北部黑土区旱年大豆适宜施肥量的研究

试验采用氮磷钾的不同组合，对氮磷钾施用量的配比与北部黑土区旱年大豆产量间的关系及对肥料利用率和经济效益的影响进行了研究。施肥与产量的分析结果表明，当满足磷钾肥施用量时，以氮肥施用纯量为75kg／hm^2的处理产量最高；当满足氮钾肥施用量时，以磷肥施用纯量为90kg／hm^2的处理产量最高；当满足氮磷肥施用量时，以钾肥施用纯量48kg／hm^2的处理产量最高。对施肥量与产量的关系进行回归分析，得出最高大豆产量所需的施肥量为：N78．3kg／hm^2、P2O5 83．3kg／hm^2。通过肥料利用率和经济效益的计算，得出经济效益最高的处理对应的施肥量为：N75kg,／hm^2、P2O5 90kg／hm^2、K2O 48kg／hm^2，相对最佳经济施肥量为：N45kg／hm^2、P2O5 60kg／hm^2、K2O 48kg／hm^2。最终根据当地的气候因素，将北部黑土区大豆最佳施肥量定为：N60kg／hm^2、P2O5 75kg／hm^2、K2O48kg／hm^2，最佳施肥配比为N：P2O5：K2O=1．25：1．56：1。图3，表4，参14。

Study on Soybean Optimum Fertilizing Rate in Drought Year in North Black Soil District of China

The experiment adopts different ratios of N, P and K fertilizer, and the relationships among the ratio of fertilizer, soybean yield, use ra-tio of fertilizer and economic benefit are studied in north black soil district of China in drought year. The testing results show: when P and K fer-tilizer is sufficient, soybean yield is the highest under the N fertilizer application at N 75 kg/hm2,;when N and K fertilizer is sufficient, soybean yield is the highest under the P fertilizer application at P205 90 kg/hm2, when N and P fertilizer is sufficieat,soybean yield is the highest under K fertilizer application at K2O 48 kg/hm2.The results of regression analysis show that the optimum applied amount of fertilizer is N 78.3 kg/hm2 and P205 83.3 kg/hm2 in order to gain the highest yield.By calculating the use ratio of fertilizer and economic benefit,the best appliedamount of fertilizer is N 75 kg/hm2, P2O5 90 kg/hm2, K20 48 kg/hm2 in order to obtaining the highest economic benefit. And the optimum rela-tively economic ratio of fertilizer is N 45 kg/hm2, P2O5 60 kg/hm2, K2O 48 kg/hm2. Finally, according to the climate factors, the optimum ap-plied amount of fertilizer is S 60 kg/hm2,P2O5 75 kg/hm2, K2O 48 kg/hm2 and the optimum ratio of N:P2O5:K2O is 1.25:1.56:1.