Changes of the physical properties of a red soil (oaidsol) undergoing cultivation were observed.The soil is located on the rolling Iand in Ju-Xian county,western Zhejiang province.Field observation reveals that the red soil,once cultivated,usually appeares a friable surface layer which reduces the rate of evaporation of soil water,accelerates the restoration of soil moisture over night,and keeps the soil temperature in a warmer condition in winter.These effects may improve the soil physical condition for better crop growth.On the other hand,cultivation may alas encourage soil erosion in raining season and accelerates the evaporation of soil water in dry summer.Micro-aggregates of red soil seem to afford a better condition of soil fertility.Increasing of micro-aggregates,ranging 0.05-0.01 mm in diameter,oecurres in surface soil as cultivation proceeded.These aggregates,however,become dispersed under water flooded condition as in the case of paddy field.The improvement of physical condition of paddy soil can be accomplished by the application of manures.