A field experiment was conducted in 2016 and 2017 to study the manipulated crop micro-environment on effective light interception and heat-unit accumulation for improving sali rice production. The trial was comprised of two crop establishments, viz. system of rice intensification (SRI) and conventional rice cultivation (CRC); three transplanting dates (26thJune, 10thJuly, and 25th July) and four crop geometries (20cm x 15cm; 20cm x 20cm; 25cm x 20cm and 25cm x25cm) laid in factorial split-plot with three replications. Results revealed that the SRI crops took lesser days to attain maximum tillering, 50% flowering, and physiological maturity as compared to CRC. In spite of lesser accumulated growing degree-days (GDD), helio-thermal unit (HTU), photo-thermal unit (PTU), and light transmission ratio (LTR); the SRI establishment gave maximum grain yield. The superiority of early crops was observed in effective utilization of solar energy for grain formation. The widely spaced crops showed significantly inferior LTR with increased grain yield. Further, a significantly strong negative association was observed with LTR (-0.82**) during the vegetative phase of SRI crops. The regression model revealed that the vegetative phase of sali rice was the most critical phase in terms of higher radiation interception and dry matter production.