长期定位施肥对非石灰性潮土磷素吸附与解吸的影响

本试验基于非石灰性潮土连续28年长期定位施肥,研究了不同处理对磷的吸附与解吸的影响。结果表明:各处理磷的等温吸附曲线与Langmu ir方程有很好的拟合性。施用有机肥及其配施氮肥处理,都能显著降低土壤的最大吸磷量Xm、吸附能常数k和最大缓冲容量MBC。Xm以M2N1最小,比对照降低312.05μg/g。k和MBC以M2最小,分别比对照减少0.20、139.41μg/g。磷的解吸量与吸附量呈正比。施肥各处理磷的解吸量在不同浓度下均大于不施肥的对照处理,说明对照处理磷的结合能力较强,吸附的磷解吸也较困难,而长期施有机肥及其配施氮肥,尤其是高量有机肥及其配施氮肥的处理,固定的磷容易解吸出来。

Effect of Long-term Located Fertilization on Phosphorous Adsorption and Desorption in Non-calcareous Fluvo-aquic Soil

Based on the long-term located fertilization in non-calcareous fluvo-aquic soil for 28 years,the experiment was carried out to study the phosphorous adsorption and desorption traits of different treatments.The results showed that the adsorption curve of P coincided with Langmuir equation.Application of organic fertilizer and its combination with N could decrease the maximum adsorption capacity(Xm),the constant of adsorption energy(k) and the maximum buffer capacity(MBC).Xm of M2N1 was the lowest,reducing 312.05 μg/g compared with CK.The k and MBC of M2 were the lowest reducing 0.20 and 139.41 μg/g compared with CK respectively.The quantity of P desorption had direct ratio to that of adsorption.The desorption quantity of fertilizer treatments were higher than that of CK at every P level.In result,soil tightly binding with P in CK,the adsorptive phosphorous was difficult for desorption.But in the treatments of application of organic fertilizer and its combination with N,the phosphorous desorption was easy,especially in the treatment with high application of organic fertilizer and its combination with N.