Study On Soil Sulfur Status And Crop Response To Sulfur Fertilizer In Guizhou

A series of research methods including soil survey, pot experiment, field experiment and chemical analysis were adopted to appraise soil sulfur status and sulfur balance in Guizhou province, to study the effects of sulfur fertilizer on yield and some quality of Chinese cabbage, wheat, rice, rape and maize and the response of one crop to different sulfur fertilizer in field experiment, and to analyze the future of sulfur fertilizer in Guizhou province. The research results were as follows:1. The average of soil effective sulfur concentration in cultivated soil in Guizhou province were 55.2 ±33.4mg/kg, belonging to plentiful area, but there was 33.95% cultivated soils needed appliction sulfur fertilizer. The factors affecting the soil effective sulfur concentration were soil organism, altitude, soil category et al. There was significant relationship between the organic matter and effective sulfur and a significant quadratic regression between the effective sulfur and altitude.2. In the soil that the content of soil effective sulfur concentration was almost 30 mg/kg or lower, the yields of Chinese cabbage, rice, rape and maize were significant increased by applying sulfur fertilizer. The effects were in the order of corn(10.5%~23.5%)>rape(8.7%~15.4%)>wheat(5.8%~13.1%)>Chinesecabbage(7.6%) >rice(4.8%~9.9%).3. The regress eqution between yield of Chinese cabbage and fertilization( N, K, S) wasY=19065+961.5XN+120XK+48Xs-751.5XN2-592.5XK2+493.5Xs2+363XNXK+496.5XNXs-181.5XKXS between nitrate content of Chinese cabbage and fertilization( N, K, S) wasYNO3=688.2+107.6XN-41.2XK-24.4XS-30.1XK2+39.2Xs2-32.5XNXK-29.8XNXS.4. Various S fertilizers had different effect and dosage of application for crop. Because source of sulfur fertilizer was different, price of sulfur fertilizer had big difference. Considering profit of sulfur fertilizer, the most efficient sulfur fertilizer was phosph-gypsum and calcium-superphosphate, followed by sulfur powder and gypsum. The reasonable sulfur dosage should be 31.5~60.0 kg/hm2 for most crops in Guizhou province.5. When the content of soil available sulfur was under 16mg/kg, within!6~30 mg/kg or 30~40 nig/kg, percentages of experiment having 5% significant different level in sum were 100%, 78% or 62.5%, respectively. Sulfur fertilizer is necessary in soils that the content of soil effective sulfur concentration was almost 30 mg/kg or lower.6. Through reckoning, the conrtent of sulfur entering soil was 60.0-91.5 kg/hm2 in upland and 72.0~107.5 kg/hm2 in paddy soil. Corn and rape rotation need 54.6-114.3 kg/hm2 sulfur, rice and rape rotation need 51.2-103.3 kg/hm sulfur. Compared input and output of S in cultivated soil of Guizhou province, there was problems of potential sulfur deficiency in upland soil.7. Assumed 30mg/kg as an index of recommended application sulfur in Guizhou province, the total area of need sulfur cover 33.9% of cultivated land (about 55 x 104 hm2), on the dosage of 50kgS/ hm2, the gross demand of S was 2.75xl04t, equal to phosph-gypsum 22.9 x l04t.