Effects of Soil Matric Potential on Cowpea Yield and Irrigation Water Use Efficiency under Drip Irrigation

An experiment was carried out to investigate the effects of soil matric potential on field-grown cowpea yield and irrigation water use efficiency under drip irrigation in semi-humid areas of north China.The experiment included five treatments,which controlled soil matric potential at 0.2 m depth immediately under drip emitters controlled higher than-10 kPa,-20 kPa,-30 kPa,-40 kPa and-50 kPa,respectively.The results indicated that there were no significant differences on cowpea yield among different soil matric potential treatments.With the decreasing of soil matric potential,seasonal irrigation amount decreased,and irrigation water use efficiency increased obviously.So it is recommended that if cowpeas are well irrigated during establishment,controlling the soil matric potential at 0.2 m depth immediately under drip emitters above-50 kPa can be used as an indicator for drip irrigation scheduling during following period of cowpea growth in semi-humid areas of north China.