论文部分内容阅读
众所周知,氮、磷、钾肥是农业生产中的三大主要肥料。但如何把有限肥料较合理地分配于不同的土壤和作物,以提高肥料的利用率,却未必为广大农民所认识和掌握。同时,肥料施用合理还有利于维持土壤养分平衡、保护农业土壤环境、适应农业持续发展需要。本文即从这两方面考虑,对如何合理分配和施用氮磷钾肥问题作一般性概述,以期能帮助广大农民改变施肥上的一些错误观念和方法。一、氮肥的合理分配和施用 1.氮肥的合理分配①根据气候条件一般干旱年份或干旱地区氮肥肥效较差,湿润年份或湿润地区氮肥肥效较好。干旱条件下,作物对氮肥用量多少反应较小,产量曲线平缓;而水分供应充足时,作物对氮肥用量多少反应较大,产量曲线陡直上升。我国北方地区气候干旱缺雨,土壤墒情较差,作物生长期间,氮素淋溶损失不大,因此,根据肥料特性,氮肥分配上以硝态氮肥更适宜。我国南方气候湿润,年降雨量大,水田居多,氮素淋溶和反硝化损失较重,因此适宜分配铵态氮肥,施用时硝态氮肥尽量分配在旱作上,铵态氮肥施于水田。②根据土壤肥力条件中、低产地块每公斤氮肥的增
It is well known that nitrogen, phosphorus and potassium fertilizers are the three main fertilizers in agricultural production. However, how to allocate limited fertilizers more rationally to different soils and crops so as to improve the utilization rate of fertilizers is not necessarily understood and mastered by the majority of peasants. At the same time, the rational use of fertilizers is also conducive to maintaining soil nutrient balance, protection of agricultural soil environment, to meet the needs of sustainable development of agriculture. This article from these two considerations, on how to reasonably allocate and apply nitrogen, phosphorus and potassium fertilizer to make a general overview, with a view to helping the majority of farmers to change some of the wrong ideas and methods of fertilization. I. Rational Distribution and Application of Nitrogen Fertilizer 1. Rational Distribution of Nitrogen Fertilizer ① According to the climatic conditions Generally, nitrogen fertilizer has poor efficiency in dry years or arid areas, and nitrogen fertilizer has good efficiency in wet years or humid areas. Under drought conditions, the crops responded less to the amount of nitrogen fertilizer and the yield curve was gentle. When the water supply was sufficient, the crops responded more to the amount of nitrogen fertilizer and the yield curve rose steeply. In the northern part of our country, the climate is arid and rainy, with poor soil moisture. During crop growth, the nitrogen leaching loss is not large. Therefore, according to the characteristics of fertilizers, it is more suitable to use nitrate nitrogen fertilizer to distribute nitrogen fertilizer. In southern China, the climate is moist, annual rainfall is large, mostly paddy fields, and nitrogenous leaching and denitrification are heavier. Therefore, it is suitable to distribute ammonium nitrogen fertilizer. When applied, nitrate nitrogen fertilizer should be distributed in dry farming and ammonium nitrogen fertilizer in paddy field. ② According to soil fertility conditions, low yield plots of nitrogen fertilizer per kilogram