Studies On Planting Citrus For Sustainable Utilization Of Soil Resource In The Southern Hilly Red Soil Region Of Jiangxi Province

With the method of substituting for different year-old citrus gardens by different space-typed ones, this paper systemically studied the effects of planting Nanfeng orange on the uncultivated sloping land in Southern red soil region on the basic soil physical and chemical properties, characteristics of soil micro-organisms, the loss of soil and water, the biomass and varieties of weeds in garden, soil temperature and the concentration of nitrogen oxide n atmosphere. Additionally, this paper also made a comment on the use of pesticides in the production and management of citrus garden through analyzing the fruit quality of Nanfeng orange.The percentage of containing water in the soil,soil bulk density,soil non-capillary porosity,total soil capillary porosity, soil temperature, seepage and quantity of soil and water loss in soil were determined for 1st , 2nd ,4th and 6th year-old citrus gardens and no-exploited garden (control) in Nanfeng county, Jiangxi province to analyze the effect of exploitation of the citrus gardens on the physical property of soil. The results showed that percentage of containing water in the soil increased from 1st year-old citrus garden to 6th , 2nd , and 4th year-old citrus gardens. And they are higher than control (no-exploited garden). The changes on soil bulk density,soil non-capillary porosity and total soil capillary porosity decreased at first, and increased after then in 4 types of citrus gardens . The seepage from 0-100 cm in soil are enhanced with the increased of planting years. Largest quantity of soil and water loss in soil was found in 1st year-old citrus garden. But lower quantity of soil and water loss were observed in 6th, 2nd, , and 4th year-old citrus gardens than in control (no-exploited garden). Our results suggested that the physical property of soil would be improved, soil and water loss would be control and compatibility of water maintain would be enhanced in citrus gardens with the increased of planting years.The organic matter, total nitrogen, available nitrogen, total phosphorus, available phosphorus, total potassium and available potassium in soil were determined for 4 different year-old citrus gardens and no-exploited garden (control) in Nanfeng county, Jiangxi province. The results showed that organic matter in soil decreased from 1st year-old citrus gardens to 2nd , 4th and 6th year-old citrus gardens. Total nitrogen and available nitrogen in soil changed in different year-old citrus gardens. But they except in 4th year-old citrus garden are higher than control (no-exploited garden). Total soil phosphorus and available phosphorus enhanced with the...