In the south of loess plateau,soil water properties are excellent and crops have a prop-er water environment.The field water condition and its effect on crop yield are appraised anddryland productivitv is estimated.The results show that,the rate of field water deficiency is 30%in the east and 10%in the west;in current condition of productive forces,the potential produc-tivities in dryland are 5330～6330kg/hm² and 7700～9000kg/hm² for wheat and corn respec-tively