Study On Precise And Quantitative Fertilizer Application For High Yield Of Suyu 19

The experiments were conducted in the key laboratory of crop cultivation and physiology of Jiangsu province in Yangzhou University in 2004-2005. Using Suyu 19, a normal corn variety as material, the effect of density, nitrogen (N) application amount and N application on the accumulation of dry matter and the uptake of N, phosphorus (P) and potassium (K) were studied. The indices of the precise and quantitative fertilizer application for the high yield of the variety were clarified. The parameter of N, P and K of precise fertilizer application for high yield were deduced based on the dynamics of the accumulation of the dry matter and the uptake of N, P and K. The main results are as follows:1. The effects of density and fertilizer on the accumulation of dry matter and yieldDry matter accumulation in various stages of individual plant, plant population and grain yield were significantly different under various density treatments. In density treatments, the highest yield of the variety presented in the treatment of 67500 plants.hm^-2, the yield was 12400.7 kg.hm^-2 . The regressive equation of density (X) and grain yield (Y) was Y=-301.48X2+4158.5X^-2778.7(R2=0.9119**).In N application amount treatments, the highest yield of the variety presented in the treatment of 270 kg.hm^-2, the yield was 11910.7 kg.hm^-2. The regressive equation of N application amount (X) and yield (Y) was Y=-0.0669X²+37.476X+5454.3 (R2=0.8735**).On the base of optimal density (67500 plants.hm^-2) and N application amount (270 kg.hm^-2), the highest yield (12034.0kg.hm^-2) was presented when the ratio of base-fertilizer to ear-fertilizer (fertilized at 8-leaf stage) was 1/2 among the N applications. The correlations of the dry matter accumulation amount in seedling-jointing stage (X1), jointing-leaf age12 stage (X2), leaf age12-silking stage (X3), silking -mature stage (X4) with yield (Y) in density treatments, N application amount treatments and N applications were analyzed by multiple regression analysis. The regression equations were Y=-5830.601+1.7267X4 (R2=0.90035^**), Y=11035.8559-7.7357X2+1.2211X4 (R=0.9924^**) and Y=2.739X1+1.016X4+69.528(R2=0.9311^**), respectively. In order to get high yield, controlling optimal dry matter accumulation before silking stage and increasing dry matter accumulation after silking stage.2. The effects of density and fertilizer treatments on the uptake of N, P and KThe regressive equations of density and total uptake of N, P and K in density experiments were Y = -3.5719X2 + 50.004X + 47.552(R2 = 0.7678^*), Y = ^-2.7259X2 + 36.426X- 18.283(R2 = 0.8336^*) and Y = -4.9808X² + 70.805X - 73.865(R₂ = 0.8738*), respectively. In density experiments, the highest uptake of N, P and K were presented in the treatment of 67500 plants.hm^-2, the uptake of N, P and K were 239.14 kg.hm^-2, 115.20kg.hm^-2 and 187.85kg.hm^-2, respectively.In N application amount treatments, the regressive equations of N application amount and total uptake of N, P and K were Y = -0.001X2 + 0.581X + 133.19(R2 = 0.926**), Y= -0.0006X2 + 0.3314X + 64.214(R2 = 0.8914**) and Y = -0.0008X2 + 0.4374X + 101.54(R2 = 0.6906*), respectively. In N application amount experiments, the highest uptake of N, P and K were presented in the treatment of 270 kg.hm^-2, the uptake of N, P and K were 231.46kg·hm^-2, 117.92kg·hm^-2 and 186.36kg·hm^-2, respectively. In N applications, the highest uptake of N, P and K were presented in the ratio of base-fertilizer to ear-fertilizer (fertilized at 8-leaf stage) was 1/2, the uptake of N, P and K were 230.26kg.hm^-2, 110.00kg.hm^-2and 184.50kg.hm^-2, respectively.3. The relationships between the uptake of N, P and K in various growing phases and yieldThe yield of Suyu 19 increased with the increasing of the uptake of N, P and K. The regressive equations of total uptake of N, P and K to yield were Y = 69.108X - 4122.4(R2 = 0.9583**), Y=98.021X + 711.18(R2 = 0.7429*) and Y = 69.475X– 675.69(R2 = 0.9393**), respectively.The relationships between the uptake of N, P and K in seedling-jointing stage (X1), jointing-silking stage (X2), silking-mature stage (X3) and yield (Y) were analyzed by multivariate linear regression analysis, the regression equations were Y=-4323.324+88.645X2+74.2645X3 (R2=0.9679**, the direct path coefficients were 0.4828 and 0.6168), Y=1610.7194+157.8286X3(R2=0.5348*) and Y=-1245.0117 +94.2256X2+74.5156X3 (R2=0.9429**, the direct path coefficients were 0.6821 and 0.4188), respectively. Which indicated that the increasement of the yield was mainly because the N uptake increased after jointing stage. Secondly, the increasement of the accumulation of K also increased the yield.4. The confirmation of Stanford index parameter of N, P and KOn the base of soil productivity (5941.0 kg.hm^-2) and the uptake of N (kg.hm^-2) from soil in the jointing stage, leaf age12 stage, silking stage and mature stage were14.12, 59.26, 95.32 and 135.35, respectively. The uptake of P (kg.hm^-2) at four stages were 7.89, 17.57, 23.82 and 48.47, respectively. And the uptake of K (kg.hm^-2) were 14.70, 47.78, 69.22 and 109.72, respectively. When the target yield was 12000 kg.hm^-2, the requirement of N, P and K was 1.928 kg, 0.944 kg 1.527kg per 100kg grain, respectively. The requirement of N (kg.hm^-2) in four growing stages was 29.94, 116.34, 146.40 and 230.26, respectively. The requirement of P (kg.hm^-2) in four growing stages was 10.85, 27.41, 35.32 and 86.20, respectively. And the requirement of K (kg.hm^-2) in four growing stages was 32.33, 94.38, 132.49 and 184.50, respectively. The utilization efficiency of N, P and K were 44.09%, 25.897%, 63.26%, respectively. The N (pure N), P (P2O5) and K (K2O) application was 222.885 kg.hm^-2, 167.853 kg.hm^-2 and 54.173 kg.hm^-2, respectively.