Effects Of Different Water Managements On Cadmium Accumulation In Rice

This article researched the effects of different water managements on rice growth, cadmium accumulation in rice, rice yield, soil physical and chemical properties, cadmium forms and soil enzyme activities with growing rice on cadmium contaminated soil with three water managements of flooding, intermittent irrigation and aerobic, which in order to provide guidance for safety of growing rice. The result showed as follows:1. Intermittent irrigation and aerobic have some depressing effects to rice growing but could increase the root activity. They could also increase the absorption of nitrogen, phosphorus and potassium. The tendency of rice yield of different water managements is flooding> intermittent irrigation > aerobic.2. The cadmium content in rice and stem and leaf of flooding is higher than the content of intermittent irrigation and aerobic but lower in root under low cadmium stress. The cadmium content in root, rice, stem and leaf of intermittent irrigation and aerobic is higher than flooding’s under high cadmium stress.3. Soil p H increased as the increasing of soil cadmium content. Intermittent irrigation and aerobic could enhance soil p H in jointing and booting. Soil Eh decreased as the increasing of soil cadmium content. Intermittent irrigation and aerobic could reduce soil Eh significantly.4. Intermittent irrigation and aerobic could reduce the cadmium content in forms of acid extractable, reversible and oxidizable but could enhance the available cadmium content in some growth stages under low cadmium stress. They could enhance the cadmium content in forms of acid extractable, reversible and oxidizable under high cadmium stress.5. The activity of soil urease, neutral phosphatase, catalase and sucrase of intermittent irrigation and aerobic are higher than flooding’s in some growth stages under cadmium stress.6. Microbial biomass carbon and nitrogen content of intermittent irrigation and aerobic were lower than flooding’s in tillering,booting and maturing under low cadmium stress but higher than flooding’s under high cadmium stress.