Critical Limits of Deficiency of Nickel in Intensively Cultivated Alluvial Soils

Abstract

Although nickel (Ni) has been studied a lot as a pollutant, a very few studies have been conducted with this element as a plant nutrient. Present study was undertaken to evaluate the crop response of applied Ni and suitability of the chemical extractants for assessing the available Ni in soil using soybean as a test crop. Fifteen bulk surface (0–15 cm) soil samples with wide variation in physicochemical properties were collected from the cultivated fields of various locations. A greenhouse experiment was conducted to assess the response of soybean to applied Ni (0 and 5 mg kg− 1). There was 16.5 to 26.6% increase in the biomass yield of soybean to the applied Ni (5 mg kg− 1) over control. Effectiveness of diethylene triamine pentaacetic acid (DTPA) soil test for predicting the Ni content in plant improved, when the variation in soil pH was taken into account. Critical limit of deficiency of the DTPA-extractable Ni in soil was 0.17 mg kg− 1, and critical plant Ni concentration of deficiency for soybean was worked out as 0.20 mg kg− 1.