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The potential of cropping systems and soil amendments for carbon sequestration in soils under long‐term experiments in subtropical India
Author(s) -
MANDAL B.,
MAJUMDER B.,
BANDYOPADHYAY P. K.,
HAZRA G. C.,
GANGOPADHYAY A.,
SAMANTARAY R. N.,
MISHRA A. K.,
CHAUDHURY J.,
SAHA M. N.,
KUNDU S.
Publication year - 2007
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/j.1365-2486.2006.01309.x
Subject(s) - soil carbon , environmental science , soil water , carbon sequestration , cropping system , agronomy , soil organic matter , manure , soil fertility , compost , subtropics , fertilizer , crop residue , crop rotation , soil management , cropping , soil science , crop , biology , agriculture , carbon dioxide , ecology
An understanding of the dynamics of carbon (C) stock in soils, as impacted by management strategies, is necessary to identify the pathways of C sequestration in soils and for maintaining soil organic C (SOC) at a level critical for upkeeping soil health and also for restraining global warming. This is more important in tropical and subtropical region where soils are inherently low in organic C content and the production system is fragile. We evaluated the long‐term role of crop residue C inputs to soil in SOC sequestration and also the critical value of C inputs for maintenance of SOC across five different rice‐based cropping systems and four soil management practices including a fallow (no cultivation since initiation of the experiments) using five long‐term (7–36 years) fertility experiments in subtropical India. Cropping per se always caused a net depletion of SOC. Such depletion was inversely proportional to the amount of crop residue C incorporated into the soils ( r =−0.92, P =0.001). Balanced fertilization with NPK, however, caused an enrichment (9.3–51.8% over the control) of SOC, its extent being influenced by the cropping systems. Long‐term application of organic amendments (5–10 Mg ha −1 yr −1 ) through farmyard manure (FYM) or compost could increase SOC hardly by 10.7% constituting only 18% of the applied C, the rest getting lost through oxidation. The total quantity of soil C sequestered varied from −11.5 to 14.5 Mg C ha −1 and was linearly related ( r 2 =0.40, P =0.005) with cumulative crop residue C inputs to the soils. On an average, the rate of its conversion to SOC came out to be 6.4%. This was more in presence of added organics (6.9%) than in its absence (4.2%). For sustenance of SOC level (zero change due to cropping) we found that a minimum quantity of 2.9 Mg C is required to be added per hectare per annum as inputs. The cropping systems and the management practices that could provide C input higher than the above critical level are likely to sustain the SOC level and maintain good soil health in the subtropical regions of the Indian subcontinent.