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Biochar research has received greater interest in recent years because of its potential beneficial effects on soil properties and its efficiency as a long-term C sequester. In this study, the effect of Conocarpusbiochar application on the hydraulic properties of a sandy loam soil was investigated. Evaporation rate, water retention, soil water infiltration, and soil aggregate stability were measured in soil columns packed with a sandy loam soil amended with 5, 10, 15, and 20 g [BULLET OPERATOR] kg − 1of non-activated biochar. Results showed that cumulative evaporation was reduced by 5.4 to 12.1 as a result of increasing biochar application. The application of biochar enhanced the capacity of the soil to retain water by 8.9, 17.6, 28.1, and 30.9 for soils treated with biochar rates of 5, 10, 15, and 20 g [BULLET OPERATOR] kg − 1, respectively. Water content at field capacity increased in the top 10 cm by 7.2 to 15.9. Water-holding capacity was increased by increasing the application rate of biochar. The percentage of water-stable aggregates was increased, especially in the larger fractional sizes (2–0.25 mm). On the other hand, the application of biochar decreased saturated hydraulic conductivity and infiltration rate, but had minimal effect on other hydraulic parameters. The ability of biochar to reduce water evaporation and improve water retention of coarse-textured sandy soils can help to enhance soil quality and productivity, reduce the amount of irrigation water, and maintain crop yields for crops exposed to water stress, especially in arid and semiarid regions.

Chelate-assisted phytoextraction is a promising technique to remediate metal-contaminated soil. Batch and greenhouse experiments were conducted to assess the effects of synthetic chelators (ethylenediaminetetraacetic acid EDTA, ethylenediaminedisuccinic acid EDDS, and nitrilotriacetic acid) and low-molecular-weight organic acids (oxalic and citric acids) on the solubilization of copper, chromium, and arsenic (Cu, Cr, and As, respectively) in chromated Cu arsenate (CCA)-contaminated soil and on metal uptake and translocation in maize (Zea maysL.). Chelators significantly enhanced the solubilization of Cr, Cu, and As in the soil and markedly increased their accumulation in plant tissues. Applying 5 and 10 mmol kg−1EDDS increased plant Cu uptake by 2.8- and 3.5-fold greater than that in control soil (without chelate applications), respectively. EDTA and citric acid were more efficient for increasing Cr uptake by plant shoots, resulting in 5.0- and 5.5-fold increases, respectively, compared with that in the control. Maximum As uptake was observed in response to a treatment of 10 mmol kg−1citric acid, which was 1.9-fold greater than that in control soil. However, translocation factors, phytoextraction efficiencies, and remediation factors indicated that metal uptake was not high enough for successful phytoremediation of CCA–contaminated soil. Our results suggest that EDDS and citric acid as alternatives to EDTA may facilitate phytoextraction of contaminated soil.