Effect Of N Rate As Basal And Tillering Fertilizer On Rice Tiller And Lodging In Cold Arer Of China

A field experiment with5treatments, different N rate as basal and tillering fertilizer (N1:30kg-hm’2; N2:65kg·hm-2and N3:85kg-hm"2) with the same nitrogen rate as panicle fertilizer (35kg·hm-2), no N fertilization treatment (NO) and total N fertilizer as basal and tillering fertilizer (N4:150kg·hm-2), was conducted to study effects of N management on rice tiller and lodging.Tillers of rice, dry matter accumulation, lodging and yield of rice were measured. The objective of this study was to determine relationship between N rate as basal and tillering fertilizer and rice tiller and lodging in cold area of ChinaThere was no significant difference among the treatments at earlier tillering stage. From panicle initiation to heading, with the increasing of N rate as the basal and tillering fertilizer, the tillers of rice increased. Tiller clearly increased when N rate as the basas and tillering fertilizer ranged from0to65kg·hm-2.When N rate continued to be increased, the increasing of tillers slowed down. At the maturity, the harvested panicles decreased when N rate was over85kg·hm-2. There is a quadratic correlations (p<0.01) between N rate as basal and tillering fertilizer and the panicles of rice. N rate as basal and tillering fertilizer can not be over102kg·hm-2. Otherwise, application N will decrease the tiller number because of low tiller bearing ratio.With the increasing of N rate as the basal and tillering fertilizer, the plant height clearly increased until N rate exceeded the level of65kg·hm-2.There was no significant difference in the length of the basal internode among the different treatments when N rate as the basal and tillering fertilizer didn’t exceed the level of85kg-hm"2, but the length of internode would be clearly increased if N rate exceeded150kg·hm-2. In all treatments, the gravity center height, the steam diameter and the stem wall thickness of N2were the highest The snapping firstly increased, then decreased with N rate as the basal and tillering fertilizer increasing. So that the snapping ofN2was the highest and that of N4was the lowest The lodging resistance index increased with N rate as the basal and tillering fertilizer increasing.In the early growth stage, there are significant positive correlation between N rate as the basal and tillering fertilizer and dry matter accumulation, N accumulation of rice (p<0.01).With the increasing of N rate as the basal and tillering fertilizer, the N content of the plant increased before panicle initiation so that the accumulation of dry matter was clearly improved. N accumulation of rice was significantly increased because of higher N content and dry weight when N rate as the basal and tillering fertilizer increased before heading. The N content of Nl was rapidly increased after panicle initiation and was highest in all treatments at heading and maturity mainly because of its fewer tillers. But its total N accumulation of plant was still less than other treatment due to its less total dry matter accumulation. At the stage of tillering, panicle initiation and heading, N4had the highest dry matter accumulation and N accumulation. N uptake and dry weight of N3were highest at maturing. There were quadratic relationship between N rate as the basal and tillering fertilizer and dry matter accumulation, N accumulation of rice. So the excessive N rate as the basal and tillering fertilizer decreased the yield of rice because of its less dry matter accumulation, larger amount of translocation of stem, higher contribution ratio of stem translocation. At the same time, appropriate basal and tillering N rate increased dry matter accumulation and yield.Experiment result showed that the high N rate as the basal and tillering fertilizer could improve the growing of the plant at early stage, but decreased N accumulation and dry weight because of the bad rice population quality. Appropriate N rate as basal and tillering fertilizer would be able to increase dry matter weight and N uptake after heading, as a result of that it improved big spike initiate and increased1000-grain weight, increased rice yield and N efficiency due to reduce the N loss.