Revegetation of native desert plants enhances food security and water sustainability in arid regions: Integrated modeling assessment.

Food security and water sustainability in arid and semiarid regions are threatened by rapid population growth, declining natural resources, and global climate change. Countries in the arid regions compensate meat import by raising domestic livestock with cultivated green fodder, which diminishes lands for other crops and depletes precious water resources. This study presents for the first time an in-depth integrated food water ecosystem (FWEco) nexus modeling on the feasibility of restoring 10% of Kuwait's desert as grazing rangeland to alleviate water consumption from fodder production. Our results showed that revegetating 10% of the country's land with native species could support up to 23% of domestic livestock through natural grazing at optimal coverage (70%) and high productivity, and decrease water consumption by up to 90%. However, depending solely on natural rainfall is unlikely to achieve the optimal coverage. Strategic supplemental irrigation in the fall season (e.g., October and November) is required to maximize vegetation coverage and enhance food security and water sustainability. Significantly, strategic irrigation results in much lower net water consumption because irrigating native species requires much less water than green fodder cultivation. Therefore, revegetating desert lands with native species to restore their natural grazing service can be a sustainable approach to simultaneously improve food security and water sustainability in arid landscapes.

Investigating the applicability of UAVs in characterizing desert shrub biomass and developing biological indicators for the selection of suitable revegetation sites.

This study focused on evaluating factors influencing the growth of perennial shrubs by integrating field-based experiments and spatial analysis using unmanned aerial vehicles (UAVs) to identify ecological indicators that can help detect potential locations for restoration and revegetation of native plants. The experiment was implemented in the Al-Abduli protected area in Kuwait, which is mainly dominated by a Rhanterium epapposum community (desert shrub). Aerial imagery of the study site was acquired using UAVs during the growing season to estimate the desert shrub biomass and carbon stock. Then, soil samples were collected based on vegetation density to determine the impact of the soil's physical and chemical properties on vegetation biomass, growth, and distribution. It was found that shrub biomass was significantly correlated with crown area and shrub volume. We also observed that annual plants support the growth of perennial shrubs, as the mean shrub height and crown area (CA) are significantly higher, with averages of 0.7 m and 3 cm, respectively, in the presence of high annual plant density. However, shrubs in plots with low annual density had an average shrub height of 0.5 m and CA of 1.4 cm. Annual plants also enhance the soil by providing approximately 50% higher soil moisture, phosphorous (P), organic matter (OM), and carbon dioxide (CO2) sequestration. In addition, annual plants are mainly supported by loamy soils in the deeper soil layers. We concluded that locations covered with annual plants represent suitable soils and that this can be considered a biological indicator for convenient locations for restoration and revegetation of native perennial shrubs. Remote sensing technologies could be utilized for initial assessments to detect sites that may support annual plant growth over a large scale for classification as potential restoration and revegetation areas.

The immediate impact of the associated COVID-19's lockdown campaign on the native vegetation recovery of Wadi Al Batin Tri-state desert.

Law enforcement and massive media awareness, limiting the anthropogenic disturbance, is the way to go for implementing successful desert native vegetation recovery plans. A lesson learned on the resiliency of desert ecosystems throughout studying the native vegetation coverage in the Wadi Al-Batin desert ecosystem during the COVID-19 pandemic. Wadi Al-Batin tri-state desert (89,315 km2) covers the South-western part of Iraq, State of Kuwait, and the North-eastern part of Saudi Arabia. In this study, the spatiotemporal changes in vegetation coverage was detected, by using Sentinel-2A imageries, during the period from 2017 to 2020. For better understanding the impact of associated law enforcement and media practices during COVID-19 pandemic, native vegetation coverage of years with relevant rainfall records were compared. The results revealed that despite receiving the least amount of rain of the three years (≤93 mm), the COVID-19 year (2020) had the highest native vegetation coverage at 28.5% compared with 6% in 2017, and 2% in 2018. These results prove that the main drivers of desert vegetation deterioration are anthropogenic activities, such as quarrying, overgrazing, distractive camping, and off-road vehicle movements. Moreover, the estimated 63% vegetation coverage in Wadi Al-Batin desert in 2019 assures the significant role of precipitation in desert vegetation recovery. This bulk increase in vegetation coverage detected during COVID-19 pandemic shows that the desert vegetation adapts to harsh environments (low rainfall) and rapidly recovers once the source of the disturbance was removed by enforcing the environmental rules. Thus, the protection of natural resources and ecosystems can be achieved through the synergy between governments and civil communities, including intensive awareness of environmental impacts via media, enforcing environmental regulations, and promoting regional collaboration.

Impact of brackish groundwater and treated wastewater on soil chemical and mineralogical properties.

The long-term effect of using treated wastewater is not clearly defined: some researchers argue that it is better than freshwater for the soil health; others disapprove, claiming that irrigation with unconventional water resources causes soil degradation. This study assesses the impact of irrigation with non-traditional water on the chemical and mineralogical properties of a calcareous clayey soil from West Texas. The exponential rise in population and the realities of climate change contribute to the global increase in freshwater scarcity: non-conventional water sources, such as treated wastewater (TWW) and brackish groundwater (BGW), offer potentially attractive alternative water resources for irrigated agriculture. For this research, the differences between TWW and BGW were addressed by collecting and analyzing water samples for salt and nutrient content. Soil samples from three horizons (Ap, A, and B) were obtained from three different fields: Rainfed (RF), BGW irrigated, and TWW irrigated. Soil was analyzed for texture, salinity, sodicity, and carbon content. Clay mineralogy of the three different fields was analyzed using the B-horizons. The outcomes from the analysis showed that the BGW from the Lipan aquifer has higher salinity and is harder compared to TWW. Although the exchangeable sodium percentage (ESP), sodium adsorption ratio (SAR), and electroconductivity (EC) increased marginally compared to the control soil (RF), the soils were in good health, all the values of interest (SAR < 13, ESP < 15, pH < 8.5, and EC < 4) were low, indicating no sodicity or salinity problems. Smectite, illite, and kaolinite were identified in the three B-horizon samples using bulk X-ray diffraction (XRD). Overall, no major changes were observed in the soil. Thus, TWW and BGW are viable replacements for freshwater irrigation in arid and semi-arid regions.

Soil pedostructure-based method for calculating the soil-water holding properties.

Soil aggregates structure (pedostructure) plays a pivotal role in regulating water and nutrient circulation, and consequently defines soil health, productivity, and water use efficiency. However, the soil aggregates structure is not currently considered in the quantification of soil-water holding properties. The authors applied a thermodynamic and soil structure-based approach to quantify soil-water holding properties. The paper provides a methodology, based on pedostructure concept, to quantify field capacity (FC), permanent wilting point (PWP), and available water (AW). The validity of the developed method was tested through application to two types of soil: a loamy fine sand soil and a silt loam soil. The calculated values for FC, PWP, and AW were compared with the FAO recommended values of FC, PWP and AW. For the loamy fine sand, the calculated values were: FC = 0.208 m3/m3, PWP = 0.068 m3/m3, and AW = 0.140 m3/m3 all of which fall within the recommended values of FAO for such a soil type. Similarly, the calculated values for the silt loam were: FC = 0.283 m3/m3, PWP = 0.184 m3/m3, and AW = 0.071 m3/m3 all were in agreement with the FAO recommended ranges for such a soil type. •A thermodynamic, structure-based approach for soil water holding properties.•Unique solutions for quantifying both field capacity and permanent wilting point.

The effect of municipal treated wastewater on the water holding properties of a clayey, calcareous soil.

Wastewater reuse is a practice that has been gaining attention for the past few decades as the world's population rises and water resources become scarce. Wastewater application on soil can affect soil health, and the manner and extent to which this occurs depends heavily on soil type and water quality. This study compared the long-term (15+ years) effects and suitability of using secondary-level treated municipal wastewater and brackish groundwater for irrigation on the water holding capacity of a clayey, calcareous soil on a cotton farm near San Angelo, Texas. The soil-water holding properties were determined from the extracted hydrostructural parameters of the two characteristic curves: water retention curve and soil shrinkage curve based on the pedostructure concept. In the pedostructure concept, these hydrostructural parameters are characteristic properties of the soil aggregates structure and its thermodynamic interactions with water. Results indicate that use of secondary treated wastewater increased available water capacity in the top horizon (0-15 cm) and decreased the available water holding capacity of this particular soil in the sub-horizons (15-72 cm). The brackish groundwater irrigation resulted in no effect on available water capacity in the top horizon, but significantly decreased it in the sub-horizons as well. The rainfed soil was the healthiest soil in terms of water holding capacity, but rainfall conditions do not produce profitable cotton yields. Whereas, treated wastewater irrigated soil is producing the highest yields for the farmer. Thus, this treated wastewater source and irrigation system can serve as a suitable irrigation alternative to using brackish groundwater, enhancing the water resource sustainability of this region.