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Soil Carbon Sequestration in Long-Term Fertilization Under Jute-Rice-Wheat Agro-Ecosystem

Singh, A. K., Behera, M. S., Mazumdar, S. P., Kundu, D. K.
Communications in soil science and plant analysis 2019 v.50 no.6 pp. 739-748
NPK fertilizers, agroecosystems, alluvial soils, carbon sequestration, clay fraction, climate change, climatic factors, crops, fertilizer application, manure spreading, models, nitrogen, phosphorus, potassium, potassium fertilizers, roots, soil organic carbon, stubble, temperature
Soil organic carbon (SOC) sequestration in response to long-term fertilizer management practices under jute-rice-wheat agro-ecosystem in alluvial soils was studied using a modeling approach. Fertilizer management practices included nitrogen (N), phosphorus (P) and potassium (K) fertilization, manure application, and root-stubble retention of all three crops. Soil carbon (C) model RothC was used to simulate the critical C input rates needed to maintain initial soil C level in long timescale (44 years). SOC change was significantly influenced by the long-term fertilizer management practices and the edaphic variable of initial SOC content. The effects of fertilizer combination “100%NPK+FYM” on SOC changes were most significant over “100%NPK” fertilization. If the 100% NPK fertilizer along with manure applied with stubble and roots retention of all crops, alluvial soils of such agro-ecosystem would act as a net C sink, and the average SOC density kept increasing from 18.18 Mg ha⁻¹ during 1972 to the current average of ∼22 Mg ha⁻¹ during 2065 s. On an average, the critical C input was estimated to be 5.30 Mg C ha⁻¹ yr⁻¹, depending on local soil and climatic conditions. The critical C input could be effectively estimated using a summary model driven by current SOC level, mean annual temperature, precipitation, and soil clay content. Such information will provide a baseline for assessing soil C dynamics under potential changes in fertilizer and crop residues management practices, and thus enable development of management strategies for effectively mitigating climate change through soil C sequestration.