湿解产物与堆肥在土壤中的稳定性和腐熟度比较分析

研究了不同培养阶段湿解产物与土壤混合物(HTS)的物质变化特征、稳定性和腐熟度,并与堆肥和土壤混合物(CS)及自然土壤进行了对比。结果表明:在培养过程中,所有HTS和CS的参数变化趋势相似,HTS的温度变化接近于CS的温度变化,稍高于自然土壤的温度,低于环境温度;pH值变化不大,基本稳定在7.6左右;在培养初期,水溶性有机碳比有机态氮w(WSC)/w(Norg)小于0.55,种子发芽系数(GI)高于80%;培养14d后,w(C)/w(N)降低至小于20,w(NH4 -N)/w(NO3--N)渐渐趋于稳定至小于0.16,GI基本高于100%;49d后,HTS的CO2释放率接近CS和自然土壤的CO2释放率;种子发芽系数的变化表明,湿解产物中含有更丰富的营养元素,可以促进植物根系的生长;相关性分析显示,w(WSC)/w(Norg)、w(NH4 -N)/w(NO3--N)和GI可以作为湿解产物腐熟度的评价指标。综合各项参数表明,湿解产物在土壤中会很快达到稳定,可以安全应用。

Comparison and analysis on stability and maturity of hydrothermal-treatment products and compost in soil

The hydrothermal-treatment products (HTP) and compost mixed respectively with soil were incubated to determine their substance changes and stability in soil. Compared with the incubated natural soil, the results show that the temperature of the HTP in soil approaches to that of the compost and is lower than the environmental temperature during incubation. The pH value of the HTP is about 7.6. The stability of the HTP is accompanied by a decline in w(C)/w(N) (<20), w(WSC)/w(Norg) (<0.55), CO2 respirometry (approaching the CO2 respirometry of soil after 49 days), w(NH4 -N)/w(NO3--N) (<0.16) and an increase in GI (>100%). The changes of all measured HTP parameters in soil approach to those of the measured CS parameters, which shows that the HTP can be safe to apply as a soil amendment. The correlative analysis shows that w(WSC)/w(Norg), w(NH4 -N)/w(NO3--N)and GI can be as the index of the HTP maturity. Furthermore, the HTP contain more nutrient elements than compost does, which can promote plants growing.