Growing soybean in high soil moisture

The aim of this work is to study the biological and economic effect of growing soybeans at high soil moisture. The experiment is two-year and was conducted in the experimental field of AU - Plovdiv in 2009 and 2010. The variants are: 1) No irrigation, 2) Irrigation at 80% FC (field capacity), 3) Irrigation at 90% FC. When maintaining higher pre-irrigation moisture, the number of irrigation applications increases by an average of 3, and irrigation rates decrease by between 22 and 53%. The duration of the irrigation period increases by ten days. According to the results, the maintenance of high soil moisture for soybean is unjustified from a biological point of view, since the increase in the productive potential of the plants is not realized in reality. It can be considered that regardless of the irrigation method, the pre-irrigation humidity should be no higher than 80% FC for the soil layer 0-60 cm. When maintaining high soil moisture (above 90% FC), production costs increase by an average of 11%, without increasing the cost price and hardly affecting the net income, and the results for this indicator are not unidirectional.