长期施用含硫化肥对水稻土化学性质和水稻吸收微量元素的影响

Effects of Long-term Application of Sulphur-containing Chemical Fertilizers on Chemical Properties of Paddy Soil and Micronutrients Absorption of Rice

已持续26年的湖南祁阳红壤站长期肥料试验分三个处理:NH4Cl+KCl+KH2PO4;尿素+KCl+过磷酸钙;(NH4)2SO4+K2SO4+过磷酸钙。其土壤、水稻植株样品被用来研究长期施用含硫化肥对水稻土酸化、SO42--S在土壤中累积、土壤-水稻系统微量元素含量和水稻产量的影响。结果表明:大量(667 kg S hm-2 yr-1)施用含硫化肥15年后已导致水稻土表层土壤pH明显下降。不施硫处理SO42--S逐年下降,而施硫处理SO42--S有明显累积。施用含硫化肥24年后(1998),土壤有效Cu、B、Mn及全Ca含量有增加趋势,全Fe有减少趋势,对有效Mo、Zn及总Mg似乎没有影响。长期施用含硫化肥已显著减少水稻(特别是晚稻)吸收Fe、Mo、B、Mg、Cl,并导致水稻(特别是晚稻)产量显著下降。可见,长期施用含硫化肥可能影响水稻土性质进而影响水稻生长。

Samples of soils and rice plants gathered from the three chemical fertilization treatments (NH4Cl + KCl+ KH2PO4, Urea + KCl + superphosphate, (NH4)2SO4 + K2SO4 + superphosphate) of the Long-term FertilizerExperiment, located in Qiyang, Hunan Province and established in 1975, were used to investigate effects of apply-ing sulphur-containing chemical fertilizers on chemical properties of the paddy soil, SO42--S concentration in thesoil, micronutrients in the soil-rice system, and rice yield. Results indicate that high S input rate (667 kg ha-1 yr-1) in the form of sulphate fertilizers for 15 years had resulted in obvious soil acidification, significant accumulationof SO42-S, an increasing tendency of available Cu, B, Mn and total Ca but a decreasing tendency of total Fe.However, there was seemingly no effect in available Mo, Zn and total Mg in 1975~1998. SO42--S decreased in thetreatments without application of the fertilizer. The application also affected micronutrients (Fe, Mo, B, Mg, Cl)uptake of rice, especial late rice. The uptake was obvious greater in the treatments without application than thetreatments with the application and as a result, rice yield was higher in the former than in the latter. It can hencebe concluded that long-term application of sulphur-containing chemical fertilizers could have negative effect onrice growth and paddy soil properties.