Availability of boron under different cropping systems in soils of Morigaon district of Assam

Abstract

Boron is an essential micronutrient element for growth and development of plants. The boron availability of soil is low, the range between deficient and toxic concentrations of boron in plants and soils are very narrow. The Morigaon district is situated in the central Brahmaputra valley zone of Assam between longitude (92° and 95.5°E), latitude (26.15° and 26.5°N) and five blocks viz., Bhurbandha, Mayong, Lahorighat, Kapili, and Mairabari. Hundred numbers (100) of surface (0-15 cm) soil samples from different cropping systems were collected with an auger from Morigaon district representing twenty five (25) soil samples from each dominant cropping systems. Soil samples were analyzed to determine the availability of boron under different cropping systems in Inceptisols soils of Morigaon district and its relation to soil properties. The experimental findings revealed that the soils were sandy loam to silty clay loam in texture and strongly acidic to near neutral (4.17 to 6.94) in reaction with organic carbon content ranging from medium to high (0.51 to 1.14 per cent). EC of the soils were very low ranging from 0.01 to 0.06 dS m-1. The CEC of the soils were low and varied from 5.50 to 7.70 [cmol (p+) kg-1]. The available nitrogen and phosphorus content of the soil ranged from low to medium (219.52 to 533.12 kg/ha), (21.54 to 57.96 kg/ha) and available potassium status were low to high (104.36 to 419.46 kg/ha). The available boron content was found to be lowest in rice-rice followed by rice-rapeseed, rice-vegetable and vegetable-vegetable cropping system and values ranged from 0.29 to 0.98, 0.52 to 1.00, 0.74 to 1.14 and 1.10 to 1.38 mg kg-1, respectively. The available boron showed a positive and significant correlation ship with pH and organic carbon in all the cropping systems.