Boron Characterization, Distribution in Particle-Size Fractions, and Its Adsorption-Desorption Process in a Semiarid Tunisian Soil

Abstract

Boron is essential for crop growth but needed in very small amounts. The range between boron deficiency and toxicity for plants is quite narrow. These stress conditions gravely reduce yield and quality of many crop species. Therefore, understanding the factors and the reactions affecting boron availability in soil is necessary. Against this framework, our research aims to determine the available boron status in a semiarid soil of Dour Ismail irrigated perimeter (North Tunisia). The objectives are also to investigate boron distribution in different particle-size fractions throughout the soil profile and to understand boron adsorption-desorption mechanisms according to some soil properties. For this purpose, one soil profile was dug in the field plot that had not received any previous boron fertilization. Soil samples were gathered from the different horizons of the profile and analyzed for the main physicochemical properties. Our results showed that the studied soil is Stagnic Fluvisol (clayic). The highest boron amounts were recorded in deep horizons and were greatly affected by soil salinity, organic matter, and clay contents. However, the increase in the pH level and the high percentage of total lime significantly diminished the available boron amounts in surface layers. The investigation of depth boron distribution in the different particle-size fractions indicated a considerable contribution of the silt (2–50 µm) fraction (52% of the soil total available boron), while the coarse (>50 µm) and clay (<2 µm) fractions seem to play a less important role. The adsorption data were fitted to Freundlich adsorption isotherm. It revealed that adsorption of boron increased with the increase of boron concentrations in soil solution. Desorption isotherm denotes that the accumulated boron in soil was not easily released. Adsorption and desorption of boron in soil were greatly affected by soil properties, such as pH, salinity, sand content, clay content, total organic carbon, total nitrogen, and cation exchange capacity.

Chemistry of Boron in Soil and Management in Different Crops

“…In addition to the pH of the soil solution, the amount of B absorbed by the soil is strongly determined by soil texture. It rises in proportion to the amount of clay in the soil [23]. Illite is by far the most reactive with B of the clays, while montmorillonite is only reactive at higher pH and kaolinite is the least reactive on a mass basis [45].…”

“…This increase could be due to the decomposition of organic matter which produces acids such as tartaric, oxalic, citric, acetic, formic, and humic acid, which solubilized the unavailable fixed B in clay or CaCO 3 . Furthermore, some B gets complexed or chealeted with organic mattercontent and this B is released into the soil solution as the organic matter decomposes [42].Because minimal B adsorption on the mineral fraction occurs at low pH values, organic matter is one of the most important sources of B in acid soils [23].…”

“…Since limited B adsorption occurs on the mineral fraction at low pH values, organic matter is one of the most important sources of B in acid soils [23]. Organic matter in the soil serves as a significant source of B. Jacoby R et al [24] discovered a higher presence of B in organic matter in soils than in the mineral fraction, as well as a favorable effect of organic fertilization on B absorption.…”

Doğal Kabak Çekirdeği Kabuğunun Bor Adsorpsiyon Kapasitesi

“…Ayrıca, adsorbent yüzeyinin yüklenmesine göre adsorpsiyon veriminin şekillendiği bilinen bir gerçektir. Yapılan çalışmalar sonucu, bor adsorpsiyonu için en uygun pH değerleri 5-10 arası olduğu belirtilmiştir [37][38][39][40][41].…”

The Fungal Root Endophyte Serendipita indica (Piriformospora indica) Enhances Bread and Durum Wheat Performance under Boron Toxicity at Both Vegetative and Generative Stages of Development through Mechanisms Unrelated to Mineral Homeostasis

“…It was reported that excessive B restricts the production of starch or creates B-carbohydrate complexes, thereby causing delayed grain formation [ 35 ]. Because the range between critical concentrations for B deficiency and B toxicity is rather narrow, the yield and quality of many crops are often affected either by its deficiency or toxicity [ 36 , 37 ]. Boron deficiency can relatively easily be prevented or corrected via proper soil and/or foliar fertilization applications, whereas B toxicity has been more challenging to manage so far.…”