Objective To explore the effects of rice-amaranth intercropping on rice yield, rhizosphere soil available nutrient and As accumulation in various parts of rice.
Method Through field plot experiment, four treatments including rice monocropping (control), rice-white amaranth intercropping, rice-grain amaranth intercropping and rice-red amaranth intercropping were setted to study the changes of rice yield and As accumulation, rhizosphere soil available nutrient and organic matter contents.
Result As contents of shoot, root, husk and brown rice during harvest time in four treatments all behaved as rice-white amaranth intercropping > rice-grain amaranth intercropping > rice-red amaranth intercropping > rice monocropping. Compared with the control, rice-white amaranth intercropping significantly increased As contents of shoot, root, husk and brown rice by 88.50%, 65.38%, 68.25%, 45.45% respectively. As extract amount from soil in rice-white amaranth intercropping treatment reached 5.44 mg·m −2, which was 1.67 times significantly higher than control. The biomass per rice plant in rice-white amaranth intercropping treatment was significantly higher than control, rice-red amaranth intercropping and rice-grain amaranth intercropping, and 63.79% higher than control. Compared with control, intercropping treatments significantly reduced rice yield per unit area. Rice-white amaranth intercropping had the highest yield per unit area, which was 59.15% of control. The available nutrient and organic matter contents in rice rhizosphere soil increased in different degrees compared with monoculture.
Conclusion Rice-amaranth intercropping reduces rice yield per unit area, and significantly increases As contents in shoot, root, husk and brown rice, and available nutrient and organic matter contents in rhizosphere soil. Rice-white amaranth intercropping is the optimal scheme, as it extract the most As in As contaminated soil, and the grown amaranth meets national safety standards.