Impact of nutrient management options on carbon sequestration in long term pearlmillet mustard cropping sequence on a Typic Ustochrepts and validation of C and N model

Abstract

The present investigation, entitled quotImpact of nutrient management options on carbon sequestration in long term pearl millet-mustard cropping sequence on a Typic Ustochrepts and validation of C and N modelquot was carried out from Kharif season 2017-18 to Rabi season 2018-19 as a part of an ongoing long term fertilizer experiment is in progress on a soil classified as Typic Ustochrepts at college of Agriculture farm of RVSKVV Gwalior, since 2003 with the main aim to know the influence of integrated nutrient management on carbon sequestration, nutrient status and soil properties. The experiment was laid out under randomized block design (RBD) with 3 replications having 16 treatments in the scheduled plots (size 5 m x 3 m) comprising the different combinations of inorganic and organic fertilizers. newlineThe SOC content in soil increased where optimal, super optimal and optimal or sub optimal dose with FYM was given i.e 100%NPK, 150%NPK, 50%NPK + FYM and 75%NPK + FYM, 100%NPK + FYM whereas decreased in 50%NPK and 75%NPK, imbalanced fertility treatments (100%N, 100%NPS-K) and control plot with some exceptions. All carbon pools were observed under each fertility treatment and maximum availability of every pool vary labile carbon (CVL), labile carbon (CL), less labile carbon (CLL) and non-labile carbon (CNL) was recorded in 100%NPK+FYMat10t ha-1yr-1+Azotobactor+PSB. The active pool of SOC, calculated in 0.3 m, and 1.0 m soil layers, decreased in sub-optimal fertility doses (50%NPK, 75%NPK) control and imbalanced fertility treatment (100%N and 100%NP). In case of active: passive pool carbon ratio the optimal dose of fertility with or without FYM and super-optimal dose 150% NPK showed increased values. newlineOut of the sixteen treatments, 100%NPK+FYMat10 t ha-1yr-1 +Azotobactor +PSB remained superior over the other fertility treatments followed by 100%NPK+FYM at10 t ha-1yr-1 and sequestered higher amount of TCSQ by 103.0 and 108.8 Mg ha-1, respectively. Major contribution in carbon sequestration was furnished by agricultural cropproduct