The present study was undertaken to determine the effects of different levels of urea-N fertilizer in addition to ipil-ipil tree litter on yield of rice and insect prevalence. The field study was conducted at the Agro...The present study was undertaken to determine the effects of different levels of urea-N fertilizer in addition to ipil-ipil tree litter on yield of rice and insect prevalence. The field study was conducted at the Agroforestry Field Laboratory, Bangladesh Agricultural University, Mymensingh during July-December 2004. The treatments included 0, 90, 180, and 270 kg urea per hectare. All four treatments received five tons ipil-ipil tree litter per hectare. The experiment was laid out in a randomized complete block design (RCBD) with four replications. The results showed that the different treatments significantly influenced the yield and yield component viz. total tillers/hill, effective tillers/hill, filled grains and unfilled grains/panicle. The highest yield of 4.62 t·hm-2 with an increase of 21.57% over the control was recorded in treatment 180 kg urea·hm-2, which was statistically similar to treatment 90 kg urea·hm-2. The prevalence of insects viz. green leafhopper, brown plant hopper, rice bugs, leaf folder and stem borers were mostly correlated with N-levels. The prevalence of insects in general gradually increased with the increase of N. Therefore, this study suggests that the combined application of organic materials (tree litter of ipil-ipil) and N-fertilizer of 90 kg·hm-2 may produce good yield while minimizing insect prevalence in the rice field.展开更多
文摘The present study was undertaken to determine the effects of different levels of urea-N fertilizer in addition to ipil-ipil tree litter on yield of rice and insect prevalence. The field study was conducted at the Agroforestry Field Laboratory, Bangladesh Agricultural University, Mymensingh during July-December 2004. The treatments included 0, 90, 180, and 270 kg urea per hectare. All four treatments received five tons ipil-ipil tree litter per hectare. The experiment was laid out in a randomized complete block design (RCBD) with four replications. The results showed that the different treatments significantly influenced the yield and yield component viz. total tillers/hill, effective tillers/hill, filled grains and unfilled grains/panicle. The highest yield of 4.62 t·hm-2 with an increase of 21.57% over the control was recorded in treatment 180 kg urea·hm-2, which was statistically similar to treatment 90 kg urea·hm-2. The prevalence of insects viz. green leafhopper, brown plant hopper, rice bugs, leaf folder and stem borers were mostly correlated with N-levels. The prevalence of insects in general gradually increased with the increase of N. Therefore, this study suggests that the combined application of organic materials (tree litter of ipil-ipil) and N-fertilizer of 90 kg·hm-2 may produce good yield while minimizing insect prevalence in the rice field.
