Carbon trade-off with crop and water productivity in intensive rice-based cropping system in Eastern India

Abstract To achieve sustainable crop and water productivity, carbon efficiency of rice-toria-sweet corn system by the synergies of nutrient management, rice variety and establishment method of toria and sweet corn, a field experiment was conducted during 2018-19 and 2019-20 at Bhubaneswar, Odisha. The treatments comprising of three nutrient management [N1: 100% Soil Test Based Nitrogen Recommendation (STBNR), N2: 75% STBNR + in situ green manuring of Dhaincha (GM) and N3: 50% STBNR + GM in rice, two rice varieties (V1: ‘Manaswini’ of 130 d duration and V2: ‘Hasanta’ of 145 d duration) and three crop establishment methods in toria viz., E1: Zero Till-Flat Bed (ZT-FB), E2: Conventional Till-Flat Bed (CT-FB) and E3: Conventional Till-Furrow Irrigated Raised Bed (CT-FIRB) were tried in split plot design with four replications. Sweet corn was grown after toria following the same lay out. Application of 75% STBNR+GM proved to be the best with the maximum system rice equivalent yield (REY) of 21.10 t ha-1, input water productivity (IWP) of 0.44 kg REY ha-mm-1, C output of 14,484 kg ha-1, carbon efficiency (CE) of 8.58 and carbon sustainability index (CSI) of 7.58. ‘Manaswini’ rice-based system registered 4% higher REY as compared to ‘Hasanta’ rice-based system, but both systems were at par for IWP, carbon output, CE and CSI. System involving CT-FIRB recorded the maximum REY, IWP and carbon output, registering marginally higher values than ZT-FB and significantly higher value than CT-FB. Both CT-FIRB and ZT-FB were at par for CE and CSI.