【摘要】 从1982～1994年，对稻作制，有机肥和地下水位三因素多水平的定位试验土壤，进行磷的恒温吸附试验，研究不同稻作制和地下水位以及施用有机肥对红壤性水稻土对磷的吸持作用的影响。结果表明，各处理土壤磷的恒温吸附曲线形状都很相似，均属于高亲和力的“L”型曲线，所有吸附资料与三个已知吸附模型的拟合程度均达极显著水平，其中以一元Langmuir模型优于Freundlich和Temkin两个模型。三种稻作制比较，稻稻冬泡土壤对磷的吸持容量明显大于稻稻冬绿和稻稻冬油土壤对磷的吸持容量;施用有机肥和提高地下水位均显著增大土壤对磷的吸持容量。除去土壤游离氧化铁和无定形氧化铁后，土壤对磷的吸持容量显著下降。土壤无定形氧化铁含量与除去无定形氧化铁后土壤对磷的吸持量的降低值和一元Langmuir方程中的Qm值分别呈显著和极显著正相关。稻作制、有机肥和地下水位对供试土壤对磷的吸持作用的影响主要是通过影响其氧化铁的活性实现的。一元Langmuir方程中的Qm值与Olsen──有效磷含量呈极显著负相关。更多还原

【Abstract】 The stationary expenment was conducted for 12 years at Hunan Agricultural University to investigate the effects of rice-based cropping system, organic manure and grotmdwater level on phosphate sorption by paddy soils developed on red earth,in the treatments of 3 types of rice-based cropping systems, 3 application rates of organic manure and 2 levels of groundwater table. Results showed that the phosphate adsorption isotherms for soils in all the treatments are quite similar in shape, belonging to curve in the shape of "L" with high affinity. The adsorption data all fit in well with the three adsorption equations at a very significant level of 1.0 % ,but the One-surface Langmuir equation is better than Freundlich and Temkin equations in this respect. In comparing the three rice-based cropping systems, the soil treated with "early rice-late rice-flooded fallow in winter" has a much larger phosphate sorption capacity than soils treated with "early rice-late rice-green manure crop in winter" or"early rice-late rice-rapeseed in winter". Both applying organic manure and raising the groundwater level significantly increase the phosphate sorption capacity of the soils. After removing free Fe oxides and amorphous Fe oxides from the soil， the phosphate sorption capacity of the soil decreases markedly. The content of amorphous Fe oxides in soil is positively correlated with the decrease in the phosphate sorption capacity of the soil after amorphous Fe oxides are removed and with the Qm value in One-surface Langmuir equation, at a significance level of5.0％ and 1.0％, respectively. The effect of rice-based cropping system, organic manure and groundwater level on phosphate sorption by the tested soils is brought about mainly by influencing the activity of free iron oxides in soils. The Qm value in One-surface Langmuir equation is negatively correlated with the content of Olsen-available P, at a significance level of 1.0％.更多还原