Identifying soybean yield-limiting factors by using Comparative Performance Analysis (Case study: Golestan province - kalaleh)

One of the main problems of soybean production in the east region of Golestan, Iran province is considerable difference between actual yield and attainable yield which is called yield gap. In recent years, this gap has been impressive, and therefore, identifying soybean yield-limiting factors are essentially needed. The present study was conducted based on CPA method in 73 fields of Kalaleh )Golestan, Iran) in 2016. In this study all information related about management practices, soil characteristics and farmer socio- economic status were measured and recorded. Then, using stepwise regression, the relationship between variables and yield were considered. The results showed that there is a 2606.4 kg/ha difference (gap) between actual yield (average farmer's yield) and attainable yield (maximum farmer's yield). It was identified that farming experience, burying Plant residues in the soil, planting date, Sprinkler irrigation, the amount of used water and plant density were contributed to yield gap, 30.1, 5.1, 14.7, 13.8, 13.8 and 22.5 percent, respectively. It could be concluded that improving these factors will increase the yield up to 1802.9 kg/ha.