Measuring and Monitoring the Impact of Precision Land Levelling and Arable Cropping Systems on Aggregate Associated Carbon Fractions and Soil Carbon Stock in Sub-tropical Ecosystems

The Long term experiment (2009-10 to-2018-19) was conducted to study the effects of precision land levelled (PLL) versus traditional land levelled (TLL) systems on aggregate-associated soil organic carbon (SOC) in a farmers participatory fields under sub-tropical ecosystems (Western Uttar Pradesh) of Indian conditions. The significance of this study mainly focus to determine the suitability of various labile carbon fractions as indicators of soil quality and the stability of aggregates plays a vital role in preserving and long term storing of soil organic carbon by implementing Precision Land Levelling under various arable cropping system. The treatment comprised of sixteen alternative arable cropping systems strategies viz. R-WPLL, R-WTLL, S-WPLL, S-WTLL, R-P-MbPLL, R-P-MbTLL, R-P-OPLL, R-P-OTLL, R-C-OPLL, R-C-OTLL, O-W-MbPLL, O-W-MbTLL, M-W-MbPLL, M-W-MbTLL, M-P-MbPLL, and M-P-MbTLL etc were taken with recommended dose of fertilizers and various observations were recorded. The results indicated that the M-P-MbPLL produced 79.5 kgha-1day-1 productivity and used only 110 cm irrigation water which was 48.1 per cent less than irrigation water used for R-WPLL. The land use efficiency under R-P-MbPLL, R-P-OPLL, R-P-MbPLL, R-C-OPLL and M-P-MbPLL were recorded as 86.2, 85.1, 84.8, 84.6 and 83.9%. However, energy value in terms total input energy and energy productivity were 39.9 and 218.5 GJ ha-1 over existing R-W system (32.9 & 105.7 GJ ha-1). The quantity of water used in the R-C-O, M-W-Mb, M-P-Mb, and O-W-Mb were 46.1, 44.9, 40.1 and 36.3 per cent less than quantity of water used for R-W system. Aggregate-associated SOC contents in 0-15 cm depth were recorded highest SOC at 15-30 cm depth in PLL systems as 9.4% for both M-P-MbPLL and M-W-MbPLL. Highest PON change in arable cropping system (30.9 & 40.1%) was found in O-W-Mb with precision land levelling (T11) plots followed by R-P-O with precision land levelling (T7) plots (26.1 & 35.8%) as compared to R-W and S-W system. The values of LFOC in surface soil were 194.7, 187.9, 176.2, 170.9, 168.5, 150.6, 132.8 and 123.8 mgkg−1 in R-P-O, R-C-O, M-W-Mb, O-W-Mb, M-P-Mb, R-P-Mb, R-W and S-W with precision land levelling treatments. Higher SOC sequestration was observed with precision land leveling along with alternative arable cropping systems with O-W-MbPLL, R-C-OPLL, R-P-OPLL, O-W-MbPLL and M-P-MbPLL respectively. Therefore, PLL systems had greater soil surface aggregation and carbon storage, land levelling did not affect SOC patterns across aggregates, but changed the distribution of aggregate size, reflecting that land levelling mainly influenced soil fertility by altering soil structure.