Effect of zinc and boron application on distribution and contribution of zinc fractions to the total uptake of zinc by groundnut (Arachis hypogaea L.) in sandy loam soils of Karnataka, India

To study the effect of zinc and boron application on distribution and contribution of zinc fractions to the total uptake of zinc by groundnut (Arachis hypogaea l.) a field experiment was conducted on sandy loam soil of Shivamogga, Karnataka (Typic Haplustalf). Application of borax @ 5 kg ha-1 did not influence the distribution of zinc fraction in soil. But, an application of zinc sulphate at all the three levels (5, 10 and 20 kg ha-1) significantly increased the water soluble zinc (WS) from 0.36 to 0.52 mg kg-1 and sorbed zinc (SORB) from 3.17 to 4.55 mg kg-1 in soil at harvest of the crop. DTPA-Zn exhibited a positive and significant correlation with WS (r = 0.93**), SORB (r = 0.96**), EMnR (r = 0.94**), CA (r = 0.89**), OM (r = 0.85**) and Fe & Al-ox (r = 0.96**). But, it had a negative and significant relationship with RES (r = -0.69**). Path coefficient results revealed that all fractions except residual zinc significantly and positively correlated with total uptake of zinc by groundnut.