N、P、K肥对玉米幼苗吸收和积累重金属的影响

采用室内盆栽试验,研究复合污染土壤中施加氮肥（NH4Cl）、磷肥（Na2HPO4）和钾肥（KCl）对高生物量经济作物玉米（Zeamays L.）幼苗生长以及吸收和积累重金属的影响。结果表明,不同施肥方式和浓度处理对玉米生物量变化以及吸收重金属有不同影响,NH4Cl能显著提高玉米地上部生物量、土壤Pb、Cd有效态含量,增加玉米对重金属Pb、Cd、As的提取量,最大分别可提高1.7、2.0倍和1.2倍。不同施肥方式和处理浓度均显著影响土壤有效态Pb含量,Na2HPO4在中浓度处理时显著降低土壤Pb的有效性,高浓度时则显著增加土壤有效态As含量,使玉米地上部对As的积累量有明显提高。在不同的浓度水平下,钾肥处理使玉米提取Pb含量显著高于氮肥和磷肥,其中低浓度KCl处理使玉米提取Pb量比对照增加2.4倍。对Pb-Cd-As复合污染农田土壤来说,施用氮肥（NH4Cl）处理对强化玉米的修复效果最好。

Effects of Nitrogen, Phosphorus and Potassium Fertilizers on Heavy Metal Uptake and Accumulation by Maize Seedlings

Lead（Pb）, cadmium（Cd） and arsenic（As） are heavy metals with wide research attention. A pot-trial test was carried out under Pb-Cd-As compounded pollution conditions to study the effects of nitrogen（NH4Cl）, phosphorus（Na2HPO4） and potassium（KCl） fertilizers on seedling growth, heavy metal uptake and accumulation of maize（Zea mays）, which is a high-biomass plant. The results indicated that a significant change was observed in biomass（shoot and root） and heavy metal uptake of maize under different fertilizations and fertilizer concentrations. NH4Cl could significantly increase the aboveground biomass of maize and the accumulated Pb and Cd concentrations in plants. The extractability of Pb, Cd and As increased 1.7, 2.0 folds and 1.2 folds, respectively, with the application of NH4Cl. Both fertilizations and their concentrations could significantly affect the accumulation of Pb in plant. However, Na2HPO4 significantly reduced Pb bioavailability in soil at medium concentration（200 mg·kg^-1）, but significantly increased bioavailable As concentration in soil, which in turn significantly increased As accumulation in the shoots of maize at high Na2HPO4 concentration（400 mg·kg^-1）. Under different levels of fertilizer concentrations, Pb extraction by potassium was significantly higher than that by nitrogen and phosphorus. Compared with the control, KCl could increase Pb extraction for 2.4 folds in aboveground tissues of maize at low concentration（100 mg·kg^-1）. NH4Cl was the most effective fertilizer in enhancing phytoremediation of Pb-Cd-As contaminated soil by maize.