Influence of soil pH in vegetative filter strips for reducing soluble nutrient transport

Abstract

Low efficacy of vegetative filter strips (VFS) in reducing soluble nutrients has been reported in research articles. Solubility of phosphorus and nitrogen compounds is largely affected by pH of soil. Changing soil pH may result in a decrease in soluble nutrient transportation through VFS. This study was conducted to evaluate the effect of pH levels of VFS soil on soluble nutrient transport reduction from manure-borne runoff. Soil (loamy sand texture; bulk density 1.3 g cm-3) was treated with calcium carbonate to change pH at different pH treatment levels (5.5-6.5, 6.5-7.5, and 7.5-8.5), soil was packed into galvanized metal boxes, and tall fescue grasses were established in the boxes to simulate VFS. Boxes were placed in an open environment, tilted to a 3.0% slope, and 44.0 L manure-amended water was applied through the VFS by a pump at a rate of 1.45 L min-1. Water samples were collected at the inlet and outlet as well as from the leachate. Samples were analysed for ortho-phosphorus, ammonium nitrogen, nitrate nitrogen, and potassium. Highest transport reductions in ortho-phosphorus (42.4%) and potassium (20.5%) were observed at pH range 7.5-8.5. Ammonium nitrogen transport reduction was the highest at pH level of 6.5-7.5 and was 26.1%. Surface transport reduction in nitrate nitrogen was 100%, but leachate had the highest concentration of nitrate nitrogen. Mass transport reduction also suggested that higher pH in the VFS soil are effective in reducing some soluble nutrients transport.

The current state of knowledge on the interaction of Escherichia coli within vegetative filter strips as a sustainable best management practice to reduce fecal pathogen loading into surface waters

“…While the VGFs slow the speed of overland flows, the efficacy can vary significantly and is less well described for underground movement. Slope (Kouznetsov et al 2007), surface area, width, soil (Rahmana et al 2014), rainfall (Blaustein et al 2016), topography and hydrology can all influence the variability. Recent work has emphasized the role of preferential flow, particularly during saturation, heavy rainfall and formation of surface gullies and eddies phenomena and in particular for the environmental fate of hydrophilic compounds (Allaire et al 2015) and colloids or colloidal bound contaminants or microorganisms (Mohanty et al 2016).…”

Effect of heavy metals on pH buffering capacity and solubility of Ca, Mg, K, and P in non-spiked and heavy metal-spiked soils

“…Since cation exchange is the main mechanism of K binding to solid phases and soluble complexes does not form in the case of this cation, the importance of competition with protons is less than other specific binding cations (Almas et al 2007). Thus, the effect of pH on K solubility is less significant than Ca and Mg. Almas et al (2007) observed the reduction of cations solubility following the pH increase and suggested that both Ca and Mg have the ability for specific binding with solid phases and thus, the pH change is more effective in the case of Ca and Mg solubility than K. In the work of Rahman et al (2014), increasing the pH lowered the concentration of K in runoff, but pH change generally did not have significant effect on K solubility. Jalali (2006) suggested that in calcareous soils, there is a high H + -buffering capacity and the release of K from minerals in these soils could be affected by pH of the soil.…”

“…The excessive loss of positive charge relative to anion dissolution near the pH 8 is the possible reason for the observed increase in P concentration toward this pH (Oburger et al 2011). Rahman et al (2014) described that over the pH 7.5, the availability of Al and Fe oxides and thus adsorption of P by these compounds diminishes. Some researchers have reported the increase in P concentration following the pH raise (Madrid and Posner 1979;Cabrera et al 1981;De Smet et al 1998;Sato 2003), and some observed the enhancement of P concentration with pH reduction (Rupa et al 2001;Barrow 2002).…”

“…The pH of soil is doubtless one of the most important factors which affects P solubility (Jalali andNaderi 2012, Liu et al 2013;Qian et al 2013;VandeVoort et al 2013;Xu et al 2015). In various studies, the effect of pH change on the solubility of cations and anions in different soils has been considered (James and Riha 1986;Sharpley 1991;Simonis 1996;Ortas and Rowell 2000;Ludwig et al 2001;Gustafsson and Schaik 2003;Almas et al 2007;Devau et al 2009;Gitari et al 2009;Liang et al 2010;Devau et al 2011;Oburger et al 2011;Rahman et al 2014). However there is limited information on the effect of pH change in an acidic to basic range on the solubility of cations and anions in calcareous soils.…”

Effectiveness of Riparian Vegetated Filter Strips in Removing Agricultural Nonpoint Source Pollutants in Agricultural Runoff from the Liao River Area, China

“…Lee et al [5] found that the mixed switchgrass and wood buffer had a particularly higher capacity for removing the sediment, TN, and TP than the switchgrass buffer. Rahmana et al [23] studied the effects of soil pH changes on the VFS performance and found that changing soil pH affected soluble nutrient transportation through VFS.…”