| Popis: |
Irrigation and reuse of rural domestic sewage after safe treatment is an effective way to alleviate the contradiction between supply and demand of water resources. In this paper, four kinds of irrigation water sources (primary and secondary treated water R1 and R2, purified water R3 and river water CK) and three kinds of water level regulation (low, medium, and high water level control of W1, W2 and W3) were set to study the impact on soil and crop safety, water and nitrogen utilization, biodiversity, and establish regulation mechanism of rural domestic sewage regenerative irrigation. The results showed that, the contents of Cd and Pb increased slightly, while the contents of Cr, Cu and Zn decreased in paddy field, heavy metals content showed that stem > leaf ≈ rice in rice plants, and did not increase significantly in rice grains. With the increase of field water level, the growth rate of PPCPs (Pharmaceutical and Personal Care Products) in 60–80 cm soil layer was accelerated, and the PPCPs content in rice husk was higher than that in grain, but they were at a very low level. Compared to CK, rural domestic sewage irrigation can effectively increase rice yield, RUE (rainwater use efficiency) and NUE (nitrogen use efficiency of reclaimed water) by 5.4% − 7.6%, 6.7% − 9.4% and 21.7% − 24.2%, respectively. Meanwhile, it can improve the species diversity, community diversity and richness of rice root layer, but the biodiversity decreased with the increase of field water level. Additionally, water level regulation of W3 with R2 water resource irrigation was conducive to the exertion of comprehensive benefits. The results of demonstration area showed that the amount of fresh water was reduced to 530 mm, the yield was increased by 9.6%, and the soil and crop was safety under the reclaimed sewage irrigation. |
