Acid-Modified and Unmodified Natural Clay Deposits for In Situ Immobilization and Reducing Phytoavailability of Molybdenum in a Sandy Loam Calcareous Soil

Abstract

Molybdenum (Mo) in basic soils has high bioavailability and plant toxicity. This study aimed to investigate the effect of increasing Mo concentration on its availability and toxicity threshold in alfalfa plants grown in sandy loam calcareous soils, and the potential use of raw and acid- modified clay deposits as soil additives to immobilize Mo and reduce its phytoavailability. Raw clay deposits (RCD) were treated with H2SO4 to produce acid-modified clay deposits (AMCD). The first experiment was performed using soils treated with 0, 0.1, 1, 10, 50, and 100 mg Mo kg−1. The second experiment was conducted with soils treated with 10 or 50 mg Mo kg−1 and amended with RCD and AMCD at application rates of 0, 2.5, 5, and 10% (w/w). After harvesting, water-soluble Mo, ammonium bicarbonate-diethylenetriaminepentaacetic acid (AB-DTPA)-extractable Mo, and shoot Mo content as well as dry matter were measured. The results showed that water-soluble Mo, AB-DTPA-extractable Mo, and shoot Mo concentration increased at higher Mo soil addition. AMCD had a stronger influence on Mo immobilization and reduction effect on plant shoots compared to RCD, depending on soil Mo concentration and application rate. Applying AMCD decreased soil pH but increased salinity levels. The shoot dry matter significantly increased in soils amended with RCD and/or AMCD compared to control soils; with the highest improvement recorded for RCD at 10%. It was concluded that AMCD is an efficient immobilizing agent to reduce Mo mobility and its phytoavailability in calcareous soils. Additionally, both AMCD and especially RCD were able to create favorable conditions for plant growth.

The fate of nitrogen in animal urine patch as affected by trees and nitrogen supply on integrated crop-livestock systems

“…In sandy soil, ammonium is also poorly retained the negative charges in the soil (Alrashidi et al, 2020) due to the low clay and MO content usually found in these soils, which also increases the possibility of losses in this chemical form. Soil texture is, therefore, an essential factor in the behavior of N because it directly influences the dynamics of water in the soil.…”

Insights into the influences of biochar on the fate and transport of pesticides in the soil environment: a critical review

“…The increased pyrolysis temperature enhances the tensile strength of the raw materials, resulting in biochar particles that are smaller in size (Albalasmeh et al 2020;Ahmed et al 2021;Wani et al 2022). The functional groups on the ionic charges, surface, and porous structure of biochar aid in the detoxification (Alrashidi et al 2020), physical adsorption (Zhang et al 2020a), complexation, mobilization-immobilization (Hu et al 2020), and co-precipitation (Deng et al 2019) of metal pollutants and support phytoremediation potential of the hyperaccumulator. The physical and chemical characteristics of biochar produced from several feedstocks are displayed in Table 3.…”

Influences of Biochar on Bioremediation/Phytoremediation Potential of Metal-Contaminated Soils

“…Due to the improved tensile strength of raw materials at higher pyrolysis temperatures, it may yield smaller-sized biochar particles ( Albalasmeh et al, 2020 ). The functional groups on the surface of biochar, porous structure, and ionic charges can aid in the physical adsorption ( Zhang et al, 2020 ), co-precipitation ( Chen et al, 2022 ), complexation, mobilization/immobilization ( Hu et al, 2020 ), and detoxification ( Alrashidi et al, 2020 ) of metal pollutants and support the hyperaccumulator’s phytoremediation potential.…”