Residual Effect of Boron on Yield, Yield Parameters and Economics of Knol-Khol (Brassica oleracea var. gongylodes L.) in Coastal Regions of Odisha

Abstract

Background: Rice-vegetable is one of the remunerative and profitable cropping system 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 was 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 rice and vegetable. Farmers in coastal Odisha generally grow knol-khol after rice and apply B frequently to both rice and knol-khol. Boron is one of the essential micronutrients required for the normal growth of knol-khol and plays an important role in yield of quality knobs. Till now no proper method and dose of boron is standardized for long term rice based vegetable cropping system regarding whether application of small dose every year is suitable or bulk quantity once or application in alternate years. Methods: A field experiment was conducted at E bock of Central Research Station, under AICRP on Micronutrient, O.U.A.T, Bhubaneswar to standardize the dose and frequency of boron application for rice-knol khol 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. The experiment was laid out in a Factorial Randomized Block Design with three replications and four different doses of boron (0.5 kg ha-1, 1.0 kg ha-1, 1.5 kg ha-1 and 2.0 kg ha-1) at three different frequencies (application of boron once, alternate year and every year) were applied. Result: The maximum values of growth attributing parameters were recorded with residual effect of boron @ 1.5 kg ha-1 in every year application. 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) were recorded with residual effect of boron @ 1.5 kg ha-1 in every year application. Highest B: C ratio of (2.27) was observed with residual effect of boron applied @ 1.5 kg ha-1 in every year application.