Effects of Nitrogen Fertilizer Levels and Planting Density on Growth and Yield of Long Grain Rice

抄録

A field experiment was conducted to determine the effects of nitrogen (N) fertilizer and planting density on growth and yield of long grain rice. Four levels of N fertilizer (0, 40, 80 and 160kg N ha^-1) application at three levels each of planting density (20, 40 and 80 hills m^-2) were treated. Dry matter (DM) per hill increased almost linearly with the increase in N fertilizer; but its effect was more conspicuous before the heading stage than after. The increase in planting density generally made plant size to small. Tillers per plant increased linearly with the increase in N fertilizer levels. Grain yield and most of the yield attributes varied significantly. The highest grain yield obtained was 160kg N ha^-1, which was similar to the yield obtained at 80kg N ha^-1.