Conservation practices are encouraged to improve soil health and sustain agronomic crop production.Mehlich-3 is often used as a multi-nutrient extractant to determine soil fertility status.A study inves-tigated the im...Conservation practices are encouraged to improve soil health and sustain agronomic crop production.Mehlich-3 is often used as a multi-nutrient extractant to determine soil fertility status.A study inves-tigated the impacts of the conservation practices of gypsum,cover crops,and crop rotation on 28 Mehlich-3 extractable elements,of which 11 were considered plant nutrients,from soil at three mid-western US locations.Soil was collected from 0 to 15 and 15-30 cm depths 5 years after implementing the conservation practices.Treatments consisted of(1)with and without cereal rye(Secale cereale L.)winter cover,(2)continuous soybean[Glycine max(L.)Merr.]vs.soybean-corn(Zea mays L.)rotation,and(3)annual gypsum application(0,1.1,and 2.2 Mg ha-1).Differences were observed by site,depth,and conservation practice depending on the element evaluated.Minimal interactive effects were observed among treatments.The most consistent effect was observed for crop rotation across sites.Gypsum only affected the site with the greatest clay content,where more Ca and S were retained,and Mg and Mn displaced.Cover crop only affected elements at this high clay site,where different elements were positively or negatively affected.Results suggest that not one practice fits all,and optimum conservation practices must be tailored for the site.展开更多
To observe the availability of phosphorus by different extraction methods in some cultivated soils of Hathazari Upazilla of Chittagong District, this study was carried out with 36 surface soil samples (0 - 15 cm) belo...To observe the availability of phosphorus by different extraction methods in some cultivated soils of Hathazari Upazilla of Chittagong District, this study was carried out with 36 surface soil samples (0 - 15 cm) belonging to six soil series, namely Bijipur, Pahartali, Mirsarai, Manu, Raojan and Noapara. Physical and chemical characteristics of the soils were also determined with an objective of identifying the soil factor(s) regulating P extractability. Three P extraction methods, namely Olsen (0.5 M NaHCO3, pH 8.5), Mehlich-3 (0.2 N CH3COOH + 0.013 N HNO3 + 0.015 N NH4F + 0.25 N NH4 NO3 + 0.001 M EDTA) and Bray & Kurtz-1 (0.03 N NH4F + 0.025 N HCl) were used. There was a wide variation in the extractability of P ranging from low to high categories. Olsen method extracted the largest amount of P (2.07 - 45.36 mg·kg-1) while Bray & Kurtz-1 extracted the smallest amount (1.02 - 21.79 mg·kg-1). The mean extractable P in soils was found to be in the order of Olsen > Mehlich-3 > Bray & Kurtz-1. Soil pH was the most dominant factor in determining P extractability. Available P was negatively correlated with percentage of clay, organic carbon and CEC and positively correlated with pH. Although the three methods extracted different amounts of P from soil, values of P extracted by the different methods were strongly correlated among themselves and with the leaf phosphorus concentration of rice growing in these soils.展开更多
The objective of this study was to evaluate the effect of potassium (K) fertilization rate (0, 27.9, 56.4, 84.7, 112.9, and 141.1 kg K/ha) and cotton (Gossypium hirsutumn L.) cultivars of slightly differing maturity o...The objective of this study was to evaluate the effect of potassium (K) fertilization rate (0, 27.9, 56.4, 84.7, 112.9, and 141.1 kg K/ha) and cotton (Gossypium hirsutumn L.) cultivars of slightly differing maturity on seedcotton yield and Mehlich-3 soil-test K concentrations. The cotton cultivars “Stoneville 4892” and “Stoneville 5599” represented long-season cultivars while “Paymaster 1218” and “Deltapine 444” represented early-season cultivars. The same K fertilizer treatments were applied to the same plots during the three years of the study. Higher order interactions of cropping year, cotton cultivar and K-fertilization rates were not significant (P ≥ 0.50), indicating the two cultivars of slightly different maturity respond similarly to K-fertilization. Cropping year and K-fertilizer application rates significantly affected seedcotton yield (P P ≤ 0.0074), as well as 3-year average, and total seedcotton yields (P ≤ 0.0006). Seedcotton yields ranged from 3418 to 4127 kg·ha-1 and 2980 to 3487 kg·ha-1 in the second and third year respectively while 3-year average and total seedcotton yields were 2943 to 3443 and 8832 to 10,330 kg·ha-1. The relation between annual, 3-year average, and total K application rates and seedcotton yield was linear (R2 ≥ 0.82, P ≤ 0.0125). Potassium fertilization significantly increased post-harvest (fall) Mehlich-3 extractable soil K in all three years (P ≤ 0.0002). This study indicated that, in a representative Mississippi River Delta silt loam soil, when Mehlich-3 extractable K was -1, K fertilization was needed to increase seedcotton yield and prevent soil K depletion. This supports the current University of Arkansas fertilizer recommendations for irrigated cotton production, where application of 56 kg of K ha-1 is recommended to optimize seedcotton yield and prevent soil K reserve depletion when Mehlich-3 extractable soil test K is medium (91 - 130 mg/kg).展开更多
Sustainable agricultural practices have been steadily increasing in the last couple of decades. These management practices frequently involve cover crops, less or no-tillage, and organic fertilization. In this study, ...Sustainable agricultural practices have been steadily increasing in the last couple of decades. These management practices frequently involve cover crops, less or no-tillage, and organic fertilization. In this study, we evaluated the effects of cropping systems,tillage and no-tillage, and the application of poultry litter(PL) on selected soil physicochemical properties and soil test nutrients. Soil samples were collected from the topmost surface(0–5 cm) and subsurface(5–10 cm) layers. The general effect trend was PL application > no-tillage > cover crop > cropping type. There were more statistically significant(P ≤ 0.05) correlations between the 18 soil attributes at the topmost surface than at the subsurface. This could be due to the accumulation of external C inputs and nutrients by crop residues and PL application as well as the retaining effects of no-tillage on less mobile nutrient components. Because of their high mobility and volatile nature, total nitrogen(N), ammonia-N(NH_4^+-N), and nitrate-N(NO_3^--N) levels varied greatly(high standard deviations), showing no consistent patterns among the treatments. Compared to the soybean cropping system, corn, especially with the wheat cover crop, contributed more to the total carbon(C) and sulfur(S) in the topmost surface soils(0–5 cm). Poultry litter application greatly increased pH, cation exchange capacity(CEC), base saturation, magnesium(Mg), phosphorus(P), calcium(Ca),sodium(Na), potassium(K), manganese(Mn), copper(Cu), and zinc(Zn) in both soil layers. Contrast comparisons revealed that PL application had more of an effect on these soil chemical properties than no-tillage and cropping systems. These results will shed light on developing better nutrient management practices while reducing their runoff potentials.展开更多
The determination of available phosphorus(P)in soil is essential to the evaluation of the current fertility status,and therefore,for recommending the required phosphate fertilizers for the cultivation of crops.The mos...The determination of available phosphorus(P)in soil is essential to the evaluation of the current fertility status,and therefore,for recommending the required phosphate fertilizers for the cultivation of crops.The mostly used extractants around the country are Mehlich-1(M-1)and anionic resins(AR)and mixed resins(MR).However,there are still controversies in relation to the method that should be used,due to of particularities of each extractor.Therefore,the main objectives of this work was to assess the applicability of films of binary combination between cellulose acetate(CA)biopolymer and calcinated layered double hydroxide(LDH-c),named CAF-LDH-c,as a new extractor of available P in soils.For this,two experiments were set out.In the first one,sub-samples of an Oxisol layer 0-20 cm were used and submitted to increasing doses of total P(0,250,750 and 2,250 mg/dm3)in the form of monoammonium phosphate(MAP)at different incubation time(5,30,60 and 90 d).In the second experiment,samples of 20 soils from different origins and contents of available P were used with distinct chemical and physical attributes.The analysis of available P by M-1,AR,MR,Mehlich-3(M-3)and CAF-LDH-c extractants was done in both experiments.The efficiency of the extractants was evaluated by Pearson’s linear correlation.The correlation between values of P extracted from soil in the first experiment was highly significant among all extraction methods used,including for CAF-LDH-c.In the second experiment,CAF-LDH-c showed significant correlation(p<0.01)with M-1,M-3,AR and MR.Thus,the significant correlations of the extractant being tested(CAF-LDH-c)with those usually used indicates the possibility of this new method of routine laboratories for assessing the P availability of for the cultivation of crops.展开更多
基金support provided by United Soybean Board Project Number 1520-732-7226by state and federal funds appropriated to The Ohio State University and The Ohio Agricultural Research and Development Center。
文摘Conservation practices are encouraged to improve soil health and sustain agronomic crop production.Mehlich-3 is often used as a multi-nutrient extractant to determine soil fertility status.A study inves-tigated the impacts of the conservation practices of gypsum,cover crops,and crop rotation on 28 Mehlich-3 extractable elements,of which 11 were considered plant nutrients,from soil at three mid-western US locations.Soil was collected from 0 to 15 and 15-30 cm depths 5 years after implementing the conservation practices.Treatments consisted of(1)with and without cereal rye(Secale cereale L.)winter cover,(2)continuous soybean[Glycine max(L.)Merr.]vs.soybean-corn(Zea mays L.)rotation,and(3)annual gypsum application(0,1.1,and 2.2 Mg ha-1).Differences were observed by site,depth,and conservation practice depending on the element evaluated.Minimal interactive effects were observed among treatments.The most consistent effect was observed for crop rotation across sites.Gypsum only affected the site with the greatest clay content,where more Ca and S were retained,and Mg and Mn displaced.Cover crop only affected elements at this high clay site,where different elements were positively or negatively affected.Results suggest that not one practice fits all,and optimum conservation practices must be tailored for the site.
文摘To observe the availability of phosphorus by different extraction methods in some cultivated soils of Hathazari Upazilla of Chittagong District, this study was carried out with 36 surface soil samples (0 - 15 cm) belonging to six soil series, namely Bijipur, Pahartali, Mirsarai, Manu, Raojan and Noapara. Physical and chemical characteristics of the soils were also determined with an objective of identifying the soil factor(s) regulating P extractability. Three P extraction methods, namely Olsen (0.5 M NaHCO3, pH 8.5), Mehlich-3 (0.2 N CH3COOH + 0.013 N HNO3 + 0.015 N NH4F + 0.25 N NH4 NO3 + 0.001 M EDTA) and Bray & Kurtz-1 (0.03 N NH4F + 0.025 N HCl) were used. There was a wide variation in the extractability of P ranging from low to high categories. Olsen method extracted the largest amount of P (2.07 - 45.36 mg·kg-1) while Bray & Kurtz-1 extracted the smallest amount (1.02 - 21.79 mg·kg-1). The mean extractable P in soils was found to be in the order of Olsen > Mehlich-3 > Bray & Kurtz-1. Soil pH was the most dominant factor in determining P extractability. Available P was negatively correlated with percentage of clay, organic carbon and CEC and positively correlated with pH. Although the three methods extracted different amounts of P from soil, values of P extracted by the different methods were strongly correlated among themselves and with the leaf phosphorus concentration of rice growing in these soils.
文摘The objective of this study was to evaluate the effect of potassium (K) fertilization rate (0, 27.9, 56.4, 84.7, 112.9, and 141.1 kg K/ha) and cotton (Gossypium hirsutumn L.) cultivars of slightly differing maturity on seedcotton yield and Mehlich-3 soil-test K concentrations. The cotton cultivars “Stoneville 4892” and “Stoneville 5599” represented long-season cultivars while “Paymaster 1218” and “Deltapine 444” represented early-season cultivars. The same K fertilizer treatments were applied to the same plots during the three years of the study. Higher order interactions of cropping year, cotton cultivar and K-fertilization rates were not significant (P ≥ 0.50), indicating the two cultivars of slightly different maturity respond similarly to K-fertilization. Cropping year and K-fertilizer application rates significantly affected seedcotton yield (P P ≤ 0.0074), as well as 3-year average, and total seedcotton yields (P ≤ 0.0006). Seedcotton yields ranged from 3418 to 4127 kg·ha-1 and 2980 to 3487 kg·ha-1 in the second and third year respectively while 3-year average and total seedcotton yields were 2943 to 3443 and 8832 to 10,330 kg·ha-1. The relation between annual, 3-year average, and total K application rates and seedcotton yield was linear (R2 ≥ 0.82, P ≤ 0.0125). Potassium fertilization significantly increased post-harvest (fall) Mehlich-3 extractable soil K in all three years (P ≤ 0.0002). This study indicated that, in a representative Mississippi River Delta silt loam soil, when Mehlich-3 extractable K was -1, K fertilization was needed to increase seedcotton yield and prevent soil K depletion. This supports the current University of Arkansas fertilizer recommendations for irrigated cotton production, where application of 56 kg of K ha-1 is recommended to optimize seedcotton yield and prevent soil K reserve depletion when Mehlich-3 extractable soil test K is medium (91 - 130 mg/kg).
文摘Sustainable agricultural practices have been steadily increasing in the last couple of decades. These management practices frequently involve cover crops, less or no-tillage, and organic fertilization. In this study, we evaluated the effects of cropping systems,tillage and no-tillage, and the application of poultry litter(PL) on selected soil physicochemical properties and soil test nutrients. Soil samples were collected from the topmost surface(0–5 cm) and subsurface(5–10 cm) layers. The general effect trend was PL application > no-tillage > cover crop > cropping type. There were more statistically significant(P ≤ 0.05) correlations between the 18 soil attributes at the topmost surface than at the subsurface. This could be due to the accumulation of external C inputs and nutrients by crop residues and PL application as well as the retaining effects of no-tillage on less mobile nutrient components. Because of their high mobility and volatile nature, total nitrogen(N), ammonia-N(NH_4^+-N), and nitrate-N(NO_3^--N) levels varied greatly(high standard deviations), showing no consistent patterns among the treatments. Compared to the soybean cropping system, corn, especially with the wheat cover crop, contributed more to the total carbon(C) and sulfur(S) in the topmost surface soils(0–5 cm). Poultry litter application greatly increased pH, cation exchange capacity(CEC), base saturation, magnesium(Mg), phosphorus(P), calcium(Ca),sodium(Na), potassium(K), manganese(Mn), copper(Cu), and zinc(Zn) in both soil layers. Contrast comparisons revealed that PL application had more of an effect on these soil chemical properties than no-tillage and cropping systems. These results will shed light on developing better nutrient management practices while reducing their runoff potentials.
文摘The determination of available phosphorus(P)in soil is essential to the evaluation of the current fertility status,and therefore,for recommending the required phosphate fertilizers for the cultivation of crops.The mostly used extractants around the country are Mehlich-1(M-1)and anionic resins(AR)and mixed resins(MR).However,there are still controversies in relation to the method that should be used,due to of particularities of each extractor.Therefore,the main objectives of this work was to assess the applicability of films of binary combination between cellulose acetate(CA)biopolymer and calcinated layered double hydroxide(LDH-c),named CAF-LDH-c,as a new extractor of available P in soils.For this,two experiments were set out.In the first one,sub-samples of an Oxisol layer 0-20 cm were used and submitted to increasing doses of total P(0,250,750 and 2,250 mg/dm3)in the form of monoammonium phosphate(MAP)at different incubation time(5,30,60 and 90 d).In the second experiment,samples of 20 soils from different origins and contents of available P were used with distinct chemical and physical attributes.The analysis of available P by M-1,AR,MR,Mehlich-3(M-3)and CAF-LDH-c extractants was done in both experiments.The efficiency of the extractants was evaluated by Pearson’s linear correlation.The correlation between values of P extracted from soil in the first experiment was highly significant among all extraction methods used,including for CAF-LDH-c.In the second experiment,CAF-LDH-c showed significant correlation(p<0.01)with M-1,M-3,AR and MR.Thus,the significant correlations of the extractant being tested(CAF-LDH-c)with those usually used indicates the possibility of this new method of routine laboratories for assessing the P availability of for the cultivation of crops.
