Assesment of Boron in Soil, Plant and Irrigation Water under Cotton-wheat Cropping System of Northern India

Background: The use of high yielding varieties, high analysis fertilizers and intensive cultivation has depleted the fertility of soils particularly with respect to micronutrients. The deficiency of B is expected to be high in coarse-textured soils having low organic matter, high CaCO3 and high pH. Methods: Geo-referenced surface (0-15 cm, n=155) soil samples, cotton leaves at pre flowering stage (n=75), wheat flag leaves (n=80) and tube well water (n=75) samples were collected from Bathinda, Mansa and Mukatsar districts of Punjab. Result: About 5, 18 and 20 per cent of soil, cotton and wheat samples were deficient in B, respectively. Hot water soluble B in soil was significantly positively correlated with pH (r= 0.230*), ESP (0.680**), B concentration in leaves of cotton (r=0.259*) and wheat (r=0.531**) but negatively with CaCO3 in soil (r= -0.210*). About 40 per cent of tubewell waters had greater than 2.0 mg B l-1. On an average, one cm ha of tube well water may add up to 93g B ha-1 to soil.