Effects Of Distribution Patterns Of Nitrogen Fertilizer On Yield, Quality And Nitrogen Uptake Of Rice In Double-Cropping System

Effects of distribution patterns of nitrogen fertilizer on yield,quality and characters of nitrogen uptake in double-cropping rice were studied on the farm of Agricultual Institution Ganzhou, Jiangxi province.The study took early rice Jinyou 463 and late rice Xieyou 46 as test materials. The total applied nitrogen amount of 13.38 kg/mu in the all growth stages ,nitrogen applied at the earlier (basic and tillering) and middle-later stages (panicle development)respectively in a ratio of 10:0, 8:2,7:3,6:4, 5:5, 4:6 and 3:7. The main results were as follows:1. Applied the equally nitrogen rate, the treatment 7:3 achieved the tiptop both in early rice and late rice. The yield of the treatment 6:4 and 8:2 reached or exceeded 500 kg/mu,which were more than that of conventioned nitrogen pattern (early rice yield was 463.73kg/mu while late rice yield was 443.36kg/mu).The yield of treatment 5:5 increased a little but that of treatment 4:6 and 3:7 reduced. The yield of jinyou 463 and xieyou 46 ranked from high to low in different proportion of nitrogen treatment as follows 7:3,6:4,8:2,5:5,10:0,4:6, 3:7.Correlation analysis indicates that it is not significant between distribution patterns of nitrogen fertilizer and ear number per mu along with kilo grains weight while there is parabola correlation between it and grains per spike as well as burliness rate in early rice. While in late rice there is significant correlation between distribution patterns of nitrogen fertilizer and ear number per mu and negative significant correlation with grains per spike and parabola correlation with kilo grains weight and burliness rate. The sequence of contribution rate to yield is grains per spike> burliness rate> ear number per mu> kilo grains weight in early rice while that is burliness rate> grains per spike> kilo grains weight> ear number per mu.2. Reasonable stalk developments is the index of group quality. The time that deferent distribution patterns of nitrogen fertilizer reached maximum of tillers were not the same. The treatment 7:3 of early rice appeared maximum of tillers 5 days before jointing stage however that of late rice appeared 2 days after jointing stage,which arrived the highest yield. Early rice had adequate spikes at N-n+1 stage ,late rice in N-n stage. Early rice had greater spike rate,reached 72.7% while late rice only 58.4%. Correlative data indicates that there existed significant linear correlation between distribution patterns of nitrogen fertilizer and dry matter of N-n stage and jointing stage however parabola correlation with dry matter of heading stage and maturity stage. Dry matter of the treatment 7:3 was higher than other treatments at heading stage and maturity stage and that of early rice was 891.60kg/mu, 513.40kg/mu;that of late rice was 1014.16 kg/mu,641.37kg/mu.In the term of high yield,the ratio of dry matter in N-n to heading stage and heading stage to maturity stage to total dry matter of early rice was 46.5%,45.6% and that of late rice was 42.4%,36.76%.There existed significant linear correlation between dry matter of heading stage to maturity stage while the ratio of heading stage to maturity stage to yield was similar between early rice and late rice (71.5% and 72.1%).3. Study shows that Nitrogen content of N-n stage and jointing stage were gradually samller with earlier stage Nitrogen proportion greater ,but that of heading stage and maturity stage changed contrarily both in early rice and late rice . The ratio of the nitrogen absorbed of N-n stage gradually greater with increasing early stage Nitrogen proportion,while that of jointing stage did not change clearly, that of heading stage changed contrarily .There existed parabola correlation between the quatity of nitrogen absorbed and the ratio to total of heading stage to maturity stage and earlier stage nitrogen proportion however linear correlation with that of N-n to heading stage. In the term of high yield,the ratio of N-n stage to heading stage and heading stage to maturity stage to total nitrogen absorbed of early rice was 46.16% and 23.89%, late rice was 28.78% and 30.56% .Total nitrogen absorbed of early rice was 10.5 kg and that of late rice was 11.8 kg.Nitrogen utilization efficiency of the treatment 7:3 and 6:4 were the highest,that of early rice was 42.8%,41.3% and that of late rice was 42.6%,46.1%.The ratio of ealier stage nitrogen application was small that the N-requirement per 100 kg grain was high .The N-requirement per 100 kg grain highest yield of early rice and late rice were 2.04-2.10kg and 2.00-2.13kg.The N-agronomy efficiency of treatment 7:3 was higher than the others in the double-cropping rice and 12.80kg and 15.70kg grains could be produced per kg nitrogen fertilizer,then the treatment 6:4 could produce 11.06kg and 15.10kg grains ;the treatment 8:2 could produce 10.86kg and 14.40kg grains .As a result under the condition of the total applied nitrogen amount of 13.38 kg/mu in the all growth stage , the ratio 7:3 and 6:4 were easy to increase yield , nitrogen utilization efficiency and the N-agronomy efficiency .4.The test showed that increasing later stage ratio could improve the milling quality both in early rice and late rice in accord with past conclusion .It is complex that nitrogen fertilizer proportion affects external quality .Increasing later stage nitrogen ratio , chalkiness and chalkiness ratio declined gradually which benefits to the milling quality . Diferent treatments affect amylose and protein content insignificantly . Gel consistency first increased and then decreased which shows that the balance of early and late nitrogen application benefit to gel consistency .Diferent nitrogenous fertilizer proportion affect characters of RVA greatly . With decreasing early stage nitrigen ratio ,peak visc, hot plasm visc ,breakdown and final visc first decreased and then increased .Among the treatments ,every character of the treatment 5:5 was the least which indicated that the quality was the worst and increasing early stage proportion could make quality better .But setback changed contrarily and the quality of the treatment 5:5 was the worst. Peak time and pasting temp of diferent treatment varied insignificantly except the treatment 5:5 . Effect of nitrogen proportion on quality were same on early rice and late rice.