Q86: Deficiency of boron (B) can be corrected by application of... - Soil Fertility and Fertilizer Use - ICAR AIEEA PG 2024 - Agronomy | Agrigyan

Common boron fertilizer sources:

• Borax (Sodium tetraborate decahydrate, $\text{Na}_2\text{B}_4\text{O}_7\cdot 10\text{H}_2\text{O}$): Contains $11.34\%\text{ B}$ by pure chemical stoichiometry ($\text{MW } 381.37\text{ g/mol}$), while the statutory commercial fertilizer standard under the Fertilizer Control Order (FCO, 1985) specifies a minimum of $10.5\%\text{ B}$ (widely cited in Indian agronomical exams).
• Boric acid ($\text{H}_3\text{BO}_3$): Contains $17.5\%\text{ B}$, highly water-soluble for soil and foliar spray.
• Solubor (Di-sodium octaborate tetrahydrate, $\text{Na}_2\text{B}_8\text{O}_{13}\cdot 4\text{H}_2\text{O}$): Contains $20.5\%\text{ B}$, ideal for foliar nutrition.
• Lime ($\text{CaCO}_3$): Soil amendment for acidic soils; does not supply boron.