Seasonal drought is one of the main constraints to agricultural development of upland in the area of red soil of China.The responses of crops under five farming systems to drought stress are reported in this paper.The differences of water potentials between air and crop leaves were about 100 times higher than those between crop leaves and soil in the surface layer of 10cm.The differences between the latter were around 100 times higher than those between soils in the layers of lOcm and 70cm as well.The differences of water potentials were lower in the treatments of minimum tillage and narrow ridge tillage than those in the treatments of conventional tillage and wide ridge tillage respectively, indicating the serious water stress in former treatments.The results of diurnal variation of water potentials in soil-plant-atmosphere continuum (SPAQ indicated that peanut is more tolerant to drought than soybean and corn.Leaf water potential decreased with the increase of soil water potential and its relationship could be expressed by binomial equations.In the treatments of ridge tillage, leaf water potential was more related to the water potential of soil in deeper layers than to that of soil surface in the treatment of minimum tillage.Water potentials of soils or leaves increased with the increase of soil and air temperatures respectively.The effect of temperature on water potentials of soils and leaves were affected by farming practices and crop communities.Results showed that seasonal drought in the region is caused by integration of water stress and high temperature.