目前,全世界有2亿多公顷灌溉农田,常用的灌溉方法主要有三种:1.引水灌溉方法,2.喷灌,3.定位灌溉法。在全球水资源紧缺的情况下,各国都在研究节水省力的科学灌溉方法。确定农作物何时需要灌溉的常用方法如下:1.水平衡法。小区通过计算进、出土壤—植物—气候系统的水量来估算农田灌溉的需要。2.张力测量法。把张力计放在农作物根部,根据张力越大 At present, there are more than 200 million hectares of irrigated farmland in the world. There are mainly three commonly used irrigation methods: 1. Diversion irrigation methods, 2. Sprinkler irrigation, and 3. Positioning irrigation methods. In the context of the global shortage of water resources, all countries are studying scientific methods for saving water and labor. The common methods for determining when crops need irrigation are as follows: 1. Water balance method. The community estimates the need for farmland irrigation by calculating the amount of water entering and exiting the soil-plant-climate system. 2. Tension measurement. Place the tensiometer at the root of the crop, according to the greater the tension