Residual effect of boron on yield, yield parameters and economics of Knol-Khol (Brassica oleracea var. gongylodes L.) in coastal regions of Odisha

Rice-vegetable is one of the remunerative and profitable cropping systems in Odisha to be grown in kharif and rabi season, respectively. From GPS based soil survey and analysis by AICRP on Micronutrient, OUAT, Bhubaneswar, it was observed that boron deficiency is widespread in soils of Odisha (8-79%) and is a major constraint in light texture sandy loam soils under vegetable production. Growing of a shallow rooted crop like rice as direct crop followed by a deep-rooted vegetable crop can utilize leached boron efficiently from subsoil thereby benefitting both. farmers in coastal Odisha generally grow knol-khol after rice.

A field experiment was conducted at E-block of Central Research Station under AICRP on micronutrient, OUAT, Bhubaneswar to standardize the dose and frequency of boron application for rice-knolkhol cropping system, where boron is applied to first crop and knol-khol gets residual boron. In the present investigation, residual effect of different graded doses of boron and its frequency of application on growth, yield, quality, post-harvest shelf life and economics of knol-khol for the year 2018-19 was studied under factorial randomized block design with three replications and four doses of boron (0.5, 1.0 , 1.5 and 2.0 kg ha^-1) at three different frequencies (application of boron once, alternate year and every year).

The maximum values of growth parameters, highest yield and yield attributing characters such as diameter of knob (8.70 cm), length of knob (6.53 cm) and total knob yield (224.72 q ha^-1), highest B: C (2.27) were recorded with residual effect of boron @ 1.5 kg ha^-1 in every year application.