作物不同,吸收营养物质种类和数量就不同。收获后土壤中残留的有效养分有差别,根系分泌物、伴生杂草、病害、虫害也不尽相同。所以,不同作物对下茬的影响不同,就形成了茬口的好坏。但是,茬口的好坏不是绝对的。如大豆茬通常认为是最好的茬口,对很多作物都有利,但对大豆本身来说却是不好的茬口。了解茬口和科学换茬是作物高产稳产的重要措施。 大豆茬 农民称之为软茬、油茬。大豆根可固氮,又有残根落叶遗留土中,能增加土壤中氮素和有机质,显著提高土壤肥力和作物产量,因而可作许多作物的良好前荐。但大豆茬不宜种甜菜、烟草、啤酒大麦,否则 Different crops, different types and amounts of nutrients are absorbed. There are differences in effective nutrients remaining in the soil after harvest, root exudates, associated weeds, diseases, pests are not the same. Therefore, the impact of different crops on the next crop is different, it formed a stubble good or bad. However, the quality of stubble is not absolute. Such as soybean stubble is generally considered to be the best stubble, for many crops are beneficial, but for soybean itself is a bad stubble. Understanding crop stalks and scientific cropping is an important measure of high and stable crop yield. Soybean stubble farmers called stubble, oil stubble. Soybean root can be nitrogen, there are residual leaves remaining leaves, can increase soil nitrogen and organic matter, significantly improve soil fertility and crop yield, which can be used for many crops before the recommendation. However, soybean stubble should not beet, tobacco, barley beer, or else