Purpose

Comparatively few field experiments have been conducted to monitor the long-term effects of Si fertilizer amendments on the mitigation of Cd and As accumulation in rice grains.

Materials and methods

A 4-year field trial (eight growing seasons) was established in paddy fields to investigate the effects of different Si fertilizers on the mitigation of Cd and As uptake in rice cultivars. Cultivars for the spring and summer growing seasons were chosen based on their local popularity to investigate the effect of Si fertilizers on different cultivars.

Results and discussion

Average Cd concentrations in spring rice grains (0.020 ± 0.006 mg/kg) were much lower than those in summer rice grains (0.416 ± 0.370 mg/kg) regardless of rice cultivar. Spring rice grains contained slightly higher average As concentrations (0.43 ± 0.07 mg/kg) than summer rice grains (0.30 ± 0.09 mg/kg). Silicon fertilizers, except sodium silicate, significantly decreased grain Cd concentrations. Calcium silicate fertilizer substantially decreased grain Cd, by up to 55.1 ± 17.6%, and to a greater extent than that in response to Si-potash fertilizer, by up to 26.4 ± 7.9%, probably because of competition between Cd and Ca for Ca transport channels. Slow-release Si fertilizer resulted in the greatest decrease in grain Cd concentration (69.0% ± 8.6%). Slow-release fertilizer may provide a longer-term Si source and higher efficiency of use for rice than readily soluble Si.

Conclusions

Silicon fertilizers substantially reduced Cd, but not As, concentrations in summer rice grains for a long term (eight growing seasons). Calcium silicate fertilizer reduced grain Cd concentrations more significantly than potassium silicate fertilizer. Calcium silicate fertilizer exhibited higher efficacy of Cd reduction in grains regardless of rice cultivar or growing season. Slow-release Si fertilizer showed superior ability for Cd mitigation than that of soluble Si fertilizers.

中文翻译：

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在为期4年的田间试验中，硅肥减轻了水稻对镉和砷的吸收

目的

很少进行田间试验来监测硅肥改良剂对缓解水稻籽粒中Cd和As积累的长期影响。

材料和方法

在稻田中建立了一个为期4年的田间试验（八个生长季节），以研究不同硅肥对缓解水稻品种中Cd和As吸收的影响。根据其在当地的流行程度选择春季和夏季生长季节的品种，以研究硅肥对不同品种的影响。

结果和讨论

无论水稻品种如何，春季水稻籽粒中的平均Cd浓度（0.020±0.006 mg / kg）要比夏季水稻籽粒中的平均Cd浓度（0.416±0.370 mg / kg）低得多。春季稻米的平均砷含量（0.43±0.07 mg / kg）比夏季稻米（0.30±0.09 mg / kg）略高。除硅酸钠外，硅肥可显着降低谷物中Cd的浓度。硅酸钙肥料使谷物中的Cd降低了55.1±17.6％，比施硅钾肥时降低了26.4±7.9％，这可能是由于Cd和Ca之间竞争钙运输渠道。缓慢释放的硅肥导致谷物中Cd浓度的下降幅度最大（69.0％±8.6％）。

结论

长期（八个生长季节），硅肥可显着降低夏季稻谷中的Cd浓度，但不会降低As浓度。硅酸钙肥料比硅酸钾肥料显着降低了谷物中Cd的浓度。不论水稻品种或生长季节如何，硅酸钙肥料均具有较高的降低镉含量的功效。缓释硅肥的缓解镉能力优于可溶性硅肥。