[Dynamics of soil enzyme activity and nutrient content in intercropped cotton rhizosphere and non-rhizosphere]

The study with high yield cotton-wheat double cropping system showed that soil urease, invertase, protease and catalase activities in intercropped cotton field had the same changing trends with those in mono-cultured cotton field, but were significantly higher in intercropped than in mono-cultured cotton rhizosphere and non-rhizosphere at all development stages of cotton. During the intergrowth period of wheat and cotton, soil nutrient contents in intercropped cotton rhizosphere and non-rhizosphere were lower than or had little difference with those in mono-cultured cotton rhizosphere and non-rhizosphere, but became significantly higher after wheat harvested. The changing trends of soil nutrient contents in intercropped cotton field had little difference from those in mono-cultured cotton field, but the nutrient absorption peak appeared late. The soil enzyme activities and nutrient contents were generally higher in rhizosphere than in non-rhizosphere of both intercropped and mono-cultured cotton. Soil nutrient contents had significant (P < 0.05, n = 32) or very significant (P < 0.01, n = 32) correlation with the activities of soil urease, invertase and protease, but had little correlation with soil catalase activity.