| The studies were conducted in the Yangzhou University experimental farm of key laboratory of crop cultivation and physiology of Jiangsu province in 2008-2009. Using two super higher yield normal maize varieties, Suyu20 and Jundan20, which have potential (13500-15000 kg/ha) yield as materials, the nitrogen (N) rate was calculated according to the super higher target yield, the study of precise and quantitative N application was conducted to achieve expected super higher target yield, and the accumulation of N, P and K, with the Stanford equation parameters were clarified. Based on the study, the N precise and quantitative application technology system was constructed, which could afford theory and technique support for maize higher yield and higher efficiency cultivation. The main results were as follows:1. The relations between N application rate and grain yieldGrain yield of Suyu20 and Jundan20 were significantly different under different N rate treatments. In the study, the highest yield for Suyu20 and Jundan20 were presented when N rate was 495 kg/ha, which were 16784 and 16287 kg/ha, respectively. In 2008 and 2009, direct path coefficients of total grain numbers to grain yield were 0.9989** and 0.9892** for Suyu20, 0.9922** and 0.9755** for Jundan20, respectively, indicated that the increment of yield were mainly due to the increment of total grain numbers. The parabola curve of yield were observed with the increment of N rate, the regressive equation of N application amount and yield was y = -0.176x2 + 177.07x– 28304 (R2 = 0.9994**) for Suyu20, y = -0.176x2 + 177.07x– 28304 (R2 = 0.9994**) for Jundan20, respectively.2. The effects of N rate on the accumulation of N, P and KThe results showed that with the increment of N rate (<495 kg/ha), the accumulation amount of N, P and K were increased, whereas it were decreased when N rate were excessive, which presented as a parabola. When N rate was 495 kg/ha, the highest N, P and K accumulation amount were presented, which were 353.9, 175.2, 195.2 kg/ha for Suyu20, and 342.2, 178.9, 204.0 kg/ha for Jundan20, respectively. The regressive equations of N accumulation amount of different organs at maturity and grain yield was Y=-7320.42+87.67X1-409.72X3+134.07X7, with direct path coefficients were 0.2552, -0.5072 and 1.2266 for Suyu20, Y=-1140.67+324.42X2+4.39X3-236.84X5+56.68X7, with direct path coefficients were 0.5426, 0.0054, -0.2283 and 0.6857 for Jundan20, respectively, indicated the increment of yield were mainly due to the increment of N accumulation in grain. In the study, in the treatment with highest yield, the ratio of N, P and K accumulation amount was 1: 0.5: 0.9.3. The relationships between the accumulation amount of N, P and K in various growing phases and yieldThe yield of Suyu20, Jundan20 was increased with the increment of the uptake of N, P and K. The relationships between the uptake of N, P and K in seedling-jointing stage (X1), jointing-sulking stage (X2), sulking-mature stage (X3) and yield (Y) were analyzed by multivariate linear regression analysis. For Suyu20, the equations were Y= -1716.11 +49.92X2 +73.14X3, with the direct path coefficients 0.9897 and 0.9765 for N; Y=-9956.79+1099.89X3, with the direct path coefficients 0.9649 for P, and Y=-2303.404+370.48X2, with the direct path coefficients 0.9871 for K, respectively. For Jundan20, the equations were Y=-1599.45+53.93X2+66.3X3, with the direct path coefficients 0.9954 for N, Y=-11315.13+1189.55X3, with the direct path coefficients 0.9702 for P, and Y=-4678.51+130.41X2, with the direct path coefficients 0.9825 for K, respectively. Based on the equations, it were observed that improvement of yield must increase the N, P and K accumulation amount, and the cultivation measures were focused on the increment of N and K amount between jointing and flowering, and the increment of P amount after flowering.4. The confirmation of Stanford index parameter of NBased on the soil productivity 6052kg/ha and soil N supply 170.95 kg/ha for Suyu20. Under the treatment with highest yield, the requirement of N for 100 kg grain was 2.11kg and N use efficiency was 37.0%. According to Stanford equation, achieve the target yield (15000 kg/ha), the N application was 389.2 kg/ha. Based on the soil productivity 6171 kg/ha and soil N supply 159.7 kg/ha for Jundan20. Under the treatment with highest yield, the requirement of N for 100 kg grain was 2.10kg and N use efficiency was 36.9%. According to Stanford equation, achieve the target yield (15000 kg/ha), the N application was 420.0 kg/ha.
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