Influence of some nursery management and crop establishment practices on the performance of rainfed lowland rice.

Seeding density in the seedbed significantly affected the height of rice which was transplanted using 40 days old seedlings (DOS) but did not influence the height of rice when seedlings were fertilized in the nursery with nitrogen and transplanted at 20 DAS. Transplanted rice that used 40 DOS had about 8.2 percent lower height than that which used 20 DOS. However, rice transplanted using 40 DOS produced more tillers than that which used 20 DOS. Higher seeding density in the seedbed (50 kg seed per 250 sq.m.) resulted in lesser number of tillers as well as LAI in the first four weeks after transplanting. Rice transplanted using 20 or 40 DOS had highest LAI values at flowering stage. Plants transplanted using 20 DOS had higher LAI than those transplanted using 40 DOS. Nitrogen application in the seedbed did not influence LAI after transplanting. Higher seeding density in the seedbed delayed the flowering and maturity of transplanted rice. Plants transplanted 40 DAS matured 7 days earlier but had longer growth duration by 13 days than those transplanted 20 DAS. Plants transplanted 40 DAS also produced more panicles, but their panicles were smaller, had less filled grains and low grain weight, and therefore, low grain yield than those that were transplanted 20 DAS. Plants transplanted at an early age (12 and 15 DAS) had longer recovery period and resulted in higher survival percentage under submergence than those transplanted at a later age (18 and 21 DAS). Plants fertilizer with nitrogen at 12 and 8 days before transplanting (DBT) also had higher survival percentage under submergence than those fertilized at 4 DBT and the control (unfertilized). Plants having shorter height before submergence had a higher percent increase in height during submergence. This increase in plant height was attributed to rapid elongation of leaf sheath rather than leaf blade. Pruning of roots before transplanting significantly reduced plant height and shoot and root biomass. Plants fertilized with nitrogen at 12 and 8 DBT had higher soluble sugar content in the leaf blade and leaf sheath than those fertilized at 4 DBT and the control. In contrast, plants transplanted in N-fertilized trays had lower soluble sugar content than those transplanted without fertilizer.