赤日炎炎,“大雨”倾盆,茁壮粗大的玉米植株上,一张张湿漉漉的叶片,水珠淋淋。这是在中午的玉米地里,喷灌在大显身手。人们都认为,喷灌有很多优点,如浇灌均匀,省水,不受地形限制等。但是,美国农业部盐水灌溉实验室的科研人员认为,喷灌虽好,但还要使用得法。否则,利害相抵,得不偿失。例如,日当中午,阳光直射,温度高,蒸腾大,浇在叶片上的水很快蒸发,最 Red hot, “heavy rain” pouring, robust corn plants, a piece of wet leaves, dripping water. This is in the noon of the corn fields, sprinkler irrigation in their display. People think that sprinkler irrigation has many advantages, such as watering evenly, saving water, without terrain restrictions. However, researchers at the U.S. Department of Agriculture’s Salt Irrigation Laboratory believe that sprinkling irrigation is good but it is also well-used. Otherwise, the balance of benefits will outweigh the benefits. For example, at noon in the afternoon, direct sunlight, high temperature, large transpiration, water poured on the leaves quickly evaporated, most