Journal of Hunan Ecological Science

【Objective】To investigate the effect of lime applied to paddy soil with different texture on regulating acid and reducing cadmium. 【Method】The effects of lime on soil pH increase, available cad- mium content decrease and cadmium reduction of rice were analyzed in sand, loam and clay paddy fields in Changzhutan area of Hunan Province. 【Result】Lime application of 1 500 kg / hm2 can significantly in- crease soil pH, reduce soil available cadmium content, and then significantly reduce the absorption and accumulation of cadmium in rice. The effects of acid regulation and cadmium reduction were as follows: sandy soil > loam soil > clay, early rice season > late rice season. In the early rice season, the soil pH increased by 0. 29 ~ 0. 63 units of liming 1 500 kg / hm2 in the early rice season, the available cadmium content in soil decreased by 13. 91% ~ 22. 74% , and the cadmium content in rice decreased by 26. 48% ~ 56. 21% . In late rice season, soil pH increased by 0. 51 ~ 1. 34 units, the available cadmium content in soil decreased by 18. 20% ~ 28. 66% , and the cadmium content in rice decreased by 32. 30% ~ 50. 52% . The cadmium content of early rice in sandy soil, loam soil and clay increased by 25. 75% , 44. 93% and 38. 72% , and that of late rice increased by 44. 60% , 80. 24% and 51. 34% , respectively, with each increment of soil pH 1 unit. 【Conclusion】The effects of lime applied to paddy fields with differ- ent soil textures are different. In the actual production process, a reasonable amount of lime should be se- lected according to soil pollution characteristics, soil pH and soil texture. In particular, the amount of lime applied to clay should be increased to improve the effect of acid regulating and cadmium reducing.

lime; cadmium; soil texture; acid conditioning and cadmium passivation; heavy metal