Boron Availability in Post-Monsoon Dry Period in Different Identified Soil Series of Acidic Fluvisols of Northern Plains of West Bengal, India.

The series-based information on boron (B) is not comprehensively available in the Fluvisols of north-eastern Terai region of India. This region is frequently reported to be deficient in available B (av-B) due to intense leaching and low solubility of primary B minerals. The present experiment was conducted in the Cooch Behar district with the aim to assess the surface soil (0–15 cm) status of av-B in four dominant soil series (Lotafela, Matiarkuthi, Rajpur and Balarampur) in post-monsoon months of dry winter. Hot water (HW) and 0.01 M hot calcium chloride (HCC) (0.01 M CaCl₂) were used to extract av-B, where HW extracted higher amount of B than HCC in all soil series. The mean HW-B concentration was highest in the Rajpur series (1.71 mg kg^–1) followed by Balarampur (1.64 mg kg^–1), Matiarkuthi (1.58 mg kg^–1) and Lotafela (1.57 mg kg^–1). Similar result was also notice in HCC-B. The four principal components explained 79.58% of the total variance, while pH and SOC contributed maximum variability among all the soil factors under study. Spatial interpolated (Inverse Distance Weighted) maps and nutrient index value (NIV) based fertility rating showed the soils in the study area were not deficient in av-B, with a majority of portions exceeding the B critical limit of toxicity for sensitive crops. Boron availability also got increased in dry periods with assured irrigation supply to winter crops along with the high depth of water table of the Terai region. Accordingly, the local farmers need to check excess B fertilizer (borax) application in dry post-monsoon periods considering long-term effects of B fertilizers on soil, cropping system and production economics. [ABSTRACT FROM AUTHOR]