Nitrogen and Phosphorus Fertilization for some Atriplex Plants Grown on Metal-contaminated Soils

Abstract

ABSTRACTThere is little information available about the impact of nitrogen and phosphorus fertilization on the uptake of metals by Atriplex plants. A series of pots experiments were conducted to define the metals uptake response of four Atriplex species to urea (U) and superphosphate (SP) fertilization. The studied Atriplex species were river saltbush (Atriplex amnicola), wavy saltbush (Atriplex undulata), quail saltbush (Atriplex lentiformis), and old man saltbush (Atriplex nummularia). The growth and metals uptake of Atriplex species were significantly (P < 0.05) affected by the fertilizer treatments. U reduced the soil pH by 10% compared to the control. SP reduced the availability of Zn, Pb, and Cd by 24, 16, and 28% compared to the control. U increased the shoots Zn and Pb by 16 and 20% compared to SP. The combined application of U+SP reduced the Zn and Pb concentrations in the shoots by 10 and 13% compared to U alone. U increased the root-to-shoot transfer of Zn and Pb by about 30 and 49%. Root phosphorus (P) and calcium (Ca) limit the translocation of metals to the Atriplex shoots and this may be by the precipitation of the metals in the roots. The study clearly showed that it is feasible to apply P fertilizer to alleviate root-to-shoot transfer of Zn and Pb. Moreover, pure N application should be avoided to minimize the occurrence of high levels of Zn and Pb in the Atriplex shoots.