稻壳炭对不同土壤磷淋溶的影响

Effects of Rice Hull Biochar on Phosphorus Leaching from Different Types of Soil

生物炭用作土壤改良剂受到广泛关注,其对土壤磷素有效性的影响研究较少。本研究通过为期52周的室内土柱淋溶试验研究生物炭对3种类型土壤磷淋溶的影响。以500°C温度下热解30min制得的稻壳炭和该水洗稻壳炭为试验材料,分别以15%的重量比添加到酸性红壤、弱碱性风沙土和碱性盐土中,不加稻壳炭的土壤分别为各自处理的对照。试验测定了淋溶液的磷酸盐累积淋失量、土壤pH值、土壤有效磷含量、酸性磷酸酶活性、中性磷酸酶活性和碱性磷酸酶活性。结果表明:稻壳炭可增加红壤的pH值,但会降低风沙土和盐土的pH值;培养第20周之前,生物炭养分被红壤固定,第20周之后,生物炭促进磷酸盐的淋失;在整个淋溶时期内,原样生物炭和水洗炭均促进风沙土和盐土的磷酸盐淋失;原样生物炭在整个培养时期内均显著增加红壤的有效磷含量,但其只在第4周显著增加风沙土和盐土的有效钾含量;生物炭对不同类型酸度土壤磷酸酶活性的影响不尽相同,但部分磷酸酶活性的增强对磷酸盐含量的增加起到一定作用。以上结果表明,稻壳炭促进了3种类型土壤磷酸盐的淋失并能在短期内增加土壤中有效磷含量。

Remediation of soil with biochar has caused extensive concern, and less research has been done on the effects of biochar on phosphorus leaching from different types of soil. Here, we analyzed the effects of amendment with rice hull biochar on three types of soil over 13 months via a laboratory simulation test with soil column. The rice husk biochar was produced at 500 益 for 30 minutes, and washed biochar was made by the rice husk biochar. They were added to acidic red soil, alkaline sandy soil and weakly alkaline coastal solonchak in the weight ratio of 15%, respectively, and the soil without biochar as control. The phosphate cumulative leachate losses, pH, available phosphorus abundance of soils, acid phosphatase activities, alkaline phosphatase, neutral phosphatase activities and alkaline phosphatase activities were determined. The results were as follows that biochar amendment increased the pH of red soil but decreased the pH of both sandy and coastal solonchak soils. Biochar fixated of phosphates before 20 weeks, and it promoted the leaching of phosphates after 20 weeks. Original biochar （OBC） and washed biochar （WBC） accelerated the phosphates leaching in all leaching stages. OBC significantly increased the available phosphorus abundance of red soil, however, it significantly increased the available phosphorus abundance of sandy soil and coastal solonchak in the 4th week. OBC and WBC had different effects on phosphatase activities in different types of soil, but the increase of partial phosphatase activities has a certain effect on the enhancement of phosphate contents. The results were indicated that rice husk biochar accelerated phosphate leaching, and it improved the available phosphorus amounts in short time for these three soils.