Boron fertilizers: Use, challenges and the benefit of slow-release sources – a review

Authors : Fien DEGRYSE

Pages : 111-122

View : 19 | Download : 10

Publication Date : 2017-12-30

Article Type : Review Paper

Abstract :Boron (B) is an essential plant nutrient, but can be toxic when present in excess. Boron is usually present as an uncharged molecule (H 3 BO 3 0 ) in the soil solution and is highly mobile in most soils. Deficiency of B is therefore quite common in high-rainfall environments, especially on sandy soils. Boron fertilizers are commonly used to correct its deficiency in crops. The most commonly used fertilizers are soluble sodium borates (e.g., borax), but care should be taken with rates and placement of such B products, since elevated B concentrations may result in seedling toxicity and yield reduction. Moreover, significant leaching losses of applied B may occur in high-rainfall environments. Slow-release B sources reduce both the risk of seedling toxicity and of leaching, and can provide adequate supply of B over a longer period. This may allow for lower B rates or less frequent application compared to soluble fertilizers. The most commonly used slow-release B sources are sparingly soluble ores, such as colemanite. The limited data in the literature indicate that the release rate of B from slow-release sources in soil depends both on fertilizer characteristics and soil properties. However, more research is needed to predict the release rate of B from various B ores for given soil and climatic conditions. In recent years, slow-release coatings and matrices for N fertilizers have received considerable attention and these new technologies may potentially also be adopted for B-containing fertilizers. 
Keywords : Boron, Toxicity, Deficiency, Leaching, Slow release fertilizer