Impact of rice straw mulch on growth, yield components and yield of direct seeded lowland rice (Oryza sativa L.)

Abstract

The impact of a rice straw mulch (RSM) under optimal mineral fertilized conditions on growth, yield components and yield of dry direct seeded (DDSR) and wet direct seeded rice (WDSR) was evaluated under field conditions over four consecutive seasons to include two dry (DS) and two wet (WS) seasons, in the dry zone of Sri Lanka. The RSM could be applied in WDSR in both seasons and DDSR in WS at a rate of 4t/ha without affecting the seedling density. RSM in WDSR, especially at initial stages of plant growth (i.e. 35 days after sowing) increased plant height, length of the longest root and total root length significantly than in non mulched and DDSR-RSM plots. Shoot and root biomass were also significantly increased by RSM in WDSR in both seasons. Rice straw mulch increased panicle number per unit area and number of spikelets per panicle in WDSR-RSM in both seasons. A significantly high yield could be achieved in WDSR-RSM, WDSR-chemical weeding (C) and DDSR- C treatments in both seasons. The yield enhancement was attributed to yield components, principally panicle number per unit area and number of spikelet per panicle. There was a greater panicle number per unit area in the DS while the WS favors more spikelets per panicle. The study indicated the possibility of enhancing the rice plant growth, yield components and yields of rice in wet- direct seeded lowland rice by rice straw mulch in both seasons in this region. Tropical Agricultural Research Vol. 24 (4): 325-335 (2013)

Keywords

• dry- direct seeded rice, grain, mulch, wet-direct seeded rice, yield components