Modeling the Effect of Pot Culture on Yield and Water Use of Soybean in Gorgan

Transplanting or pot culture has been mentioned as a promising approach to increase crop yield and decrease irrigation water use in recent years. Using simulation models to assess pot culture is a valuable way in investigating the effect on yield, water consumption and other properties of crops such as soybean. For this purpose, several pot culture levels (seedling sizes) plus direct sowing were evaluated in soybean using SSM-iCrop2 for four different sowing dates in Gorgan, Iran. Seedling sizes were 13, 18, 24 and 29 cm2 per plant leaf area and at 200, 250, 300 and 350 °C cumulative temperature, respectively. Sowing dates were June 10 (early), June 25 (usual), July 14 (late) and July 27 (very late). The results of simulation showed that direct seed planting method at late sowing date (14 July) and all treatments at very late sowing date (27 July) are not feasible and cannot be recommended due to disturbance that cause in sowing of next crop in double cropping system of the region. Transplanting method at early (10 June), usual (25 June) and late planting dates resulted in earlier maturity. There was no significant difference between two methods regarding seed yield at early and usual planting dates, but at late planting date transplanting method resulted in higher yield compared to direct seed planting method. Seedling size had no significant effect on yield. In addition, there was no significant difference among sowing methods in all planting dates in terms of net irrigation requirement of soybean. It was concluded that transplanting is only preferred at late sowing date for its higher yield, but considering the higher production costs of this method compared to direct sowing, it is necessary to find some cost-effective measures before pot culture could be adopted by farmers.