Decision Support Tool(DST)enables farmers to make site-specific crop management decisions;however,comprehensive calibration can be both costly and time-consuming.This study assessed the production and economic benefit...Decision Support Tool(DST)enables farmers to make site-specific crop management decisions;however,comprehensive calibration can be both costly and time-consuming.This study assessed the production and economic benefits of two calibrations of the Nutrient Expert(NE)tool for rice in Sri Lanka’s Alfisols:the basic calibration(Nutrient Expert Sri Lanka 1,NESL1)and the comprehensive calibration(Nutrient Expert Sri Lanka 2,NESL2).NESL1 was developed by adapting the South Indian version of NE to local conditions,while NESL2 was an updated version,using three years of data from 71 farmer fields.展开更多
Surface charge, secondary adsorption- desorption and form distribution of Cu2+ and Zn2+ in Ultisols and Alfisols having adsorbed phosphate were studied by potentiometric titration, adsorption equilibrium and sequentia...Surface charge, secondary adsorption- desorption and form distribution of Cu2+ and Zn2+ in Ultisols and Alfisols having adsorbed phosphate were studied by potentiometric titration, adsorption equilibrium and sequential extraction method, respectively. The soil surface negative charges increased whereas the amount of positive charges decreased with increase of P adsorbed. The soil secondary adsorption capacity for Cu2+ and Zn2+ was positively significantly correlated with the amount of P adsorbed by the soils, which could be described by the Langmuir equation. The amounts of Cu2+ and Zn2+ desorption from soils were decreased after P adsorption by the soils and the relationship between them was linear. After the soils adsorbed P, form distribution of Cu2+ and Zn2+ in soils changed remarforbly.展开更多
Returning crop straw to the field not only improves the nitrogen(N) supplying capacity and N retention of soil but also decreases the amount of rural organic waste and prevents air pollution. Therefore, understanding ...Returning crop straw to the field not only improves the nitrogen(N) supplying capacity and N retention of soil but also decreases the amount of rural organic waste and prevents air pollution. Therefore, understanding the mechanisms of the N release and re-adsorption dynamics on crop straw residue during straw decomposition in agricultural soil is important, and this understanding can help us strengthen N fertilizer management during the crop growth period. An on-farm incubation experiment was conducted in the Jianghan Plain in Central China under flooded conditions using the nylon mesh bag method. Results showed that the decomposition rate of crop straw was much faster at the beginning of the incubation stage, whereas it was steady during the later stage with no observed differences among the three types of crop straw. After 120 d of incubation, the cumulative decomposition proportion of rice straw, wheat straw and rape straw was 72.9, 56.2, and 66.9%, respectively. The proportion of N that released from the three crop straws was 52.0, 54.4 and 54.9%, respectively. The zeta potentials and Brunauer, Emmett and Teller(BET) surface area of the rice, wheat and rape straw residues increased gradually as the decomposition period progressed. The water adsorption capacity of the rice straw was significantly affected during the decomposition period. The saturated water adsorption capacity of rice straw was the highest at 30 d of decomposition(4.17 g g^–1) and then decreased slightly. The saturated water adsorption of wheat and rape straws reached the lowest value at 30 d and then gradually increased and became stable. All the results demonstrated that crop straw and straw residue can re-adsorb NH4^+ ions from the surrounding solution. The re-adsorption was affected by the decomposition period and concentration of exogenous NH4^+ and was independent of the crop species via the combined efforts of physical and chemical adsorption, ion exchange and water retention on residue surfaces. Future studies will focus on straw returning and N fertilizer application at different levels of moisture content of the soil reduce potential negative effects such as water-logging and excess N caused by the straw substrate.展开更多
Two Inceptisols and an Alfisol of the Indravati Catchment area in Chattisgarh, India, comprising several gradientsin physical and chemical properties were studied to relate phosphate sorption and desorption to soil pr...Two Inceptisols and an Alfisol of the Indravati Catchment area in Chattisgarh, India, comprising several gradientsin physical and chemical properties were studied to relate phosphate sorption and desorption to soil properties. Fromthe P isotherm curve, the standard P requirement (SPR) of the soils was determined. Phosphate sorption data were alsofitted both to the Langmuir and Freundlich Equations. The mean sorption maximum values for three different soil serieswere: Bastar > Geedam > Mosodi. The fraction of added phosphate sorbed for the 3 series followed this same trend asdid SPR; the phosphate sorption maximum and the maximum phosphate buffering capacity, which were estimated by theLangmuir isotherm; and the Freundlich constant 1/n. However, phosphate desorption, as well as the maximum recoverypercent did not follow this order. The phosphate affinity constant (K) was also different following the same progressionfor the 3 soil series as the Freundlich constant K’, which measured sorption strength. Meanwhile, an inverse order existedfor K and K’ versus the percent desorbed relative to the sorbed as well as the maximum recovery percent. In addition,significant correlation coefficients among sorption parameters of P and soil factors were found.展开更多
Alfisols in USA taxonomy are “deciduous forest” soils having an argillic horizon with a base saturation in the control section greater than 35%. Alfisols are geographically extensive and support productive agricultu...Alfisols in USA taxonomy are “deciduous forest” soils having an argillic horizon with a base saturation in the control section greater than 35%. Alfisols are geographically extensive and support productive agriculture and deciduous forest ecosystems. Understanding Alfisol genesis, including the presence and intensity of the dominant soil processes, facilitates best management practices that provide stewardship for these soil resources and improves forest and agriculture productivity. Four Alfisols, presently having mature forest settings and located in the central United States along the Mississippi River, were selected for soil and landscape description, classification, and delineation of the dominant soil forming processes. Excavated soils were described and routinely sampled for subsequent physical, chemical, and mineralogical analysis. An aqua regia digestion protocol provided elemental analysis for identifying and inferring the intensity of soil forming processes. The dominant soil forming factors include 1) organic matter accumulation, 2) clay eluviation-illuviation, 3) acidification, 4) base cation accumulation in the A horizons by the forest vegetation, 5) Fe-oxyhydroxide formation, and 6) clay mineral synthesis. Two soils were developed entirely in Peoria loess and two soils were developed in Peoria Loess overlying Ordovician limestone residuum. Ecological site descriptions provide land managers information for evaluating land suitability and the capability to implement different management activities without ecosystem disturbance. Best management practices for the described landforms and based on their Ecological Site Descriptions are presented.展开更多
The role of maize-legume cropping system on soil quality, carbon sequestration and yield of maize in a Northern Guinea Savanna Alfisol, Nigeria was assessed in 2014 and 2015 rain-fed cropping seasons. The experiment w...The role of maize-legume cropping system on soil quality, carbon sequestration and yield of maize in a Northern Guinea Savanna Alfisol, Nigeria was assessed in 2014 and 2015 rain-fed cropping seasons. The experiment was a Randomized Complete Block Design (RCBD), replicated three times and treatments were Sole (Mono crop) Maize (M), Desmodium (D) and Soybeans (S);Maize/soybeans intercrop (MS), Maize/Desmodium intercrop (MD), Maize Strip cropped with Soybean (MS 2:4) and Maize Strip cropped with Desmodium (M:D 2:4). Data obtained were evaluated for Organic carbon, available phosphorus, total nitrogen, soil pH, and CEC, Bulk density, Soil moisture, mean weight diameter and grain yield of Maize. Results show that mean soil acidity (pH water, 6.37;pH CaCl2, 5.78), mean organic carbon (5.23 to 5.69 g·kg-1) and mean total nitrogen improved (0.66 g·kg-1) in 2015 over values in 2014. Mean weight diameter (MWD) increased from 0.59 in 2014 to 1.05 in 2015;indicating a better aggregation across treatments. Treatment M resulted in significantly higher bulk density (Bd) than other treatments at 8 weeks after planting (WAP) and 16WAP, suggesting that soils under mono-crop maize were impaired for sustainable crop production. Soil organic carbon (SOC) sequestered in macro aggregates under MS (1.38 g·kg-1) was significantly higher than the other treatments. Best maize grain yield (GY) was under sole maize (M) and maize strip cropped with Desmodium (MD2:4) (3.13 t·ha-1 and 2.90 t·ha-1 in 2015, respectively). Maize strip cropped with Desmodium and maize/soybean intercrop enhanced better soil chemical and physical properties than sole maize. Soil quality (SQ) under MD2:4 ranked best (SQ1) for sustainable maize grain production and environmental conservation. Therefore, land use strategies that focus protection of soil organic carbon against further depletion and erosion, contribute nitrogen and/or replenishment of depleted carbon stocks through management techniques that involve legume/cereal cropping systems are advocated for sustainable agricultural production in the Nigerian Savanna zone Alfisols.展开更多
Lime and coal flying ash applications could mitigate pollution from acid deposition and improve the buffering ability of two acidic soils sampled from Zhejiang Province. The results showed that soil alkalinity and aci...Lime and coal flying ash applications could mitigate pollution from acid deposition and improve the buffering ability of two acidic soils sampled from Zhejiang Province. The results showed that soil alkalinity and acidified buffering capacities (QpHs ) were significantly increased, especially for liming treatment; whereas, the amounts of SO24- adsorbed by treated soils were decreased to some degrees because net negative charges of soil oxide colloidal surfaces were increased with the decrease in soil acidity, although the soil fixation abilities for adsorbed SO24- were not reduced. These facts indicated that after the alkaline ameliorators were applied, the positive and adverse effects resulted from sulfate-type acid deposition were simultaneously existed in these soil treatments.展开更多
Alfisols are important soils in China.They occupy about 1.25 million km^(2),or about 13%of the land area.In the current Chinese system of soil classification,burozem,yellow-brown earths,Baijiang(Planosol)soils and par...Alfisols are important soils in China.They occupy about 1.25 million km^(2),or about 13%of the land area.In the current Chinese system of soil classification,burozem,yellow-brown earths,Baijiang(Planosol)soils and parts of drab soils.They are mostly forested soils with an estimated 5-13 t/ha·yr of organic matter returned to the soils from temperate mixed conifer and broad-leaved forest.In terms of elemental bio-cycling,Ca is prominent.In a comparison of 30 profiles the average ratio of clay(B/A)was 1.47 for Cryoboralfs and Eutroboralfs;1.88 for Hapludaifs and 2.53 for Paleudalfs.From Eutroboralfs to Paleudalfs the average gain(or loss)in clay during soil development is about a factor of seven.The moisture regimes vary considerably between Hapludaifs,Cryoboralfs,and associated Cryaquepts,but the amount of water is always enough to cause significant leaching.In the weathering,and pedogenesis processes TiO_(2),MgO and Fe_(2)O_(3) are accumulated,respectively,in both A and BA horizons;but SiO_(2) and Al_(2)O_(3) tend to be leached from the solum.展开更多
In the semi-arid tropics (SAT),33% areas are occupied by Alfisols and related soils. In SAT these soils have low structural stability and thereby tend to form seal and crusts at the surface. Due to this a large propor...In the semi-arid tropics (SAT),33% areas are occupied by Alfisols and related soils. In SAT these soils have low structural stability and thereby tend to form seal and crusts at the surface. Due to this a large proportion of the rain that falls on Alfisols during the early part of the rainy season,is normally lost as runoff thus causing high soil loss as well as moisture stress to crops. Two tillage studies were conducted first at plot scale (320 m2) during 1991-95 and second at small watershed scale (1.45 ha) during 2007-10,at ICRISAT research station,Hyderabad,India. These studies were conducted to find out whether the problem of excessive runoff and soil loss during the early part of the rainy season can be controlled by various inter-row tillage systems in addition to normal intercultivation by breaking the crust or seal and thereby improving infiltration and soil moisture and reducing runoff and soil loss. The observations on rainfall,runoff,soil moisture,soil loss,soil surface roughness and crop yields were collected from both the studies. Results from these studies have shown that inter-row tillage in addition to normal intercultivation is found effective in controlling early season runoff and soil loss and increasing crop yields. The additional tillage systems are found most effective during low and medium rainfall years and not so much during high rainfall years. The additional tillage with shoe cultivators,which creates rough soil surface (11 mm depression storage),is found most effective in increasing crop yields and reducing runoff and soil loss. The additional tillage with blade harrow which generates smooth soil surface is relatively less effective. In most rainfall conditions,the normal intercultivation with one additional tillage is found adequate for controlling early season runoff and improving soil moisture and crop yields.展开更多
Studies on Soil Test Crop Response Based Integrated Plant Nutrition System(STCR-IPNS)were conducted for three years adopting the Inductive cum Targeted Yield Model,on alfisols of Unified Andhra Pradesh,Southern India ...Studies on Soil Test Crop Response Based Integrated Plant Nutrition System(STCR-IPNS)were conducted for three years adopting the Inductive cum Targeted Yield Model,on alfisols of Unified Andhra Pradesh,Southern India during summer 2016-2018 in order to develop fertilizer prescriptions through IPNS for the desired yield targets of Sesamum under field conditions.The bases for making the fertilizer prescriptions viz.nutrient requirement(NR),contribution of nutrients from soil(Cs),fertilizer(Cf)and vermicompost(CVC)were computed using the field experimental data.Making use of these basic parameters,the fertilizer prescription equations were developed under NPK alone and under IPNS for the desired yield targets of Sesamum for a range of soil test values.The quantity of fertilizers contributed by the application of vermicompost was assessed.Nutrient requirement to produce 100 kg of sesame seed was worked out to be 10.20 kg N,3.90 kg P2O5 and 5.22 kg K2O.In the present investigation,the requirement of N was higher which is followed by K2O and P2O5.The requirement of N was 2.62 times higher than P and 1.95 times higher than K.The percent contribution of N,P and K was 12.25,15.75 and 6.00 from soils,41.68,22.85 and 59.97 from fertilizer and 9.87,6.74 and 18.65 from organic manures,respectively.Thus the Inductive cum Targeted Yield Model used to develop fertilizer prescription equations provides a strong basis for soil fertility maintenance consistent with high productivity and efficient nutrient management in farming for sustainable and enduring agriculture.展开更多
The residual effect of organic and mineral fertilizers on selected chemical properties of an Alfisol in the long term soil fertility trial established in 1950 at Samaru, Nigerian savanna was assessed. The trial was le...The residual effect of organic and mineral fertilizers on selected chemical properties of an Alfisol in the long term soil fertility trial established in 1950 at Samaru, Nigerian savanna was assessed. The trial was left fallow for fourteen years due to lack of funds. Topsoil was collected from plots that received three levels of cow dung （D）, nitrogen （N） and phosphorus （P） in all possible combinations. The soils were analyzed for selected chemical properties. Except for significant effect of applied P on available P, sole application of cow dung, N or P had no significant effect on all the measured soil properties. The interaction of D and P significantly affected the mean values of exchangeable Ca, Mg, K and ECEC in the range of 1.12-1.96, 0.62-1.11, 0.37-0.64 and 2.82-4.11 cmol/kg respectively. The most important results were the ability of the plot that received neither D nor P to significantly increase these parameters than the plots that received only one of the treatments. The results show that the fallow period has changed the effects of application of organic and mineral fertilizers on the soil chemical properties under continuous cultivation by modifying them towards those of a native savanna Alfisol.展开更多
Bisequal soils in northern Wisconsin were described and characterized with the intent to determine if a near total elemental analysis protocol may estimate the effect of selected soil pedogenic pathways on soil morpho...Bisequal soils in northern Wisconsin were described and characterized with the intent to determine if a near total elemental analysis protocol may estimate the effect of selected soil pedogenic pathways on soil morphology. The protocol reveals that gross elemental soil profile distributions do provide evidence that certain pedogenic processes are operating within a group of soils. Concentration differences between instrumental neutron activation analysis and an aqua regia digestion protocol infer that alkali metals, alkaline earth metals, transition metals and the rare earth elements are only incompletely weathered from primary minerals. Transition metals, alkali metals, alkaline earths, metalloids, and the rare earth elements all show inter-horizon mobility. Lessivage and the mobility of elements presumably adsorbed on soluble or suspended organic materials are the dominant soil processes influencing the soil profile redistribution of elements and the majority of these elements are shown to correlate with the soil profile distribution of Fe. Base cycling by the forest vegetation was shown to support A horizon enrichment of Ca, Sr, Ba, P, S, Mn, Zn, Sn and Pb. For clinical practice, elemental analysis may reveal important soil profile elemental differences when applied to variation of one soil forming factors, such as a chronosequence or toposequence within a landscape or soil association. Advantages and limitations of the protocol in identifying pedogenic pathways are discussed.展开更多
A major nutritional problem to crops grown in highly weathered Brazilian soils is phosphorus (P) deficiencies linked to their low availability and the capacity of the soils to fix P in insoluble forms. Our studies exa...A major nutritional problem to crops grown in highly weathered Brazilian soils is phosphorus (P) deficiencies linked to their low availability and the capacity of the soils to fix P in insoluble forms. Our studies examined factors that might influence P behavior in soils of the Amazon region. This study was conducted to evaluate the maximum phosphate adsorption capacity (MPAC) of the soils developed from mafic rocks (diabase), their parent materials and other factors resulting in the formation of eutrophic soils having A chernozemic horizon associated with Red Nitosols (Alfisol) and Red Latosols (Oxisol) of the Amazonian environment. The MPAC was determined in triplicates as a function of the remnant P values. The different concentrations used to determine the MPAC allowed maximum adsorption values to be reached for all soils. The Latosol (Oxisol) and Nitosol (Alfisol) soils presented higher phosphate adsorption values that were attributed to the oxidic mineralogy and high clay texture while the Chernosol (Mollisol) soils presented the lowest phosphate adsorption values.展开更多
Soil morphological, physical and chemical properties are described at four locations along an elevational transect in the northeastern part of the Moldavian Plateau (Romania). These data contribute to the knowledge of...Soil morphological, physical and chemical properties are described at four locations along an elevational transect in the northeastern part of the Moldavian Plateau (Romania). These data contribute to the knowledge of the soils of this area and to their classification according to the USDA-Soil Taxonomy, FAOWRB and the SRTS-Romanian System. The soils were classified as Inceptisols, Alfisols and Mollisols, according to the USDA-Soil Taxonomy;Gleysol, Chernozem and Luvisol, according to the FAO-WRB and Gleiosol, Cernoziom, Preluvosol, Luvosol, according to the SRTS-Romanian System. The selected soils have a range of properties that represent the soilscape of the Moldavian subcarpathian plateau, characterised by a natural forest with oak as the dominant species. The selected soil parameters decreased with increasing elevation;calcium carbonate and clay leaching and accumulation are the main soil formation processes.展开更多
基金supported by the National Research Council of Sri Lanka(Grant No.NRC TO 16-07).
文摘Decision Support Tool(DST)enables farmers to make site-specific crop management decisions;however,comprehensive calibration can be both costly and time-consuming.This study assessed the production and economic benefits of two calibrations of the Nutrient Expert(NE)tool for rice in Sri Lanka’s Alfisols:the basic calibration(Nutrient Expert Sri Lanka 1,NESL1)and the comprehensive calibration(Nutrient Expert Sri Lanka 2,NESL2).NESL1 was developed by adapting the South Indian version of NE to local conditions,while NESL2 was an updated version,using three years of data from 71 farmer fields.
基金Project (No. 49871043) supported by the National Natural Science Foundation of China.
文摘Surface charge, secondary adsorption- desorption and form distribution of Cu2+ and Zn2+ in Ultisols and Alfisols having adsorbed phosphate were studied by potentiometric titration, adsorption equilibrium and sequential extraction method, respectively. The soil surface negative charges increased whereas the amount of positive charges decreased with increase of P adsorbed. The soil secondary adsorption capacity for Cu2+ and Zn2+ was positively significantly correlated with the amount of P adsorbed by the soils, which could be described by the Langmuir equation. The amounts of Cu2+ and Zn2+ desorption from soils were decreased after P adsorption by the soils and the relationship between them was linear. After the soils adsorbed P, form distribution of Cu2+ and Zn2+ in soils changed remarforbly.
基金supported by the National Key Research & Development Program of China (2018YFD0200900)the Young and Middle-Aged Talents Project of Hubei Provincial Department of Education, China (Q20181303)the Open Fund of Key Laboratory of Fertilizer Utilization, Ministry of Agriculture and Rural Affairs, China (KLFAW201901)。
文摘Returning crop straw to the field not only improves the nitrogen(N) supplying capacity and N retention of soil but also decreases the amount of rural organic waste and prevents air pollution. Therefore, understanding the mechanisms of the N release and re-adsorption dynamics on crop straw residue during straw decomposition in agricultural soil is important, and this understanding can help us strengthen N fertilizer management during the crop growth period. An on-farm incubation experiment was conducted in the Jianghan Plain in Central China under flooded conditions using the nylon mesh bag method. Results showed that the decomposition rate of crop straw was much faster at the beginning of the incubation stage, whereas it was steady during the later stage with no observed differences among the three types of crop straw. After 120 d of incubation, the cumulative decomposition proportion of rice straw, wheat straw and rape straw was 72.9, 56.2, and 66.9%, respectively. The proportion of N that released from the three crop straws was 52.0, 54.4 and 54.9%, respectively. The zeta potentials and Brunauer, Emmett and Teller(BET) surface area of the rice, wheat and rape straw residues increased gradually as the decomposition period progressed. The water adsorption capacity of the rice straw was significantly affected during the decomposition period. The saturated water adsorption capacity of rice straw was the highest at 30 d of decomposition(4.17 g g^–1) and then decreased slightly. The saturated water adsorption of wheat and rape straws reached the lowest value at 30 d and then gradually increased and became stable. All the results demonstrated that crop straw and straw residue can re-adsorb NH4^+ ions from the surrounding solution. The re-adsorption was affected by the decomposition period and concentration of exogenous NH4^+ and was independent of the crop species via the combined efforts of physical and chemical adsorption, ion exchange and water retention on residue surfaces. Future studies will focus on straw returning and N fertilizer application at different levels of moisture content of the soil reduce potential negative effects such as water-logging and excess N caused by the straw substrate.
文摘Two Inceptisols and an Alfisol of the Indravati Catchment area in Chattisgarh, India, comprising several gradientsin physical and chemical properties were studied to relate phosphate sorption and desorption to soil properties. Fromthe P isotherm curve, the standard P requirement (SPR) of the soils was determined. Phosphate sorption data were alsofitted both to the Langmuir and Freundlich Equations. The mean sorption maximum values for three different soil serieswere: Bastar > Geedam > Mosodi. The fraction of added phosphate sorbed for the 3 series followed this same trend asdid SPR; the phosphate sorption maximum and the maximum phosphate buffering capacity, which were estimated by theLangmuir isotherm; and the Freundlich constant 1/n. However, phosphate desorption, as well as the maximum recoverypercent did not follow this order. The phosphate affinity constant (K) was also different following the same progressionfor the 3 soil series as the Freundlich constant K’, which measured sorption strength. Meanwhile, an inverse order existedfor K and K’ versus the percent desorbed relative to the sorbed as well as the maximum recovery percent. In addition,significant correlation coefficients among sorption parameters of P and soil factors were found.
文摘Alfisols in USA taxonomy are “deciduous forest” soils having an argillic horizon with a base saturation in the control section greater than 35%. Alfisols are geographically extensive and support productive agriculture and deciduous forest ecosystems. Understanding Alfisol genesis, including the presence and intensity of the dominant soil processes, facilitates best management practices that provide stewardship for these soil resources and improves forest and agriculture productivity. Four Alfisols, presently having mature forest settings and located in the central United States along the Mississippi River, were selected for soil and landscape description, classification, and delineation of the dominant soil forming processes. Excavated soils were described and routinely sampled for subsequent physical, chemical, and mineralogical analysis. An aqua regia digestion protocol provided elemental analysis for identifying and inferring the intensity of soil forming processes. The dominant soil forming factors include 1) organic matter accumulation, 2) clay eluviation-illuviation, 3) acidification, 4) base cation accumulation in the A horizons by the forest vegetation, 5) Fe-oxyhydroxide formation, and 6) clay mineral synthesis. Two soils were developed entirely in Peoria loess and two soils were developed in Peoria Loess overlying Ordovician limestone residuum. Ecological site descriptions provide land managers information for evaluating land suitability and the capability to implement different management activities without ecosystem disturbance. Best management practices for the described landforms and based on their Ecological Site Descriptions are presented.
文摘The role of maize-legume cropping system on soil quality, carbon sequestration and yield of maize in a Northern Guinea Savanna Alfisol, Nigeria was assessed in 2014 and 2015 rain-fed cropping seasons. The experiment was a Randomized Complete Block Design (RCBD), replicated three times and treatments were Sole (Mono crop) Maize (M), Desmodium (D) and Soybeans (S);Maize/soybeans intercrop (MS), Maize/Desmodium intercrop (MD), Maize Strip cropped with Soybean (MS 2:4) and Maize Strip cropped with Desmodium (M:D 2:4). Data obtained were evaluated for Organic carbon, available phosphorus, total nitrogen, soil pH, and CEC, Bulk density, Soil moisture, mean weight diameter and grain yield of Maize. Results show that mean soil acidity (pH water, 6.37;pH CaCl2, 5.78), mean organic carbon (5.23 to 5.69 g·kg-1) and mean total nitrogen improved (0.66 g·kg-1) in 2015 over values in 2014. Mean weight diameter (MWD) increased from 0.59 in 2014 to 1.05 in 2015;indicating a better aggregation across treatments. Treatment M resulted in significantly higher bulk density (Bd) than other treatments at 8 weeks after planting (WAP) and 16WAP, suggesting that soils under mono-crop maize were impaired for sustainable crop production. Soil organic carbon (SOC) sequestered in macro aggregates under MS (1.38 g·kg-1) was significantly higher than the other treatments. Best maize grain yield (GY) was under sole maize (M) and maize strip cropped with Desmodium (MD2:4) (3.13 t·ha-1 and 2.90 t·ha-1 in 2015, respectively). Maize strip cropped with Desmodium and maize/soybean intercrop enhanced better soil chemical and physical properties than sole maize. Soil quality (SQ) under MD2:4 ranked best (SQ1) for sustainable maize grain production and environmental conservation. Therefore, land use strategies that focus protection of soil organic carbon against further depletion and erosion, contribute nitrogen and/or replenishment of depleted carbon stocks through management techniques that involve legume/cereal cropping systems are advocated for sustainable agricultural production in the Nigerian Savanna zone Alfisols.
文摘Lime and coal flying ash applications could mitigate pollution from acid deposition and improve the buffering ability of two acidic soils sampled from Zhejiang Province. The results showed that soil alkalinity and acidified buffering capacities (QpHs ) were significantly increased, especially for liming treatment; whereas, the amounts of SO24- adsorbed by treated soils were decreased to some degrees because net negative charges of soil oxide colloidal surfaces were increased with the decrease in soil acidity, although the soil fixation abilities for adsorbed SO24- were not reduced. These facts indicated that after the alkaline ameliorators were applied, the positive and adverse effects resulted from sulfate-type acid deposition were simultaneously existed in these soil treatments.
文摘Alfisols are important soils in China.They occupy about 1.25 million km^(2),or about 13%of the land area.In the current Chinese system of soil classification,burozem,yellow-brown earths,Baijiang(Planosol)soils and parts of drab soils.They are mostly forested soils with an estimated 5-13 t/ha·yr of organic matter returned to the soils from temperate mixed conifer and broad-leaved forest.In terms of elemental bio-cycling,Ca is prominent.In a comparison of 30 profiles the average ratio of clay(B/A)was 1.47 for Cryoboralfs and Eutroboralfs;1.88 for Hapludaifs and 2.53 for Paleudalfs.From Eutroboralfs to Paleudalfs the average gain(or loss)in clay during soil development is about a factor of seven.The moisture regimes vary considerably between Hapludaifs,Cryoboralfs,and associated Cryaquepts,but the amount of water is always enough to cause significant leaching.In the weathering,and pedogenesis processes TiO_(2),MgO and Fe_(2)O_(3) are accumulated,respectively,in both A and BA horizons;but SiO_(2) and Al_(2)O_(3) tend to be leached from the solum.
文摘In the semi-arid tropics (SAT),33% areas are occupied by Alfisols and related soils. In SAT these soils have low structural stability and thereby tend to form seal and crusts at the surface. Due to this a large proportion of the rain that falls on Alfisols during the early part of the rainy season,is normally lost as runoff thus causing high soil loss as well as moisture stress to crops. Two tillage studies were conducted first at plot scale (320 m2) during 1991-95 and second at small watershed scale (1.45 ha) during 2007-10,at ICRISAT research station,Hyderabad,India. These studies were conducted to find out whether the problem of excessive runoff and soil loss during the early part of the rainy season can be controlled by various inter-row tillage systems in addition to normal intercultivation by breaking the crust or seal and thereby improving infiltration and soil moisture and reducing runoff and soil loss. The observations on rainfall,runoff,soil moisture,soil loss,soil surface roughness and crop yields were collected from both the studies. Results from these studies have shown that inter-row tillage in addition to normal intercultivation is found effective in controlling early season runoff and soil loss and increasing crop yields. The additional tillage systems are found most effective during low and medium rainfall years and not so much during high rainfall years. The additional tillage with shoe cultivators,which creates rough soil surface (11 mm depression storage),is found most effective in increasing crop yields and reducing runoff and soil loss. The additional tillage with blade harrow which generates smooth soil surface is relatively less effective. In most rainfall conditions,the normal intercultivation with one additional tillage is found adequate for controlling early season runoff and improving soil moisture and crop yields.
基金This work was carried out under part of AICRP on Soil Test Crop Response,ICAR at PJTSAU,Hyderabad-500030,India.
文摘Studies on Soil Test Crop Response Based Integrated Plant Nutrition System(STCR-IPNS)were conducted for three years adopting the Inductive cum Targeted Yield Model,on alfisols of Unified Andhra Pradesh,Southern India during summer 2016-2018 in order to develop fertilizer prescriptions through IPNS for the desired yield targets of Sesamum under field conditions.The bases for making the fertilizer prescriptions viz.nutrient requirement(NR),contribution of nutrients from soil(Cs),fertilizer(Cf)and vermicompost(CVC)were computed using the field experimental data.Making use of these basic parameters,the fertilizer prescription equations were developed under NPK alone and under IPNS for the desired yield targets of Sesamum for a range of soil test values.The quantity of fertilizers contributed by the application of vermicompost was assessed.Nutrient requirement to produce 100 kg of sesame seed was worked out to be 10.20 kg N,3.90 kg P2O5 and 5.22 kg K2O.In the present investigation,the requirement of N was higher which is followed by K2O and P2O5.The requirement of N was 2.62 times higher than P and 1.95 times higher than K.The percent contribution of N,P and K was 12.25,15.75 and 6.00 from soils,41.68,22.85 and 59.97 from fertilizer and 9.87,6.74 and 18.65 from organic manures,respectively.Thus the Inductive cum Targeted Yield Model used to develop fertilizer prescription equations provides a strong basis for soil fertility maintenance consistent with high productivity and efficient nutrient management in farming for sustainable and enduring agriculture.
文摘The residual effect of organic and mineral fertilizers on selected chemical properties of an Alfisol in the long term soil fertility trial established in 1950 at Samaru, Nigerian savanna was assessed. The trial was left fallow for fourteen years due to lack of funds. Topsoil was collected from plots that received three levels of cow dung （D）, nitrogen （N） and phosphorus （P） in all possible combinations. The soils were analyzed for selected chemical properties. Except for significant effect of applied P on available P, sole application of cow dung, N or P had no significant effect on all the measured soil properties. The interaction of D and P significantly affected the mean values of exchangeable Ca, Mg, K and ECEC in the range of 1.12-1.96, 0.62-1.11, 0.37-0.64 and 2.82-4.11 cmol/kg respectively. The most important results were the ability of the plot that received neither D nor P to significantly increase these parameters than the plots that received only one of the treatments. The results show that the fallow period has changed the effects of application of organic and mineral fertilizers on the soil chemical properties under continuous cultivation by modifying them towards those of a native savanna Alfisol.
文摘Bisequal soils in northern Wisconsin were described and characterized with the intent to determine if a near total elemental analysis protocol may estimate the effect of selected soil pedogenic pathways on soil morphology. The protocol reveals that gross elemental soil profile distributions do provide evidence that certain pedogenic processes are operating within a group of soils. Concentration differences between instrumental neutron activation analysis and an aqua regia digestion protocol infer that alkali metals, alkaline earth metals, transition metals and the rare earth elements are only incompletely weathered from primary minerals. Transition metals, alkali metals, alkaline earths, metalloids, and the rare earth elements all show inter-horizon mobility. Lessivage and the mobility of elements presumably adsorbed on soluble or suspended organic materials are the dominant soil processes influencing the soil profile redistribution of elements and the majority of these elements are shown to correlate with the soil profile distribution of Fe. Base cycling by the forest vegetation was shown to support A horizon enrichment of Ca, Sr, Ba, P, S, Mn, Zn, Sn and Pb. For clinical practice, elemental analysis may reveal important soil profile elemental differences when applied to variation of one soil forming factors, such as a chronosequence or toposequence within a landscape or soil association. Advantages and limitations of the protocol in identifying pedogenic pathways are discussed.
文摘A major nutritional problem to crops grown in highly weathered Brazilian soils is phosphorus (P) deficiencies linked to their low availability and the capacity of the soils to fix P in insoluble forms. Our studies examined factors that might influence P behavior in soils of the Amazon region. This study was conducted to evaluate the maximum phosphate adsorption capacity (MPAC) of the soils developed from mafic rocks (diabase), their parent materials and other factors resulting in the formation of eutrophic soils having A chernozemic horizon associated with Red Nitosols (Alfisol) and Red Latosols (Oxisol) of the Amazonian environment. The MPAC was determined in triplicates as a function of the remnant P values. The different concentrations used to determine the MPAC allowed maximum adsorption values to be reached for all soils. The Latosol (Oxisol) and Nitosol (Alfisol) soils presented higher phosphate adsorption values that were attributed to the oxidic mineralogy and high clay texture while the Chernosol (Mollisol) soils presented the lowest phosphate adsorption values.
文摘Soil morphological, physical and chemical properties are described at four locations along an elevational transect in the northeastern part of the Moldavian Plateau (Romania). These data contribute to the knowledge of the soils of this area and to their classification according to the USDA-Soil Taxonomy, FAOWRB and the SRTS-Romanian System. The soils were classified as Inceptisols, Alfisols and Mollisols, according to the USDA-Soil Taxonomy;Gleysol, Chernozem and Luvisol, according to the FAO-WRB and Gleiosol, Cernoziom, Preluvosol, Luvosol, according to the SRTS-Romanian System. The selected soils have a range of properties that represent the soilscape of the Moldavian subcarpathian plateau, characterised by a natural forest with oak as the dominant species. The selected soil parameters decreased with increasing elevation;calcium carbonate and clay leaching and accumulation are the main soil formation processes.
