scholarly journals Factors governing soil water repellency under tillage management: The role of pore structure and hydrophobic substances

Author(s):  
Shengping Li ◽  
Jinjing Lu ◽  
Guopeng Liang ◽  
Xueping Wu ◽  
Mengni Zhang ◽  
...  
Soil Research ◽  
2005 ◽  
Vol 43 (3) ◽  
pp. 251 ◽  
Author(s):  
J. J. Keizer ◽  
A. J. D. Ferreira ◽  
C. O. A. Coelho ◽  
S. H. Doerr ◽  
M. C. Malvar ◽  
...  

Certain organic compounds derived from living organisms or their decaying parts are generally accepted to induce soil water repellency. Water repellency may therefore be expected to increase with proximity to organisms releasing hydrophobic compounds. This hypothesis is tested here for Eucalyptus globulus trees, since eucalypt species are frequently associated with elevated repellency levels. In a young, first-rotation plantation on coastal dune sands in central Portugal, repeat measurements of water repellency using the ‘Molarity of an Ethanol Droplet’ (MED) test were carried out in situ between April 2001 and May 2002. On 25 dates, repellency was measured at initially 2 and later 3 distances on 2 sides of 8–11 randomly selected trees. On 15 occasions, additional repellency measurements were performed within small grids aside 3 of the selected trees. The postulated decrease in topsoil water repellency with increased distance from eucalypt tree stems was found to apply on several individual measurement dates, as well as, more unexpectedly since repellency usually is a transient phenomenon, for the study period as a whole. The results confirm the general association of eucalypt trees with water repellency, and indicate that tree stem proximity is an important but not sufficient factor to explain repellency distribution in topsoil.


2020 ◽  
Author(s):  
Shengping Li ◽  
Jinjing Lu ◽  
Aurore Degré

<p>Soil water repellency (SWR) has significant consequences for crop yield, carbon sequestration, aggregate stability, soil erosion, and water movement. It is known to be linked to hydrophobic substances and pore structure. Conservation agriculture could affect SWR through both aspects. However, most of the studies have only focused on hydrophobic substances due to the complexity of soil pore structure measurement and quantification. In this study, X-ray computed tomography at a resolution of 27.27 μm was used to calculate the shape, porosity, and connectivity of the pore network and reveal the impact of hydrophobic substances and pore structure on SWR. All samples were collected from two long-term experimental fields. The treatments were conventional tillage with residue removal (CT), reduced tillage with residue incorporated (RT), and no-tillage with residue mulch (NT) in both of the fields. The water repellency index was determined using the intrinsic sorptivity method by measuring the water and ethanol sorptivity. The results showed that RT and NT treatment increased the porosity of pores of 55-165 μm in diameter that had a positive relationship with ethanol sorptivity and water repellency index, respectively. However, the total porosity and the porosity of >165 μm in diameter had no significant link with SWR properties. RT and NT treatments could enhance ethanol sorptivity by increasing pore connectivity. However, pore connectivity had no effect on water sorptivity because of the hydrophobic substances. NT treatment also reduced water sorptivity by increasing pore surface area and hydrophobic substances. Soil organic carbon and microbial biomass carbon, both of them as hydrophobic substances, were higher under RT and NT treatment than CT. Microbial biomass carbon was more positively correlated to SWR than soil organic carbon, which indicates that microbial biomass carbon is a better indicator explaining tillage effects on SWR. Overall, RT and NT treatment could increase the water repellency index, which was a result of the interactions between pore structure and hydrophobic substances. In order to unravel the mechanisms underlying conservation tillage impacts on SWR more accurately, it is essential to determine both pore structure and hydrophobic substances at the same time.</p>


2013 ◽  
Vol 77 (5) ◽  
pp. 1732-1743 ◽  
Author(s):  
I. Hallin ◽  
P. Douglas ◽  
S.H. Doerr ◽  
R. Bryant

2009 ◽  
Vol 73 (2) ◽  
pp. 541-549 ◽  
Author(s):  
E. R. Graber ◽  
S. Tagger ◽  
R. Wallach

2013 ◽  
Vol 64 (5) ◽  
pp. 667-680 ◽  
Author(s):  
K. Mainwaring ◽  
I. L. Hallin ◽  
P. Douglas ◽  
S. H. Doerr ◽  
C. P. Morley

Geoderma ◽  
2021 ◽  
Vol 402 ◽  
pp. 115264
Author(s):  
Enoch V.S. Wong ◽  
Philip R. Ward ◽  
Daniel V. Murphy ◽  
Matthias Leopold ◽  
Louise Barton

2014 ◽  
Vol 65 (3) ◽  
pp. 360-368 ◽  
Author(s):  
I. Kim ◽  
R. R. Pullanagari ◽  
M. Deurer ◽  
R. Singh ◽  
K. Y. Huh ◽  
...  

2013 ◽  
Vol 22 (4) ◽  
pp. 515 ◽  
Author(s):  
Naama Tessler ◽  
Lea Wittenberg ◽  
Noam Greenbaum

Variations in forest fires regime affect: (1) the natural patterns of community structure and vegetation; (2) the physico-chemical properties of soils and consequently (3) runoff, erosion and sediment yield. In recent decades the Mediterranean ecosystem of Mount Carmel, north-western Israel, is subjected to an increasing number of forest fires, thus, the objectives of the study were to evaluate the long-term effects of single and recurrent fires on soil water repellency (WR) and organic matter (OM) content. Water repellency was studied by applying water drop penetration time (WDPT) tests at sites burnt by single-fire, two fires, three fires and unburnt control sites. Water repellency in the burnt sites was significantly lower than in the unburnt control sites, and the soil maintained its wettability for more than 2 decades, whereas after recurrent fires, the rehabilitation was more complicated and protracted. The OM content was significantly lower after recurrent than after a single fire, causing a clear proportional decrease in WR. The rehabilitation of WR to natural values is highly dependent on restoration of organic matter and revegetation. Recurrent fires may cause a delay in recovery and reduced productivity of the soil for a long period.


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