Abstract:

The aim was to explore the application effects of different water management measures in cadmium (Cd) moderately polluted farmland and ensure food safety production. In this experiment, five water management measures (conventional irrigation, whole growth period flooding, moist irrigation, periodic moist irrigation and twice field drying at tillering-heading stage) were adopted to carry out the indoor pot experiments. The experiment measured the growth status of rice, the Cd content in different parts of rice at various growth stages (tillering stage, booting stage, filling stage and maturity stage), and calculated the Cd enrichment and transport coefficients as well as changes in soil pH and organic matter. The results showed that the moist irrigation treatment increased the 1000-grain weight of rice by 8.64%, and significantly reduced the Cd content in the roots, stems and leaves of rice at tillering stage. Compared with conventional irrigation treatment, moist irrigation could significantly reduce the Cd content in mature rice grains, with a decrease of 78.83% (P<0.05), followed by the whole growth period flooding treatment (with a decrease of 39.69%). In addition, the whole growth period flooding and moist irrigation treatments mainly reduced the Cd content in rice by inhibiting the migration of Cd from stems and leaves to grains. Based on rice production and actual situation, it was recommended to use moist irrigation as a water management measure for rice planting in moderately Cd-contaminated farmland.

Key words: soil heavy metals, moist irrigation, enrichment coefficient, water management, food safety