Key Laboratory of Pollution Ecology and Environment Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China.
University of Chinese Academy of Sciences, Beijing, 100039, People's Republic of China.
Environ Sci Pollut Res Int. 2019 May;26(13):12940-12947. doi: 10.1007/s11356-019-04848-1. Epub 2019 Mar 20.
Solanum nigrum L. is a hyperaccumulator and shows very high phytoremediation potential for Cd-contaminated soil. Fertilizer addition to soil is an effective pathway to improve Cd hyperaccumulation. This article compared the strengthening roles of commonly used four nitrogen fertilizers with three organic fertilizers on S. nigrum hyperaccumulating Cd at the same total nitrogen level. The results showed that Cd concentrations in roots and shoots of S. nigrum were not affected by the addition of inorganic nitrogen like NHHCO, NHCl, (NH)SO, and CHNO compared with the control without nitrogen addition. However, Cd concentrations in S. nigrum roots and shoots were significantly decreased (p < 0.05) when the organic nitrogen was added in the form of chicken manure, pig manure, and commercial organic fertilizer (by 15.6% and 15.1%, 30.1% and 23.6%, 20.3% and 16.8%, respectively). On the other hand, of all nitrogen treatments, the addition of (NH)SO and CHNO to the soil enormously increased S. nigrum biomass, i.e., S. nigrum shoot biomass increased 2.0- and 2.1-fold compared with the control. Correspondingly, Cd loads in S. nigrum shoots were also the highest in former two treatments and amounted to 79.91 μg pot and 80.17 μg pot, respectively. Compared with the control, the addition of three organic fertilizers significantly increased (p < 0.05) pH and decreased (p < 0.05) available Cd concentrations in the soil, which could be the main reasons for their negative effects on S. nigrum accumulating Cd. (NH)SO and CHNO significantly increased S. nigrum biomasses and exerted no effects on the available soil Cd concentration, which made them more better fertilizers in practice. In general, the same fertilizer may show different effects on different hyperaccumulators. The selection of fertilizer should be decided in accordance with the specific conditions in the phytoremediation practice of contaminated soil.
龙葵是一种超富集植物，对镉污染土壤具有很强的植物修复潜力。向土壤中添加肥料是提高镉超富集能力的有效途径。本文比较了在相同总氮水平下，常用的四种氮肥和三种有机肥对龙葵超富集镉的强化作用。结果表明，与不添加氮的对照相比，添加碳酸氢铵、氯化铵、硫酸铵和硝酸铵等无机氮源对龙葵的根和地上部镉浓度没有影响。然而，当以鸡粪、猪粪和商品有机肥的形式添加有机氮时，龙葵的根和地上部镉浓度显著降低（p<0.05），分别降低了 15.6%和 15.1%、30.1%和 23.6%、20.3%和 16.8%。另一方面，在所有氮处理中，向土壤中添加硫酸铵和硝酸铵极大地增加了龙葵的生物量，即龙葵地上部生物量比对照增加了 2.0 倍和 2.1 倍。相应地，龙葵地上部的镉负荷在前两种处理中也最高，分别达到 79.91μg 盆和 80.17μg 盆。与对照相比，三种有机肥的添加显著增加（p<0.05）了土壤的 pH 值，降低（p<0.05）了有效态镉的浓度，这可能是它们对龙葵积累镉产生负面影响的主要原因。硫酸铵和硝酸铵显著增加了龙葵的生物量，对土壤有效镉浓度没有影响，因此在实际应用中它们是更好的肥料。一般来说，相同的肥料可能对不同的超富集植物表现出不同的效果。在污染土壤的植物修复实践中，应根据具体情况选择肥料。
