长期施用含硫化肥对水稻产量和养分吸收的影响

1975年开始在湖南祁阳红壤站布置了含硫化肥长期定位试验。3个处理(无硫、低硫和高硫)的施硫量分别为0、112、604 kg hm-2a-1。结果表明:SO42-—S在施硫处理的土壤和植株中都有明显的累积,连续施用含硫化肥24年后,表土中SO42-—S含量增加了158~229%,施硫处理稻草中硫浓度比对照高43~57%,而稻谷中硫浓度在处理问无显著差异;施硫对水稻的短期效应(1~7年)为提高产量和品质,中期效应(8~15年)为无显著作用,而长期效应(16年后)为负面影响,长期施用含硫化肥导致水稻(特别是晚稻)对Mg、Fe、B、Mo等元素的吸收量显著减少,并使高硫处理晚稻稻谷产量显著下降(1990~1997年比1982~1989年平均下降31.6%)。

Effects of Long-term Application of Sulfur-Containing Chemical Fertilizers on Yield and Nutrient Uptake by Rice

A long-term trial located in Qiyang,Hunan Province and established in 1975 were used to investigate the effects of sulfur-containing chemical fertilizers on soil and rice.The application rates of SO~(2-)_4-S in 3 treatments(CK,Low S and High S) were 0,112,604 kg ha~(-1)·yr~(-1),respectively.Results obtained were listed as follows.Long-term application of sulfur-containing chemical fertilizers resulted in significant accumulation of SO~(2-)_4-S in the soils and in the rice plants.The concentration of SO~(2-)_4-S in the surface soils(0 to 20 cm) increased by 158-229% after applying sulfur-containing chemicalfertilizers for 24 years.The concentration of SO~(2-)_4-S in the straws of rice in treatments with the application were 143-157% as high as in the treatment with CK.However,the concentration of SO~(2-)_4-S in the grains hadn't obvious difference among the treatments.Application of sulfur-containing chemical fertilizers improved yield and quality of rice from 1975 to 1981.But the application had not obvious effect on yield of rice from 1982 to 1989 and had significant negative effect on the yield after 1990.Long-term application of sulfur-containing chemical fertilizers significantly decreased some micronutrients(Mg,Fe,B,Mo)absorption of rice,especially of late rice.As a result,grain yield of late rice decreased significantly in the treatment with high S.The grain yield'in the treatment with high S in 1990-1997 was 68.4% as high as in 1982-1989.