Effects of Different Organic Materials and Passivators on Cadmium Uptaking and Balance of Ryegrass in Low Environmental Capacity Soil

A field plot experiment was conducted to study the effect of different passivators, organic materials and their combined application on the growth of ryegrass, Cd uptaking and balance in low environmental capacity soil. The results showed that the yield of ryegrass was increased significantly by 35.76% after applied of organic fertilizer as compared with the control. Application of lime significantly increased soil pH by 0.79 and decreased the available Cd content by 19.34% compared to the control. Similarly, the increase of soil pH was observed after applied of red mud; the using of organic manure could also relief the proceeding of soil acidity effectively. In this experiment, the lime, the red mud and the organic manure all could restrain the bio-availability of Cd and decreased Cd content in ryegrass, especially, the organic manure had the best effectiveness to Cd reduction by 42.71%（p<0.05） compared with the control. Organic-neutralization technology could achieve the purposes of safety ryegrass production and soil acidity modification with low Cd content(<0.2 mg/kg) organic materials or decreasing the use level of organic material to ensure the ryegrass’s quality and soil sustainable use.