Response of Cauliflower to Molybdenum, Lime and Their Residue on an Acid Sandy Loam

To ameliorate the problem of whiptail of cauliflower (Molybdenum-deficiency) in the Chotanagpur plateau of Bihar, a field study was conducted during three successive seasons: kharif 1986; rabi 1986 and kharif 1987 with two lime levels (0 and 3.1 t ha⁻¹) and with seven Mo levels (0–3.0 kg ha⁻¹). Molybdenum significantly reduced the percentage unmarketable curd yield due to Mo-deficiency from 14.8% at control to 6.3% at 2.0 kg Mo ha⁻¹ but higher Mo rates increased the percentage (7.5–8.4%) causing curd deformity similar to that of Modeficiency; and increased curd diameter, weight and yield up to 1.5 kg Mo ha⁻¹. Increasing Mo rates significantly increased Mo, Ca and Mg in leaf and available Mo in soil but reduced K in leaf. Massive losses of over 96% of applied Mo were observed at the conclusion of the study and significant residual available Mo in soil persisted only where the original Mo application rate was higher than 1.5 kg ha⁻¹. Lime significantly increased curd diameter, weight and yield, Mo, Ca and K in leaf and available Mo as well as pH of soil. During rabi season, percentage unmarketable curd yield due to Mo deficiency was significantly lower (1.2%) compared to kharif seasons (9.4–15.9%). The enhancement of available Mo in soil due to lime was significant only in the kharif seasons. Successive croppings depressed Mo, Ca, Mg and K in leaf Both Mo and lime application Significantly enhanced the net returns, especially in rabi 1986. Application of 1.5 kg Mo ha⁻¹ accompanied by lime mitigated whiptail of cauliflower and produced high curd yield for three successive cauliflower crops.