The ability of Distichlis spicata to grow sustainably within a saline discharge zone while improving the soil chemical and physical properties

Soil Research ◽  
2008 ◽  
Vol 46 (1) ◽  
pp. 37 ◽  
Author(s):  
M. R. Sargeant ◽  
C. Tang ◽  
P. W. G. Sale

Landholder observations indicate that the growth of Distichlis spicata in saline discharge sites improves the soil condition. An extensive soil sampling survey was conducted at the Wickepin field site in Western Australia, where D. spicata had been growing for 8 years, to test the hypothesis that this halophytic grass will make improvements in chemical and physical properties of the soil. Soil measurements included saturated hydraulic conductivity, water-stable aggregates, root length and dry weight, electrical conductivity, pH, and soil nitrogen and carbon. Results confirm that marked differences in soil properties occurred under D. spicata. For example, a 12-fold increase in saturated hydraulic conductivity occurred where D. spicata had been growing for 8 years, compared to adjacent control soil where no grass had been growing. There were also improvements in aggregate stability, with the most notable improvements in the top 0.10 m of soil, again with the greatest improvements occurring where 8 years of growth had occurred. Soil nitrogen and carbon increased under the sward, with the biggest increases occurring in the top 0.10 m of soil. Electrical conductivity measurements were more variable, mostly due to the large spatial and temporal variation encountered. However, the findings generally support the proposition that the growth of D. spicata does not lead to an accumulation of salt within the rooting zone.


1998 ◽  
Vol 3 (2) ◽  
pp. 69 ◽  
Author(s):  
M.I. Choudhary ◽  
A.M. AI-Omran ◽  
A.A. Shalaby

Information on the effectiveness of soil conditioners over a prolonged period is scarce. A laboratory experiment was undertaken to evaluate the effectiveness of a polyacrylamide (Broadleaf P4) soil conditioner on the physical properties of sandy soil subjected to wetting and drying cycles. Four concentrations of Broadleaf P4 0, 0.2, 0.4, and 0.6% on dry weight basis were uniformly mixed with a calcareous sandy soil. Addition of Broadleaf P4 to sandy soil increased the water holding capacity, decreased the bulk density, and increased the porosity and void ratio at 0 and 16 wetting and drying cycles. The coefficient of linear extensibility increased considerably with increasing concentrations of the polymer. The addition of polymer at 0 and 16 cycles increased considerably the retention and availability of water in sandy soil. Saturated hydraulic conductivity decreased with increasing concentrations of Broadleaf P4 whereas unsaturated hydraulic conductivity at 0 and 16 cycles showed an increase with increasing soil moisture contents. After I6 wetting and drying cycles, the capacity of the soil to hold water was lost on average by 15.8% when compared to the 0 wetting and drying cycle. The effectiveness of the soil conditioner on bulk density, coefficient of linear extensibility, available water and saturated hydraulic conductivity was reduced on average by 14.1, 24.5, 21.l and 53.7% respectively. The significant changes in soil properties between 0 and 16 cycles suggested that the effectiveness of the conditioner decreased with the application of wetting and drying cycles. However, its effect was still considerable when compared to untreated soil under laboratory conditions.



2009 ◽  
Vol 89 (4) ◽  
pp. 473-488 ◽  
Author(s):  
A Biswas ◽  
B C Si

The relationship between soil properties may vary with their spatial separation. Understanding this relationship is important in predicting hydraulic parameters from other soil physical properties. The objective of this study was to identify spatially dependent relationships between hydraulic parameters and soil physical properties. Regularly spaced (3-m) undisturbed soil samples were collected along a 384 m transect from a farm field at Smeaton, Saskatchewan. Saturated hydraulic conductivity, the soil water retention curve, and soil physical properties were measured. The scaling parameter, van Genuchten scaling parameter α (VGα), and curve shape parameter, van Genuchten curve shape parameter n (VGn), were obtained by fitting the van Genuchten model to measured soil moisture retention data. Results showed that the semivariograms of soil properties exhibited two different spatial structures at spatial separations of 20 and 120 m, respectively. A strong spatial structure was observed in organic carbon, saturated hydraulic conductivity (Ks), sand, and silt; whereas a weak structure was found for VGα and VGn. Correlation circle analysis showed strong spatially dependent relationships of Ks and VGα; with soil physical properties, but weak relationships of θs and VGn with soil physical properties. The spatially dependent relationships between soil physical and soil hydraulic parameters should be taken into consideration when developing pedotransfer functions. Key words: Spatial relationship, geostatistics, linear coregionalization model, principal component analysis, pedotransfer function



1986 ◽  
Vol 66 (4) ◽  
pp. 737-742
Author(s):  
J. A. MILLETTE ◽  
R. S. BROUGHTON

Monolith column construction and sampling procedures were described for organic soil profiles and used to measure the variation with depth of saturated hydraulic conductivity, bulk density and fiber content. The top 0.30 m of the organic soil was more permeable, had a greater bulk density and had a greater fiber content than the soil layer between 0.60 and 0.90 m from the soil surface. These columns can be used for correlations studies between physical properties and studies of the dynamic nature of the physical properties of organic soils. Key words: Saturated hydraulic conductivity, bulk density, fiber content, organic soil, monolith columns



2004 ◽  
Vol 129 (3) ◽  
pp. 449-457 ◽  
Author(s):  
Philippe Jobin ◽  
Jean Caron ◽  
Pierre-Yves Bernier ◽  
Blanche Dansereau

Hydrophilic polymers or hydrogels have shown potential to increase water retention of media and to reduce irrigation frequency. This property would be particularly useful in the production of fast growing species in which large amounts of water are needed. This study evaluated the effect of two acrylic-based hydrogels on water desorption curve and hydraulic conductivity of substrates and on plant growth. The duration of their effects was also investigated. Rooted cuttings of Surfinia (Petunia ×hybrida `Brilliant Pink') were transplanted into 30-cm pots containing one of three different substrates amended with one of two types of hydrogels, a commercial acrylic polymer, and a commercial acrylic-acrylamide copolymer, and grown for 9 weeks under well watered conditions and then imposed with a drought. Results indicated that both polymer types gave similar results. The substrates' physical properties (air-filled porosity, available water) at potting time were significantly affected by hydrogel addition, but differences vanished within 9 weeks of growth. Hydrogels had no significant effect on the point at which plant wilted and on the substrate's unsaturated hydraulic conductivity. Shoot dry weight was affected by substrate and hydrogel and was positively correlated to water content between container capacity and -10 kPa of water potential, or between container capacity and the soil water potential at plant turgor loss.



Agriculture ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1293
Author(s):  
Abdulaziz G. Alghamdi ◽  
Abdulrasoul Al-Omran ◽  
Arafat Alkhasha ◽  
Zafer Alasmary ◽  
Anwar A. Aly

Water management and irrigation conservation in calcareous sandy soil are of significant importance for sustaining agricultural production, especially in arid and semi-arid region that facing scarcity of water resources. The changes in hydro-physical characteristics of calcareous sand soil were investigated after date palm waste-derived biochar application in column trials. Significance of pyrolysis temperature (300 °C, 500 °C, and 700 °C), particle size [<0.5 mm (D0.5), 0.5–1 mm (D1), and 1–2 mm (D2)], and application rate (1%, 2.5%, and 5%) were studied. Variations in infiltration rate, intermittent evaporation, and saturated hydraulic conductivity as a function of aforementioned factors were investigated. After amending the top 10-cm soil layer with different biochar and application rates, the columns were subjected to six wetting and drying cycles by applying 25 cm3 tap water per week over a 6-week period. Overall, biochar application resulted in decreased saturated hydraulic conductivity, while improved cumulative evaporation. Specifically, biochar produced at 300 °C and 500 °C demonstrated 10.2% and 13.3% higher cumulative evaporation, respectively., whereas, biochar produced at 700 °C with 5% application rate resulted in decreased cumulative evaporation. Cumulative evaporation increased by 5.0%, 7.7% and, 7.8% for D0.5, D1 and D2 (mm) on average, respectively, as compared with the untreated soil. Thus, biochar with particle size 0.5–1 mm significantly improved hydro-physical properties when applied at 1%. Generally, using biochar produced at medium temperature and small particle size with appropriate application rates could improve the soil hydro-physical properties.



2013 ◽  
Vol 831 ◽  
pp. 331-335 ◽  
Author(s):  
Ren Peng ◽  
Yu Jing Hou ◽  
Xue Dong Zhang ◽  
Qing Lei Sun

A model waste mixing with kaolin, sand, and peat was developed. The physical properties of the waste were compared with the real municipal solid waste (MSW). The influence of unit weight on compression factor, shear strength, and saturated hydraulic conductivity was acquired. In addition, the homogeneous of the soil model was detected using the IWHR 450g-ton centrifuge and the newly developed centrifuge-robot.



2018 ◽  
Author(s):  
Shuhua Yi ◽  
Yujie He ◽  
Xinlei Guo ◽  
Jianjun Chen ◽  
Qingbai Wu ◽  
...  

Abstract. Soils on the Qinghai-Tibetan Plateau (QTP) have distinct physical properties from agricultural soils due to weak weathering and strong erosion. These properties might affect permafrost dynamics. However, few studies have investigated both quantitatively. In this study, we selected a permafrost site on the central region of the QTP and excavated soil samples from 20 cm to 200 cm. We measured soil porosity, thermal conductivity, saturated hydraulic conductivity and matric potential in the laboratory. Finally, we ran a simulation model replacing default sand or silty clay parameters with different combinations of these measured parameters. Results showed that gravel content (diameter > 2 mm) was ~ 55 % on average in soil profile; soil porosity was less than 0.3; saturated hydraulic conductivity ranged from 0.004–0.03 mm s−1; saturated matric potential ranged from −14 to −604 mm. When default sand or silty clay parameters were substituted with these measured values, the model errors of soil temperature, soil liquid water content, active layer depth and permafrost lower boundary were reduced. The root mean squared errors of active layer depths simulated using measured parameters, and the default sand and silty clay parameters were about 0.28, 1.06, 1.83 m, respectively. Among these measured parameters, porosities, which were much smaller than soil textures used in land surface models, played a dominant role in reducing model errors. We also demonstrated that soil water dynamic processes should be considered, rather than using static properties under frozen and unfrozen soil states as in most permafrost models. We concluded that it is necessary to consider the distinct physical properties of soil and water dynamics on the QTP when simulating dynamics of permafrost in this region. It is important to develop methods for systematic measuring physical properties of gravelly soil and to develop a spatial dataset for porosity because of its importance in simulating permafrost dynamics in this region.



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