Nitrogen-Boron Interaction in Cauliflower (Brassica oleracea var botrytis L.) on an Alfisol

A field experiment was conducted on a B-deficient (HWS 0.1 mg kg⁻¹) red sandy loam soil (Ultic Haplustalf) with cauliflower (cv. Pusa Snowball-I). Significant response to N levels (50–300 kg ha⁻¹) in respect of curd weight, diameter and yield was obtained at 200 kg ha⁻¹ over 50 kg ha⁻¹. Any further increment in N adversely affected these parameters. The severity of stem hollow (on 1–5 scale) decreased and that of curd rot increased significantly at 300 kg ha⁻¹ over 50 kg ha⁻¹. Quantitatively, minimum curd rot (17–23%) and maximum stem hollow (85%) and stem rot (45%) was seen at N application rate of 150–200 and 300 kg ha⁻¹, respectively. Increasing levels of B (‘no-B’, 0.0125 and 0.125% boric acid; each applied thrice through foliar spray) significantly increased curd size and yield and supressed Ca content of leaf tissue while that of B increased. The maximum reduction in the percentage of curd rot was at 250 kg ha⁻¹ in ‘no-B’ control while at 0.0125 and 0.125 per cent boric acid concentrations, the corresponding N levels were 200 and 150 kg ha⁻¹, respectively. The severity of stem hollow markedly reduced with increasing N levels only when B supply was adequate. The results !ihow that stem hollow and curd rot of cauliflower are direct manifestation of B-deficiency and proper balancing of N and B is required for high curd yield and low stem hollow and curd rot.