Effects Of Application Of Nitrogen Fertilizer On Yield And Quality Of Rice Seedlings Broadcasted Among High Standing-stubbles Under No-tillage Condition

Effects of different nitrogen applying amount (75,150,225 kg/hm~2) and assigning proportion of nitrogen fertilizer(applying basic N ,tillering N and panicle N as 10:0:0, 7:3:0, 7:0:3 and 4:3:3)on yield and grain quality of Rice Seedlings Broadcasted among High Standing-stubbles under No-tillage condition were studied, by taking the treatment without applying nitrogen as CK. The results showed as follows:1. Increasing nitrogen applying amount accelerated the happening of tillers. Moreover, with the increasing of the amount of nitrogen applied, the leaf area and SPAD value of flag leaf enhanced, the leaf area index(LAI), specific leaf area (SLA), leaf area ratio (LAR), and leaf area duration (LAD) improved obviously, and they were all higher when applying N as 7: 0: 3 and 4: 3: 3 at late growth stage.2. With the increasing of amount of nitrogen applied, amount of dry matter accumulated at every growth stage increased, and weight of dry matter per day also improved. With the increasing of amount of nitrogen applied, the percentage of dry matter distributed to leaf increased, that distributed to stem and panicle declined. As far as the percentage of dry matter distributed to leaf was concerned, the two assigning proportions which applying N as 10: 0: 0 and 7:3:0 was separately higher than the other two proportions which applying N as 7: 0: 3 and 4:3:3, but as far as the percentage of dry matter distributed to panicle was concerned, the trend was opposite.3. Nitrogen is the indispensable nutrient to rice production. Increasing nitrogen applying amount, improved N-content of leaf and stem ,and increased the amount of N leaving in straw at maturing stage(MS). With the increasing of nitrogen applying amount, total N accumulated(TNA) at every stage improved notably, but N production efficiency and N harvest index (NHI) reduced. At tillering stage(TS) and jointing stage (JS), TNA was higher when applying N as 10: 0: 0 and 7: 3: 0, but at heading stage (HS )and MS, it was higher when applying N as 7: 0: 3 and 4: 3: 3. According to regression analyzing, parabola relationship between yield and TNA at MS was found, from the equation it could be caculated that the yield was highest when N-uptaking amount was 150.5 kg/hm~2.4. Yield varied under different N application. With the increasing of nitrogen applying amount yield improved, and it was highest when amount of N applied was 150kg/hm~2, but the increasing extent of the yield took on falling trend when amount of N applied was beyond 150kg/hm~2. Among four different assigning proportions of nitrogen fertilizer, the yield of which applying N as 4:3:3 was highest of all. Increasing nitrogen applying amount affected the component of yield too, the number of effective panicles improved obviously, the seed setting rate descend, and the number of seed per panicle improved in some scope, but at high N level it declined.5. Increasing the nitrogen applying amount properly ,in certain range, was good for improving nutrient quality, machining quality and cooking quality, but the high N rate was bad these important quality characters such as milled rice rate, head rice rate and for chalkiness. Under different condition of N-application, the character of RVA profile of rice flour varied, peak viscosity and setback fell with the increasing of nitrogen applying amount, pasting temperature and breakdown value improved,...