SO42-和Cl-对稻田土壤养分及其吸附解吸特性的影响

利用长期定位试验 ,比较了长期施用含SO₄^2-和Cl^- 化肥 22年后稻田土壤的 pH值、养分状况及其吸附解吸特性。结果表明 ,长期施用含SO₄^2-化肥 ,土壤有机质、速效氮和速效钾的含量较高 ,但全量氮磷钾的含量较低 ;长期施用含Cl^- 化肥 ,土壤全量氮磷钾和速效磷的含量较高 ,但pH值相对较低。长期施用含上述二种阴离子的化肥后 ,土壤对H₂PO₄^-的最大吸附量均较大 ,且在Cl^- 处理下土壤对H₂PO₄^-吸附的结合能较大 ,而SO₄^2-处理下土壤在同等吸附量时对H₂PO₄^-的解吸量相应较多。长期施用含SO₄^2-的化肥亦使土壤对钾素的供应强度较大 (ΔK0的绝对值较大 )、缓冲能力增强 (AR0值较高 ) ,而长期施用含Cl^- 的化肥时则与SO₄^2-相反

Effect of long-term applying inorganic fertilizers with SO42- or Cl- on nutrients and adsorb-desorption in paddy soils

The influences of pH, nutrient situation and absorb-desorption of paddy soil after 22 years long-term experiment of applied inorganic fertilizers with SO₄^2- or Cl^- were studied. The results showed that when applied inorganic fertilizers containing SO₄^2-, there were higher contents of organic matter and available N and K, but the contents of total N, P, K were all relative lower. While long-term application of inorganic fertilizers containing Cl^-, the contents of total N, P, K and available P were higher, but the pH value was lower. It was advantage to increased the largest adsorption capacity of H₂PO₄^- by applying inorganic fertilizers with SO₄^2- or Cl^- for long-term in paddy soil. There was a greater K value of adsorbed H₂PO₄^- by paddy soil when application of inorganic fertilizers containing Cl^-, but the desorption amount of H₂PO₄^- was larger in equal absorption capacity range by paddy soil when applied inorganic fertilizers containing SO₄^2-. Long-term application of inorganic fertilizers containing SO₄^2- was useful to increasing the buffering and supplying power to K⁺, while the effects were just opposite for applying Cl^- fertilizers.