Using Wastewater in Irrigation: The Effects on Infiltration Process in a Clayey Soil

Soil water infiltration is a critical process in the soil water cycle and agricultural practices, especially when wastewater is used for irrigation. Although research has been conducted to evaluate the changes in the physical and chemical characteristics of soils irrigated by treated wastewater, a quantitative analysis of the effects produced on the infiltration process is still lacking. The objective of this study is to address this issue. Field experiments previously conducted on three adjacent field plots characterized by the same clayey soil but subjected to three different irrigation treatments have been used. The three irrigation conditions were: non-irrigated (natural conditions) plot, irrigated plot with treated wastewater for two years, and irrigated plot with treated wastewater for five years. Infiltration measurements performed by the Hood infiltrometer have been used to estimate soil hydraulic properties useful to calibrate a simplified infiltration model widely used under ponding conditions, that were existing during the irrigation stage. Our simulations highlight the relevant effect of wastewater usage as an irrigation source in reducing cumulative infiltration and increasing overland flow as a result of modified hydraulic properties of soils characterized by a lower capacity of water drainage. These outcomes can provide important insights for the optimization of irrigation techniques in arid areas where the use of wastewater is often required due to the chronic shortage of freshwater

High-resolution synchrotron imaging shows that root hairs influence rhizosphere soil structure formation

In this paper, we provide direct evidence of the importance of root hairs on pore structure development at the root-soil interface during the early stage of crop establishment. This was achieved by use of high resolution (~5 μm) synchrotron radiation computed tomography (SRCT) to visualise both the structure of root hairs and the soil pore structure in plant-soil microcosms. Two contrasting genotypes of barley (Hordeum vulgare L.), with and without root hairs, were grown for 8 days in microcosms packed with sandy loam soil at 1.2 g cm-3 36 dry bulk density. Root hairs were visualised within air filled pore spaces, but not in the fine-textured soil regions. - We found that the genotype with root hairs significantly altered the porosity and connectivity of the detectable pore space (> 5 μm) in the rhizosphere, as compared with the no-hair mutants. Both genotypes showed decreasing pore-space between 0.8 mm and 0.1 mm from the root surface. Interestingly the root-hair-bearing genotype had a significantly greater soil pore volume-fraction at the root-soil interface. - Effects of pore structure on diffusion and permeability were estimated to be functionally insignificant under saturated conditions when simulated using image based modelling

An overview of the utilisation of microalgae biomass derived from nutrient recycling of wet market wastewater and slaughterhouse wastewater

Microalgae have high nutritional values for aquatic organisms compared to fish meal, because microalgae cells are rich in proteins, lipids, and carbohydrates. However, the high cost for the commercial production of microalgae biomass using fresh water or artificial media limits its use as fish feed. Few studies have investigated the potential of wet market wastewater and slaughterhouse wastewater for the production of microalgae biomass. Hence, this study aims to highlight the potential of these types of wastewater as an alternative superior medium for microalgae biomass as they contain high levels of nutrients required for microalgae growth. This paper focuses on the benefits of microalgae biomass produced during the phycore-mediation of wet market wastewater and slaughterhouse wastewater as fish feed. The extraction techniques for lipids and proteins as well as the studies conducted on the use of microalgae biomass as fish feed were reviewed. The results showed that microalgae biomass can be used as fish feed due to feed utilisation efficiency, physiological activity, increased resistance for several diseases, improved stress response, and improved protein retention

Development and analysis of the Soil Water Infiltration Global database.

In this paper, we present and analyze a novel global database of soil infiltration measurements, the Soil Water Infiltration Global (SWIG) database. In total, 5023 infiltration curves were collected across all continents in the SWIG database. These data were either provided and quality checked by the scientists who performed the experiments or they were digitized from published articles. Data from 54 different countries were included in the database with major contributions from Iran, China, and the USA. In addition to its extensive geographical coverage, the collected infiltration curves cover research from 1976 to late 2017. Basic information on measurement location and method, soil properties, and land use was gathered along with the infiltration data, making the database valuable for the development of pedotransfer functions (PTFs) for estimating soil hydraulic properties, for the evaluation of infiltration measurement methods, and for developing and validating infiltration models. Soil textural information (clay, silt, and sand content) is available for 3842 out of 5023 infiltration measurements (~76%) covering nearly all soil USDA textural classes except for the sandy clay and silt classes. Information on land use is available for 76% of the experimental sites with agricultural land use as the dominant type (~40%). We are convinced that the SWIG database will allow for a better parameterization of the infiltration process in land surface models and for testing infiltration models. All collected data and related soil characteristics are provided online in *.xlsx and *.csv formats for reference, and we add a disclaimer that the database is for public domain use only and can be copied freely by referencing it. Supplementary data are available at https://doi.org/10.1594/PANGAEA.885492 (Rahmati et al., 2018). Data quality assessment is strongly advised prior to any use of this database. Finally, we would like to encourage scientists to extend and update the SWIG database by uploading new data to it

Development and analysis of the Soil Water Infiltration Global database

In this paper, we present and analyze a novel global database of soil infiltration measurements, the Soil Water Infiltration Global (SWIG) database. In total, 5023 infiltration curves were collected across all continents in the SWIG database. These data were either provided and quality checked by the scientists who performed the experiments or they were digitized from published articles. Data from 54 different countries were included in the database with major contributions from Iran, China, and the USA. In addition to its extensive geographical coverage, the collected infiltration curves cover research from 1976 to late 2017. Basic information on measurement location and method, soil properties, and land use was gathered along with the infiltration data, making the database valuable for the development of pedotransfer functions (PTFs) for estimating soil hydraulic properties, for the evaluation of infiltration measurement methods, and for developing and validating infiltration models. Soil textural information (clay, silt, and sand content) is available for 3842 out of 5023 infiltration measurements ( ∼ 76%) covering nearly all soil USDA textural classes except for the sandy clay and silt classes. Information on land use is available for 76% of the experimental sites with agricultural land use as the dominant type ( ∼ 40%). We are convinced that the SWIG database will allow for a better parameterization of the infiltration process in land surface models and for testing infiltration models. All collected data and related soil characteristics are provided online in *.xlsx and *.csv formats for reference, and we add a disclaimer that the database is for public domain use only and can be copied freely by referencing it. Supplementary data are available at https://doi.org/10.1594/PANGAEA.885492 (Rahmati et al., 2018). Data quality assessment is strongly advised prior to any use of this database. Finally, we would like to encourage scientists to extend and update the SWIG database by uploading new data to it

BIOPHYSICAL CONTROLS ON RHIZOSPHERE DYNAMICS

Soil structure directly determines important soil physical properties including porosity, hydraulic conductivity, water retention, and mechanical strength. It also indirectly influences almost all biological and chemical processes that occur in soil. Conversely, the development, stability, and dynamics of soil structure are dictated by the very physical, chemical, and biological processes that occur within the structured soil. There is ample empirical evidence showing the effectiveness of wetting and drying in the presence of organic matter in soil aggregation and stabilization. However, the mechanisms that bond the particles together under this process need more investigation. The goal of this dissertation was to understand and develop quantitative description of the role of wetting and drying cycles in presence of exudates in the formation and stabilization of soil aggregates within the rhizosphere.In this dissertation, I (a) developed a new, easy and rapid method to measure the carbohydrate and total carbon concentrations using UV spectrophotometry, (b) examined whether the association between plant root and bacteria exudates with neutral sand particles occurred and defined the mechanism of this association, (c) developed a conceptual/mathematical model describe the soil aggregation mechanism in presence of exudates under multiple wetting and drying cycles, (d) examined the mechanisms that affect rhizosphere water dynamics and whether these dynamics are a result of the osmotic potential induced by root exudates or the soil structure modification that occurred because of these exudates, and (e) developed a mathematical model to quantitatively describe the experimental results of the effect of water potential induced by root exudates on water evaporation rate.This dissertation presented a framework for in-depth understanding on how wetting and drying cycles in the presence of exudates promote soil aggregation and stabilization within the rhizosphere. It also advanced our understanding of the benefits of presence of root exudates in the rhizosphere on water retention and evaporation rate and provided the right-scale physics for high resolution computational modeling of water dynamics around the plant roots and root water uptake

BIOPHYSICAL CONTROLS ON RHIZOSPHERE DYNAMICS

Soil structure directly determines important soil physical properties including porosity, hydraulic conductivity, water retention, and mechanical strength. It also indirectly influences almost all biological and chemical processes that occur in soil. Conversely, the development, stability, and dynamics of soil structure are dictated by the very physical, chemical, and biological processes that occur within the structured soil. There is ample empirical evidence showing the effectiveness of wetting and drying in the presence of organic matter in soil aggregation and stabilization. However, the mechanisms that bond the particles together under this process need more investigation. The goal of this dissertation was to understand and develop quantitative description of the role of wetting and drying cycles in presence of exudates in the formation and stabilization of soil aggregates within the rhizosphere.In this dissertation, I (a) developed a new, easy and rapid method to measure the carbohydrate and total carbon concentrations using UV spectrophotometry, (b) examined whether the association between plant root and bacteria exudates with neutral sand particles occurred and defined the mechanism of this association, (c) developed a conceptual/mathematical model describe the soil aggregation mechanism in presence of exudates under multiple wetting and drying cycles, (d) examined the mechanisms that affect rhizosphere water dynamics and whether these dynamics are a result of the osmotic potential induced by root exudates or the soil structure modification that occurred because of these exudates, and (e) developed a mathematical model to quantitatively describe the experimental results of the effect of water potential induced by root exudates on water evaporation rate.This dissertation presented a framework for in-depth understanding on how wetting and drying cycles in the presence of exudates promote soil aggregation and stabilization within the rhizosphere. It also advanced our understanding of the benefits of presence of root exudates in the rhizosphere on water retention and evaporation rate and provided the right-scale physics for high resolution computational modeling of water dynamics around the plant roots and root water uptake

Shading solutions for sustainable water management: impact of colors and intensities on evaporation and water quality

Abstract This study investigated the effectiveness of suspended shade covers in reducing evaporation rates and improving evaporation suppression efficiency. The experiment tested different shading colors (black, white, and green) and intensities (50, 70, and 90%) while considering ecological and economical aspects. Evaporation was determined using class-A evaporation pans, and various microclimatic variables were measured below the shade covers. Additionally, water quality parameters such as EC, phosphate, nitrate, and chloride concentrations were monitored. The results showed that black covers had the highest evaporation suppression efficiency with values of 56.8, 53.6, and 51.7% observed under 90% shading intensity for the black, green, and white covers, respectively. Despite variations in water quality parameters which all met Jordanian and FAO standards for irrigation water, the economic feasibility of installing these covers was found to be viable due to the resulting benefits in water conservation and crop production. However, selecting the best shading cover should consider the multipurpose use of agricultural reservoirs, including aquaculture, and further studies are recommended to investigate other overlapping aspects on a reservoir scale

Assessment of Water Quality of Key Dams in Jordan for Irrigation Purposes with Insights on Parameter Thresholds

Dams play a vital role as a primary water supply for irrigation in Jordan, necessitating an assessment of their water quality. This study aimed to evaluate the suitability of irrigation water in a key number of Jordanian dams, namely Al Kafrain, Al Waala, King Talal (KTD), Mujib, Shuaib, and Sharhabil. Monthly readings of major water parameters (EC, Cl−, SO42−, HCO3−, Na+, Ca2+, and Mg2+) were recorded for seven years (2015–2021) for each dam. The assessment criteria included the sodium adsorption ratio (SAR), soluble sodium percentage (SSP), residual sodium carbonate (RSC), magnesium adsorption ratio (MAR), kelley ratio (KR), total hardness (TH), and water quality index (WQI) using both average (APL) and maximum permissible limits (MPL). Additionally, USSL, Wilcox, Doneen, Piper, and Gibbs diagrams were applied. The findings indicate that all the dams demonstrated suitability for irrigation based on the SAR, SSP, RSC, MAR, and KR values. The USSL diagrams showed most samples falling under C2S1 and C3S1, except KTD, which fell under C3S2. According to the Wilcox diagram, the water was either Excellent to Good or Good to Permissible, while the KTD water was classified as Permissible to Doubtful. Furthermore, the water chemistry was found to be mainly influenced by rock weathering, as revealed in the Gibbs diagram, and has no restriction on permeability, according to the Doneen diagram. The WQI showed that all the dams fall in the Good and Excellent category for irrigation using APL, while applying MPL, all the dams were in the Excellent category, which demonstrates the necessity of considering extreme events and regulatory thresholds