Nutrient and crop establishment methods determine carbon efficiency and crop-water productivity in intensive rice-based cropping system in Eastern India

Abstract

Achieving sustainable crop-water productivity and carbon efficiency of intensive cropping systems such as rice (Oryza sativa)-toria (Brassica campestris L. var. toria)-sweet corn (Zea mays con var. saccharata var. rugosa) system in Eastern India, need synergies of nutrient management, rice variety and crop establishment methods. Efficient nutrient management in rice, tillage and establishment of toria and sweet corn, were identified in two years (2018-19 and 2019-20) replicated field experiment conducted at Bhubaneswar, Odisha, India. 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.