The effect of graded doses of nickel on the yield, the nickel content of lettuce and the soil respiration

Abstract

In this paper results of a growth experiment carried out with four different uncontaminated agricultural soils and one serpentine soil which is rich in nickel and chromium are presented. The effects of pedogenic nickel and graded doses of applied nickel on the yield and nickel content of lettuce (Laectuca sativa L.) are discussed. In case of neutral to alkaline soils the average percent Ni uptake of the applicated soil nickel through lettuce plants was lower than in acid sandy soils. NaN03‐soluble soil Ni, irrespective of soil type, is better suited to predict the decrease in yield and increase in Ni‐concentration of lettuce leaves as compared to total soil Ni (Added+ Native) and CaCl2 soluble soil Ni. Graded doses of Ni in an acid sandy loam soil showed that IC80 (concentration at which the carbon mineralisation was reduced to 20%) was observed at 90 mg of total soil Ni per kg dry soil. In contrast, NEL (No Effect Level) was observed at 27 mg total soil Ni per kg dry soil.