ABSTRACT
The yields realized under rice-wheat rotation are generally low in the geographical regions prone to B deficiency and a sound B application schedule recommendation is required for the sustainable yields and enhanced soil fertility. The effect of different B application schedules involving different dosages and frequency of B application was investigated on yields and B nutrition of rice-wheat rotation and changes in the chemical fractions of B in soil in six years field study carried out on a sandy loam (Typic hapludoll). Based on the average grain yields of rice and wheat during the period of experimentation, application of 1.5 kg B as borax ha−1 to rice crop on alternate years was the profitable practice for mollisols as it gave an average yearly production of 5.51 t of rice grain and 4.28 t of wheat grain ha−1. The average concentration of B in flag leaves and grains of rice was much lower compared to wheat crop. The recommended schedule of B application to rice-wheat rotation resulted in a Benefit: Cost ratio of 11: 1 and also maintained the optimum level of B in soil. Most of the added B markedly increased specifically bound (0.05 M KH2PO4 extractable), ammonium oxalate (pH 3.3) extractable fractions followed by residual and organically bound fraction in the soil.
Acknowledgements
The authors are grateful to Indian Council of Agricultural Research, New Delhi for supporting the research work under All India Coordinated Research Scheme on Micro- and Secondary-Nutrients and Pollutant Elements in Soil and Plants.
Disclosure statement
No potential conflict of interest was reported by the author(s).
Author’s contribution
AKS planned the experiment. SPP, AP and PCS carried out field experiments, chemical analysis. SPP, SKB and PCS carried out statistical analysis and wrote the paper.