木薯渣堆肥及其对难溶性磷的活化试验研究

Study on cassava waste composting and it's phosphorus transformation with pre-mixing insoluble phosphate

试验以干鸡粪、米糠、堆肥返料作调理剂,同时加入不同含量的磷矿粉,对木薯渣进行好氧堆肥,研究木薯渣堆肥过程中堆肥理化性质的变化及木薯渣堆肥对难溶性磷的活化作用。试验设置磷矿粉加入量10%(T1)、15%(T2)、20%(T3)和不加磷矿粉(CK)四个处理,干鸡粪、米糠、堆肥返料的添加量均为10%、15%和20%。在堆肥过程中,四个处理均在55℃以上高温持续了25d,超过了国家规定的标准。在堆肥结束时,各处理水分含量均降至30%左右,pH升高至弱碱性,淀粉降解率均在90%以上,水溶性碳(DOC)含量均降至10g·kg-1以下,达到了基本腐熟的标准。证明木薯渣通过堆肥能达到稳定无害化状态。在堆肥结束时,T1、T2、T3有效磷增加量分别为12.58、12.81、12.96g·kg-1,对磷矿粉的活化率分别为23.53%、17.07%、14.50%,T1活化效果最好。研究结果表明木薯渣堆肥对难溶性磷有一定的活化作用,可为解决堆肥资源化产品中植物可利用磷含量偏低的难题开拓一条生物学途径。

This study conducted the aerobic composting process of cassava waste mixed with dried chicken manure, rice bran, cas- sava waste compost recycle and powdered rock phosphate. The change of physicochemical properties and phosphorus transformation of insoluble phosphate were analyzed during the composting process. The experimental design of composting included four treat- ments, i.e., addition of rock phosphate at 0 （CK）, 10% （T1）, 15%（T2）, 20%（T3）. In the composting, the addition amount of dried chicken manure, rice bran, and compost recycle were all at 10%, 15% and 20%, respectively. The results showed that in the com- posting process, temperature above 55 ℃ lasted for 25 days which surpassed the national standard. At the end of composting, for all treatments, water content all declined to about 30%, pH value all increased to weak alkaline, degradation rates of starch were all above 90%, and content of dissolved organic carbon （DOC） all decreased to lower than 10 g.kg-1. These results indicate that the four treatments basically reached maturity standard and the composts were stable and harmless. Meanwhile, at the end of composting, the content of available phosphorus ofT1, T2, andT3 increased by 12.58 g.kg-1, 12.81 g-kg-1, 12.96 g＇kgl, respectively and the trasfor- mation rates ofT1, T2, T3 were 23.53%, 17.07%, 14.50%, respectively. The results suggest that insoluble phosphate would be trans- formed to some extent in the process of cassava waste compost, which can provide a biological way to slove the problem of low plant available phosphorus in the composting production.