Potential for remediation of water repellent soils by inoculation with wax-degrading bacteria in south-western Australia

Roper, Margaret M.

doi:10.2478/s11756-006-0189-3

Cited by 31 publications

(29 citation statements)

References 24 publications

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“…In the vast regions of south-eastern Australia which have large areas of infertile soils incapable of retaining water for much of the year, farmers have tried a range of options. A potential biological solution is to increase populations of wax-degrading bacteria that consume hydrophobic compounds (Roper 2006). Tillage of soil is a physical solution as the abrasion of particles by farm implements can remove hydrophobic coatings from soil surfaces (Buczko et al 2006).…”

Section: Amelioration Of Water Repellencymentioning

confidence: 99%

A brief overview of the causes, impacts and amelioration of soil water repellency - a review

Hallett¹

2008

Soil Water Res.

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This article describes the phenomenon of soil water repellency, starting from the fundamental principals of water transport and storage in soil. Soil water repellency is a reduction in the rate of wetting and retention of water in soil caused by the presence of hydrophobic coatings on soil particles. For crop production and the maintenance of amenity turf, water repellency can stress plants resulting in poorer yield quality or grass 'playability' , respectively. The biological causes of water repellency, primarily the influence of fungi, will be discussed, as an understanding of the source of the problem will be beneficial in developing solutions. Exacerbation of repellency through climate change and the use of 'engineered' soils for amenity surfaces will be demonstrated using research findings from around the globe. In developing solutions to soil water repellency, its positive benefits, if maintained at very low levels, need to be considered. Water repellency is a key process in the physical stabilisation of soil and its impact on evaporation also needs to be considered. Before developing a rapid solution to repellency based only on water transport rates, a holistic understanding of the impacts on soil water relations is essential.

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Section: Amelioration Of Water Repellencymentioning

confidence: 99%

A brief overview of the causes, impacts and amelioration of soil water repellency - a review

Hallett¹

2008

Soil Water Res.

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“…and Roseomonas sp. (ROPER 2006). Water repellency (WR) tends to be both spatially and temporally highly variable.…”

mentioning

confidence: 99%

The impact of vegetation on hydraulic conductivity of sandy soil

Lichner¹,

Orfánus²,

Nováková³

et al. 2007

Soil Water Res.

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The objective of this study was to assess the impact of vegetation on the hydraulic conductivity of sandy soil at the locality Mláky II at Sekule (southwest Slovakia). The measurements were taken on the surface of a meadow (Meadow site), a 30-year old Scots pine (Pinus sylvestris) forest (Forest site) and a glade (Glade site). In the glade, the measurements were also taken in the depth of 50 cm (Pure sand) to reduce the influence of vegetation on the soil properties. It was found that the unsaturated hydraulic conductivity kr(−2 cm) as reduced due to the soil water repellency increased in the same order: Forest soil < Glade soil ≈ Meadow soil < Pure sand, similarly as decreased the water drop penetration time tp: Forest soil > Glade soil ≈ Meadow soil > Pure sand, which could refer to an inverse proportionality between the capillary suction and hydrophobic coating of the soil particles. The saturated hydraulic conductivity Ks increased in the following order: Meadow soil < Glade soil ≈ Forest soil < Pure sand; more than two-times higher Ks at both the Forest and Glade sites than that at the Meadow site could be the result of both the patchy growth of vegetation with some areas of bare soil at the Glade site and the macropores (dead roots) in more homogeneous humic top-layer at the Forest site. The share Br of flux through the pores with radii r longer than approximately 0.5 mm decreased in the order: Forest soil » Meadow soil > Glade soil » Pure sand, revealing the prevalence of preferential flow through macropores (dead roots) in the Forest site and a negligible share of macropores in the Pure sand.

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“…Inoculation of selected actinobacteria into water-repellent soils in the laboratory under controlled conditions reduced repellency from severe (MED 2.7) to low (MED 1.0) after 150 days compared with the non-inoculated control, which did not change during the course of the experiment (Roper 2004). In the field, improvements in soil wettability following inoculation were less successful, likely due to competition from natural microflora and adverse environmental conditions (Roper 2006). Field data suggested that enhancing existing populations of wax-degrading actinobacteria was more promising.…”

Section: Microbial Inoculation For Wax Decompositionmentioning

confidence: 98%

“…Farmer observations that lime noticeably improved soil wettability in the south-west region of Western Australia led to experiments in the laboratory and in the field demonstrating that the addition of lime to water-repellent soils reduced repellency by 1-3 MED units (Roper 2005(Roper , 2006. For example, in the laboratory under controlled moisture and temperature conditions, treatment of very severely repellent (MED 4.0) soil with lime resulted in significant improvements in wettability (to MED <1.0) over 150 days.…”

Section: Enhancing Existing Populations Of Wax-degrading Bacteria In mentioning

confidence: 99%

Management options for water-repellent soils in Australian dryland agriculture

Roper

Davies²,

Blackwell³

et al. 2015

Soil Res.

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Abstract. Water-repellent ('non-wetting') soils are a major constraint to agricultural production in southern and south-west Australia, affecting >10 Mha of arable sandy soils. The major symptom is dry patches of surface soil, even after substantial rainfall, directly affecting agricultural production through uneven crop and pasture germination, and reduced nutrient availability. In addition, staggered weed germination impedes effective weed control, and delayed crop and pasture germination increases the risk of wind erosion. Water repellency is caused by waxy organic compounds derived from the breakdown of organic matter mostly of plant origin. It is more prevalent in soils with a sandy surface texture; their low particle surface area : volume ratio means that a smaller amount of waxy organic compounds can effectively cover a greater proportion of the particle surface area than in a fine-textured soil. Water repellency commonly occurs in sandy duplex soils (Sodosols and Chromosols) and deep sandy soils (Tenosols) but can also occur in Calcarosols, Kurosols and Podosols that have a sandy surface texture. Severity of water repellency has intensified in some areas with the adoption of no-till farming, which leads to the accumulation of soil organic matter (and hence waxy compounds) at the soil surface. Growers have also noticed worsening repellency after 'dry' or early sowing when break-of-season rains have been unreliable.Management strategies for water repellency fall into three categories: (i) amelioration, the properties of surface soils are changed; (ii) mitigation, water repellency is managed to allow crop and pasture production; (iii) avoidance, severely affected or poorly producing areas are removed from annual production and sown to perennial forage. Amelioration techniques include claying, deep cultivation with tools such as rotary spaders, or one-off soil inversion with mouldboard ploughs. These techniques can be expensive, but produce substantial, long-lasting benefits. However, they carry significant environmental risks if not adopted correctly. Mitigation strategies include furrow-seeding, application of wetting agents (surfactants), no-till with stubble retention, on-row seeding, and stimulating natural microbial degradation of waxy compounds. These are much cheaper than amelioration strategies, but have smaller and sometimes inconsistent impacts on crop production. For any given farm, economic analysis suggests that small patches of water repellency might best be ameliorated, but large areas should be treated initially with mitigation strategies. Further research is required to determine the long-term impacts of cultivation treatments, seeding systems and chemical and biological amendments on the expression and management of water repellency in an agricultural context.

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Potential for remediation of water repellent soils by inoculation with wax-degrading bacteria in south-western Australia

Cited by 31 publications

References 24 publications

A brief overview of the causes, impacts and amelioration of soil water repellency - a review

A brief overview of the causes, impacts and amelioration of soil water repellency - a review

The impact of vegetation on hydraulic conductivity of sandy soil

Management options for water-repellent soils in Australian dryland agriculture

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