镉污染耕地大豆安全生产模式的探究

为探索大豆在我国南方镉（Cd）污染耕地上安全可行的种植模式，本研究通过低积累品种筛选，结合钝化剂施用，在镉污染安全利用区土壤总镉含量为（0.49±0.04）mg·kg^-1，pH为6.31]开展田间试验。结果表明：各品种大豆籽粒镉含量均未超过国家限量标准，其中浙农6号、浙鲜9号、浙鲜12号和浙鲜19号具有镉低积累性状。将上述4个品种在镉污染严格管控区土壤总镉含量为（1.69±0.25）mg·kg^-1，pH为4.65]开展不同钝化剂施用量对大豆镉积累能力影响试验，发现1 500 kg·hm^-2钝化剂施用下，4个品种大豆籽粒镉含量下降30.4%~79.0%，其中浙鲜9号、浙鲜12号籽粒镉含量降至0.13 mg·kg^-1，符合国家食品安全限量标准（0.2mg·kg^-1）。3 000 kg·hm^-2钝化剂施用量下大豆籽粒镉积累能力与1 500 kg·hm^-2无显著差异。1 500 kg·hm^-2钝化剂处理分别使浙农6号、浙鲜9号和浙鲜12号的产量提高了14.7%、16.7%、16.1%。研究表明，施用1 500 kg·hm^-2钝化剂可使浙鲜9号与浙鲜12号大豆籽粒中镉含量降低至国家食品安全限量标准内。

Research on a safe production method for soybeans on cadmium-contaminated farmland

To discover a safe and feasible planting method for soybeans on cadmium(Cd)-contaminated farmland in southern China, low-Cd soybean cultivars were screened. Combined with the application of soil amendment, a field experiment was conducted in a strictly monitored Cd-contaminated upland field to test the accumulation of Cd in soybean tissues, as well as the yield. Field experiments were carried out in a section of the Cd-contaminated area that was deemed safetotal soil Cd content(0.49±0.04)mg·kg^-1, pH 6.31] in order to screen low Cd accumulation cultivars. The results show that the Cd content of the soybean grains did not exceed the national limit and that the varieties Zhenong6, Zhexian9, Zhexian12, and Zhexian19 exhibited low levels of Cd accumulation. These four cultivars were then planted in a strictly monitored Cd-contaminated upland fieldtotal soil Cd content(1.69±0.25)mg·kg^-1, pH 4.65] to test the effect of soil amendment on soybean Cd accumulation. The application of 1 500 kg·hm^-2 soil amendment led to decreased soybean grain Cd content by 30.4%~79.0%; that of Zhexian9 and Zhexian12 dropped to 0.13 mg·kg^-1, reaching the national food safety limit(0.2 mg·kg^-1). There was no significant difference in the Cd accumulation of soybean grains between treatments with 3 000 kg · hm^-2 or 1 500 kg · hm^-2 soil amendment. The yields of Zhenong6, Zhexian9, and Zhexian12 increased by 14.7%, 16.7%, and 16.1% respectively with 1 500 kg·hm^-2 application of soil amendment. Therefore, applying 1 500 kg · hm^-2 soil amendment and planting Zhexian9 and Zhexian12 can meet the conditions of safe soybean planting in a strictly monitored Cd-contaminated upland field.