玉米是一种产量高而需氮多的作物。在大面积上,由于供氮不足,玉米经常处于饥饿状态,所以任何生育期增施氮肥效果都很明显。但是近年来,杂交玉米普及,氮素化肥增多,一部分高产玉米地,则往往因氮肥施用不合理,引起徒长倒伏,造成减产。如何因条件制宜地合理施用氮肥,目前仍是一个值得探讨的问题。 一、“两头重”施肥法 试验示范概况 关于玉米高产的施肥技术,湄潭县群众在长年累月的生产实践中积累了丰富的经验。早在十年前,联合公社九硐桥生产队老农李正芳提出,玉米最后一次追肥应该在出天花时施用。我们采用他的办法,种2.6亩丰 Corn is a high-yielding crop that requires more nitrogen. In a large area, maize is often starved due to insufficient nitrogen supply, so the effect of applying nitrogen fertilizer during any growth period is obvious. However, in recent years, with the popularization of hybrid corn and the increase of nitrogen fertilizers, a part of high-yield corn fields are often irrigated due to the unreasonable use of nitrogen fertilizers, resulting in the loss of yield. How to apply nitrogen fertilizer reasonably and appropriately is still a problem worth exploring. First, the “two heavy” fertilization test demonstration Overview Maize high yield fertilization technology, the people of Meitan County in the long years of production practice has accumulated rich experience. As early as ten years ago, Li Zhengfang, a veteran of the Jiuzhaodou production team of the Joint Commune, proposed that the last corn top dressing should be applied when it is top-heavy. We use his approach, planting 2.6 acres of abundance