Background In the Indo-Gangetic Plain,rice-wheat is the most extensively practiced crop rotation.The escalating issue of crop residue burning,particularly rice straw,and the necessity to lower the exorbitant expenses ...Background In the Indo-Gangetic Plain,rice-wheat is the most extensively practiced crop rotation.The escalating issue of crop residue burning,particularly rice straw,and the necessity to lower the exorbitant expenses associated with fertilizer inputs stand out as significant challenges for farmers in the region.A well-suited integrated nutrient management(INM)strategy that focuses on recycling crop residues can serve as a solution to address these issues.Such a strategy not only mitigates air pollution resulting from residue burning but also helps combat water pollution due to nitrate losses from agroecosystems.Field experiments were used to evaluate the suitability of eight INM-modules that included various combinations of inorganic fertilizer rates(50%,100%,150%of recommended dose),crop residues(wheat and rice stubble retention at 30 cm standing stubble equivalent to 1/3 the straw yield),rice straw compost(RSC),farmyard manure(FYM),and green manuring(GM),compared to 100%recommended dose of fertilizers(F)and no fertilizer application.Results There was a considerable improvement in nitrogen mineralization,grain yields,and nitrogen use efficiency under GM+RSC-F50 and GM+FYM-F50.These INM modules would permit a 50%reduction in the use of chemical fertilizers.There was a little yield penalty with in situ rice residue incorporation at 100%F;however,this could be overcome with 150%F fertilizer application.In situ retention of wheat straw with a full application of fertilizer resulted in steadily rising crop yields over time.Changes in the redox potential,soil pH,and soil organic carbon best accounted for the observed trajectories in nitrogen use efficiency.Conclusion The most promising INM modules for adoption by farmers in the Indo-Gangetic Plain to judiciously use crop residues and curtail chemical fertilizer inputs are green manuring with Sesbania aculeata+rice straw compost at 5 t ha^(−1)+only 50%of recommended dose of fertilizers(GM+RSC-F50),and green manuring with Sesbania aculeata+farmyard manure at 5 t ha^(−1)+only 50%of recommended dose of fertilizers(GM+FYM-F50).Sole incorporation of crop residues without nitrogen augmentation from other sources might not help curtail chemical fertilizer use.Composting rice straw,which otherwise is widely burnt,proved a useful nitrogen source and a vital component of INM.Waste rice straw composting at the community scale and its application as a nutrient source can help achieve sustainable nitrogen management in the agroecosystems of Indo-Gangetic Plain.展开更多
The quantification of phosphorus(P) in bulk soil and P distribution in different size fractions of water-stable aggregates(WSAs)are important for assessing potential P loss through runoff. We evaluated available and t...The quantification of phosphorus(P) in bulk soil and P distribution in different size fractions of water-stable aggregates(WSAs)are important for assessing potential P loss through runoff. We evaluated available and total P distribution within WSAs of a sitty clay to clay soil in a long-term fertility experiment of a rice-wheat cropping system in India. Surface soil samples were collected from seven plots amended with NPK fertilizers in combination with or without organic amendments, farmyard manure(FYM), green manure(GM), and paddy straw(PS). The plot with no NPK fertilizers or organic amendments was set as a control. The soil samples were separated by wet sieving into four soil aggregate size fractions: large macroaggregates(> 2.0 mm), small macroaggregates(0.25–2.0 mm), fine microaggregates(0.05–0.25 mm), and a silt + clay-sized fraction(< 0.05 mm). Structural indices were higher in the soil receiving organic amendments than in the soil receiving inorganic fertilizer alone. Organically amended soil had a higher proportion of stable macroaggregates than the control and the soil receiving inorganic fertilizer alone, which were rich in microaggregates. Total and available P contents within WSAs were inversely related to the aggregate size, irrespective of treatment. The distribution of available and total P in the soil aggregate size fraction was as follows: silt + clay-size fraction > small macroaggregates > fine microaggregates> large macroaggregates. Within a size class, aggregate-associated available and total P contents in the organically amended soil were in the following order: FYM > PS ≥ GM. The available P content of the microaggregates(< 0.25 mm) was 8-to 10-times higher than that of the macroaggregates(> 0.25 mm), and the total P content of the microaggregates was 4-to 5-times higher than that of the macroaggregates. Cultivation without organic amendments resulted in more microaggregates that could be checked by the application of organic amendments such as FYM and GM, which increased the proportion of water-stable macroaggregates by consolidating microaggregates into macroaggregates.展开更多
基金supported by the National Innovations in Climate Resilient Agriculture(NICRA)initiative(Grant number:ICAR-DARE-NICRA-03)the ICAR-Central Soil Salinity Research Institute,Karnal.
文摘Background In the Indo-Gangetic Plain,rice-wheat is the most extensively practiced crop rotation.The escalating issue of crop residue burning,particularly rice straw,and the necessity to lower the exorbitant expenses associated with fertilizer inputs stand out as significant challenges for farmers in the region.A well-suited integrated nutrient management(INM)strategy that focuses on recycling crop residues can serve as a solution to address these issues.Such a strategy not only mitigates air pollution resulting from residue burning but also helps combat water pollution due to nitrate losses from agroecosystems.Field experiments were used to evaluate the suitability of eight INM-modules that included various combinations of inorganic fertilizer rates(50%,100%,150%of recommended dose),crop residues(wheat and rice stubble retention at 30 cm standing stubble equivalent to 1/3 the straw yield),rice straw compost(RSC),farmyard manure(FYM),and green manuring(GM),compared to 100%recommended dose of fertilizers(F)and no fertilizer application.Results There was a considerable improvement in nitrogen mineralization,grain yields,and nitrogen use efficiency under GM+RSC-F50 and GM+FYM-F50.These INM modules would permit a 50%reduction in the use of chemical fertilizers.There was a little yield penalty with in situ rice residue incorporation at 100%F;however,this could be overcome with 150%F fertilizer application.In situ retention of wheat straw with a full application of fertilizer resulted in steadily rising crop yields over time.Changes in the redox potential,soil pH,and soil organic carbon best accounted for the observed trajectories in nitrogen use efficiency.Conclusion The most promising INM modules for adoption by farmers in the Indo-Gangetic Plain to judiciously use crop residues and curtail chemical fertilizer inputs are green manuring with Sesbania aculeata+rice straw compost at 5 t ha^(−1)+only 50%of recommended dose of fertilizers(GM+RSC-F50),and green manuring with Sesbania aculeata+farmyard manure at 5 t ha^(−1)+only 50%of recommended dose of fertilizers(GM+FYM-F50).Sole incorporation of crop residues without nitrogen augmentation from other sources might not help curtail chemical fertilizer use.Composting rice straw,which otherwise is widely burnt,proved a useful nitrogen source and a vital component of INM.Waste rice straw composting at the community scale and its application as a nutrient source can help achieve sustainable nitrogen management in the agroecosystems of Indo-Gangetic Plain.
文摘The quantification of phosphorus(P) in bulk soil and P distribution in different size fractions of water-stable aggregates(WSAs)are important for assessing potential P loss through runoff. We evaluated available and total P distribution within WSAs of a sitty clay to clay soil in a long-term fertility experiment of a rice-wheat cropping system in India. Surface soil samples were collected from seven plots amended with NPK fertilizers in combination with or without organic amendments, farmyard manure(FYM), green manure(GM), and paddy straw(PS). The plot with no NPK fertilizers or organic amendments was set as a control. The soil samples were separated by wet sieving into four soil aggregate size fractions: large macroaggregates(> 2.0 mm), small macroaggregates(0.25–2.0 mm), fine microaggregates(0.05–0.25 mm), and a silt + clay-sized fraction(< 0.05 mm). Structural indices were higher in the soil receiving organic amendments than in the soil receiving inorganic fertilizer alone. Organically amended soil had a higher proportion of stable macroaggregates than the control and the soil receiving inorganic fertilizer alone, which were rich in microaggregates. Total and available P contents within WSAs were inversely related to the aggregate size, irrespective of treatment. The distribution of available and total P in the soil aggregate size fraction was as follows: silt + clay-size fraction > small macroaggregates > fine microaggregates> large macroaggregates. Within a size class, aggregate-associated available and total P contents in the organically amended soil were in the following order: FYM > PS ≥ GM. The available P content of the microaggregates(< 0.25 mm) was 8-to 10-times higher than that of the macroaggregates(> 0.25 mm), and the total P content of the microaggregates was 4-to 5-times higher than that of the macroaggregates. Cultivation without organic amendments resulted in more microaggregates that could be checked by the application of organic amendments such as FYM and GM, which increased the proportion of water-stable macroaggregates by consolidating microaggregates into macroaggregates.
