Evaluation of Direct Application of Enzymes to Remediate Soil Water Repellency

Abstract

<jats:p>Organic coatings on sand particles can cause soil water repellency (SWR) where a soil does not spontaneously wet; this leads to challenges in water management and crop production. In laboratory studies, we evaluated a novel approach using direct application of 10 enzymes at three (low, medium, high) dosages to remediate SWR on two sand turfgrass soils in a 3-day incubation study and a second study at high dosage with 1-day incubation. A soil:solution ratio of 1:1 (10 g soil and 10 mL solution) was used and a deionized water control included. For Soil 7, a very strongly hydrophobic soil from a localized dry spot turfgrass area with a water drop penetration time (WDPT) of 7440 seconds (untreated) and 332 to 338 seconds (water-treated), the high dosage rates of laccase, chitinase, and protease at 1 and 3 days incubation resulted in WDPT of less than 60 seconds (i.e., hydrophilic soil). Pectinase exhibited similar results only in the 3-day incubation study. On the strongly hydrophobic Soil 21 (WDPT of 655 seconds untreated; 94 to 133 water-treated) from the dry area of a fairy ring-affected area on a turfgrass site, high dosages of chitinase, laccase, pectinase, and protease reduced WDPT to less than 60 seconds in both studies; and medium dosage rates were also effective for all but protease in the 3-day incubation study. Each of the four most effective enzymes for reducing WDPT, noted previously, demonstrated a significant exponential or logarithmic relationship between decreasing WDPT and increasing enzyme dosage. Further studies in field situations will be required to determine enzyme effectiveness on SWR and water management.</jats:p>

A review of a novel enzyme system for the management of thatch and soil water repellency in turfgrass

“…Enzymes with potential to remediate SWR (Zeng et al, 2014) In laboratory studies we evaluated a novel approach using direct application of 10 enzymes at three (low, high) dosages to remediate SWR on two sand turfgrass soils in a 3-d incubation study and a second study at high dosage with 1-d incubation. A soil solution ratio of 1:1 w/w(10 g of soil and 10-ml solution) was used and a deionized water control included.…”

“…The direct application of enzymes that are specific for degradation of hydrophobic organic fractions believed to contribute to SWR could provide for longer term and more effective alleviation of SWR than the repeated use of wetting agents (WA; Liu, Zeng et al, 2013;Zeng et al, 2014). Lignolytic enzymes which are capable of lignin degradation are produced extracellularly by certain microbes such as white-rot fungi (Blanchette, 1984).…”

“…Soils were incubated for 3 d in a 1:1 soil/enzyme solution and oven dried prior to performing water drop penetration time (WDPT) tests. Data presented was abstracted from Zeng et al, 2014 Section (Far Hills, NJ), we performed two field studies with seven treatments in total. Since direct application of selected enzymes to soil exhibiting SWR was not previously reported, these studies were exploratory to determine the feasibility and to refine field testing protocols.…”

“…Soils were incubated for 3 d in a 1:1 soil/enzyme solution and oven dried prior to performing water drop penetration time (WDPT) tests. Data presented was abstracted from Zeng et al., 2014…”

“…The most effective remediation practice has been the use of wetting agents (soil surfactants); however, this is costly and often limited to only a short‐term alleviation of the problem, with repeated applications needed (Moore et al., 2010; Müller & Deurer, 2011). The direct application of enzymes that are specific for degradation of hydrophobic organic fractions believed to contribute to SWR could provide for longer term and more effective alleviation of SWR than the repeated use of wetting agents (WA; Liu, Zeng et al., 2013; Zeng et al., 2014).…”