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

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.

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 Muktsar districts of Punjab.

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 >2.0 mg B l^-1. On an average, one cm ha of tube well water may add up to 93 g B ha^-1 to soil.