Direct and residual effect of boron on growth parameters and yield of rice-wheat grown under the Inceptisol of Varanasi

Abstract

A pot experiment was conducted in net house of the Department of Soil Science and Agricultural Chemistry, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, India during kharif 2017 and rabi 2017-18 to evaluate the direct effect boron (B) fertilizers on plant growth parameters of rice and their residual effect on subsequent wheat crop grown in B deficient soil (0.42 mg kg-1). The experiment comprised of 9 B levels i.e., 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 and 4.0 kg B ha-1 in soil as borax (B:11%) along with basal dose of nitrogen, phosphorus and potassium as treatments in a completely randomized design (CRD) with three replications. The result showed that among the levels of boron the direct application of 1.5 kg B ha-1 soil along with RDF to rice was most beneficial and brought highest improvement in growth parameters and on succeeding wheat crop the most beneficial and highest yield was in residual B of 3.0 kg B ha-1. The yield increased due to residual effect of B was statistically lower than the direct effect of B. Boron concentration in soils ranged from 0.54 to 0.43 mg kg-1 in rice and 0.29 to 1.25 mg kg-1 in wheat. The plant growth attributes like plant height, Greenness index, and number of tillers along with yield were increased by the direct and residual effect of B levels. The application of boron did not increase grain yield of rice and wheat significantly over RDF. However, application of B @ 2 kg ha-1 or higher doses significantly decreased the rice grain yield. In, wheat, the grain yield was at par in all the treatments. A significant residual effect of B application in rice was noticed even after the harvest of wheat crop particularly at highest doses of application.