| The purpose of this study was to explore the effects of different irrigation treatments on soil enzyme activities and heavy metal contents and to evaluate the potential ecological risks of reclaimed water from vegetable residues (VW) and tap water (TW) to provide a theoretical basis for farmland reuse of reclaimed water from plateau summer vegetable residues. The indoor soil column simulation test was conducted and tap water was used as the control. Two irrigation levels of full irrigation (90% field water capacity, 09FC) and inadequate irrigation (70% field water capacity, 07FC) were set. An irrigation period of 18 days was used and 16 irrigation periods were accumulated to study the spatial and temporal variation characteristics of catalase (CAT), urease (UE), sucrase (IA), alkaline phosphatase (ALP) activities and heavy metal (Pb, Zn, Cr, Cd, Cu) contents in soil under different irrigation levels of reclaimed water from vegetable residues, and to evaluate the correlation and potential ecological risk. The results showed that compared with TW-07FC, the UE and IA activities in 0~20 cm soil layer under long\|term reclaimed water inadequate irrigation were significantly increased by 31.36% and 6.55%, respectively. Compared with TW-09FC, the ALP activity was significantly increased by 15.63% under reclaimed water full irrigation (P<0.05). There were no significant changes in CAT activity (P>0.05). With the increase of irrigation times, the two irrigation levels of reclaimed water increased the contents of Pb, Cr and Zn in soil, but the increasing effect was not significant (P>0.05). Compared with tap water irrigation, the content of Cd in soil had no significant change (P>0.05), and the content of Cu in soil tended to decrease. Correlation analysis showed that CAT activity was positively correlated with Cu and Zn contents (P<0.01). IA activity was negatively correlated with Cr content (P<0.05), ALP activity was positively correlated with Zn content (P<0.05), and negatively correlated with Cd content (P<0.05). In condusion, long\|term irrigation with reclaimed water could increase the activities of IA, UE and ALP in 0~20 cm soil, and improve the conversion rate of soil nutrients. Reclaimed water irrigation can cause the accumulation of some heavy metal elements, but it is far below the allowable value stipulated in the soil environmental quality risk control standard for soil contamination of agricultural land. |