Modelling climate smart rice-wheat production system in the middle Gangetic plains of India

Abstract

A simulation study based on water balance approach and field experimentation with rice-wheat cropping system was carried out by employing daily rainfall and evaporation (2002–2016) and edaphic data of Experimental Farm of the university, Pusa (25.98°N, 85.67°E, 52 m amsl), Bihar, situated under middle Indo-Gangetic Plains. The aims of the study were to optimize transplanting dates and assess irrigation requirement and water productivity of rice with a view to achieve climate smart rice-wheat production system. The suitability of advancing wheat planting under this cropping system was also evaluated for escaping terminal heat stress during reproductive to maturity period. Under rice-wheat system, late transplanting of rice during kharif season (monsoon season, synonymously also called as wet season) and, consequently, late planting of wheat during rabi (winter) season tend to reduce grain yield significantly under a set of adverse environmental conditions during flowering to maturity phases of both the crops. The study revealed that rice crop of 150-day duration (seed to seed) could be successfully transplanted early in the kharif season during 20–30 June and be harvested by 25 October–5 November with the use of average 404–425-mm irrigation water to achieve potential yield and higher water productivity (1.648–1.731 kg m−3 ha−1). Early rice harvesting ensured early completion of wheat planting before 15 November, which helped in escaping terminal high-temperature stress during the reproductive phase. Hence, higher system productivity can be achieved by shifting the planting dates of rice and wheat through optimum utilization of natural resource environment (moisture and thermal regimes) and offsetting the negative impacts of erratic monsoon rains on rice growth and terminal heat stress and hailstorm on subsequent wheat crop.