不同磷石膏添加比例对稻壳与油枯堆肥过程的影响及基质化利用的评价

Effect of phosphogypsum addition on the rice husk and oil cake composting process and evaluation of its physicochemical character as a substrate

为探索稻壳和磷石膏两种固体废弃物资源化利用的新途径,以稻壳和油枯为发酵堆体原料,研究添加磷石膏对堆肥基质化发酵进程及腐熟后基质品质的影响。磷石膏添加量基于堆体有机物料(干重)的10%、20%、30%、40%和50%(分别记为A10、A20、A30、A40和A50),以磷石膏添加量为0作为对照(CK)。结果表明,磷石膏的添加促进了堆肥温度的快速升高,但其添加量超过有机物干物质的40%时会导致堆肥高温时间变短;以堆肥过程中水溶性NH_4^+-N、C/N、T_(C/N)值[(不同时期C/N)/(初始C/N)]和种子发芽指数(GI)作为堆肥腐熟的判断标准来综合判断堆肥腐熟进程,表明添加磷石膏可以促进堆肥发酵进程,其中A40处理的堆肥发酵效果最好。从基质化利用的角度来看,堆体腐熟结束时,A40处理的全磷和全钾含量均显著高于其他处理,堆体容重、持水孔隙度、通气孔隙度等指标均达到了理想性基质的要求。A40处理腐熟后的堆肥更适合作为作物栽培基质。

In this study, rice husk and oil cake were used as main raw composting materials, and different proportions of phosphogypsum were added to study the effect on composting efficiency and compost quality as a substrate. The proportions added were 0, 10%, 20%, 30%,40%, and 50% of the dry weight base. The six treatments were referred to as CK, A10, A20, A30, A40, and A50. The results showed that the addition of phosphogypsum was beneficial for rapid temperature increase and retaining this temperature for a long time. However, the thermophilic phase was shortened when the added dose of phosphogypsum was over 40%. The content of water-soluble NH4＋-N, the C/N ratio,the T（C/N）value（the ratio of C/N in different periods from the beginning of composting process）, and the germination index（GI） during the composting process were used to comprehensively evaluate the composting efficiency. The results indicated that the addition of phosphogypsum could promote the fermentation process during composting, especially for the A40 treatment. As substrates, the total phosphorus and total potassium contents were significantly higher in the A40 treatment than for the other treatments, and the bulk density, water-holding porosity, and ventilatory porosity of the composting mass met the requirements of an ideal substrate.