三维荧光光谱结合荧光区域指数分析方法评估堆肥腐熟度

摘要

Assessment of compost maturity is a definitive factor for compost product quality. The methods of fluorescence excitation-emission matrix (EEM) spectroscopy combined with fluorescence regional integration (FRI) analysis were utilized to rapidly measure the maturity of compost during composting of rapeseed meal and rice straw. The tested materials were fermented for 16 days including a thermophilic phase of eight days (from the seventh day to the fourteenth day) with temperature over 50℃ and a cooling period from the fourteenth day to the last day with temperature 32 ℃. Dissolved organic carbon ( DOC) , dissolved organic nitrogen ( DON) and electrical conductivity (EC) were stable at a low level at the beginning stage of the composting period (0-6 days) , while these parameters then rapidly increased to 10.47 mg/L, 7.52 mg/L and 5.76 mS/cm respectively. Further investigation revealed that the chemical parameters related to compost maturity showed a significantly positive correlation with the parameters of FRI (i. e. , fulvic acid-like (PⅢ,n) , humic acid-like (PV,n) and their ratio ( PV,n/PⅢ,n) (R > 0. 942, P < 0. 01) and a negative correlation with P1,n (R < -0.871, P < 0. 05). Consequently, the parameters of PⅢ,n, PV,n,PV,n/PⅢ,n and P1,n could be effectively applied as indicators for the assessment of the maturity of composting.%评估堆肥腐熟度是确保堆肥产品质量的重要保证.采用三维荧光光谱结合荧光区域指数分析方法快速评估菜粕和稻糠堆肥过程中的腐熟度.结果表明:菜粕和稻糠堆肥可在16d内完成一次发酵,其中第7～14天为高温期(＞50℃,共8d)；随后,堆体进入降温期,第16天降至32℃.堆肥初期(第0～6天)DOC(溶解性有机碳)、DON(溶解性有机氮)质量浓度和EC(电导率)先稳定在一个较低的水平；在堆肥高温期(第7 ～14天),ρ(DOC)、ρ(DON)和EC则分别迅速升至10.47 mg/L、7.52 mg/L和5.76 mS/cm.堆肥腐熟度相关指标[即ρ(DOC)、ρ(DON)和EC]与FRI(荧光区域指数)方法中PⅢ,n、Pv,n、Pv,n/PⅢ,n指标的变化趋势一致,并且具有极显著相关性(R ＞0.942,P＜0.01)；而与PⅠ,n变化趋势相反,也具有显著的相关性(R＜-0.871,P＜0.05).因此,PⅢ,n、PⅤ,n、PⅤ,n/PⅢ,n与PⅠ,n可以用于表征堆肥腐熟度.