Priming of soil structural and hydrological properties by native woody species, annual crops, and a permanent pasture

Soil Research ◽  
2002 ◽  
Vol 40 (2) ◽  
pp. 207 ◽  
Author(s):  
I. A .M. Yunusa ◽  
P. M. Mele ◽  
M. A. Rab ◽  
C. R. Schefe ◽  
C. R. Beverly

Impermeable subsoil is a major constraint to root growth and water infiltration in most duplex soils of Australia, but can be ameliorated by channels or biopores created by dead and decomposed roots of plant species that are adapted to these soils. In the current study, we evaluated whether a 6-year phase of native woody species planted in belts created sufficient biopores to significantly improve the soil structure of a yellow Chromosol, us (but not E. nitens) plantations in Tasmania because of low mean minimum temperatures. Conditions within 3 weeks of planting induced severe photoinhibition in non-shaded seedlings. This was associated with increased anthocyanin and photodamage in non-shaded E. nitens and E. globulus. As a result, there was 20% mortality in non-shaded E. globulus. In contrast, shaded seedlings of both species had levels of photoinhibition and anthocyanin that were largely similar to those before planting and there was no photodamage. Levels of anthocyanin indicated that its synthesis responded to the severity of photoinhibition. Height growth and levels of mortality indicated that cold-induced photoinhibition, and not frost tolerance alone, determines the range of environments where E. globulus can be successfully planted. In contrast, the tolerance of E. nitens seedlings to cold-induced photoinhibition may be a factor in the demonstrated success of this species as a high-altitude plantation species. subsoil constraint, Acacia spp., Eucalyptus spp., Casuarina spp., biological drilling, porosity, hydraulic conductivity, preferential flow.

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 909
Author(s):  
Luis Cueto-Felgueroso ◽  
María José Suarez-Navarro ◽  
Xiaojing Fu ◽  
Ruben Juanes

Water infiltration and unsaturated flow through heterogeneous soil control the distribution of soil moisture in the vadose zone and the dynamics of groundwater recharge, providing the link between climate, biogeochemical soil processes and vegetation dynamics. Infiltration into dry soil is hydrodynamically unstable, leading to preferential flow through narrow wet regions (fingers). In this paper we use numerical simulation to study the interplay between fingering instabilities and soil heterogeneity during water infiltration. We consider soil with heterogeneous intrinsic permeability. Permeabilities are random, with point Gaussian statistics, and vary smoothly in space due to spatial correlation. The key research question is whether the presence of moderate or strong heterogeneity overwhelms the fingering instability, recovering the simple stable displacement patterns predicted by most simplified model of infiltration currently used in hydrological models from the Darcy to the basin scales. We perform detailed simulations of constant-rate infiltration into soils with isotropic and anisotropic intrinsic permeability fields. Our results demonstrate that soil heterogeneity does not suppress fingering instabilities, but it rather enhances its effect of preferential flow and channeling. Fingering patterns strongly depend on soil structure, in particular the correlation length and anisotropy of the permeability field. While the finger size and flow dynamics are only slightly controlled by correlation length in isotropic fields, layering leads to significant finger meandering and bulging, changing arrival times and wetting efficiencies. Fingering and soil heterogeneity need to be considered when upscaling the constitutive relationships of multiphase flow in porous media (relative permeability and water retention curve) from the finger to field and basin scales. While relative permeabilities remain unchanged upon upscaling for stable displacements, the inefficient wetting due to fingering leads to relative permeabilities at the field scale that are significantly different from those at the Darcy scale. These effective relative permeability functions also depend, although less strongly, on heterogeneity and soil structure.


Biologia ◽  
2015 ◽  
Vol 70 (11) ◽  
Author(s):  
Radka Kodešová ◽  
Karel Němeček ◽  
Anna Žigová ◽  
Antonín Nikodem ◽  
Miroslav Fér

AbstractPlants influence the water regime in soil by both water uptake and an uneven distribution of water infiltration at the soil surface. The latter process is more poorly studied, but it is well known that roots modify soil structure by enhancing aggregation and biopore production. This study used a dye tracer to visualize the impact of plants on water flow in the topsoil of a Greyic Phaeozem. Brilliant blue was ponded to 10 cm height in a 1 m × 1 m frame in the field immediately after harvest of winter wheat (Triticum aestivum L.). After complete infiltration, the staining patterns within the vertical and horizontal field-scale sections were studied. In addition, soil thin sections were made and micromorphological images were used to study soil structure and dye distribution at the microscale. The field-scale sections clearly documented uneven dye penetration into the soil surface, which was influenced by plant presence and in some cases by mechanical compaction of the soil surface. The micromorphological images showed that root activities compress soil and increases the bulk density near the roots (which could be also result of root water uptake and consequent soil adhesion). On the other hand in few cases a preferential flow along the roots was observed.


2021 ◽  
Vol 299 ◽  
pp. 113672
Author(s):  
Chunfeng Chen ◽  
Xin Zou ◽  
Ashutosh Kumar Singh ◽  
Xiai Zhu ◽  
Wanjun Zhang ◽  
...  

2017 ◽  
Vol 21 (11) ◽  
pp. 5503-5515 ◽  
Author(s):  
Hiroyuki Hirashima ◽  
Francesco Avanzi ◽  
Satoru Yamaguchi

Abstract. The heterogeneous movement of liquid water through the snowpack during precipitation and snowmelt leads to complex liquid water distributions that are important for avalanche and runoff forecasting. We reproduced the formation of capillary barriers and the development of preferential flow through snow using a three-dimensional water transport model, which was then validated using laboratory experiments of liquid water infiltration into layered, initially dry snow. Three-dimensional simulations assumed the same column shape and size, grain size, snow density, and water input rate as the laboratory experiments. Model evaluation focused on the timing of water movement, thickness of the upper layer affected by ponding, water content profiles and wet snow fraction. Simulation results showed that the model reconstructs relevant features of capillary barriers, including ponding in the upper layer, preferential infiltration far from the interface, and the timing of liquid water arrival at the snow base. In contrast, the area of preferential flow paths was usually underestimated and consequently the averaged water content in areas characterized by preferential flow paths was also underestimated. Improving the representation of preferential infiltration into initially dry snow is necessary to reproduce the transition from a dry-snow-dominant condition to a wet-snow-dominant one, especially in long-period simulations.


2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Anna P. Rodrigues ◽  
Elena Moltchanova ◽  
David A. Norton ◽  
Matthew Turnbull

AbstractBiotic factors such as the presence of invasive animal and/or plant species are well known as major causes of ecological degradation and as limiting either natural or assisted (human-induced) ecological restoration. However, abiotic aspects of the landscape, such as water availability and soil physical/chemical conditions can also potentially limit restoration and should be considered. Dryland ecosystems are amongst the world’s most threatened and least protected. New Zealand’s drylands have been drastically changed, initially through burning, agricultural and grazing practices and the impacts of introduced herbivores and plants. This research aimed at identifying some of the key environmental factors preventing the reestablishment of native woody species in a New Zealand dryland ecosystem. The experiments involved a combination of shading, irrigation and grazing exclusion. The results showed that supplemental water was not beneficial for the survival and growth of the native seedlings, unless combined with shade. Fencing proved important for establishment, even though the species used are regarded in the literature as unpalatable to herbivores. The results indicated that the presence of shade was fundamental for the establishment and growth of the native seedlings likely due to improvements in the microclimate, soil aeration, and water availability to seedlings.


2003 ◽  
Vol 19 (3) ◽  
pp. 315-324 ◽  
Author(s):  
W. Zangaro ◽  
S. M. A. Nisizaki ◽  
J. C. B. Domingos ◽  
E. M. Nakano

Arbuscular mycorrhizal (AM) fungi colonization and response were studied in seedlings of 80 native woody species belonging to different successional groups from the Tibagi River Basin, Paraná State, south Brazil. This study includes data from 43 native woody species already published. The results with 80 species did not differ from the results of the 43 species. The experiment was carried out in a greenhouse in plastic bags filled with a mix of subsoil (85%) and sand (15%), inoculated or not with spores of native AM fungi obtained from rhizosphere soil of different native tree species in an area with natural vegetation dominated by woody pioneer species. The successional groups were represented by 16 pioneer, 20 early secondary, 29 late-secondary and 15 climax species. The AM response and colonization in the greenhouse were 5.9 and 4.2 times greater in the early successional species than in the late-successional species, respectively. Seedlings of 49 woody species were collected in the interior under the canopy of the tropical forest of the Mata dos Godoy State Park and in a cleared area dominated by woody pioneer species. The percentage of AM colonization in the field was 54.9, 40.4, 7.2 and 3.1 for the pioneer, early secondary, late-secondary and climax species, respectively. The response to AM inoculation was strongly and directly related to AM colonization in the greenhouse and field and inversely related to seed weight. The AM colonization in the greenhouse was strongly and directly related to AM colonization in field. The late-successional species showed lower AM colonization and response than early successional species. The accentuated mycotrophism of the early successional species may be involved in their establishment, growth, survival and early forest structuring on low-fertility soils.


2008 ◽  
Vol 16 (3) ◽  
pp. 267 ◽  
Author(s):  
K. RASA ◽  
R. HORN ◽  
M. RÄTY

Water repellency (WR) delays soil wetting process, increases preferential flow and may give rise to surface runoff and consequent erosion. WR is commonly recognized in the soils of warm and temperate climates. To explore the occurrence of WR in soils in Finland, soil R index was studied on 12 sites of different soil types. The effects of soil management practice, vegetation age, soil moisture and drying temperature on WR were studied by a mini-infiltrometer with samples from depths of 0-5 and 5-10 cm. All studied sites exhibited WR (R index >1.95) at the time of sampling. WR increased as follows: sand (R = 1.8-5.0) < clay (R = 2.4-10.3) < organic (R = 7.9-undefined). At clay and sand, WR was generally higher at the soil surface and at the older sites (14 yr.), where organic matter is accumulated. Below 41 vol. % water content these mineral soils were water repellent whereas organic soil exhibited WR even at saturation. These results show that soil WR also reduces water infiltration at the prevalent field moisture regime in the soils of boreal climate. The ageing of vegetation increases WR and on the other hand, cultivation reduces or hinders the development of WR.;


Soil Research ◽  
2005 ◽  
Vol 43 (5) ◽  
pp. 575 ◽  
Author(s):  
D. M. Bakker ◽  
G. J. Hamilton ◽  
D. J. Houlbrooke ◽  
C. Spann

Waterlogging and poor soil structure in the root-zone of duplex soils in Western Australia has long been recognised as a major constraint to the production of agricultural crops and pastures. The effect of raised beds on waterlogging, soil structure, and productivity of duplex soils was investigated. Five experimental sites were established, monitored, and operated over 5 years as well as 3 larger scale demonstration sites which were operated over 4 or 3 years. Treatments consisted of raised beds and a normal no-till seed bed as the control. The beds were made with a bed former after the soil had been deep cultivated. Bulk density and steady-state infiltration rate observations indicated significant and lasting improvements in soil structure in the beds. The incidence of waterlogging in raised beds was reduced and this was accompanied by an increase in runoff from the raised beds. The average grain yield increase from the beds was 18% for a variety of crops across a range of climatic conditions and duplex soils. Seven years after the introduction of raised beds for broad-acre farming in Western Australia, more than an estimated 30 000 ha of crops is now grown on raised beds.


2021 ◽  
Author(s):  
John Koestel ◽  
Lorenzo Garbari ◽  
Daniel Iseskog

&lt;p&gt;While the basic processes of water infiltration into soil are well understood, their details are difficult to quantify due to the opaque nature of soil. In this study, we investigated the potential and limitations of X-ray radiography to measure the water front progression in a narrow sample (15 &amp;#215; 15 &amp;#215; 1 cm) filled with dry soil under simulated rainfall of high intensity (53 mm/h). The temporal resolution of the acquired infiltration movies was 133 milliseconds. We evaluated three different kinds of soil samples. i) Bare samples filled with a 1:1 mixture of a sandy loam and peat. ii) The same soil-peat mixture, but cropped with &lt;em&gt;Trifolium incarnatum&lt;/em&gt;, &lt;em&gt;Trifolium repens&lt;/em&gt;, &lt;em&gt;Lathyrus odoratus&lt;/em&gt; and &lt;em&gt;Lupinus regalis&lt;/em&gt;, all of them plants that have been reported to induce water repellency; prior to the experiments, the plants were harvested and only the roots remained in place. iii) Sandy loam soil that had been incubated for four weeks in an outside garden plot. Due to time limitations of the project, the incubation period was in early spring, which meant that plant growth in the samples was negligible. All three sample types were replicated five times, resulting in 15 individual samples. We carried out the infiltration experiments in four-fold replications, from which it follows that we collected 60 individual infiltration movies. After each infiltration round, the samples were placed in a drying room to reset them to a similar initial moisture content. The experiments aimed at testing i) whether the infiltration patterns of the four consecutive infiltration runs conducted on each sample remained identical and ii) to document differences in infiltration patterns between bare, cropped and incubated samples. We found that increasing X-ray scattering with increasing soil water contents made it challenging to evaluate the image data quantitatively. Advantages of our setup are that X-ray captures the complete water content at a specific depth and that sample boxes with irregularly shaped walls can be used to prevent preferential flow along the walls. Preliminary analyses of the data showed that the infiltration fronts in the bare and the incubated samples were less uniform than the ones for the cropped samples. In contrast, the likelihood of observing the same infiltration pattern in all four consecutive infiltration runs was larger for the bare and the incubated samples. The latter fact may have been caused by the interaction with root exudates in the cropped samples that may have been redistributed or mineralized during the wetting-drying cycles. We conclude that the here presented setup has large potential to investigate unstable infiltration phenomena into soil after an image correction approach has been developed that removes X-ray scattering artifacts. Alternatively, scattering may be suppressed by using a collimator during image acquisition.&lt;/p&gt;


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