Effect of Sulphur in Rainfall, Irrigation Water and Percocolating Water on Soil Sulphur in Jiangxi Province

摘要

Ten rainfall and irrigation water-collecting posts were set up in different ecotype districts of Jiangxi rnProvince, China, to quarterly measure S content in rainfall and irrigation water. A rainwater chemical rncomposition-collecting device was used to collect the sulphur in rainfall, and the amount of sulphur adsorbed rnon the resin column in the device was determined. The soil percolating water was gathered using 6 lysimeters,rnbuilt up according to the profile sequence of the red soil derived from red sandstone and the red soil derived rnfrom Quaternary red clay, separately. On the lysimeters peanuts, soybean and radish were grown in rotation.rnTwo treatments were designed: without S addition and with S addition at a rate of 14 kg S ha-1. The SO42-rncontents in rainfall, irrigation water and soil percolating water were determined by the turbidimetry.rnThe results in 1997 showed that the average annual S content in rainwater was 28.13 kg S ha-1, the rnaverage S content in irrigation water was 1.7 mg S L-1, and the average content of SO24- in soil percolation rnwater was 2.30 kg S ha-1 year-1 and 4.70 kg S ha-1 year-1 in treatments without and with sulphur rnapplication, respectively. In Jiangxi Province, apart from the losses by runoff and leaching, the sulphur in rnrainfall available to crops is 7.3 kg S ha-1 year-1 and additional S application is required. When rice is rngrown, however, irrigation water can supply 6.9 kg S ha-1, which, along with the sulphur in rainfall, can rnalmost meet the S requirement of one cropping of rice.