System of rice intensification and irrigated transplanted rice: Effect on crop water productivity

Irrigated lowland rice production with continuous standing water (TPR) in the Indo-Gangetic Plains of South Asia requires huge quantity of irrigation water input. Yield of wheat grown following rice is generally low in such system as the soil undergoes radical changes in their physical properties upon puddling and on continuous submergence. Therefore, in the present investigation, an alternate method of establishing rice crop known as system of rice intensification (SRI) followed by wheat performance was evaluated at IARI Experimental Farm, New Delhi (77°12′ E, 28°36′N). Results showed that SRI yielded the same as TPR treatment (5.4 t ha−1) but required 23% less irrigation water input during the crop growth period. Crop water productivity when computed per unit evapotranspiration (WPET) and per unit total water input including irrigation water and rainfall (WPIR), SRI showed significant improvement over TPR treatment. The saturated hydraulic conductivity of the 0–30 cm soil layer was significantly higher in SRI compared to the TPR system, indicating the beneficial effects of the former. Grain yields of post-rice wheat were also slightly higher where preceding rice crop had been under SRI treatment. However, when total productivity of the system was calculated and expressed in terms of rice equivalent yield (REY), the differences between the two treatments were not significant.