蒙脱石对有机物料施入土壤磷形态和有效性的影响

以冷砂黄泥和矿子黄泥为研究对象,猪粪沼渣为有机物料,分别添加0%、5%、7.5%和10%质量分数的蒙脱石,采用室内培养试验研究了蒙脱石对施有机物料土壤pH、磷形态和有效性的影响.结果表明,有机物料对两种土壤pH无显著影响,而蒙脱石使土壤pH显著提高.施加有机物料使两种土壤铝结合态磷(Al-P)含量和分布比例提高,铁结合态磷(Fe-P)含量培养后期提高、比例略有下降,闭蓄态磷(O-P)含量无明显变化、比例下降.有机物料对冷砂黄泥中钙结合态磷(Ca-P)的含量无明显影响、比例下降,却使矿子黄泥Ca-P含量和比例提高.在施加有机物料基础上添加蒙脱石后,冷砂黄泥Al-P和O-P含量和比例下降,Fe-P含量无明显变化、比例下降,Ca-P含量和比例大幅度提高;矿子黄泥Fe-P和O-P含量和比例下降,Al-P含量无明显变化、比例下降,Ca-P含量和比例大幅度提高.培养过程中,有机物料使冷砂黄泥和矿子黄泥有效磷含量分别提高了17.9%~38.0%和17.1%~33.7%,土壤磷的活化系数也显著提高,添加蒙脱石后使两种土壤有效磷含量分别降低8.8%~35.5%和1.1%~11.6%.相关分析结果表明,蒙脱石通过提高pH和Ca-P含量、降低Al-P含量降低冷砂黄泥磷的有效性,通过提高pH、降低Fe-P含量降低矿子黄泥磷的有效性,对冷砂黄泥磷有效性的影响较矿子黄泥大.

Effect of Montmorillonite on Fractions and Availability of Phosphorus in Soils Applied with Organic Fertilizer

An incubation experiment was carried out to study the effect of montmorillonite on pH, the fractions and availability of phosphorus in a sandy yellow soil (SY) and a mineral flavicant soil (MF) applied with biogas residues of swine manure (BSR). The rates of montmorillonite applied were 0%, 5%, 7.5% and 10%, respectively. The results indicated that soil pH was not affected by BSR, but was significantly increased by montmorillonite. In both soils, application of BSR caused an increase in the content and proportion of Al-P during the incubation, and an increase in the content but a slight decrease in the proportion of Fe-P in later period of incubation. The concentration of O-P was not markedly changed, but its proportion was decreased by applying BSR in both soils. The changes of Ca-P varied with soils. BSR had no significant influence on Ca-P content, but decreased the proportion of Ca-P in SY, meanwhile, it increased both Ca-P content and proportion in MF. Addition of montmorillonite in soils applied with BSR decreased the contents and proportions of Al-P and O-P, and the proportion of Fe-P did not change the contents of Fe-P, but increased the content and proportion of Ca-P in SY. In MF, montmorillonite could decrease the contents and proportions of Fe-P and O-P, and the proportion of Al-P did not affect the content of Al-P, but increased the contents and proportions of Ca-P greatly. The contents of available phosphorus (A-P) were enhanced by 17.9%-38.0% and 17.1%-33.7% in SY and MF respectively, and the phosphorus activation coefficient (PVC) was significantly improved in both soils by applying BSR. The contents of A-P were reduced by 8.8%-35.5% and 1.1%-11.6% in SY and MF respectively. Correlation analysis showed that montmorillonite reduced the availability of phosphorus through increasing pH and contents of Ca-P, decreasing the content of Al-P in SY, and through increasing pH and decreasing content of Fe-P in MF. The availability of phosphorus in SY was influenced more obviously than that in MF by montmorillonite.