Nickel accumulation parameters, coefficients of transfer, tolerance index, and nutrient uptake by red clover grown on nickel polluted soils

Abstract

Red clover (Trifolium partense L.) dry matter and tolerance index (Ti) responses to increasing nickel level varied with soil texture. In general, a reduction in dry matter was observed at Ni levels above 50 mg/kg for sandy loam and loamy soils, and above 10 mg/kg for sandy soil. However, Ni concentration in clover tops increased linearly as applied Ni level increased in soil solution. The rate of increase was in the following order: sandy loam > silt loam > sandy soils. The coefficient of transfer factor for Ni from soil to plant declined in the order: sandy loam > sand > silt loam soils. Nickel accumulation parameter of clover varied with the applied N source. The interaction between applied Ni and some nutrients as affected by the N source was studied. A synergetic effect of applied Ni on N, Ni, Zn, and Cu uptake was observed. In contrast, an antagonistic effect of applied Ni on Co uptake by clover grown on sandy loam soil was observed.