Effects Of Nitrogen Application In Heading Stage On Yield And Quality Of Different Rice Varieties

To clear the effects of urea application amount in heading stage on the growth, yield andquality of rice,the experiments were carried out with randomized block design on857farm in2012, using Longjing26and Longjing31as test materials. Nitrogen fertilizer (urea, N content of46%) was set up five gradient: CK=0kg hm-2、N1=22.5kg hm-2、N2=45kg hm-2、N3=67.5kg hm-2、N4=90kg hm-2, CK was CK. The main results were as follows:1. The effects of nitrogen application amount in heading stage on the growth of riceThe effects of nitrogen fertilizer in heading stage on plant height was not obvious ofLongjing26; The effects of nitrogen fertilizer on plant height and the first panel length; Applynitrogen fertilizer in heading stage was beneficial to plant height of Longjing31, the increasingrange of plant height was4.2%-10.8%;Apply nitrogen fertilizer had an inhibitory action on the first panel length,the treatmentswere2.9%-8.6%less than CK. The plant height and the first panel length of the treatments andCK had reached significant or extremely significant level of Longjing31.2. The effects of nitrogen application in heading stage on quality of rice group(1)Leaf area, high efficient leaf area of rice obviously increased with the increasing ofnitrogen fertilizer amount in heading stage;(2)The total amount of spikelets or valid spikeletswith nitrogen application rate showed a single peak curve, Longjing31was more obvious:Thetotal spikelets (valid spikelets) was5.92Million m-2(5.11Million m-2)with nitrogen fertilizeramount of45kg hm-2;3. The effects of nitrogen application in heading stage on yield of riceApplication nitrogen amount in heading stage and grain yield showed the single peak curve:the quality of Longjing26was the most(10300kg hm-2)with application nitrogen amount of22.5kg hm-2,quality was increased by11.3%; the yield of Longjing31was the most(12730kg hm-2)with application nitrogen amount of45kg hm-2，yield was increased by31.9%,significantly higher than that of CK.4. The effects of nitrogen application in heading stage on quality of rice(1)Nitrogen application amount and brown rice rate, milled rice rate and head milled ricerate showed a single peak curve, nitrogen application amount eached significant or extremelysignificant level and the effect of head milled rice rate; Milled rice rate and head milled rice rateof Longjing26and Longjing31reached the highest value with nitrogen application amount of90kg hm-2；(2)With the increasing of nitrogen application amount, varieties of chalky rice rate and chalkiness degree increase, the chalky rice rate and chalkiness degree increased. Nitrogenapplication amount of90kg hm-2and chalky rice rate and chalkiness degree reached the highest,significantly higher than the control and other treatments;(3)The effects of application nitrogenin heading stage had little difference on taste value; No obvious effect on eating low amount ofnitrogen, the taste value obviously decreased with the nitrogen amount increased.5. The effects of nitrogen application on head milled rice yield of riceThe head milled rice yield and fruiting nitrogen showed a single peak curve, The headmilled rice yield of Longjing26was the most (6821kg hm-2)with nitrogen application amountof67.5kg hm-2, increased by15.8%than that of CK; The head milled rice yield of Longjing31was the most(8869kg hm-2)with nitrogen application amount of45kg hm-2, increased by20.8%-33.1%, significantly higher than that of CK.