Relative changes in total available boron, boron content at different growth stages and total boron uptake by black gram under different sources and doses of boron

A field experiment was conducted to investigate the “Relative changes in Boron fractions in black gram Rhizosphere” was contemplated with two objectives: 1) To find out the suitable source, dose and method of boron for black gram, and 2) To study the changes in relative boron fractionation under black gram Rhizosphere. To achieve the present objectives a field experiment was conducted with Greek gram var. IPU2-43 in factorial randomized block design with three sources, four doses and two methods of application of boron replicated thrice at Bihar Agricultural College Farm of BAU, Sabour during the year 2018-19. Three sources were: S1: Borax, S2: Solubor and S3: Boric acid; Doses: D1: 0.5 kg ha-1, D2: 1.0 kg ha-1, D3: 1.5 kg ha-1, D4: 2.0 kg ha-1and methods: soil and foliar application. Based on the findings of field experiment it can be concluded that the application of graded doses of boron enhanced the growth and yield as well as concentration and uptake of boron. The result showed that highest value (101.62 mg/kg of soil) of total available boron was recorded under D4S1and lowest value (96. 38 mg/kg of soil) was recorded under D1S2. The highest boron content at the vegetative stage in plant was found in the solubor applied plots (8.96 mg kg-1) which were significantly superior over boric acid and borax treated plots. Among the plots receiving various different doses of boron, the highest boron content was observed at 2.0 Kg B ha-1 (8.49 mg kg-1) which was significantly superior to the plots under D1 and D2 and at par with plots receiving 1.5 Kg B ha-1 (8.18 mg kg-1). At the flowering stage in plant higher boron content was found in solubor (10.16 mg kg-1) applied through foliar application which significantly varied from the rest of the two sources. The content recorded under the other two sources was found to be statistically at par. Regarding the application of different doses of boron the highest boron content was found at 2.0 kg B ha-1 (10.02 mg kg-1) which statistically at par with that at 1.5 kg B ha-1 (9.90 mg kg-1). Foliar application of solubor recorded highest value (14.13 mg kg-1) of boron content in grain. Boron content in the grain at harvesting. However, among the plots receiving different doses of boron it was found that the boron content in seed in the plots receiving 2.0 Kg B ha-1 (14.25 mg kg-1) was significantly higher than other three plots. Regarding the boron content in the straw at harvest it was found the highest boron content in straw was recorded under plots which received Solubor through foliar application (17.09 mg kg-1).Total uptake at 1.5 kg B ha-1 was at par with 2.0 kg B ha-1 but significantly superior over the rest of the lower doses.