蚯蚓堆制猪粪过程中Cu、Zn形态变化与关键酶活性间关系的研究

Relationship between Cu and Zn speciations and key enzyme activity in the process of vermicomposting pig manure

本研究以半腐熟猪粪为研究对象,利用蚯蚓进行生物处理,探讨蚯蚓堆制猪粪过程中重金属形态与关键酶活间的关系。采用MBCR连续浸提法,研究了猪粪中重金属(Cu、Zn)的赋存形态和关键酶(脲酶、蔗糖酶、碱性磷酸酶、脱氢酶)的相关性。试验设4个处理,分别接种3种密度的蚯蚓(基质均为2 kg猪粪):对照处理(猪粪2 kg,不接种蚯蚓,CK);处理1,蚯蚓处理(蚯蚓/基质为1/40,T1);处理2,蚯蚓处理(蚯蚓/基质为1/20,T2);处理3,蚯蚓处理(蚯蚓/基质为1/10,T3)。研究表明,与CK相比,T1、T2、T3各处理的重金属含量与酶活性的变化如下:重金属Cu的含量分别降低了19.66%、24.81%、26.41%,Zn含量分别降低了10.82%、14.34%、19.58%;蔗糖酶活性分别升高55.47%、46.87%和34.83%,碱性磷酸酶活性分别升高了116.38%、100.48%和94.65%,脲酶活性分别降低了42.02%、26.73%和10.08%,脱氢酶活性分别升高了32.79%、58.97%、53.87%。由本试验得出,蚯蚓处理后的堆制物中Cu、Zn两种重金属元素的含量下降,重金属形态随着蚯蚓处理向稳定态转化,两种重金属的形态均表现为残渣态含量较高。蚯蚓堆制过程中,各处理较CK处理能够显著提高酶活性。Cu、Zn的各化学形态与酶活性的关系是,可还原提取态和可氧化提取态对堆制物酶活性的抑制作用最大,残渣态和弱酸提取态对堆制物酶活性有一定的抑制作用,水溶态对堆制物酶活性影响程度较小。

In this research, semi-decomposed pig manure was used to study the relationship between heavy metal speciations and key enzyme activity during vermicomposting. The MBCR method was used to determine the speciations of cooper(Cu)and zinc(Zn). The key enzymes included urease, alkaline phosphatase, catalase, and invertase. The experiment involved four treatments with different earthworm densities for vermicomposting 2 kg of semi-decomposed pig manure. The treatment of the control(CK)only had 2 kg of substrate without earthworms. The earthworm substrate ratio for treatments T1, T2, and T3 was 1∶40, 1∶20, and 1∶10, respectively. The results showed that,compared with CK, the contents of Cu in treatments T1, T2, and T3 decreased by 19.66%, 24.81%, and 26.41%, respectively, whereas the corresponding Zn contents in the treatments decreased by 10.82%, 14.34%, and 19.58%. The enzyme activity of invertase increased by55.47%, 46.87%, and 34.83%, respectively;urease decreased by 42.02%, 26.73%, and 10.08%, respectively;alkaline phosphatase increased by 116.38%, 100.48%, and 94.65%, respectively;and dehydrogenase increased by 32.79%, 58.97%, and 53.87%, respectively, for T1, T2, and T3 treatments. The content of Cu and Zn in the vermicompost decreased, and the speciations of Cu and Zn tended to be stable in residual form. Furthermore, vermicomposting could significantly increase enzyme activity, which was inhibited by the oxidizable and reducible specifications of Cu and Zn, followed by the residual and acid-soluble specifications. Additionally, the water-soluble specifications of heavy metals had little effect on enzyme activity.