scholarly journals Infiltration and Soil Water Distribution in Irrigation Furrows Treated with Polyacrylamide

2020 ◽  
Vol 63 (5) ◽  
pp. 1451-1464
Author(s):  
Rick D. Lentz ◽  
Eduardo Bautista ◽  
Anita Koehn ◽  
Robert Sojka
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Irrigation Water ◽  
Water Distribution ◽  
Water Soluble ◽  
Inflow Rate ◽  
Lower Section ◽  
Irrigation Uniformity ◽  
Advance Time ◽  
Soil Water Distribution

HighlightsControl furrows with 1× inflow rates were compared with 3× advance inflows treated with 10 mg L-1 polymer (WSPAM).WSPAM reduced sediment loads in furrow streams by 89%, despite its 3× greater advance inflows.WSPAM furrow advance times and infiltrated volumes were greater than predicted from increased inflows alone.WSPAM enabled reduced upper-section infiltration and increased lower-section infiltration relative to control furrows.Abstract. Few if any studies have measured the effects of water-soluble anionic polyacrylamide (WSPAM) on infiltration and soil water distribution in different segments of irrigation furrows. We conducted a four-year study on a silt loam soil with 1.5% slopes. Control furrows received no WSPAM and inflows were 15.1 L min-1, whereas WSPAM was applied using 10 mg L-1 a.i. to 45 L min-1 inflows during furrow advance. Despite its greater advance phase inflow rates, WSPAM application reduced sediment concentrations in furrow streams by an average of 89% relative to the control. A surface irrigation model, WinSRFR 5.1, was used to separate furrow inflow rate effects on infiltration from that of WSPAM. Relative to results predicted by simulation for the entire furrow, the polymer treatment: (1) increased advance time an average 1.4-fold, (2) increased advance-phase infiltrated volume 1.5-fold, and (3) increased infiltration volume at the common opportunity time 1.2-fold. Hence, these effects resulted from WSPAM and not from differences in treatment inflow rates. Treatment infiltration amounts varied markedly among irrigations and years, as did the intensity of WSPAM effects. These were attributed mainly to differences in infiltration opportunity time, but temporal differences in soil water content during furrow formation, irrigation water electrical conductivity, initial soil surface water content and water temperature, and the irrigation-long, furrow-stream mean sediment content also appear to have influenced infiltration rates. Although inconsistent, WSPAM increased net furrow infiltration in the lower section and reduced infiltration in the upper section relative to control furrows. This effect could not be explained by the greater inflow rate and shorter advance time of the WSPAM treatments and was attributed to spatially variable WSPAM effects on infiltration opportunity time and possibly irrigation water viscosity. The WSPAM management approach, while protecting against furrow erosion, may potentially provide a means of improving irrigation uniformity and reducing associated percolation water and nutrient losses. Keywords: Furrow advance, Irrigation, Irrigation uniformity, Polymers.

Gap thinning improves soil water content, changes the vertical water distribution, and decreases the fluctuation

2018 ◽  
Vol 48 (9) ◽  
pp. 1042-1048 ◽  
Author(s):  
Zhe Wang ◽  
Qihua He ◽  
Bin Hu ◽  
Xueyong Pang ◽  
Weikai Bao
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Forest Restoration ◽  
Water Distribution ◽  
Gap Size ◽  
Eastern Tibetan Plateau ◽  
Soil Water Conditions ◽  
Gap Creation ◽  
Soil Water Distribution

Although it is clear that gap thinning significantly increases the soil water content (SWC) of the topsoil, less is known about whether and how this treatment affects deeper layers. From December 2008 to April 2012, we monitored the SWC at depths of 10, 20, 30, 45, 60, and 90 cm in gap creation treatments (small gap size of 30 m2, intermediate gap size of 80 m2, and unthinned plots) in a typical pine plantation in the eastern Tibetan Plateau. Among gap treatments, differences in SWC and its coefficient of variation (CV) at each depth and the soil water content proportion (SWCP) of the whole soil profile at specific depths were compared. Gap thinning improved SWC and decreased the CV at each depth. The SWCPs in thinned plots were lower at depths from 10 to 30 cm compared with unthinned plots but higher at depths of 45 and 60 cm. Also, in each season, the patterns were similar to the general results. In conclusion, gap thinning improves the SWC, changes the vertical soil water distribution, and decreases the SWC heterogeneity. The soil water conditions in intermediate gaps are more appropriate for local forest restoration.

Effect of Soil Water Content on the Removal of Volatile Chlorinated Hydrocarbons from Soil by Mechanical Soil Aeration

2015 ◽  
Vol 737 ◽  
pp. 541-548 ◽  
Author(s):  
Yan Ma ◽  
Xiao Ming Du ◽  
Yi Shi ◽  
Zhi Fen Wang ◽  
Shi Jie Wang ◽  
...  
Keyword(s):  
Distribution Coefficient ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Water Distribution ◽  
Effective Diffusion ◽  
Chlorinated Hydrocarbons ◽  
Soil Aeration ◽  
Volatile Chlorinated Hydrocarbons ◽  
Soil Water Distribution

Mechanical soil aeration is an easy, effective, and low-cost soil remediation technology; in particular, it is suitable for large sites contaminated by volatile chlorinated hydrocarbons (VCHs). Mechanical soil aeration encourages the volatilization of soil contaminants, but soil moisture, which reduces the amount of open pores, may hinder this process. The present study examined the remediation of silty soil containing 1,2-dichloroethane (1,2-DCA), chloroform (TCM), trichloroethylene (TCE), and tetrachloroethylene (PCE) using mechanical soil aeration and evaluated the influence of soil water content on the efficiency of the process. For artificially contaminated soil, the following conclusions were reached: (i) moisture undermines the volatilization of contaminants. When the soil water content increased from 5% to 20%, the residual concentrations of 1,2-DCA, TCM, TCE, and PCE in the soil increased from 0.08, 0.10, 0.09, and 0.48 mg/kg to 1.43, 0.81, 1.16, and 1.43 mg/kg, respectively. The effective diffusion coefficients also decreased from 1.88×10-2, 1.43×10-2, 1.88×10-2, and 1.30×10-2 cm2/s to 1.71×10-6, 1.30×10-6, 1.71×10-6, and 1.18×10-6 cm2/s, respectively. (ii) Residual contaminants are related to the octanol-water partition coefficient. The soil-water distribution coefficient of PCE was highest among the hydrocarbons (3.72), and the residual contaminants were mainly adsorbed on soil particles. The soil-water distribution coefficient of DCA was lowest (0.42), and the residual contaminants were mainly dissolved in the soil water.

A simple numerical model to estimate water availability in saline soils

Soil Research ◽  
2018 ◽  
Vol 56 (3) ◽  
pp. 264 ◽  
Author(s):  
Mohammad Hossein Mohammadi ◽  
Mahnaz Khataar
Keyword(s):  
Numerical Model ◽  
Water Content ◽  
Soil Water ◽  
Water Uptake ◽  
Soil Salinity ◽  
Irrigation Water ◽  
Weighting Function ◽  
Water Salinity ◽  
Irrigation Water Salinity ◽  
Evapotranspiration Rate

We developed a numerical model to predict soil salinity from knowledge of evapotranspiration rate, crop salt tolerance, irrigation water salinity, and soil hydraulic properties. Using the model, we introduced a new weighting function to express the limitation imposed by salinity on plant available water estimated by the integral water capacity concept. Lower and critical limits of soil water uptake by plants were also defined. We further analysed the sensitivity of model results to underlying parameters using characteristics given for corn, cowpea, and barley in the literature and two clay and sandy loam soils obtained from databases. Results showed that, between two irrigation events, soil salinity increased nonlinearly with decreasing soil water content especially when evapotranspiration and soil drainage rate were high. The salinity weighting function depended greatly on the plant sensitivity to salinity and irrigation water salinity. This research confirmed that both critical and lower limits (in terms of water content) of soil water uptake by plants increased with evapotranspiration rate and irrigation water salinity. Since the presented approach is based on a physical concept and well-known plant parameters, soil hydraulic characteristics, irrigation water salinity, and meteorological conditions, it may be useful in spatio-temporal modelling of soil water quality and quantity and prediction of crop yield.

Soil Water Distribution and Movement in Layered Soils of a Dam Farmland

2010 ◽  
Vol 24 (14) ◽  
pp. 3871-3883 ◽  
Author(s):  
Peipei Zhao ◽  
Ming-an Shao ◽  
Ahmed A. Melegy
Keyword(s):  
Soil Water ◽  
Water Distribution ◽  
Layered Soils ◽  
Soil Water Distribution

scholarly journals A thermodynamic formulation of root water uptake

2016 ◽  
Vol 20 (8) ◽  
pp. 3441-3454 ◽  
Author(s):  
Anke Hildebrandt ◽  
Axel Kleidon ◽  
Marcel Bechmann
Keyword(s):  
Soil Water ◽  
Water Uptake ◽  
Water Distribution ◽  
Bound Water ◽  
Root Water Uptake ◽  
Flow Path ◽  
Thermodynamic Evaluation ◽  
Entire Flow ◽  
Soil Water Distribution

Abstract. By extracting bound water from the soil and lifting it to the canopy, root systems of vegetation perform work. Here we describe how root water uptake can be evaluated thermodynamically and demonstrate that this evaluation provides additional insights into the factors that impede root water uptake. We derive an expression that relates the energy export at the base of the root system to a sum of terms that reflect all fluxes and storage changes along the flow path in thermodynamic terms. We illustrate this thermodynamic formulation using an idealized setup of scenarios with a simple model. In these scenarios, we demonstrate why heterogeneity in soil water distribution and rooting properties affect the impediment of water flow even though the mean soil water content and rooting properties are the same across the scenarios. The effects of heterogeneity can clearly be identified in the thermodynamics of the system in terms of differences in dissipative losses and hydraulic energy, resulting in an earlier start of water limitation in the drying cycle. We conclude that this thermodynamic evaluation of root water uptake conveniently provides insights into the impediments of different processes along the entire flow path, which goes beyond resistances and also accounts for the role of heterogeneity in soil water distribution.

Development of a soil water dispersion index (SOWADIN) for testing the effectiveness of soil-wetting agents

Soil Research ◽  
1989 ◽  
Vol 27 (1) ◽  
pp. 17 ◽  
Author(s):  
Y Sawada ◽  
LAG Aylmore ◽  
JM Hainsworth
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Water Distribution ◽  
Soil Column ◽  
Water Repellent ◽  
Computer Assisted ◽  
Dispersion Index ◽  
Soil Columns ◽  
Water Dispersion ◽  
Soil Wetting

Computer-assisted tomography (CAT) applied to gamma-ray attenuation measurements has been used to develop an index termed the soil water dispersion index (SOWADIN), which describes quantitatively the amount and distribution of water in soil columns. The index, which is determined by classifying pixels in a scanned slice into three categories according to their attenuation coefficients, contains two numerical values. The first value corresponds to the water content of the scanned slice and the second value is a measure of the dispersion of the water throughout the slice. Artificially wetted zones were created in soil columns to give one-third of the scanned layer wetted with various patterns of wetted-area distribution. The SOWADIN values obtained accurately reflected the differences in water distribution associated with the different patterns. Application of SOWADIN to columns of a water-repellent sand before and after treatment with a soil-wetting agent clearly illustrates both the increase in water content and improvement in water distribution in the soil column following treatment.

Mobility of a Polyether Trisiloxane Surfactant in Soil: Soil/Water Distribution Coefficients and Leaching in a Soil Column

2016 ◽  
Vol 227 (2) ◽  
Author(s):  
Amandine Michel ◽  
Conrad Dietschweiler ◽  
Martina Böni ◽  
Michael Burkhardt ◽  
Heinz-Jürgen Brauch ◽  
...  
Keyword(s):  
Soil Water ◽  
Water Distribution ◽  
Soil Column ◽  
Distribution Coefficients ◽  
Soil Water Distribution

scholarly journals Monitoring of Soil Water Content in Maize Rotated with Pigeonpea Fallows in South Africa

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2761
Author(s):  
Misheck Musokwa ◽  
Paramu L. Mafongoya ◽  
Paxie W. Chirwa
Keyword(s):  
South Africa ◽  
Water Content ◽  
Soil Water ◽  
Water Distribution ◽  
Smallholder Farmers ◽  
Block Design ◽  
Maize Production ◽  
Soil Water Tension ◽  
Continuous Maize ◽  
Water Tension

Maize production under smallholder systems in South Africa (RSA) depends on rainfall. Incidences of dry spells throughout the growing season have affected maize yields negatively. The study examined water distribution and water use efficiency (WUE) of maize rotated with two-year pigeonpea fallows as compared to continuous maize without fertilizer. A randomized complete block design, replicated three times, was used with four treatments, which included continuous unfertilized maize, natural fallow-maize, pigeonpea + grass-pigeonpea-maize, and two-year pigeonpea fallow-maize. Soil water mark sensors were installed 0.2; 0.5; and 1.2 m on each plot to monitor soil water tension (kPa). Soil samples were analyzed using pressure plates to determine water retention curves which were used to convert soil water tension to volumetric water content. Maize rotated with two-year pigeonpea fallows had higher dry matter yield (11,661 kg ha−1) and WUE (20.78 kg mm−1) than continuous maize (5314 kg ha−1 and 9.48 kg mm−1). In this era of water scarcity and drought incidences caused by climate change, maize rotated with pigeonpea fallows is recommended among smallholder farmers in RSA because of its higher WUE, hence food security will be guaranteed.

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