Journal of the Indian Society of Soil Science

A greenhouse study was carried out using a B deficient soil (hot water extractable B, 0.23 mg kg¹)of Missa series (Typic Ustochrept). Sixrates of B, ranging from 0 to 8 mg B kg⁻¹ soil were applied as H₃B0₃ along with adequate N,P,K and Zn as basal fertilizers. Four plants of Indian mustard (Brassica juncea L., cv. Westar) were grown in each pot. Two plants were harvested after 4 weeks of germination and the other two after 8 weeks of germination. Biomass production was enhanced with B fertilization. Application of B @ more than 2 mg B kg⁻¹ proved toxic as dry matter yield was drastically reduced. Critical B concentration in whole shoots of mustard was 57 mg B kg⁻¹ for four-week-old plants and 28 mg B kg⁻¹ for eight-week-plants.