Long-Term Impact of Boron Addition at Various Dosages to a Groundnut-Cabbage System on Crop Yield and Boron Dynamics in Typic Haplustepts

The addition of boron (B) fertilizers to soils with low B content is required for augmenting crop yield. Therefore, it is imperative to have knowledge about the impact of long-term B addition at various dosages on crop yield and soil-B dynamics. A field experiment of a 6-year duration was carried out at Anand Agricultural University, Gujarat, India to study the influence of long-term B fertilization in the groundnut ( Arachis hypogaea L.)-cabbage ( Brassica oleracea var. capitata) cropping system in different rates and frequencies on yield of crops and soil-B dynamics. The direct effect of B addition on groundnut yield and the residual effect on succeeding cabbage crop yield was eval-uated. The treatments of the experiment encompassed various combinations of three frequencies and four rates of B application including one control (no B application). The application of B at different rates and frequencies significantly increased groundnut and cabbage yield in comparison to yield attained under the control. The addition of 1.0 kg B ha −1 in alternate years was found op-timum for enhancing the yield of groundnut and cabbage crops grown on study soil. Boron appli-cation enhanced B content in groundnut pod, haulm, cabbage and available B in soil. Optimal available B content in soil was 1.25 mg kg −1 for both groundnut pod and cabbage-head yield. The application of B with different rates and frequencies significantly enhanced B fractions in soil. The content of different fractions improved with the increase in rates of B application. The percentage contribution of various B fractions towards total B content followed the order: readily soluble B (0.43 to 0.55%) < specifically adsorbed B (0.74 to 0.98%) < organically bound B (0.70 to 1.55%) < ox-ide bound B (1.26 to 3.11%) < residual boron B (93 to 96.8%). Path analysis revealed the highest contribution of total boron towards groundnut-pod yield with a coefficient value of 4.30. Whereas oxide-bound boron fraction contributed to the maximum extent with a coefficient value of 0.91 towards cabbage-head yield. This information will be useful for B management in the ground-nut-cabbage cropping system grown on studied soil.