DTPA-extractable Zn, Cu, Mn and Fe in Trans-Gangetic Plains of Northern India

Abstract

Samples of surface soil, covering Trans-Gangetic Plains of northern India, were analysed for DTPA-extractable micronutrient cations and soil properties. The soils were alkaline in reaction with low salt content and low to medium in organic carbon content. These soils were somewhat calcareous in nature and loamy sand to sapdy loam in texture. Considerable variability in the contents of different micronutrients was observed, however, mean value for available Zn, Cu, Mn and Fe were 0.37, 0.87, 7.11 and 4.91 ppm, respectively. Majority of the soils were deficient in Zn, marginal in Fe and sufficient in Cu and Mn. Available Zn, Cu, Mn and Fe were significantly and negatively correlated with pH and positively with organic carbon. The multiple regression equations revealed 7, 23, 3 and 14% variations in available Zn, Cu, Mn and Fe, respectively, were accounted for by the combined effect of pH, EC, CaC0₃ and organic carbon contents. Organic carbon/organic mailer was found to be the most effective soil parameter affecting the status of micronutrients in the soils.