论文部分内容阅读
应用Zadoks划分的生育阶级,本研究对冬小麦在第25生育阶段(GS25)的施氮量(N25)进行了测定,其目的在于使先前的预测第30生育阶段(GS30)需氮量(N30)的模型得到更合理的应用。为使施氮量的边际利润最大,在美国弗吉尼亚州6个实验站提出了二次规划模型。利用这些模型,先解决了确定GS25及GS30产生最大效益所需的氮量;其次,在GS25生育阶段分别用0,30,60和100公斤/公顷的施氮水平代替由规划模型确定的施氮量,分别测定各施氮水平的产量和效益。然后再求出规划模型施氮水平所对应的产量(Y)与其他施氮水平各自对应产量(Y~R)之差值(D) (D=Y-Y~R);最后选择D的均值和标准差最小所对应的施氮量作为GS25的最优施氮量。另外,本研究采用了3种氮肥与小麦的价格比(2.0,4.0和8.0),结果表明,当价格比为2.0或4.0时,最佳施氮量为50—60公斤/公顷;当价格比为8.0时,则为40—50公斤╱公顷。
The application of Zadoks classification of the fertility class, the study of winter wheat in the 25th stage of growth (GS25) nitrogen content (N25) was measured, the purpose is to make the previous prediction of the 30th growth stage (GS30) nitrogen demand (N30) The model gets a more reasonable application. In order to maximize the profit margin of nitrogen application, a quadratic programming model was proposed at six experimental stations in Virginia, USA. Using these models, the amount of nitrogen required to determine the maximum benefit of GS25 and GS30 was first determined. Second, nitrogen applied at 0, 30, 60 and 100 kg / ha was used instead of nitrogen The yield and benefit of each nitrogen level were determined. And then find the difference (D) (D = YY ~ R) between the yield (Y) and the corresponding yield (Y ~ R) corresponding to the nitrogen application level in the model. Finally, choose the mean and standard of D The nitrogen application rate corresponding to the minimum difference was taken as the optimal nitrogen application rate for GS25. In addition, the price ratios (2.0, 4.0 and 8.0) of three kinds of nitrogenous fertilizer to wheat were used in this study. The results showed that when the price ratio was 2.0 or 4.0, the optimal nitrogen application rate was 50-60 kg / ha. When the price ratio It is 40-50 kg / ha at 8.0.