Use of Two Industrial Wastes as Soil Amendments: Effect on Dissolved Reactive Phosphorus in Runoff

Abstract

To control the dissolved reactive phosphorus (DRP) concentration in a soil solution, a number of soil amendments were tested. In the current study, Blast Furnace Slag (BFS) and Water Treatment Residues (WTR) were tested on bare soil under two rainfall intensities and two soil roughness levels. The soil was fertilized with P (KH 2 PO 4 ) at a rate of 400 kg ha −1 while BFS and WTR were applied at a rate of 5 g per 100 g of soil. Two soil roughness levels were exposed to artificial rainfall intensities of 30 and 65 mm h −1 . Three rainfall events were performed on each treatment. The runoff water generated over an area of 0.5 m 2 with a slope of 8% was collected at different time intervals and analyzed for DRP, Al, Fe, and K concentrations. The results showed that, regardless of rainfall intensity and soil roughness, the concentration of DRP in the runoff water increased with increasing runoff time from the unamended plots. However, in the BFSand WTR-amended soils, the DRP concentration decreased with runoff time. Dissolved reactive P and DRP loads were the lowest from the WTR-amended plots, followed by the control and the BFS treatment plots. Water treatment residues reduced the mean DRP concentration by 27.3% and the DRP load by 32% compared to unamended plots. The two rainfall intensities significantly affected the DRP concentration and load. Under the low rainfall intensity, the DRP concentration and load were higher compared to the high rainfall intensity. The overall DRP concentration was not affected by changes in soil roughness. However, the DRP loads were higher from the plots with low soil roughness levels, especially during the first and second runs. Both the BFS and WTR were also effective in reducing the DRP concentrations in the drain water collected during the runoff events. The concentrations of Al, Fe, and K in the runoff water were not affected by the soil amendments. However, the electrical conductivity and pH readings were higher from the BFS-amended plots.

Impacts of Biochar and Other Amendments on Soil-Carbon and Nitrogen Stability: A Laboratory Column Study

“…3). Although biochar had the highest surface area (Supplemental Table S1), WTR also likely sorbed soil OM by specific bonding as WTR possesses abundant Fe and Al-hydroxides (Agyin-Birikorang and O'Connor, 2007;Ahmad et al, 2012;Ippolito et al, 2011;Miller et al, 2011). On the other hand, the increase in dissolved C in leachates of the HA-treated soil compared to the control may have been due to enhanced microbial colonization and biomass as well as leaching of the HA itself (Fig.…”

Does phosphogypsum addition affect phosphate rock dissolution in acid soils?

“…However, there is still a need to better manage PR dissolution and subsequent availability of P. The direct use of PR is generally limited to a range of situations where the combination of soil properties and cropping systems offer optimal conditions that allow dissolution rates to match short-term plant P demand. Several management options have been proposed to increase PR dissolution such as 1) partial acidulation (Ahmad et al, 2019), 2) biologically mediated solubilization (Magallon-Servin et al, 2020) and 3) incorporation with various additives such as elemental sulphur (César et al, 2020), some industrial wastes (Ahmad et al, 2012) and agro-industrial wastes (Vassilev et al, 2006). However, increasing the number of industrial wastes used as additives in circular manner due to their low price, is an important research topic as there is a need for promising chemical and biotechnological routes that provide a costeffective solubilization of PR.…”