Alternative cropping strategies for assured and efficient crop production in upland rainfed rice areas of eastern India based on rainfall analysis

The productivity of rice in rainfed upland soils of eastern India is very low (< 1 t/ha) and unstable because of erratic monsoon, moisture deficit during dry spells, light textured with less fertile soils and several biological constraints (weeds, pests and diseases). Keeping the urgent need of augmenting the productivity of vast rainfed upland rice ecosystem of eastern India (4.3 million ha), crop diversification technology was generated through on-farm research trials in representative upland rice soils of eastern India after analyzing agro-climatic (rainfall variability, probability and onset of effective monsoon) and edaphic (soil water retention properties) constraints and prospects. Based on rainfall analysis, direct seeded, low water requiring, rice substituted alternative upland crops namely maize, groundnut, pigeonpea, greengram and blackgram (sole or intercropping) was sown in light textured upland rice soils on 24th meteorological weeks (11-17 June) in 3 years 2000-2002 with two to three summer ploughings during pre-monsoon shower (May). Study revealed that in deficit rainfall years (2000 and 2002), when rice yield was affected adversely in light textured upland, higher rice equivalent yield and rain water use efficiency were obtained from groundnut + pigeonpea intercropping followed by sole groundnut and sole pigeonpea. Study also revealed that productivity of rice substituted crops in the same upland did not fluctuate much between rainfall excess (2001) and rainfall deficit years (2002 and 2000). Double cropping in rainfed upland rice soils was also explored through maize-horsegram/sesamum rotation with increased productivity and rainwater use efficiency. The crop diversification technology was found to be very effective for drought mitigation. (C) 2004 Elsevier B.V. All rights reserved.