silt loam and sandy loam soils. The results of the simulations show that the differences among cumulative snowmelt infiltration into clay, silty clay loam and silt loam soils after 24 h of continuous infiltration are small. Infiltration into a lighter-textured sandy loam after 24 h was on average 23% higher than in the other three soils with most of the increase occurring in the first 5 h of the simulation. Key Words: Soil texture, snowmelt, infiltration, frozen soils
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28

Fouli, Ymène, Barbara J. Cade-Menun, and Herb W. Cutforth. "Freeze–thaw cycles and soil water content effects on infiltration rate of three Saskatchewan soils." Canadian Journal of Soil Science 93, no. 4 (September 2013): 485–96. http://dx.doi.org/10.4141/cjss2012-060.

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Fouli, Y., Cade-Menun, B. J. and Cutforth, H. W. 2013. Freeze–thaw cycles and soil water content effects on infiltration rate of three Saskatchewan soils. Can. J. Soil Sci. 93: 485–496. Many soils at high latitudes or elevations freeze and thaw seasonally. More frequent freeze–thaw cycles (FTCs) may affect ecosystem diversity and productivity because freeze–thaw cycles cause changes in soil physical properties and affect water movement in the landscape. This study examined the effects of FTCs (0, 1, 5, and 10) and antecedent soil water content [at soil water potentials (SWP) −1.5, −0.033 and −0.02 MPa] on the infiltration rate of three Saskatchewan soils (a clay, a loam, and a loamy sand). A tension infiltrometer was used at tensions [water potentials of the tension infiltrometer (WPT)] −5, −10 and −15 cm. Infiltration rates increased with increasing SWPs for the loam and clay soils due to higher infiltrability into drier soils. Infiltration rates decreased with increasing SWPs for the loamy sand, probably the result of less surface tension, unimodal porosity, and increased gravitational potential. Infiltration rates either decreased or did not change with increasing FTCs, and this may be due to increased water viscosity as temperatures approach freezing. Also, ice may have formed in soil pores after frequent FTCs, causing lower infiltration rates. Infiltration rates for clay at −1.5 MPa were higher than for loam or loamy sand, probably the result of clay mineralogy and potential shrinking and cracking. Soil texture and initial water content had a significant effect on infiltration rates, and FTCs either maintained or lowered infiltration rates.
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29

Hermawan, Bandi, Pajrina Pajrina, Sumardi Sumardi, and Indra Agustian. "Application of a Dielectric Measurement Technique for Calculating Water Loss from Two Texture-contrasting Soils Grown with Upland Rice." TERRA : Journal of Land Restoration 1, no. 1 (May 26, 2018): 8–14. http://dx.doi.org/10.31186/terra.1.1.8-14.

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Most of the water loss from the soil profile occurred through the evapotranspiration process especially when the plant covers were under maximum growth periods. This study aimed to apply a technique of measuring a dielectric variable for calculating soil water content and crop water use in the coarse and medium textured soils grown with upland rice. A couple of wires were inserted into the soil repacked in a 10-kg polybag grown with upland rice, the electrical impedance representing the dielectric value was measured using an instrument called the impedance meter. The impedance values were converted into the soil water content using a nonlinear regression model of ? = a.ebZ where a and b were constants. Results showed that the proposed technique of measuring the electrical impedance has successfully been applied to calculate the soil water content and the water use by upland rice grown in loamy sand and sandy loam soils. Cumulative water loss from loamy sand was about 4 L plant-1 higher for the coarse loamy sand in the first 30 days of a measurement period, but about 10 L plant-1 higher for finer sandy loam on the 90th day of the rice growth period. Higher biomass of upland rice in the sandy loam soil could increase the evapotranspiration rates and be the main reason for higher water use in this soil.
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30

Kinfe, Birhanu, and Thomas F. Peeper. "Persistence of Chlorsulfuron and BAY SMY 1500 in Air Dry Soil at Room Temperature." Weed Technology 7, no. 1 (March 1993): 29–32. http://dx.doi.org/10.1017/s0890037x00036812.

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Persistence of BAY SMY 1500 and chlorsulfuron during storage for 0 to 6 mo at room temperature in air-dry clay loam soil with pH 7.6 and sandy loam soil with pH 6.6 was determined with conventional wheat bioassay procedures. BAY SMY 1500 had predicted half-lives greater than 6 mo in both soils. Half-lives of chlorsulfuron were 6.0 and 3.2 mo in the clay loam soil and sandy loam soil, respectively.
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31

Kotoula-Syka, Eleni, Ilias G. Eleftherohorinos, Athanasios A. Gagianas, and Achilleas G. Sficas. "Persistence of Preemergence Applications of Chlorsulfuron, Metsulfuron, Triasulfuron, and Tribenuron in Three Soils in Greece." Weed Science 41, no. 2 (June 1993): 246–50. http://dx.doi.org/10.1017/s004317450007613x.

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A pot bioassay, based on root growth of pregerminated corn, was used to evaluate factors influencing field persistence of chlorsulfuron, metsulfuron, triasulfuron, and tribenuron, which were applied preemergence at 0, 10, 20, and 40 g ai ha−1to wheat grown in three soils that differed in texture (sandy loam, sandy clay loam, and silty clay loam) and pH (7.9, 4.7, and 7.6). Residual activity and leaching of all herbicides in all soils increased with increasing rate of application, with the exception of tribenuron which showed practically no residual activity and leaching in sandy clay loam soil. Sunflower sown 4 mo after tribenuron application in all soils was not injured by any rate used but was significantly affected by the other herbicides. Lentil and sugarbeet also were affected by all herbicides in all soils. These three crops sown 8 mo after herbicide application were not affected by any herbicide used in the sandy clay loam soil but were injured by chlorsulfuron, triasulfuron, and metsulfuron in the sandy loam soil. Only lentil and sugarbeet were injured by chlorsulfuron in the silty clay loam soil.
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32

Batal, K. M., D. M. Granberry, and B. G. Mullinix. "Nitrogen, Magnesium, and Boron Applications Affect Cauliflower Yield, Curd Mass, and Hollow Stem Disorder." HortScience 32, no. 1 (February 1997): 75–78. http://dx.doi.org/10.21273/hortsci.32.1.75.

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The effects of three rates of N, Mg, and B on cauliflower (Brassica oleracea, Botrytis group) yield, average curd mass, and hollow stem disorder were evaluated on sandy and clay loam soils. Cultivars White Empress and Stovepipe were tested on the sandy loam soil and `White Empress' was tested on the clay loam soil. Maximum mean curd mass and maximum yields were obtained with the highest N rates (269 and 381 kg·ha-1) applied to sandy loam and clay loam soils, respectively. Yield response to increased N rates varied with cultivar. Increasing Mg from 22.5 to 90 kg·ha-1 did not affect yield or curd mass on clay loam soil, but increased yield and mean curd mass on sandy loam soil. The Mg effect on curd mass was influenced by N and B rates. On both soil types, the higher Mg and B rates reduced the incidence of hollow stem, but the Mg effect was influenced by N applications. On clay loam soil, increasing B from 2.2 to 8.8 kg·ha-1 reduced hollow stem but had no effect on yield or curd mass. On sandy loam soil, B at 4.4 kg·ha-1 maximized yield and curd mass, but the hollow stem disorder continued to decrease as B rates were increased from 2.2 to 8.8 kg·ha-1.
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33

Solodkyy, Serhiy, Volodymyr Hidei, Iurii Sidun, Oleksii Hunyak, and Yurii Turba. "USING WASTEPAPER SLUDGE ASH (WSA) AS A MATERIAL FOR SOIL STRENGTHENING FOR THE CONSTRUCTION OF LAYERS OF PAVEMENT." Theory and Building Practice 2021, no. 1 (June 22, 2021): 85–91. http://dx.doi.org/10.23939/jtbp2021.01.085.

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The article considers the possibility of using wastepaper sludge ash (WSA) as a soil reinforcement material for the construction of layers of road wear. Loamy sand, sandy loam, silty clay loam, silty clay were chosen as soils for strengthening. The maximum density of the soil skeleton at optimum humidity was established by the method of Proctor. Wastepaper sludge ash and Portland cement grade 400 were used separately for soil strengthening. Six compositions of strengthened soil for each type of soil were investigated according to the strength criterion of water-saturated samples at the age of seven, fourteen and twenty-eight days. The research results indicate that wastepaper sludge ash can be used to strengthen different types of soils with the achievement of following grades of stabilized soil: M10, M20, M40.
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34

Goetz, Andrew J., Robert H. Walker, Glenn Wehtje, and Ben F. Hajek. "Sorption and Mobility of Chlorimuron in Alabama Soils." Weed Science 37, no. 3 (May 1989): 428–33. http://dx.doi.org/10.1017/s0043174500072179.

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Soil thin-layer chromatography and a soil solution technique were used to evaluate chlorimuron adsorption and mobility in five Alabama soils. The order of adsorption was atrazine > metribuzin > chlorimuron; mobility was chlorimuron > metribuzin > atrazine. The order of adsorption of chlorimuron in the five soils was Sumter clay > Eutaw clay > Lucedale fine sandy loam > Decatur silt loam > Dothan sandy loam, and Rfvalues were 0.63, 0.73, 0.69, 0.76, and 0.80, respectively. Chlorimuron mobility and adsorption were not highly correlated to any one soil type. Adsorption of all herbicides was inversely related to soil pH. Maximum chlorimuron adsorption in the Hiwassee loam was attributed to the high hematite and gibbsite content of the soil.
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35

Wali, Pardeep, Vinod Kumar, and J. P. Singh. "Effect of soil type, exchangeable sodium percentage, water content, and organic amendments on urea hydrolysis in some tropical Indian soils." Soil Research 41, no. 6 (2003): 1171. http://dx.doi.org/10.1071/sr01090.

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Urea has emerged as one of the most extensively used sources of nitrogen fertiliser in recent years because of its low cost per unit nitrogen. Urea hydrolysis in soils is an enzymatic decomposition process by the enzyme urease. The effects of soil type, exchangeable sodium percentage, moisture regime, and organic manures and their levels on the kinetics of urea hydrolysis were studied in a series of laboratory incubation experiments at 25 ± 1�C. Urea transformation followed first-order kinetics, and the first-order rate constants for soils varied from 0.0321 to 0.1182/h. The rate of urea hydrolysis in the different soils increased with greater clay content and followed the order: Gulkani clay loam > Dadupur loam > Hisar sandy loam > Jakhol silty clay loam > Bawal loamy sand > Balsamand sand. Increasing the exchangeable sodium percentage in soils decreased the rate of urea hydrolysis both at field capacity and flooded conditions (2 cm standing water). Application of vermicompost, sheep manure, poultry manure, pig manure, and urban waste to soil at the 1% level increased the rate of hydrolysis over the untreated soil.
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36

Jabro, J. D., W. B. Stevens, W. M. Iversen, B. L. Allen, and U. M. Sainju. "Irrigation Scheduling Based on Wireless Sensors Output and Soil-Water Characteristic Curve in Two Soils." Sensors 20, no. 5 (February 29, 2020): 1336. http://dx.doi.org/10.3390/s20051336.

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Data-driven irrigation planning can optimize crop yield and reduce adverse impacts on surface and ground water quality. We evaluated an irrigation scheduling strategy based on soil matric potentials recorded by wireless Watermark (WM) sensors installed in sandy loam and clay loam soils and soil-water characteristic curve data. Five wireless WM nodes (IRROmesh) were installed at each location, where each node consisted of three WM sensors that were installed at 15, 30, and 60 cm depths in the crop rows. Soil moisture contents, at field capacity and permanent wilting points, were determined from soil-water characteristic curves and were approximately 23% and 11% for a sandy loam, and 35% and 17% for a clay loam, respectively. The field capacity level which occurs shortly after an irrigation event was considered the upper point of soil moisture content, and the lower point was the maximum soil water depletion level at 50% of plant available water capacity in the root zone, depending on crop type, root depth, growth stage and soil type. The lower thresholds of soil moisture content to trigger an irrigation event were 17% and 26% in the sandy loam and clay loam soils, respectively. The corresponding soil water potential readings from the WM sensors to initiate irrigation events were approximately 60 kPa and 105 kPa for sandy loam, and clay loam soils, respectively. Watermark sensors can be successfully used for irrigation scheduling by simply setting two levels of moisture content using soil-water characteristic curve data. Further, the wireless system can help farmers and irrigators monitor real-time moisture content in the soil root zone of their crops and determine irrigation scheduling remotely without time consuming, manual data logging and frequent visits to the field.
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37

Valdés-Rodríguez, Ofelia Andrea, Odilón Sánchez-Sánchez, Arturo Pérez-Vázquez, Joshua S. Caplan, and Frédéric Danjon. "Jatropha curcasL. Root Structure and Growth in Diverse Soils." Scientific World Journal 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/827295.

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Unlike most biofuel species,Jatropha curcashas promise for use in marginal lands, but it may serve an additional role by stabilizing soils. We evaluated the growth and structural responsiveness of youngJ. curcasplants to diverse soil conditions. Soils included a sand, a sandy-loam, and a clay-loam from eastern Mexico. Growth and structural parameters were analyzed for shoots and roots, although the focus was the plasticity of the primary root system architecture (the taproot and four lateral roots). The sandy soil reduced the growth of both shoot and root systems significantly more than sandy-loam or clay-loam soils; there was particularly high plasticity in root and shoot thickness, as well as shoot length. However, the architecture of the primary root system did not vary with soil type; the departure of the primary root system from an index of perfect symmetry was14±5% (mean ± standard deviation). AlthoughJ. curcasdeveloped more extensively in the sandy-loam and clay-loam soils than in sandy soil, it maintained a consistent root to shoot ratio and root system architecture across all types of soil. This strong genetic determination would make the species useful for soil stabilization purposes, even while being cultivated primarily for seed oil.
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38

Kirksey, K. Bruce, Robert M. Hayes, William A. Krueger, Charles A. Mullins, and Thomas C. Mueller. "Clomazone Dissipation in Two Tennessee Soils." Weed Science 44, no. 4 (December 1996): 959–63. http://dx.doi.org/10.1017/s0043174500094996.

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Clomazone dissipation in soil was examined in field and laboratory experiments. Field studies suggested a potential for injury to rotational crops such as wheat. Field half-lives were 5 to 29 d (average of 9 field studies was 19 d) for the Etowah clay loam (fine-loamy, siliceous, thermic typic Paleudult) and Lily loam (fine-loamy, siliceous, thermic typic Hapludult) soils. Clomazone had an average half-life of 34 d under lab conditions, indicating slower dissipation in the lab than in the field. Clomazone was moderately adsorbed to soil as indicated by a Kdof about 1, and a Komof 52 in the two soils.
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39

Zheng, Z., L. E. Parent, and J. A. MacLeod. "Influence of soil texture on fertilizer and soil phosphorus transformations in Gleysolic soils." Canadian Journal of Soil Science 83, no. 4 (August 1, 2003): 395–403. http://dx.doi.org/10.4141/s02-073.

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The P dynamics in soils should be quantified in agricultural soils to improve fertilizer P (FP) efficiency while limiting the risk of P transfer from soils to water bodies. This study assessed P transformations following FP addition to Gleysolic soils. A pot experiment was conducted with five soils varying in texture from sandy loam to heavy clay, and receiving four FP rates under barley (Hordeum vulgare L.)-soybean (Glycine max L.) rotations. A modified Hedley procedure was used for soil P fractionation. Soil resin-P and NaHCO3-Pi contents were interactively affected by texture and FP. The NaHCO3-Po, NaOH-Po, HCl-P and H2SO4-P were only affected by soil texture. Proportions of 78 and 90% of the variation in labile and total P were, respectively, related to soil clay content. The FP addition increased resin-P, NaHCO3-Pi and NaOH-Pi and -Po contents in coarse-textured soils, but the amount added was not sufficient to mask the initial influence of soil texture on the sizes of soil P pools. Plant P uptake was proportional to FP rate but less closely linked to clay content. The average increase in labile P per unit of total FP added in excess of plant exports was 0.85, 0.8 2 , 0.73, 0.55 and 0.24 for the sandy loam, loam, clay loam, clay and heavy clay soil, respectively. The results of this study stress the important of considering soil texture in Gleysolic soils when assessing P accumulation and transformations in soils, due to commercial fertilizers applied in excess of crop removal. Key words: P fractions, clay content, fertilizer P, plant P uptake, soil texture
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40

Azooz, R. H., and M. A. Arshad. "Soil water drying and recharge rates as affected by tillage under continuous barley and barley-canola cropping systems in northwestern Canada." Canadian Journal of Soil Science 81, no. 1 (February 1, 2001): 45–52. http://dx.doi.org/10.4141/s00-029.

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In areas of the northwestern Canadian Prairies, barley and canola are grown in a short growing season with high rainfall variability. Excessively dry soil in conventional tillage (CT) in dry periods and excessively wet soil in no-tillage (NT) in wet periods could cause a significant decrease in crop production by influencing the availability of soil water. The effects of CT, NT and NT with a 7.5-cm residue-free strip on the planting rows (NTR) on soil water drying (–dW/dt) and recharge (dW/dt) rates were studied in 1992 and 1993 during wet and dry periods to evaluate the impact of NTR, NT and CT systems on soil moisture condition. The soils, Donnelly silt loam and Donnelly sandy loam (both Gray Luvisol) were selected and soil water content by depth was measured by time domain reflectometry. Water retained at 6 matric potentials from –5 to –160 kPa were observed. In the field study, –dW/dt was significantly greater in CT than in NT in the silt loam for the 0- to 30-cm layer during the first 34 d after planting in 1992. The 0- to 30-cm soil layer in CT and NTR dried faster than in NT during a period immediately following heavy rainfall in the silt loam in 1993. The drying coefficient (–Kd ) was significantly greater in CT and NTR than in NT in the silt loam soil in 1993 and in the sandy loam soil in 1992 in the top 30-cm depth. The recharge coefficient (Kr) was significantly greater in NT and NTR than in CT for the silt loam soil. The NTR system increased the –dW/dt by 1.2 × 10-2 to 12.1 × 10-2 cm d-1 in 1992 and 1993 in the silt loam soil and by 10.2 × 10-2 cm d-1 in 1993 in the sandy loam soil as compared with NT. The dW/dt was 8.1 × 10-2 cm d-1 greater in NTR in 1992 and 1993 in the silt loam soil and was 1.9 × 10-2 greater in NTR in 1992 than in CT in the sandy loam soil. The laboratory study indicated that NT soils retained more water than the CT soils. The NTR practice maintained better soil moisture conditions for crop growth than CT in dry periods than NT in wet periods. Compared with NT, the NTR avoided prolonged near-saturated soil conditions with increased soil drying rate under extremely wet soil. Key words: Water drying, water recharge, water depletion, wet and drying periods, hydraulic properties, soil capacity to retain water
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41

GRANT, C. A. "THE EFFECT OF K AND Cl FERTILIZER ADDITIONS ON BARLEY HERBAGE YIELD AND NUTRIENT CONTENT IN UNDISTURBED AND ARTIFICIALLY COMPACTED SOIL CORES." Canadian Journal of Plant Science 69, no. 3 (July 1, 1989): 729–39. http://dx.doi.org/10.4141/cjps89-089.

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Disturbed soil cores, at two bulk densities, and undisturbed soil cores were collected from two fields which had been maintained under reduced tillage management. Dry matter yield of growth chamber-grown barley in the disturbed soil cores was equal to or lower than that produced in the undisturbed cores but was unaffected by degree of soil compaction. Increase in dry matter yield in response to K or Cl fertilization was greater in disturbed than undisturbed soils. Compaction did not generally influence response to KCl fertilization. Soil disturbance did not consistently influence concentration of N, K or Cl in barley tissue. Tissue content of Zn was increased by soil disturbance in the clay loam soil and decreased by soil disturbance in the sandy loam soil. Compaction did not influence tissue content of N or Cl. Compaction did not influence K content of plants grown on the clay loam soil, which initially had high levels of plant-available K, but reduced K content of plants grown on K-deficient sandy loam soil. Increased compaction also reduced the Zn content of plants in the sandy loam soil but increased Zn content of plants in the clay loam soil. Application of KCl or CaCl2 increased Cl content of barley tissue and tended to reduce the N content of the tissue, particularly in the clay loam soil. Application of KCl or KNO3 increased K concentration in barley tissue grown on the K-deficient sandy loam soil but not on the higher K clay loam soil.Key words: Potassium, chloride, zinc, compaction, bulk density, barley
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42

Mundra, M. C., Raj Pal, R. S. Siyag, and S. R. Poonia. "Unsaturated water transmission characteristics of soils in relation to texture, aggregate size and initial moisture content." Journal of Agricultural Science 112, no. 2 (April 1989): 199–204. http://dx.doi.org/10.1017/s0021859600085105.

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SummaryTo study the effect of soil texture, aggregate size and initial moisture content on soil water diffusivity, D(θ), and unsaturated hydraulic conductivity, K(θ), horizontal absorption experiments were conducted on samples of loamy sand, sandy loam and clay–loam soils as well as on artificially prepared water-stable aggregates of a clay–loam sample (sizes 0.·25–0–25, 0·25–0·5, 0·5–1, 1–2, and 2–4 mm). For comparable moisture contents, D(θ) followed the order loamy sand > sandy loam > clay–loam. The effect of initial moisture content on D(θ) varied with soil texture. K(θ), which was evaluated using D(θ) for air-dry initial moisture content and the slopes of the water retention curves, also varied with soil texture.The D(θ) function for air-dry initial moisture content increased with the decrease in aggregate size, the increase being more pronounced below a size of 1 mm. Values of D(θ) obtained from initially airdry soil and at 10% of saturation moisture content did not differ greatly from one another. The K(θ) function was almost the same for aggregate sizes 1–2 and 2–4 mm. In the size ranges of < 1 mm, K(θ) increased with the decrease in aggregate size. The particle/aggregate size range of 0·1–0·5 mm was the most conducive to unsaturated water flow.
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43

Villa, Yocelyn B., Sat Darshan S. Khalsa, Rebecca Ryals, Roger A. Duncan, Patrick H. Brown, and Stephen C. Hart. "Organic matter amendments improve soil fertility in almond orchards of contrasting soil texture." Nutrient Cycling in Agroecosystems 120, no. 3 (June 24, 2021): 343–61. http://dx.doi.org/10.1007/s10705-021-10154-5.

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AbstractThe effects of organic matter amendments (OMA) on soil fertility in permanent cropping systems like orchards is under-studied compared to annual cropping systems. We evaluated experimentally the impact of OMAs on soil fertility in almond (Prunus dulcis) orchards over a two-year period with annual applications. Two OMAs, derived from composted green waste (GWC) or composted manure wood chips (MWC), were applied as surface mulch and compared to a control at two sites with different soil textures (sandy loam and loamy sand). OMAs increased soil moisture content (0–0.1 m depth) at both sites by 27–37%. Both amendments increased soil inorganic N at the sandy loam (GWC: 194%; MWC: 114%) and loamy sand (GWC: 277%; MWC: 114%) sites the month following application, but soil inorganic N concentrations quickly decreased to values similar to those of control plots. After two-years, the GWC and the MWC amendments increased the soil cation exchange capacity (CEC) by 112% and 29%, respectively, in the sandy loam site, but no change was observed in the loamy sand site. The greatest increase in soil extractable K occurred in the GWC-amended plots at the sandy loam site even though the initial K concentration of MWC was higher. Both OMAs increased soil organic carbon (SOC) after two years, but the SOC increase in the GWC-amended plots was greater. Our results suggest that OMAs can significantly improve soil fertility after one or two annual applications, and that fertility gains appear to be dependent on soil texture than the nutrient concentrations of the OMA.
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44

Gullap, M. Kerim, H. Ibrahim Erkovan, and Ali Koc. "The effect of bovine saliva on growth attributes and forage quality of two contrasting cool season perennial grasses grown in three soils of different fertility." Rangeland Journal 33, no. 3 (2011): 307. http://dx.doi.org/10.1071/rj10063.

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The aim of this study was to determine the response of Dactylis glomerata L. (Orchardgrass) and Festuca ovina L. (Sheep fescue), to bovine saliva application in a loamy soil (most fertile), a sandy loam and a sandy soil (least fertile). The effects of cutting and cutting + saliva on relative height growth rate (RHGR), above- and belowground biomass and forage quality attributes [crude protein, NDF (neutral detergent fibre) and ADF (acid detergent fibre)] were investigated. The results showed that the cutting and cutting + saliva treatments resulted in greater RHGR than the control, but only with D. glomerata in the sandy soil did the application of saliva increase the RHGR. However, saliva applied after cutting increased the aboveground biomass averaged over all species and all three soils. Saliva applied to D. glomerata increased the belowground biomass in the sandy loam and sandy soils but decreased it in F. ovina in the sandy soil. The application of saliva had no effect on the crude protein or the NDF content of either species in any of the soils. On the other hand, the application of saliva after clipping increased the ADF of F. ovina but decreased that of D. glomerata averaged over all three soils. Averaged over both species, the ADF was increased by the addition of saliva in the sandy soil, had no significant effect in the sandy loam (P > 0.05) and was slightly increased in the loam.
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45

Franzluebbers, A. J., and M. A. Arshad. "Water-stable aggregation and organic matter in four soils under conventional and zero tillage." Canadian Journal of Soil Science 76, no. 3 (August 1, 1996): 387–93. http://dx.doi.org/10.4141/cjss96-046.

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Zero tillage management reduces soil exposure and disturbance and, therefore, may improve soil aggregation and organic matter sequestration under some environments. We determined the distribution and soil organic C (SOC) content of five water-stable aggregate (WSA) classes at depths of 0–50, 50–125 and 125–200 mm in a loam, a slit loam, a clay loam, and a clay soil managed for 4–16 yr under conventional shallow tillage (CT) and zero tillage (ZT) in the Peace River region of northern Alberta and British Columbia. Macroaggregation (> 0.25 mm and mean weight diameter (MWD) were greater under ZT than under CT in coarse-textured soils at a depth of 0–125 mm. Under CT, macroaggregation and MWD increased with increasing clay content, thereby reducing the potential of ZT to improve these properties in soils with high clay content. Concentration of SOC tended to be greatest in macroaggregates and lowest in microaggregates of coarse-textured soils, but was not different among WSA classes of fine-textured soils. Soil organic C content of macroaggregates under ZT was 0.34, 0.40, 0.62, and 0.16 kg m−2 greater than under CT at a depth of 0–200 mm in the loam, silt loam, clay loam and clay soil, respectively. Our results suggest that implementation of ZT in this cold semiarid climate can quickly improve WSA of coarse-textured soils and potentially increase SOC sequestration, albeit more slowly than in warmer more humid climates, when macroaggregation is improved. Key words: Aggregation, soil organic matter, soil texture, tillage
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46

Sharma, Arun, and K. C. Pancholi K.C. Pancholi. "Effect of Vegetation Biomass on Emissivity of Loam Soil." International Journal of Scientific Research 2, no. 4 (June 1, 2012): 61–62. http://dx.doi.org/10.15373/22778179/apr2013/121.

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47

Singh, R. P. "The Influence of Organic Cosolvent (Methanol) on the Adsorption of Carbofuran on Three Different Types of Indian Soils." Adsorption Science & Technology 13, no. 5 (October 1996): 305–15. http://dx.doi.org/10.1177/026361749601300501.

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The adsorption of carbofuran on three different types of uncontaminated Indian soils (loam, silt clay loam, sandy loam) at various volume fractions (0.25, 0.50, 0.75, 1.0) of methanol (fS) has been studied by the batch shake technique. The adsorption of carbofuran was higher on loam soil, followed by silt clay loam and sandy loam soils, and decreased with increasing fS values on all soils. From the adsorption data, adsorption partition coefficients KD (ml/g) were evaluated and the KD values converted to mole-based partition coefficients Km (mol/g). These values were utilised to test the cosolvent theory. The Km values for soils, when normalised on foc, gave values of Kmoc, and a plot of log Kmoc versus fS resulted in a single line whose equation was determined by linear regression analysis as log Kmoc = –1.12 + 2.84; r2 = 0.96. The aqueous phase partition coefficient KDw (mol/g) normalised on f∞ for carbofuran extrapolated from this relationship was 4.1, The slope may be related to the effect of carbofuran solubility and to carbofuran–soil and solvent–soil interactions. The data presented suggested that methanol–soil interaction may not increase the accessibility of carbofuran to soil organic matter to the same extent as reported for less hydrophobic organic solutes.
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48

Tuttle, C. L., M. S. Golden, and R. S. Meldahl. "Soil compaction effects on Pinustaeda establishment from seed and early growth." Canadian Journal of Forest Research 18, no. 5 (May 1, 1988): 628–32. http://dx.doi.org/10.1139/x88-092.

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Soil bulk density was related to loblolly pine (Pinustaeda L.) seedling establishment and growth during the first 28 weeks after sowing. Seedling heights were lower when bulk densities exceeded 1.3 Mg m−3 on a sandy clay loam and 1.4 Mg m−3 on a loamy sand. Heights were also lower for bulk densities below 1.2 Mg m−3 on the sandy clay loam soil. Seedling depth of rooting, root weight, and shoot weight were reduced at high bulk densities on both a sandy clay loam and a loamy sand. However, root and shoot weights were also reduced when bulk density fell below 1.3 Mg m−3 on the sandy clay loam. Bulk densities for best seedling growth were 1.3 Mg m−3 for the sandy clay loam and 1.4 Mg m−3 for the loamy sand.
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49

John Hendel, Edward Topp,, Zexun Lu, and Ralph Chapman. "Biodegradation of caffeine in agricultural soil." Canadian Journal of Soil Science 86, no. 3 (May 1, 2006): 533–44. http://dx.doi.org/10.4141/s05-064.

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Caffeine (1,3,7-trimethylxanthine) could represent a useful marker of contamination of effluent from agricultural land receiving biosolids. The persistence characteristics of caffeine in three agricultural soils was investigated. In laboratory microcosms of moist soil incubated at 30°C, [8-ring-14C]-caffeine was rapidly and thoroughly mineralized to 14CO2 in a sandy loam and a loam soil, and less rapidly in a silt loam soil. Caffeine mineralization was very responsive to soil temperature and moisture. Mineralization of caffeine was hastened by the addition of liquid municipal biosolids (LMB) from three municipal sewage-treatment plants (MSTPs) that aerate this material. In contrast, LMB from three MSTPs that did not aerobically digest their LMB did not accelerate caffeine mineralization. Autoclaved LMB had no effect on caffeine dissipation. Abacterium, designated Pseudomonas sp. Strain TH1, was isolated from aerated LMB. The bacterium first demethylated caffeine to 3,7-dimethylxanthine, and then mineralized the molecule. Inoculation of Pseudomonas sp. Strain TH1 into soil hastened mineralization of [8-ring-14C]-caffeine. In summary, caffeine was more stable in a silt loam soil than a sandy loam or loam soil, but biodegradation in all three soils was quite uniform upon the addition of caffeine-degrading bacteria or aerated biosolids. We suggest that caffeine would likely not be a suitably conservative chemical marker for detecting chronic contamination of agricultural drainage water following fertilization wit hLMB. Aerobic digestion of LMB promotes the enrichment of caffeine-degrading microorganisms. Key words: Caffeine biodegradation, biosolids chemical marker, biosolids organic contaminant, water quality
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50

Singh, Jagrati, S. Saggar, D. L. Giltrap, and Nanthi S. Bolan. "Decomposition of dicyandiamide (DCD) in three contrasting soils and its effect on nitrous oxide emission, soil respiratory activity, and microbial biomass—an incubation study." Soil Research 46, no. 7 (2008): 517. http://dx.doi.org/10.1071/sr07204.

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The objective of this work was to study the degradation kinetics of a nitrification inhibitor (NI), dicyandiamide (DCD), and evaluate its effectiveness in reducing nitrous oxide (N2O) emissions in different types of soils. Three soils contrasting in texture, mineralogy, and organic carbon (C) content were incubated alone (control) or with urine at 600 mg N/kg soil with 3 levels of DCD (0, 10, and 20 mg/kg). Emissions of N2O and carbon dioxide (CO2) were measured during the 58-day incubation. Simultaneously, subsamples were collected periodically from the incubating soils (40-day incubation) and the amounts of DCD, NH4+, and NO3− were determined. Our results showed that the half-life of DCD in these laboratory incubating soils at 25°C was 6–15 days and was longer at the higher rate of DCD application. Of the 3 soils studied, DCD degradation was fastest in the brown loam allophanic soil (Typic orthic allophanic) and slowest in the silt loam non-allophanic soil (Argillic-fragic Perch-gley Pallic). The differences in DCD degradation among these soils can be attributed to the differences in the adsorption of DCD and in the microbial activities of the soils. Among the 3 soils the highest reduction in N2O emissions with DCD from the urine application was measured in the non-allophanic silt loam soil followed by non-allophanic sandy loam soil and allophanic brown loam soil. There was no adverse impact of DCD application on soil respiratory activity or microbial biomass.
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