scholarly journals THE EFFECT OF COMPACTION ON WATER RETENTION IN THE VINEYARD’S ROOT ZONE

AGROFOR ◽  
2019 ◽  
Vol 3 (3) ◽  
Author(s):  
Markela KOZAITI ◽  
Sofia KOSTOPOULOU
Keyword(s):  
Soil Water ◽  
Water Retention ◽  
Root Zone ◽  
Characteristic Curve ◽  
Distance Sampling ◽  
Soil Bulk Density ◽  
Soil Water Retention ◽  
Traffic Impact ◽  
In The Beginning ◽  
Water Retention Properties

In vineyards, frequent machinery traffic between the vine rows results in spatialand temporal changes in soil structure that affect the water retention properties inthe root zone. Compaction effects on the soil water characteristic curve in the rootzone were evaluated in three vineyards of different soil types (a Cl, a ClL, and aSiL with increased sand percentage). Soil cores were collected from a) the tilledsoil on the vine-row and b) the compacted soil of ruts produced by machinerytraffic within the inter-row distance. Sampling was carried out at two depths (0-15cm and 15-30cm) and at two time intervals, the first in spring when agriculturalvehicles had accomplished 6-8 passes and the second in autumn, after ca 20 passes.The results of the first sampling in the beginning of the cultivation period revealedthat compaction increased soil bulk density of the three vineyards in both depths.Drainage pores collapsed to smaller ones while plant available water and texturalporosity increased. The effect of compaction was more pronounced on the surface(0-15 cm) of the more fine textured soils. In autumn, at the end of the cultivationperiod, it was found that the soil water retention characteristics in the vineyardsroot zone were not substantially further affected by machinery traffic. Weconcluded that machinery traffic impact on the studied properties was intense inspring when the soil in vineyards was loose from tillage before the cultivationperiod and had temporally increased moisture content which results in decreasedstrength.

scholarly journals Carboxylated nanocellulose superabsorbent: Biodegradation and soil water retention properties

2021 ◽  
pp. 51495
Author(s):  
Ruth M. Barajas‐Ledesma ◽  
Vanessa N. L. Wong ◽  
Karen Little ◽  
Antonio F. Patti ◽  
Gil Garnier
Keyword(s):  
Soil Water ◽  
Water Retention ◽  
Soil Water Retention ◽  
Water Retention Properties

Method for Quick Prediction of Hydraulic Conductivity and Soil-Water Retention of Unsaturated Soils

2018 ◽  
Vol 2672 (52) ◽  
pp. 108-117 ◽  
Author(s):  
Shaoyang Dong ◽  
Yuan Guo ◽  
Xiong (Bill) Yu
Keyword(s):  
Finite Element ◽  
Hydraulic Conductivity ◽  
Soil Properties ◽  
Soil Water ◽  
Unsaturated Soil ◽  
Unsaturated Soils ◽  
Hydraulic Properties ◽  
Water Retention ◽  
Characteristic Curve ◽  
Soil Water Retention

Hydraulic conductivity and soil-water retention are two critical soil properties describing the fluid flow in unsaturated soils. Existing experimental procedures tend to be time consuming and labor intensive. This paper describes a heuristic approach that combines a limited number of experimental measurements with a computational model with random finite element to significantly accelerate the process. A microstructure-based model is established to describe unsaturated soils with distribution of phases based on their respective volumetric contents. The model is converted into a finite element model, in which the intrinsic hydraulic properties of each phase (soil particle, water, and air) are applied based on the microscopic structures. The bulk hydraulic properties are then determined based on discharge rate using Darcy’s law. The intrinsic permeability of each phase of soil is first calibrated from soil measured under dry and saturated conditions, which is then used to predict the hydraulic conductivities at different extents of saturation. The results match the experimental data closely. Mualem’s equation is applied to fit the pore size parameter based on the hydraulic conductivity. From these, the soil-water characteristic curve is predicted from van Genuchten’s equation. The simulation results are compared with the experimental results from documented studies, and excellent agreements were observed. Overall, this study provides a new modeling-based approach to predict the hydraulic conductivity function and soil-water characteristic curve of unsaturated soils based on measurement at complete dry or completely saturated conditions. An efficient way to measure these critical unsaturated soil properties will be of benefit in introducing unsaturated soil mechanics into engineering practice.

scholarly journals Prediction of soil water retention properties using pore-size distribution and porosity

2013 ◽  
Vol 50 (4) ◽  
pp. 435-450 ◽  
Author(s):  
Christopher T.S. Beckett ◽  
Charles E. Augarde
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Soil Water ◽  
Water Retention ◽  
Adsorbed Water ◽  
Retention Data ◽  
Soil Water Retention ◽  
Pore Size Distributions ◽  
Water Retention Properties

Several models have been suggested to link a soil's pore-size distribution to its retention properties. This paper presents a method that builds on previous techniques by incorporating porosity and particles of different sizes, shapes, and separation distances to predict soil water retention properties. Mechanisms are suggested for the determination of both the main drying and wetting paths, which incorporate an adsorbed water phase and retention hysteresis. Predicted results are then compared with measured retention data to validate the model and to provide a foundation for discussing the validity and limitations of using pore-size distributions to predict retention properties.

scholarly journals Improvement of Economic Water Productivity of Cucumber by using Soil Water Retention Technology under Subsurface Trickle Irrigation System

2019 ◽  
Vol 26 (3) ◽  
pp. 68-72
Author(s):  
Fatima Sadoon Mushab ◽  
Sabah Anwer Almasraf
Keyword(s):  
Water Use Efficiency ◽  
Soil Water ◽  
Water Use ◽  
Water Retention ◽  
Root Zone ◽  
Irrigation System ◽  
Water Productivity ◽  
Trickle Irrigation ◽  
Soil Water Retention ◽  
Use Efficiency

Subsurface soil water retention (SWRT) is a recent technology for increasing the crop yield, water use efficiency and then the water productivity with less amount of applied water. The goal of this research was to evaluate the existing of SWRT with the influence of surface and subsurface trickle irrigation on economic water productivity of cucumber crop. Field study was carried out at the Hawr Rajab district of Baghdad governorate from October 1st, to December 31st, 2017. Three experimental treatments were used, treatment plot T1 using SWRT with subsurface trickle irrigation, plot T2 using SWRT with surface trickle irrigation, while plot T3 without using SWRT and using surface tickle irrigation system. The obtained results showed that the economic water productivity in plot T1 was greater than plots T2 and T3. The increasing value was about 65 % and 124 %, respectively. The benefit of the installing SWRT along with subsurface trickle irrigation in the crop root zone assisted to keep the water, nutrients and fertilizers during the root zone profile, improving the field water use efficiency and then the parameter of water productivity.

scholarly journals Estimating soil water retention for wide ranges of pressure head and bulk density based on a fractional bulk density concept

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Huihui Sun ◽  
Jaehoon Lee ◽  
Xijuan Chen ◽  
Jie Zhuang
Keyword(s):  
Water Content ◽  
Bulk Density ◽  
Soil Water ◽  
Water Retention ◽  
Pore Space ◽  
Pressure Head ◽  
Soil Bulk Density ◽  
Residual Water ◽  
Soil Water Retention ◽  
Residual Water Content

Abstract Soil water retention determines plant water availability and contaminant transport processes in the subsurface environment. However, it is usually difficult to measure soil water retention characteristics. In this study, an analytical model based on a fractional bulk density (FBD) concept was presented for estimating soil water retention curves. The concept allows partitioning of soil pore space according to the relative contribution of certain size fractions of particles to the change in total pore space. The input parameters of the model are particle size distribution (PSD), bulk density, and residual water content at water pressure head of 15,000 cm. The model was tested on 30 sets of water retention data obtained from various types of soils that cover wide ranges of soil texture from clay to sand and soil bulk density from 0.33 g/cm3 to 1.65 g/cm3. Results showed that the FBD model was effective for all soil textures and bulk densities. The estimation was more sensitive to the changes in soil bulk density and residual water content than PSD parameters. The proposed model provides an easy way to evaluate the impacts of soil bulk density on water conservation in soils that are manipulated by mechanical operation.

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