Production maximization of rainy season rice (Oryza sativa) through effective use of water and solar radiation under modified system of rice intensification in Assam

Abstract

A field experiment was conducted in a farmers’ field at Nepalikhuti, Golaghat, Assam during the rainy (kharif) season of 2016 and 2017, to find out the effect of different transplanting dates and hill densities of rice (Oryza sativa L.) under system of rice intensification (SRI) which was compared with conventional rice cultivation (CRC). The experiment was designed in factorial split-plot with 2 crop-establishment methods (SRI and CRC) and 3 transplanting dates (26 June, 10 and 25 July) in the main plot; and 4 different hill densities (20 cm × 10 cm, 20 cm × 20 cm, 25 cm × 20 cm and 25 cm × 25 cm) in the subplots and replicated thrice. With an increased grain yield of 5.71 t/ha, SRI-establishment showed a significant yield advantage of 0.83 t/ha coupled with 2.64% more consumptively used water and 1.29 kg/ha-mm more water-use efficiency over CRC. Results showed strong positive correlation (0.95**) between water-use efficiency (WUE) and yield attributes primarily the effective tillers/m². Regression analysis revealed that irrespective of establishment methods, the consumptive use (CU) of water, accumulated incident photosynthetically active radiation (AIPAR), radiation-use efficiency (RUE) and heat-use efficiency (HUE) greatly influenced the grain yield. However, in SRI, WUE appeared to be an additional key determinant of grain yield. Between 2 establishment methods, SRI was found to be more competent in utilizing water and solar radiation owing to its ideal canopy environment.