Heat utilization vis-à-vis crop performance of mechanically transplanted rice (Oryza sativa L.) as affected by tillage systems and nitrogen levels

Abstract

The experiment comprising of four tillage methods viz., puddling (PTR), conventional tillage without puddling (CT), reduced tillage (RT) and zero tillage (ZT) and four nitrogen levels at 0, 100, 125 and 150 kg ha-1 was conducted in a strip plot design with four replications at Punjab Agricultural University, Ludhiana during 2010 and 2011 to study the effect of tillage and nitrogen levels on productivity and heat utilization in mechanically transplanted rice. Results revealed that periodic plant height and dry matter accumulation by the crop recorded at 30, 60, 90 DAT and at harvest, leaf area index (LAI) and photosynthetically active radiation (PAR) interception by the crop at panicle emergence stage and the grain yield were statistically at par in mechanical transplanting in CT and PTR but significantly higherthan that in RT and ZT. Application of 150 kg N ha-1 recorded significantly higher LAI, PAR interception, number of tillers and grain yield than that in 0, 100 and 125 kg N ha-1. Mechanical transplanting in CT recorded highest accumulation of growing degree days (GDD) and highest heat use efficiency (HUE). The accumulated GDD and HUE increased significantly with each successive increase in nitrogen dose from 0 to 150 kg ha-1.