Effect Of N Management On Lodging Resistance Of Daohuaxiang 2

In recent years, there are many researches on the influence of nitrogen fertilizer on rice. But only few are about Daohuaxiang2. The field trials was conducted in 2014 to determine the responses of lodging resistance, group quality, dry matter accumulation and yield of Daohuaxiang2 under different N managements. There are five N management: N0(without N); N1(basal, tillering, panicle:25,0,40); N2(basal, tillering, panicle:25,30,20); N3(basal, tillering, panicle:25,30,40); N4(basal, tillering, panicle:25,30,60); N5(basal, tillering, panicle:25,60,40)(kg N). The main results were showed below:The group quality can be improved at an appropriate N rate, and it is the basic to get a high yield. The earbearing tiller rate increased with panicle-N rate and panicle-N proportion, and declined with basal+tillering-N rate. N5 had the highest earbearing tiller rate. The tiller and panicle number increased with increasing basal+tillering-N rate and panicle-N rate. N4 had the most panicle, which was significant higher than N0, N1 and N2, but there was no significant difference between N3 and N5. The weight of efficient leaf and total effective leaf and invalid green leaf of rice at heading increased with both increasing basal+tllering-N and panicle-N rate. The proportion of efficient leaf increased with increasing panicle-N rate, but it declined with increasing basal+tillering-N rate, N4 had the highest proportion of efficient leaf. The quantity of green leaf reduced more from heading to 23 days after heading at lower panicle-N proportion, and N2 and N5 reduced the most.Optimal basal+tllering-N and panicle-N rate make rice have suitable morphology and mechanics characteristics, then increases the lodging resistance. Rice had sutible plant height and gravity center at an optimal N rate. The length of the first internode increased with increasing basal+tillering-N rate and panicle-N rate, N4 had the highest height of gravity center and plant height. Panicle length increased significantly(p<5%) with increasing panicle-N rate and proportion. When increased the basal+tillering-N rate, the height of gravity center of rice increased first, then declined. The lodging index had a significant positive liner corresponding relationship with the plant height(p<1%). N0 had the highest internode density, reduced basal+tillering-N rate could stop internode density from declining sharply. and lodging resistance had a significant negative liner corresponding relationship with internode density(p<1%). N0 had the lowest lodging index, while N4 and N5 had the highest lodging index. When the total N rate was more than 95kg·ha-1, the lodging index declined significantly.After heading, the dry matter accumulation, especially in the panicle, is the key method to get a high yield. An optimal N rate can make rice had the suitable yield components, then get a high yield. Panicle-N rate had no significant influence on dry matter accumulation at heading, bue the dry matter accumulation at maturity increased significantly with panicle-N. The panicle number increased more with increasing panicle-N rate than basal+tiller-N rate. Filled grain rate and grain number declined with excess N application, and when increased the panicle-N rate, filled grain rate of rice declined significantly. When the basal+tiller-N rate was 55kg·ha-1, and the panicle-N was 40kg·ha-1(N3), we got the highest yield.