Integration of conservation agriculture with best management practices for improving system performance of the rice-wheat rotation in the Eastern Indo-Gangetic Plains of India

摘要

Cereal production systems in the Eastern Indo-Gangetic Plains (E-IGP) are traditional, with low yield and low farm income, and they have largely missed out on the benefits of the Green Revolution. To enhance productivity, alleviate environmental and management constraints, and enhance farmers' income in the rice-wheat cropping system of the E-IGP, new approaches that are more productive and sustainable need to be developed. Conservation agriculture (CA) together with best management practices (BMP) used in other parts of the IGP offer potential to be extended in the E-IGP. A study was conducted during 2009-2011 with the objective of evaluating a range of approaches for enhancing the productivity and economic returns of rice-wheat-based cropping systems in the E-IGP. Four scenarios (S) involving a range of crop and resource management practices with crop rotations (including legumes theta) were compared with one another, of which Scenario 1 represented farmers practice. The lowest yields of wheat (2.78-3.07 t ha(-1)) and rice (4.38-6.52 t ha(-1)) were recorded with the current farmers' practices (S1), consisting of intensive tillage (wet tillage or puddling in rice and dry tillage in wheat) followed by inefficient crop establishment practices (transplanting in rice and broadcasting in wheat) with complete removal of crop residues. Avoiding tillage in wheat (S2) and including mungbean increased the yields of wheat and the succeeding rice crop by 21-31%. and 5-10%, respectively. The yields of wheat and rice increased further by 46-54% and by 10-24%, respectively, with the inclusion of more CA components (S3). In S4, which was designed to include higher cropping intensity and diversification (potato and maize-rice-cowpea rotation) with CA components, 144-163% higher rice equivalent system productivity was attained. Irrigation water productivity in the winter season increased by 39-48% in S2, by 72-84% in 53, and by 137-138% in S4 when compared to S1 while in the rainy season it increased by 14-18% in S2, by 46-56% in S3, and by 71-88% in S4. S4 had the highest net returns ($2855-4193 ha(-1)), followed by S3 ($1883-3246 ha(-1)). However, the system's highest benefit-cost ratio was recorded with S3 due to its lower cost of crop cultivation. The results of this study showed that there is enormous untapped potential to improve overall system performance through the adoption of CA in integration with BMP in the intensive system of the E-IGP of India