Decreasing Water Availability Research Articles

Application of RNN-LSTM in Predicting Drought Patterns in Pakistan: A Pathway to Sustainable Water Resource Management

Water is a fundamental and crucial natural resource for human survival. However, the global demand for water is increasing, leading to a subsequent decrease in water availability. This study addresses the critical need for improved water resource forecasting models amidst global water scarcity concerns exacerbated by climate change. This study uses the best weather and water resource forecasting model for sustainable development. Employing a Recurrent Neural Network–Long Short-Term Memory (RNN-LSTM) approach, the research enhances drought prediction capabilities by integrating secondary data of the rainfall, temperature, and ground and surface water supplies. The primary objective is to forecast water resources under changing climatic conditions, facilitating the development of early warning systems for vulnerable regions. The results from the LSTM model show an increased trend in temperature and rainfall patterns. However, a relatively unstable decrease in rainfall is observed. The best statistical analysis result was observed with the LSTM model; the model’s accuracy was 99%, showing that it was quite good at presenting the obtained precipitation, temperature, and water data. Meanwhile, the value of the root mean squared error (RMSE) was about 13, 15, and 20, respectively. Therefore, the study’s results highlight that the LSTM model was the most suitable among the artificial neural networks for forecasting the weather, rainfall, and water resources. This study will help weather forecasting, agriculture, and meteorological departments be effective for water resource forecasting.

Impacts of Climate Change and Adaptation Strategies for Rainfed Barley Production in the Almería Province, Spain

Mediterranean water-stressed areas face significant challenges from higher temperatures and increasingly severe droughts. We assess the effect of climate change on rainfed barley production in the aridity-prone province of Almería, Spain, using the FAO AquaCrop model. We focus on rainfed barley growth by the mid-century (2041–2070) and end-century (2071–2100) time periods, using three Shared Socio-economic Pathway (SSP)-based scenarios: SSP1-2.6, SSP2-4.5, and SSP5-8.5. Using the paired t-test, Spearman and Pearson correlation coefficient, Root Mean Squared Error, and relative Root Mean Squared Error, we verified AquaCrop’s ability to capture local multi-year trends (9 or more years) using standard barley crop parameters, without local recalibration. Starting with a reference Initial Soil Water Content (ISWC), different soil water contents within barley rooting depth were modelled to account for decreases in soil water availability. We then evaluated the efficiency of different climate adaptation strategies: irrigation, mulching, and changing sowing dates. We show average yield changes of +14% to −44.8% (mid-century) and +12% to −55.1% (end-century), with ISWC being the main factor determining yields. Irrigation increases yields by 21.1%, utilizing just 3% of Almería’s superficial water resources. Mulches improve irrigated yield performances by 6.9% while reducing irrigation needs by 40%. Changing sowing dates does not consistently improve yields. We demonstrate that regardless of the scenario used, climate adaptation of field barley production in Almería should prioritize limiting soil water loss by combining irrigation with mulching. This would enable farmers in Almería’s northern communities to maintain their livelihoods, reducing the province’s reliance on horticulture while continuing to contribute to food security goals.

Declining Tradeoff Between Resistance and Resilience of Ecosystems to Drought

AbstractResistance and resilience are widely used to characterize ecosystem drought stability. Tradeoff between resistance and resilience have been reported, but its long‐term trends remain uncertain at global scale. Based on remotely sensed vegetation indices, we assessed the spatiotemporal dynamics of drought resistance and resilience. Result revealed that there was a significant decline in the tradeoff between resistance and resilience, corresponding to a substantial increase in the proportion of areas with high resistance‐high resilience or low resistance‐low resilience. In the South Sahel, South Africa and Central China, the increased precipitation and vegetation coverage contribute to enhanced drought stability constructed by resistance and resilience; while rising temperature, decreased water availability and deforestation lead to declined stability in northeastern North America, South America and the Congo region. Increases in the areas with low resistance‐low resilience resulting from declining tradeoffs warn of increased regional ecosystem vulnerability.

Functional diversity enhances dryland forest productivity under long-term climate change.

Short-term experimental studies provided evidence that plant diversity increases ecosystem resilience and resistance to drought events, suggesting diversity to serve as a nature-based solution to address climate change. However, it remains unclear whether the effects of diversity are momentary or still hold over the long term in natural forests to ensure that the sustainability of carbon sinks. By analyzing 57 years of inventory data from dryland forests in Canada, we show that productivity of dryland forests decreased at an average rate of 1.3% per decade, in concert with the temporally increasing temperature and decreasing water availability. Increasing functional trait diversity from its minimum (monocultures) to maximum value increased productivity by 13%. Our results demonstrate the potential role of tree functional trait diversity in alleviating climate change impacts on dryland forests. While recognizing that nature-based climate mitigation (e.g., planting trees) can only be partial solutions, their long-term (decadal) efficacy can be improved by enhancing functional trait diversity across the forest community.

Monitoring cotton water status with microtensiometers

AbstractStem water potential (Ψstem) is a key indicator for assessing plant water status, which is crucial in understanding plant health and productivity. However, existing measurement methods for Ψstem, characterized by destructiveness and intermittency, limit its applicability. Microtensiometers, an emerging plant-based sensor, offer continuous monitoring capabilities and have shown success in certain vine and tree species. In this study, we investigate the efficacy of microtensiometers ability to monitor the Ψstem of cotton (Gossypium hirsutum L.) under three distinct irrigation treatments in Maricopa, Arizona, an extremely hot, arid environment. We analyze the diurnal dynamics of Ψstem across the irrigation regimes and compare these measurements with midday leaf water potentials (Ψleaf) obtained using a dewpoint potentiometer. Our results demonstrate that the microtensiometer-derived Ψstem closely follows known diurnal patterns of Ψleaf, tracking with vapor pressure deficit (VPD) and responding to variations in irrigation levels and soil moisture content. Time cross-correlation analysis reveals an 80-minute lag in Ψstem response to changing VPD under non-water limiting conditions, which shortens under water-limiting conditions. Additionally, we establish a robust linear relationship (R2adj = 0.82) between Ψstem and Ψleaf, with this relationship strengthening as water availability decreases. Notably, we observe mean gradients of 1.2 and 0.06 MPa between soil vs. stem and stem vs. leaf water potentials, respectively. Moreover, Ψstem data proves to be more sensitive in distinguishing between irrigation treatments earlier in the growing season compared to Ψleaf, leaf temperature and leaf gas exchange parameters. These findings highlight the utility of microtensiometers as valuable tools for monitoring water status in smaller-stemmed row crops such as cotton.

Learning from local knowledge on changes in tree-cover and water availability: the case of the contested agroforested landscape of the Mt. Elgon Water Tower, Uganda

Participatory Rural Appraisal was used to compare stakeholder perceptions of spatial and temporal variation in tree cover and water availability using Uganda’s Mt. Elgon Water Tower as a case study. This study was guided by the research question: How do multi-level stakeholders’ perceptions of changes in tree-cover and water availability vary across spatial and temporal scales of the water tower? Five Participatory Rural Appraisal tools were applied to understand multi-level stakeholders’ perspectives on the changes in tree-cover and water availability. Data was collected from farmers’ focus group discussions, key experts from local government offices and structured household interviews with local communities. This study focused on the upper and lower zones of the water tower, which differ in terms of proximity to Mt. Elgon National Forest Park, household water-use, elevation, and tree-cover. Results showed that there are both similarities and differences in perceptions of changes in tree cover and water availability among stakeholders. Farmers and key experts perceived a decrease in water availability and a decrease in overall tree cover for the period 1990–2020. There are differences in stakeholders’ perceptions of water availability across the zones and sub-catchments. For instance, more farmers in Sipi River Sub-catchment perceived a decrease in water availability during 2006–2020 compared to 1990–2005 period. There were notable contradictions in farmers’ and key experts’ perceptions on tree cover. Farmers’ perceptions of 1990–2020 precipitation were in agreement with trends in existing precipitation data. Declining trends of natural tree cover especially outside the Mt. Elgon national forest park pose great threat to water resources originating from forests. Changes in tree cover and water availability in the study area can be partly explained by the tree species grown. Local stakeholders’ perceptions complemented the existing data gaps in explaining the changes in tree cover and water availability. Participatory Rural Appraisal tools are helpful for documenting the perceptions of local communities. However, this cannot replace reliable data resulting from large-scale efforts for monitoring changes and variations in tree-cover and water availability. The findings of this paper can be valuable to inform strategies for community involvement in sustainable agroforested landscape management.

Drought potential index using Normalized Difference Drought Index (NDDI) method based on Geographical Information System (GIS) in Slogohimo, Wonogiri Indonesia

Climate change is an impact caused by global warming. The phenomenon due to climate change is El Nino, which affects a long dry season. Central Java is an area heavily affected by drought caused by El Nino, one of which is Wonogiri Regency, which has the potential to cause crop failures, forest fires, and decreased water availability, which can be detrimental. Drought potential analysis was carried out to estimate the distribution of the drought index in Slogohimo District, Wonogiri Regency. The method used is the Normalized Difference Drought Index (NDDI), which combines vegetation density and wetting level using Landsat imagery—the NDDI index transformation method on a scale ranging from very low to very high (severe). The results show that the distribution of drought potential in Slogohimo District, Wonogiri Regency, is classified as very low to very high class. Still, the broadest area is classified as low. The tendency for drought to occur in the Slogohimo area is spread from the east to the south. This research suggests the application of organic mulch for improvement to reduce the potential for drought. Apart from being an effort to modify soil temperature, organic mulch also functions as a soil conditioner, which impacts adding soil pores to increase water retention.

Hydroclimatic Vulnerability of Wetlands to Upwind Land Use Changes

AbstractDespite their importance, wetland ecosystems protected by the Ramsar Convention are under pressure from climate change and human activities. These drivers are altering water availability in these wetlands, changing water levels or surface water extent, in some cases, beyond historical variability. Attribution of the effects of human and climate activities is usually focused on changes within the wetlands or their upstream surface and groundwater inputs. However, the reliance of wetland water availability on upwind atmospheric moisture supply is less understood. Here, we assess the vulnerability of 40 Ramsar wetlands to precipitation changes caused by land use and hydroclimatic change occurring in their upwind moisture‐supplying regions. We use moisture flows from a Lagrangian tracking model, atmospheric reanalysis data, and historical land use change (LUC) data to assess and quantify these changes. Our analyses show that historical LUC has decreased precipitation and terrestrial moisture recycling in most wetland hydrological basins, decreasing surface water availability (precipitation minus evaporation). The most substantial effects on wetland water availability occurred in the tropic subtropical regions of Central Europe and Asia. Overall, we found wetlands in Central Asia and South America to be the most vulnerable by a combination of LUC‐driven effects on runoff, high terrestrial precipitation recycling, and recent decreases in surface water availability. This study stresses the need to incorporate upwind effects of land use changes in the restoration, management, and conservation of the world's wetlands.

Long-term health outcomes associated with hydration status.

Body water balance is determined by fundamental homeostatic mechanisms that maintain stable volume, osmolality and the composition of extracellular and intracellular fluids. Water balance is maintained by multiple mechanisms that continuously match water losses through urine, the skin, the gastrointestinal tract and respiration with water gains achieved through drinking, eating and metabolic water production. Hydration status is determined by the state of the water balance. Underhydration occurs when a decrease in body water availability, due to high losses or low gains, stimulates adaptive responses within the water balance network that are aimed at decreasing losses and increasing gains. This stimulation is also accompanied by cardiovascular adjustments. Epidemiological and experimental studies have linked markers of low fluid intake and underhydration - such as increased plasma concentration of vasopressin and sodium, as well as elevated urine osmolality - with an increased risk of new-onset chronic diseases, accelerated aging and premature mortality, suggesting that persistent activation of adaptive responses may be detrimental to long-term health outcomes. The causative nature of these associations is currently being tested in interventional trials. Understanding of the physiological responses to underhydration may help to identify possible mechanisms that underlie potential adverse, long-term effects of underhydration and inform future research to develop preventative and treatment approaches to the optimization of hydration status.

Effects of improved water retention by increased soil organic matter on the water balance of arable soils: A numerical analysis

AbstractClimate change will lead to prolonged droughts in various regions of the world, which may significantly affect agricultural production. This is particularly problematic for soils with low water retention capacity, which cannot store sufficient water for crops. In this paper, we investigate how a change in the water‐holding capacity of the soil material, as could be achieved by increasing the soil organic carbon (SOC) amount, affects the components of the soil water balance (evaporation, transpiration, and groundwater recharge). Specifically, we state the hypothesis that an increased water‐holding capacity in a shallow soil layer, as it is achieved through SOC enrichment at the soil surface, will result in more water being stored near the soil surface and lost to unproductive evaporation, thereby reducing the amount of water available to plants and groundwater recharge. The hypothesis was tested by numerical simulations, employing the Hydrus‐1D program package to model the water balance in a soil–plant–atmosphere system for an arable crop in hydrologically contrasting years. The study considered soils with varying textures and different depths of a soil layer with increased SOC content. The soil hydraulic properties (SHP) of the soil material, including the effect of SOC on the SHP, were determined using a recently developed pedotransfer model based on data from over 500 samples. We showed that both the improved water retention by SOC and its vertical distribution affect the soil water balance in a complex manner. In sandy soils, increasing the water‐holding capacity in shallow layers up to 0.1 m led to enhanced evaporation and thus a decrease in water availability for crops. However, deeper incorporated SOC could ameliorate these negative effects. Our findings suggest that not only the amount but also the vertical SOC distribution should be considered if enrichment of SOC shall be applied to mitigate the effect of droughts.

Urbanization-Driven Land Use Shifts, Diminished Traditional Water Ponds, and Their Impacts on Water-Dependent Livelihood: A case of Panchkhal Municipality, Kavre District

The escalating trend of urbanization is reshaping land use patterns, impacting the hydrological cycle, and giving rise to issues like intensified floods and prolonged droughts. Concurrently, Traditional Water Ponds, essential for sustaining surface and ground hydrology, flood control, and livelihood water access, are rapidly declining. In the Panchkhal Municipality of Kavre District, the dependency of households on water for vegetable cultivation, and effective land and watershed management is imperative. This prompted a comprehensive study to analyze changing land use, the status of traditional water ponds, and their repercussions on water-dependent livelihoods. Presently, a concerning 73% of traditional water ponds are either completely abandoned or repurposed for construction. Urbanization has surged dramatically, with a 1662.5% growth rate in the past two decades, reshaping the landscape. This transformation directly affects supplementary water sources that support livelihoods. Notably, traditional spring sources (kuwas) have dried up, with 60 % of the respondent experiencing a decrease in water availability in kuwas which has been fulfilled by the construction of wells, tap, and water pumps.

Interplay between climate change and climate variability: the 2022 drought in Central South America

Since 2019, Central South America (CSA) has been reeling under drought conditions, with the last 4 months of 2022 receiving only 44% of the average total precipitation. Simultaneously to the drought, a series of record-breaking heat waves has affected the region. The rainfall deficit during October–November-December (OND) is highly correlated with the Niño3.4 index, indicating that the OND 2022 rainfall deficit is partly driven by La Niña, as observed in previous droughts in this region. To identify whether human-induced climate change was also a driver of the OND 2022 rainfall deficit, we analysed precipitation over the most impacted region. Our findings revealed a pattern of decreased rainfall over the past 40 years, although we cannot definitively conclude whether this trend exceeds what would be expected from natural variations. To clarify if this trend can be attributed to climate change, we looked at 1-in-20-year low rainfall events over the same region in climate models. The models show that the severity of low rainfall events decreases (i.e. they become wetter, the opposite of the trend observed in most weather records), although this trend is again not significant and is compatible with natural variability. Therefore, we cannot attribute the low rainfall to climate change. Moreover, our analysis of effective precipitation potential (evapotranspiration minus rainfall) shows that, in climate models, the increase in temperature does partly compensate for the increase in rainfall but only to offset the wetting, and does not lead to a significant climate change signal in effective precipitation. However, higher temperatures in the region, which have been attributed to climate change, decreased water availability in the models in late 2022, indicating that climate change probably reduced water availability over this period also in the observations, increasing agricultural drought, although this study did not quantify this effect. This means that even though the reduced rainfall is within the natural variability, the consequences of drought are becoming more severe due to the strong increase in extreme heat. The case of the OND 2022 rainfall deficit and the ongoing drought in CSA is a clear example of the interplay between climate variability and human-induced climate change. This shows the importance of considering not only those aspects associated with climate change but also climate variability in order to understand and attribute particular events or trends at the regional level.

Impact of Climate Change on the Chemical Compositions and Antioxidant Activity of Mentha pulegium L.

A central position in Moroccan ethnobotany is held by the Mentha genus, serving as a vital reference for aromatic and medicinal plants within the Lamiaceae family. The profound importance of Mentha species in the daily lives of Moroccans is recognized, and the primary objective of this study is to assess the impact of rising temperatures and decreasing precipitation on the primary and secondary metabolites of Mentha pulegium under the following climatic conditions: sample 1, cultivated under standard temperature and precipitation conditions during the first year; sample 2, subjected to an 8 °C temperature increase and a 25% reduction in water supply; and sample 3, exposed to a 12 °C temperature rise and a 50% decrease in water availability. Phytochemical screening results reveal a progressive decline in primary metabolites from sample 1 to sample 3 due to the increase in temperature and decrease in precipitation. Conversely, a distinct trend is observed in secondary metabolites and the yield of essential oil, increasing from sample 1 to sample 2 as the temperature rises and precipitation decreases. Remarkably, in sample 3, the yield of essential oil decreases as climatic conditions further deteriorate. Additionally, GC analysis demonstrates that modifications in the chemical compositions of essential oils occur because of the disruption of climatic parameters, particularly in the major compounds. Similarly, changes in climatic parameters significantly influence antioxidant activity, with sample 2 exhibiting the highest activity, as reflected by an IC50 value (half-maximal inhibitory concentration) of 14,874.04 μg/mL, followed by the third sample at 8488.43 μg/mL, whereas the first sample exhibits the lowest activity at 4505.02 μg/mL. In summary, the complex relationship between climatic factors and the chemical composition of Mentha pulegium is highlighted by our experiment, emphasizing its implications for medicinal properties within an ecological context.

EFEKTIVITAS KOMBINASI KOAGULAN SINTETIK DAN BIOKOAGULAN TERHADAP PENINGKATAN MUTU BAKU AIR SUNGAI TABALONG

Tabalong River is used as the raw water source for PDAM Tabalong. The large number of industrial activities in the district produces residual products that eventually pollute the watershed, resulting in a decrease in water quality and availability. Parameters that do not meet the standard quality standards as clean water based on Government Regulation No. 22 of 2021 class I are turbidity, color, TSS, dissolved Fe, dissolved Mn, and E. coli. This river water requires treatment with coagulation - flocculation technology with the jar test method. The technology requires a coagulant whose role is to precipitate colloidal particles. The commonly used coagulant is poly aluminum chloride (PAC). It is abundant but produces high concentrations of sludge, so coagulants that are biodegradable, biocompatible, non-toxic, and abundant are needed. These properties are found in biocoagulants in the form of chitosan. The coagulant in this study is synthetic (PAC) and bicoagulant (chitosan) by determining the optimum dose in river water treatment in the rainy season. The optimum dose is used to combine the ratio between coagulants. The ratio is (100:0, 25:75, 50:50, 75:25, and 0:100) which is analyzed for its effectiveness from each parameter. The optimum dose of PAC is 10 ppm and chitosan is 20 ppm. The best effectiveness is the PAC-chitosan combination in the form of a ratio of 0:100, which is in the form of chitosan which is able to reduce the levels of these parameters to meet the quality standards.

8 Impacts of Future Climate Scenarios on the Beef Industry of the Great Plains and Western Us

Abstract Global average temperatures have increased by 1.1 degrees Celsius compared with pre-Industrial times and future temperature increases will be driven by anthropogenic greenhouse gas emissions trends. Impacts of climate change vary by geographic regions, with the Great Plains and Western US likely to experience increased temperatures, increased frequency of drought, and more extreme precipitation events. These climate impacts can affect the beef industry in those regions in multiple ways from increasing heat stress, decreasing forage availability, impacting forage quality, and reducing water availability for drinking water and feed production. In the southwestern US, increasing temperatures are likely to increase evapotranspiration, reduce snow cover, and lead to earlier snow melts, all of which can contribute to the aridification of the region. For cow-calf production within the region, aridification will reduce the forage biomass available for grazing cattle operations and reduce carrying capacity, creating potential vulnerabilities to rangeland ecosystems and rural communities dependent upon the cattle industry. Increased incidence of heat waves in the Great Plains and Western US can negatively impact vulnerable cattle populations, such as finishing cattle, particularly those housed in environments with minimal heat stress mitigation measures. Decreased water availability can potentially shift cattle production and feed production away from arid regions dependent upon vulnerable water resources, such as the Colorado River and Ogallala aquifer. In general, the increased climate variability and aridification of some parts of the Great Plains and Western US will create risks for the beef industry that will likely necessitate changes, from shifting cattle population to increased use of heat stress mitigation strategies.

Evapotranspiration and Yield Impact Tools for More Water-Use Efficient Alfalfa Production in Desert Environments

Drought and climate change have decreased water availability for agriculture, especially in the desert of southwestern USA. Efficiency enhancements in irrigation management aimed at conserving water are key to adjust to limits in water supply, improve profitability and sustainability of alfalfa production in arid and semiarid areas. This study intended to conduct a field-scale analysis to develop yield and ET estimation tools for the effective use of irrigation water in a desert alfalfa production system. Extensive data collection and trials were carried out over three years in nine fully irrigated commercial alfalfa fields in the low deserts of California. The seasonal crop water consumption measured using the residual of energy balance method varied from 1381 mm to 1596 mm across the experimental sites and crop seasons. Variable seasonal dry mater (DM) yields ranged from 23.01 Mg ha−1 to 29.90 Mg ha−1. The results indicated that the first five cuttings each year were the most productive cuttings with a mean DM value ranged between 3.29 (cut 1) and 4.21 (cut 4) Mg ha−1 but declined in later cuttings. An average annual water productivity (WP) value of 17.0 kg ha−1 mm−1 was determined across the sites varying from 15.5 to 18.9 kg ha−1 mm−1. The findings suggested that one may lose up to 1.44 Mg ha−1 alfalfa yields with moderate summer deficit irrigation strategies, using 40% less water applied than full irrigation practices over the summer period of July–September. A more severe summer water deficit, with no irrigation event over the summer period of July–September may result in a potential water savings of 0.234–0.246 (ha·m) ha−1 and 19–21% seasonal yield losses in the desert environment. This study describes the seasonal yield pattern, the crop water use-production function, and the crop coefficient values for various harvest cycles over the crop season. These tools may assist farmers to quantify water savings and estimate yield losses for more accurate and effective irrigation management strategies to meet water conservation objectives and for the resiliency of alfalfa production in the desert region.

Agrivoltaics mitigate drought effects in winter wheat.

Climate change is expected to decrease water availability in many agricultural production areas around the globe. At the same time renewable energy concepts such as agrivoltaics (AV) are necessary to manage the energy transition. Several studies showed that evapotranspiration can be reduced in AV systems, resulting in increased water availability for crops. However, effects on crop performance and productivity remain unclear to date. Carbon-13 isotopic composition (δ13 C and discrimination against carbon-13) can be used as a proxy for the effects of water availability on plant performance, integrating crop responses over the entire growing season. The aim of this study was to assess these effects via carbon isotopic composition in grains, as well as grain yield of winter wheat in an AV system in southwest Germany. Crops were cultivated over four seasons from 2016-2020 in the AV system and on an unshaded adjacent reference (REF) site. Across all seasons, average grain yield did not significantly differ between AV and REF (4.7 vs 5.2 t ha-1 ), with higher interannual yield stability in the AV system. However, δ13 C as well as carbon-13 isotope discrimination differed significantly across the seasons by 1‰ (AV: -29.0‰ vs REF: -28.0‰ and AV: 21.6‰ vs REF: 20.6‰) between the AV system and the REF site. These drought mitigation effects as indicated by the results of this study will become crucial for the resilience of agricultural production in the near future when drought events will become significantly more frequent and severe.

Changes in physical and hydraulic properties in sandy soils of the Pampa Biome under different uses

ABSTRACT The naturally fragile sandy soils of the Pampa Biome (PB) may be degraded with the introduction of poorly managed agricultural crops. Anthropic use can markedly decrease vegetation cover on sandy soils, leaving them more exposed to erosive agents. Decreases in organic matter content, biodiversity, and nutrient availability, increased soil compaction, and decreased water availability are also some of the impacts caused on PB soils by implementing poorly managed agricultural crops. In Rio Grande do Sul, in areas with sandier soils, the intense replacement of PB with commercial crops that has occurred in recent years (2000-2020) may be starting a disastrous cycle of degradation of these soils. However, it is not yet known how much these soils are degraded by recent anthropic use. There are no local scientific publications dedicated to the diagnosis of the degradation of these soils by anthropic use. Therefore, the need for this study was based on the objective of evaluating the physical and hydraulic properties of sandy PB soils with the insertion of agricultural crops. The study was conducted on three different soils, where soil samples were collected under three systems of use (extensive cattle raising on native grassland, eucalyptus afforestation, and soybean crop). Our results show that it can take more than nine years for soybean and ten years for eucalyptus land-use change to indicate some level of degradation in soil physical and hydraulic properties after replacing PB with these cultivated crops.

Impact of Climate Change on water security and Endorsing importance of Rainwater Harvesting Technology in Nepal

The day-by-day increment in the concentration of greenhouse gases (GHGs) in the atmosphere is widely believed to be a main contributing factor for climate change. It affects widely on diverse sectors such as water resources, agriculture, forestry, human health, biodiversity, and snow cover and aquatic life. Nepal is experiencing the adverse impact of climate change; this includes such as a variability in temperature and precipitation, overbank flooding from snow-fed rivers, and variability in available river and stream water quantity. Climate in the Nepal Himalayas is changing faster than the global average. Moreover, the changes in the high-altitudes have been found more pronounced than in the low-altitudes. Since, there is no definite trend that could be found in the annual precipitation records, clear decreasing trends could be seen in annual number of rainy days during the study period of 1971-2000. The glaciers in the Nepal Himalayas are shrinking rapidly and there will be no glaciers left by 2180. An accelerated glacier melt will cause an increase in water availability at the beginning but ultimately a decrease in water availability after the glaciers disappear. This will widen the gap between water supply and demand. Changing climate may further exacerbate the water stress which already happening in Nepal due to the monsoon dominated climate. Climate change (CC) will also further increase the seasonal imbalance- too much of water during rainy season and too less of it during dry seasons. Rainwater harvesting technology has the potential to provide numerous benefits to communities and individuals, particularly in areas where water resources are scarce or unreliable. From the analysis and through our research work it is found that if we can simply install and construct rainwater harvesting technology in our individual household only. It nearly fulfills about 15-25% of our domestic water demand. As in urban and rural area of Nepal still nearly about 50% of water demand is fulfilled by groundwater source which increase to 60-70% in dry season. The projected physical impacts of climate change on water resources would have substantial socioeconomic impacts and consequences for Nepal. The hydropower potential and agricultural production would be seriously affected by global warming. A reduction in agricultural production would be experienced due to water security and have significant impact on the food security and livelihoods of the subsistence farmers, who make the majority of the Nepal’s population. As the urgent need for climate change mitigation remains crucial, putting all the necessary resources and institutions in place for future adaptation is indispensable. The Inter-governmental Panel on Climate Change (IPCC) has listed rainwater-harvesting as a key strategy for a planned adaptation in the water sector. The policy statements about rainwater harvesting-based climate change adaptation are currently not being effectively coordinated.

Water use strategies of Nitraria tangutorum in the lake-basin region of the Badain Jaran Desert.

Information regarding plant water-use strategies is essential for understanding the hydrological processes and plant survival adaptation mechanisms in desert lake basin regions. To examine the water use strategies of plants in desert lake basin areas, water uptake patterns, water use efficiency, and water potential of Nitraria tangutorum were investigated at different distances from the lake duringhe growing seasons in the lake basin regions of the Badain Jaran Desert. The results indicate that N. tangutorum primarily absorbed groundwater in May (63.8%) and August (53.5%), relied on deep soil water in June (75.1%), and uniformly absorbed soil water from different layers in July. These observations could be explained by periodic fluctuations in the groundwater level and the consequent decrease in soil water availability, as well as plant root adjustments. As soil water availability decreases, N. tangutorum adapts to water variation by increasing its water use efficiency (WUE) and reducing its leaf water potential (Ψ). With intensified water stress, N. tangutorum gradually shifted from adventurous anisohydric regulation to conservative isohydric regulation. Thus, N. tangutorum responds to diverse degrees of environmental changes by altering its water-use strategy. A better understanding of the adaptive water use strategies developed by desert plants under varying water availability conditions provides insight into the diversity of species' reactions to long-term drought and quantifies the hydrological cycle of desert ecosystems against the background of worldwide climate warming.