模拟螟害对水稻产量影响的研究

设置了模拟螟害、氮肥和基本苗三因索随机区组试验。结果表明各因素对产量及其构成因素的影响都极显著。水稻9—15叶期,分别损失分蘖8%、20%、20%、4%、4%、1%、1%以上亩穗才显著减少,分别损失分蘖8%、20%、20%、12%、8%、4%、1%以上才显著减产。随着损失叶期和损失度增大,亩穗渐减,着粒数、实粒数和千粒重不同程度增加。12—14叶期,1%—2%的损失产量反而略提高。讨论了氮肥和基本苗对产量及其构成因素的影响,认为每亩(666.7m~2)施5kg 纯氮的氮肥、移栽3.428万棵苗/亩有利于高产。

SIMULATION OF THE DAMAGE OF STEM-BORERS TO RICE YIELD

Three factors random block experiment was carried cut to explorethe effect of simulate damage levels of stem-borers Chilo suppressalis(Walker)and Tryporyza incertulas(Walker),nitrogen levels and densi-ties of rice on the yield loss rate.The results showed that all thefactors have significant effects on rice yield and its constituents.Thedamage thresholds of ear number and rice yield in association with thereduction rate of tiller number were determined.The ear number/mudecreased and the kernel number and fertilized kernel number/ear andthousand dernel weight increased with the postponement of damagetime and increase of damage extent.In 12-14 leaves stage,the 1%-2%decrease of shoot number caused contrarily the rather enhanced riceyield.The effects of nitrogen levels and densities of rice plants on riceyield and its constituents were also discussed in detail.It is suggestedthat 5 kg of nitrogen applied and 34.28 thousands of seedlings trans-planted per mu are beneficial to high yield production.