土壤酸碱度对水稻生长及稻米镉含量的影响

以5个早稻品种、4个晚稻品种为研究材料,通过盆栽试验研究了不同酸碱度土壤水稻生长发育及稻米镉积累规律。结果表明:品种、土壤pH值及二者交互作用对水稻农艺性状及产量的影响均达到显著水平(P0.05),土壤pH值影响最大;单株产量下降的主要原因为每穗实粒数和结实率下降。早稻品种、土壤pH值及二者交互作用对精米镉含量的影响均达到极显著水平(P0.01),土壤pH值的影响最大;精米镉含量在晚稻品种间存在极显著差异(P0.01),并受土壤pH值的影响,但土壤pH值和品种交互作用的影响未达到显著水平(P0.05)。精米镉富集系数在水稻品种类型之间存在显著差异(P0.05),由高到低为超级杂交稻、常规稻、杂交稻,生育类型不存在主效应(P0.05)。精米镉含量与株高、单株产量极显著相关(P0.01),相关系数分别为0.412、0.371,与穗长、每穗实粒数、千粒重和结实率相关性不显著(P0.05)。在土壤pH值4.0~8.0范围内,精米镉含量与移栽前土壤有效镉含量极显著相关(P0.01),相关系数为0.710。

Effects of soil pH on growth and grain cadmium content in rice

A pot experiment, with 5 early-rice cultivars and 4 late-rice cultivars, was carried out to investigate the characteristics of growth and grain cadmium(Cd) accumulation in rice under different soil pH conditions. The results showed that the main effects of cultivar and soil pH as well as their interactive effects on agronomic traits and yield were significant(P<0.05), and soil pH had the greatest effects. Yield per plant significantly decreased when soil pH was lower than 5.0 or higher than 7.0. The decrease in yield per plant related to soil pH was mainly due to reductions in number of grains per panicle and seed setting rate. Cd content in polished rice was significantly(P<0.01) affected by cultivar, soil pH and their interaction in early-rice, and the greatest effect was caused by soil pH. In late-rice, both cultivar and soil pH significantly(P<0.01) affected Cd content in polished rice, while their interaction was not significant. Significant(P<0.05) difference was observed in Cd enrichment coefficient among cultivar types. Super hybrid rice had the highest Cd enrichment coefficient, followed by conventional rice and hybrid rice. Growth duration had no significant effect on Cd enrichment coefficient. Cd content in polished rice was significantly(P<0.01) correlated with plant height and yield per plant, showing correlation coefficients of 0.412 and 0.371, respectively. There was no significant correlation between Cd content in polished rice with panicle length, number of grains per panicle, 1,000-grain weight and seed setting rate. In soils with a pH range of 4.0 to 8.0, Cd content in polished rice was significantly(P<0.01) correlated with soil available Cd content before rice transplanting, with a correlation coefficient of 0.710.