不同水稻生育期络合型含铁材料对土壤砷的固化作用及稻米安全性研究

Solidification effect of complex iron-containing materials on soil arsenic during different growth stages of rice and its safety study

目的研究络合型含铁材料对土壤中砷的固化效果及其对稻米质量安全的影响。方法选取云南省不同砷背景值土壤,设置添加不同浓度络合型含铁材料的盆栽试验,采用土壤砷形态分级连续浸提法测定水稻生长不同时期的土壤中砷形态的变化,并监测水稻成熟后籽粒中砷的含量。结果高砷风险组土壤酸可提取态砷、可还原态砷和可氧化态砷,随着水稻的生长含量出现变化,其中酸可提取态砷和可还原态砷的变化呈先降低后升高的趋势,一般在抽穗期和灌浆期达到峰值,但高砷风险试验组中土壤残渣态砷没有明显的变化规律。低砷风险组土壤酸可提取态砷、可还原态砷和可氧化态砷呈先升高后降低的趋势,在孕穗期或抽穗期时含量最高;且土壤残渣态砷的含量随含铁材料浓度的增加呈逐渐降低的趋势。结论添加络合型含铁材料浓度为0.10 g·kg-1可以控制低砷风险土壤有效态砷在水稻生育期内的变化,且有降低的趋势,同时可以有效增加残渣态砷的含量,对砷的固化效果明显。且稻米籽粒中砷含量最低,但单独使用含铁材料对稻米籽粒砷含量的降低作用不显著(P>0.05)。

Objective To study the effect of completed iron-containing materials on the solidification of arsenic in soil and its effect on rice quality and safety. Methods Different arsenic background soils in Yunnan province were selected, and pot experiments with different concentrations of completed iron-containing materials were set up. The arsenic speciation of soils in different stages of rice growth was determined by soil arsenic grading continuous extraction method, and the content of arsenic in the grain after rice ripening was detected. Results With the growth of rice, the content of acid extractable arsenic, reducible arsenic and oxidizable arsenic in soil with high risk of arsenic will change. The change of acid extractable arsenic and reducible arsenic showed a trend of first decreasing and then increasing, which generally reached the peak at the heading stage and the filling stage of rice. However, there was no significant change of soil residue arsenic in the high arsenic risk test group. In the low-arsenic risk group, soil acid extracted arsenic, reducible arsenic and oxidizable arsenic increased first and then decreased, and the content was the highest at booting stage or heading stage. Moreover, the content of soil residual arsenic decreased with the increase of iron content. Conclusion Adding 0.10 g·kg-1 iron material can control the effective state of arsenic in rice soil fertility during the period of change, and has a tendency to reduce, which can effectively increase the residual state arsenic content at the same time and the curing effect of arsenic. The arsenic content in rice grains is the lowest, but the effect of using iron-containing materials alone on the arsenic content of rice grains is not significant(P>0.05).