Role of cultural and nutrient management practices in carbon sequestration in agricultural soil

Chowdhury, S. and Bolan, N. and Farrell, M. and Sarkar, B. and Sarker, J.R. and Kirkham, M.B. and Hossain, M.Z. and Kim, G.-H. (2021) Role of cultural and nutrient management practices in carbon sequestration in agricultural soil. In: Advances in Agronomy. Advances in Agronomy, 166 . Academic Press Inc., pp. 131-196. ISBN 9780128245873

Abstract

Any management practice that results in greater carbon (C) return to the soil, increases stabilization of soil C, or reduces C losses may lead to soil organic carbon (SOC) storage in soil. Therefore, SOC dynamics in soil are dictated by a balance between input and output of C in the soil, and C sequestration occurs only when the input exceeds the output. Primarily, greater C input can occur by enhancing biomass production using fertilizers with irrigation, stubble retention, crop rotation, minimum tillage, and by improving soil properties including having the appropriate pH, cation exchange capacity (CEC), and osmotic pressure. Conventional farming with intensive plowing leads to SOC decomposition, whereas conservation farming with no or minimum tillage with stubble retention may retard the decomposition of soil native organic C. Fertilizer addition may influence the decomposition of SOC. The effect of fertilizer on decomposition of soil organic matter (SOM) differs with and without the presence of organic matter as crop residues, labile C, or easily degradable C in soil. This effect of fertilizer is mostly dominated by the presence/addition of organic matter in soil rather crop management or what the pH, CEC, or osmotic pressure are. However, decomposition of crop residues or organic matter depends on their quality (biochemical properties), soil types, soil environment, the microbial community, and nutrient availability. More microbial activity with organic matter decomposition means more production of stabilized C, which is relatively recalcitrant to microbial degradation. Therefore, nutrient addition in soil may be helpful in increasing SOM stock. At least, it can maintain the SOM level if the C (energy source) for microbial growth is external like stubble or added organic matter rather than internal (native) SOM.