营养型阻控剂影响菜园土中水稻生长及其Cd吸收

为了探索以钙硅钾等营养元素为主要成分的土壤调理剂（营养型阻控剂）对镉（Cd）超标菜园土旱改水时水稻（OryzaSativa L.）生长及其Cd吸收的影响，于2014年下半年在Cd超标菜园土中施用营养型阻控剂，对不同用量（分别为0、1.5、3.0、4.5、6.0 g·kg^-1，分别记作CK、T1、T2、T3、T4）营养型阻控剂的水稻盆栽试验开展研究。结果表明：营养型阻控剂对菜园土中水稻生长没有较好的促进作用，没有提高稻谷产量。供试水稻品种黄超占各部位Cd质量分数大小顺序为根>茎叶>稻米>稻壳，且各部位间达到显著差异水平；所有处理稻米Cd质量分数均低于现行的食品安全国家标准中Cd限量指标；与CK相比，营养型阻控剂显著降低糙米、水稻茎叶、水稻根的Cd质量分数，且呈现随营养型阻控剂用量增加而降低效应更佳的剂量效应；与CK相比，处理T4对稻米、水稻茎叶、水稻根三者Cd质量分数的降低效应最佳，降幅分别为32.8%、39.7%、24.4%；营养型阻控剂显著降低水稻根、茎叶和稻谷中Cd的累积量。施用营养型阻控剂显著提高了土壤pH值，提高的最大值为0.3个单位，但对土壤DTPA-Cd质量分数有提高作用（处理T1的DTPA-Cd质量分数显著大于CK、T3）、对土壤有效态硅质量分数有降低效应（处理T2、T3的有效态硅质量分数显著小于CK）。营养型阻控剂可适用于Cd超标菜园土，通过降低根Cd生物富集系数来显著降低水稻根、茎叶和稻米Cd质量分数，本盆栽试验中营养型阻控剂降低稻米Cd质量分数的最佳用量为6.0 g·kg^-1。

Effects of nutria-amendment on the biomass and cadmium uptake of Oryza Sativa grown in vegetative soil

A pot experiment was conducted in 2014, to investigate the effects of a nutria-amendment[0（CK）, 1.5（T1）, 3.0（T2）, 4.5 g·kg^-1 （T3）, and 6.0 g·kg^-1（T4）] on the growth and cadmium（Cd）uptake by Oryza Sativa L. grown in vegetative soil with a Cd concentration over its screening standard. The results showed that compared with the control, the nutria-amendment failed to promote the growth of the whole rice plant, and to increase rice yield. The order of Cd concentrations in the rice tissues from large to small was root > straw> brown rice > husk, with a significant difference among the four rice tissues（P<0.05）. Cd concentrations of brown rice in treatments were all below the national standard value of 0.2 mg·kg^-1. In contrast with the control, the nutria-amendment significantly decreased Cd concentrations in brown rice, rice straw, and rice root, with the highest concentration decrease of 32.8%, 39.7%, and 24.4% observed under the T4 treatment, respectively. Moreover, the higher the dosage of nutria-amendment, the better the effect was on Cd concentration decrease in rice tissues. The nutria-amendment markedly increased the soil pH with the biggest increase of 0.3 units under the T4 treatment, and increased soil DTPA-Cd concentrations（DTPA-Cd concentrations of the T1 treatment were significantly bigger than those of CK and T3）, while reducing soil available Si concentrations of the T2 and T3 treatments were significantly lower than those of CK. Therefore, the nutria-amendment owing to its ability to decrease the Cd bioconcentration factor in the rice root tissues, is suitable for application to the tested vegetative soil with a Cd concentration above its screening standard. Furthermore, the 6 g per 1 kg of vegetative soil was the efficient nutria-amendment dose in the pot experiment to obtain a lower Cd concentration in brown rice.