Everyone knows that irrigation is very important to crops, different stage of the drought has big influence on the soil moisture, then the final harvest of crops or fruit trees. Such as soybeans, the soil moisture will down with the length of drought duration, and after some time of drought, the moisture will be stable to a level. After a short time irrigation, the soil moisture will recover quickly. But after long time drought, little irrigation can not guarantee that the soil moisture will recover very quickly, and the accumulation of solid material in the soybeans will with with drought duration length. If not irrigate right during this period, it will take off a large number of the soybean production. So effective and on time irrigation will have a lot of influence on crop production, and selectone excellent advanced auto irrigation controller is very important.