Quantifying the Role of Crop Management Practices on Seed Yield of Soybean in Gorgan Region in the North of Iran

To quantify the role of crop management practices on seed yield of soybean in Gorgan, 120 soybean farmers’ fields with different sowing dates and different management practices were randomly selected in Gorgan region in the north of Iran, in 2016, 2017 and 2018. Qualitative information was transformed to quantitative data. By using stepwise regression analysis a seed yield model was selected with two parameters including; delay in sowing date and number of irrigation during soybean growing season. The selected model explained 81% of the variation for seed yield. The model showed the importance of sowing date and irrigation for increasing seed yield of soybean in farmers’ fields in Gorgan region. There was negative significant linear relationship between biological and seed yield with delay in sowing date that explained 64% and 70% of the variation for these two characteristics, respectively. Each day delay in sowing date from May 22, biological and seed yield decreased 130 and 56 kg ha-1, respectively. The mean seed yield of farmers’ fields, with 0, 1, 2, 3, 4, 5 and 6 irrigation during growing season, was 955, 883, 1066, 1995, 1990, 2665 and 3769 kg ha-1, respectively. In Goragan region, soybean is planted usually from late may following harvest of winter crops such as wheat and canola. Under these environmental conditions, optimum crop management practices are required in soybean farmers’ fields to achieve high seed yield and sustainable production.