Variation In Water Availability Research Articles

Evaluating water balance components in a tropical ecological zone under land use changes

Water availability for domestic, institutional, and agricultural production is threatened by the continuous change in land use land cover (LULC). These changes in LULC features affect the dynamics of the hydrological processes such as surface runoff, infiltration, and evapotranspiration, resulting in variations in water availability especially, for human consumption and crop yield. Therefore, the Soil and Water Assessment Tool (SWAT) hydrological model was deployed to simulate the Pra River Basin (PRB)’s water balance response to changing LULC from 1986 to 2020. Open and closed forests reduced from an area of 11,071 km2 to 5902 km2 and 5125 km2 to 4990 km2 while settlement and cropland increased from 1100 km2 to 2392 km2 and 5303 km2 to 9320 km2 representing an average annual expansion rate of +24.7 km2/yr and +118 km2/yr respectively over the three decades. The growth in settlement and cropland resulted in an upsurge of more than 33 % and 20 % in surface runoff and water yield respectively, but decreases of over 4 % and 17 % in evapotranspiration and baseflow respectively. These changes have resulted in a seasonal increase in surface runoff, baseflow, and evapotranspiration (ET) during the wet season but a decrease during the dry season. The PRB has experienced a dramatic decline in forest areas, chiefly in areas where settlement and farmlands have been expanded. The areas where surface runoff and water yield showed significant upsurge and reduction in ET are the northwestern and southern enclaves of the basin. These findings can aid in effectively planning and managing land use to control the gradually depleting water resources in the basin.

Sedimentary Expressions of the Early Jurassic Jenkyns Event in an Inland Lacustrine System in the Yin'gen–Ejinaqi Basin, North China

AbstractThe Jenkyns Event, more widely known as the Toarcian Oceanic Anoxic Event (T‐OAE), is marked by globally distributed negative carbon‐isotope excursions, widespread oxygen depletion, and large‐scale organic carbon burial, which indicate major climate/environmental perturbations in Earth's surface systems during the Early Jurassic. Although extensive research has been conducted in European continental settings, particularly in the western peri‐Tethys regions, the impacts of this event beyond Europe remains largely unexplored. Here, a multiapproach study including investigations into the spore‐pollen assemblages, pyrite framboids, clay minerals, total organic carbon (TOC) levels, and organic carbon isotope (δ13Corg) levels in a lacustrine borehole section (MED1) from the Yin'gen–Ejinaqi Basin, North China, provides evidence of the occurrence of the Jenkyns Event and its extensive sedimentary responses in the eastern Tethys terrestrial systems. Two distinct spore‐pollen assemblages have been identified in MED1 (drilling depth: 982.4 m to 1267.5 m), with the Cycadopites–Protopinus–Osmundacidites assemblage in the lower part (1267.5 m to 1132.9 m) indicating a middle Early Jurassic age and the Classopollis assemblage in the upper part (1132.9 m to 985.7 m) suggesting a Toarcian age. Framboidal pyrite data suggest more anoxic conditions during the deposition of black mudstone and shale intercalations in the lower part of the Classopollis assemblage (1132.9 m to 1066.9 m), which combined with organic carbon enrichment and negative δ13Corg excursions, are considered the paleoenvironmental response to the Jenkyns Event in the study area. Furthermore, the evolution of vegetation groups changed from plant groups characterized by bisaccate and cycad pollen, as well as fern spores, to vegetation groups represented by Cheirolepidiaceae pollen across the Jenkyns Event, as evidenced by spore‐pollen data, together with the clay mineral assemblage change characterized by a notable increase in illite at the expense of kaolinite, suggests that while a subtropical‐temperate climate persisted, a change toward warmer and drier conditions most likely occurred in the early Toarcian in the study area. In contrast to the humidification evidenced in many coastal settings, this aridification trend in the Yin'gen–Ejinaqi Basin aligns with the conditions in many inland areas. It is hypothesized that the underlying cause of these divergent changes may be linked to certain patterns of spatially variable water availability on land, potentially driven by extremified hydrological conditions.

Effects of hydrological variability on the sustainable use of water in a regional economy. An application to Tuscany

Existing input-output (IO) models have mainly focused on water demand. Some studies have incorporated water supply (availability), but do not take into account its natural variability, an essential element when performing a water stress analysis. The present study integrates the hydrological variability of water availability into a hydroeconomic IO model, considering its exogenous effects on water supply and its exogenous effects on water demand. Two endogenous effects are considered: i) changes in blue water requirements in the agricultural industry due to variations in precipitation and evapotranspiration, and ii) changes in grey water requirements in all discharging industries due to variations in runoff and groundwater recharge. By means of a T-years hydrological series and Monte Carlo simulations, the model allows estimating T values of the Extended Water Exploitation Index (EWEI), obtaining its empirical probability distribution and confronting it with scarcity thresholds. Additionally, the model includes a methodology to incorporate intra-annual variation, obtaining the critical month EWEI and defining a more transparent and endogenous scarcity threshold. Empirically tested for the Italian region of Tuscany considering a multivariate hydrological model for the generation of a 100-year hydrological series, our results allow a more in-depth analysis of water scarcity in the region.

Comparative Analysis of Water Stress Regimes in Avocado Plants during the Early Development Stage.

The avocado cv. Hass requires a suitable rootstock for optimal development under water stress. This study evaluated the performance of two avocado rootstocks (ANRR88 and ANGI52) grafted onto cv. Hass under four water stress conditions, 50% and 25% deficit, and 50% and 25% excess during the nursery stage. Plant height, leaf area (LA), dry matter (DM), and Carbon (OC) content in the roots, stems, and leaves were measured. Root traits were evaluated using digital imaging, and three vegetation indices (NDVI, CIRE, and MTCI) were used to quantify stress. The results showed that genotype significantly influenced the response to water stress. ANRR88 exhibited adaptation to moderate to high water deficits. ANGI52 adapted better to both water deficit and excess, and showed greater root exploration. LA and DM reductions of up to 60% were observed in ANRR88, suggesting a higher sensitivity to extreme changes in water availability. More than 90% of the total OC accumulation was observed in the stem and roots. The NDVI and the MTCI quantified the presence and levels of stress applied, and the 720 nm band provided high precision and speed for detecting stress. These insights are crucial for selecting rootstocks that ensure optimal performance under varying water availability, enhancing productivity and sustainability.

Simulating water-limited potato yields across the Netherlands with (SWAP-)WOFOST: Experimentation, model improvement and evaluation

Water availability explains a large part of the spatial and temporal yield variability of ware potato in the Netherlands. Climate change is projected to lead to greater variability in water availability. Therefore, an accurate simulation of crop yield as a function of water availability is of high importance. Many crop models can simulate water-limited potato yields, but as detailed experimental data on drought and oxygen stress are scarce, models are often not well calibrated and evaluated. We set up a large experiment and an on-farm observational trial to calibrate and evaluate the simulation of water-limited yield of different potato cultivars across the Netherlands. In addition, we investigated the required model complexity to accurately simulate water-limited potato yields. The crop growth model WOFOST was used for simulations either as a single model or coupled with SWAP. Yields were simulated applying either only drought stress or by including both drought and oxygen stress. We employed two methods for simulating oxygen stress in SWAP-WOFOST. The calibration improved accuracy of simulated water-limited yields as demonstrated in our model evaluation. Both on sandy and clayey soils, water-limited yields were best simulated using SWAP-WOFOST while simulating oxygen stress using a process-based method in combination with a rooting density that decreases linearly with rooting depth. On sandy soils, the bottom boundary condition of free drainage was applicable. On clayey soils measured groundwater levels (or soil water pressure heads when measurements are not available) should be used as bottom boundary condition. On sandy soils both WOFOST and SWAP-WOFOST may be used, as results were similar. On clayey soils, WOFOST is less suitable, as it cannot simulate capillary rise. SWAP-WOFOST however has many options and parameters, which can result in large differences in results. Hence, a careful model set up and evaluation is required for each application.

Nomadic responses to rainfall: Nighttime light evidence from wadis in Djibouti

This study examined the association between human activities and precipitation in dry areas, focusing on nomadic people in Djibouti. Nomadic communities often lack access to essential social services, and water resource management is crucial for their survival and social welfare. Understanding how they respond to variations in water availability could contribute to effective policy implementation. Using satellite-derived information, this study found that nighttime light brightness increased in response to precipitation around wadis, with potential water spring locations, and decreased with distance from a wadi. Specifically, we observed no effect when the distance was more than 5 km. Furthermore, no effect of precipitation was found in urban areas, while a positive effect was found in remote areas. These findings suggest that the activity of nomadic people increases around wadis in response to increased water resource availability, indicating that water supply is important for settlement projects because it can reduce water-seeking costs and improve social welfare. This study provides the first empirical evidence using satellite data and statistical analysis to show that water availability is critical for nomadic communities which can inform better resource management and policy decisions in African countries.

Disentangling drivers of annual grass invasion: Abiotic susceptibility vs. fire-induced conversion to cheatgrass dominance in the sagebrush biome

Invasive annual grasses are often facilitated by fire, yet they can become ecologically dominant in susceptible locations even in the absence of fire. We used an extensive vegetation plot database to model susceptibility to the invasive annual grass cheatgrass (Bromus tectorum L.) in the sagebrush biome as a function of climate and soil water availability variables. We built random forest models predicting cheatgrass presence or dominance (>15 % relative cover) under unburned (37,219 plots) and burned conditions (6340 plots). We mapped predicted probability of cheatgrass presence and dominance, conditional on burning. We combined predicted susceptibility with burn probability to quantify the 10-year total risk of cheatgrass dominance. Finally, we identified portions of the landscape (1) at risk of fire-induced conversion to cheatgrass dominance, (2) consistently susceptible to cheatgrass dominance, or (3) consistently resistant to cheatgrass dominance. At the scale of the sagebrush biome, we found that abiotic susceptibility to cheatgrass dominance drives total risk, regardless of fire. At local scales (i.e., individual 30 m pixels), burning increased the probability of cheatgrass dominance by a median of 14 %. Threshold-based analyses indicate that 10–31 % of the sagebrush biome was at risk of fire-induced dominance, with 55 % exhibiting abiotic resistance and 5 % exhibiting abiotic susceptibility to dominance regardless of fire. Burn probability was higher in areas predicted to be susceptible to dominance, illustrating how cheatgrass invasion can cause ecosystem conversions that are then sustained by grass-fire cycles. Disentangling the influence of abiotic conditions and fire contributes to our understanding of the mechanisms driving invasion dynamics, and modeling the probability of dominance can help anticipate where ecological transformations are at risk of occurring. Our approach can facilitate the prioritization of management actions in the sagebrush biome and be used as a framework for modeling invasion risk in other disturbance-prone ecosystems.

Revitalizing maize growth and yield in water-limited environments through silicon and zinc foliar applications

Maize is an economically vital cereal crop. However, water deficiency can severely impact its productivity. Thus, it is necessary to implement an essential approach to increase maize yield while navigating the limitations imposed by scarce water supplies. The present study aimed to investigate whether foliar applications of silicon (Si) and zinc (Zn) could mitigate the adverse effects of water deficiency and improve maize growth and yield. Field experiments were conducted in Egypt during two growing seasons (2021–2022) under three irrigation regimes: full irrigation (ET0), moderate stress (ET1), and severe stress (ET2). The treatments comprised foliar sprays of Si, Zn, Si + Zn, and water control. Phenological, growth, physiological, chemical, and yield-related traits were assessed. Results showed that adequate irrigation (ET0) enhanced most parameters compared to water stress treatments. Under ET0, the combined silicon and zinc treatment resulted in the highest values for plant height, leaf area, chlorophyll content, grains per ear, kernel weight, ear size, and yield compared to other foliar treatments. Under drought stress (ET1, ET2), Si + Zn applications maintained superiority in mitigating yield losses. Proline accumulation was highest under severe stress (ET2) in the absence of foliar sprays, indicating greater drought impacts. Correlation analysis revealed positive associations of grain yield with ear size, leaf area, kernel weight, and biological yield. Cluster analysis separated irrigation regimes and visualized the consistently beneficial effects of Si + Zn across all water levels. Overall, the results demonstrate the synergistic potential of Si and Zn supplementation to sustain maize performance and yields under varying water availability.

Preserving isohydricity: vertical environmental variability explains Amazon forest water use strategies.

Increases in hydrological extremes, including drought, are expected for Amazon forests. A fundamental challenge for predicting forest responses lies in identifying ecological strategies which underlie such responses. Characterization of species-specific hydraulic strategies for regulating water use, thought to be arrayed along an 'isohydric-anisohydric' spectrum, is a widely used approach. However, recent studies have questioned the usefulness of this classification scheme, because its metrics are strongly influenced by environments, hence can lead to divergent classifications even within the same species. Here, we propose an alternative approach positing that individual hydraulic regulation strategies emerge from the interaction of environments with traits. Specifically, we hypothesize that the vertical forest profile represents a key gradient in drought-related environments (atmospheric vapor pressure deficit, soil water availability) that drives divergent tree water use strategies for coordinated regulation of stomatal conductance (gs) and leaf water potentials (ΨL) with tree rooting depth, a proxy for water availability. Testing this hypothesis in a seasonal eastern Amazon forest in Brazil, we found that hydraulic strategies indeed depend on height-associated environments. Upper canopy trees, experiencing high VPD, but stable soil water access through deep rooting, exhibited isohydric strategies, defined by little seasonal change in the diurnal pattern of gs and steady seasonal minimum ΨL. By contrast, understory trees, exposed to less variable VPD but highly variable soil water availability, exhibited anisohydric strategies, with fluctuations in diurnal gs that increased in the dry season along with increasing variation in ΨL. Our finding that canopy height structures the coordination between drought-related environmental stressors and hydraulic traits provides a basis for preserving the applicability of the isohydric-to-anisohydric spectrum, which we show here may consistently emerge from environmental context. Our work highlights the importance of understanding how environmental heterogeneity structures forest responses to climate change, providing a mechanistic basis for improving models of tropical ecosystems.

Exploring and modelling the hydro-morphological landscape of a Himalayan basin: a geospatial study of Nandakini Basin in Uttarakhand, India

This study comprehensively examines the hydro-morphological, topo-hydrological, and physiographic features of the Nandakini catchment in the north-western Himalayas. In the absence of extensive hydrological data, employing morphometric parameters proves to be a crucial and efficient approach for delineating geological structures and assessing hydrodynamic activity in the river basin. Utilizing SRTM DEM, SOI toposheets, and GIS, the study identified twenty watersheds within the catchment, estimating its total area at 540.98 km2. The analysis revealed a 6th-order catchment with a primarily sub-dendritic to dendritic drainage pattern, susceptible to flooding and gully erosion from slow surface runoff. The elongated shape and compactness coefficient indicated delayed peak runoff. Coarse drainage texture and high relief ratio suggested increased vulnerability to erosion. Physiographic indices indicated a later youth stage of basin development, while topo-hydrological indices highlighted significant topographic and spatial variability in water availability, emphasizing erosion potential. This study provides valuable insights for developing sustainable catchment management plans and informing decision-making in water resources management for the Nandakini catchment.

No constraint on long-term tropical land carbon-climate feedback uncertainties from interannual variability

Unraveling drivers of the interannual variability of tropical land carbon cycle is critical for understanding land carbon-climate feedbacks. Here we utilize two generations of factorial model experiments to show that interannual variability of tropical land carbon uptake under both present and future climate is consistently dominated by terrestrial water availability variations in Earth system models. The magnitude of this interannual sensitivity of tropical land carbon uptake to water availability variations under future climate shows a large spread across the latest 16 models (2.3 ± 1.5 PgC/yr/Tt H2O), which is constrained to 1.3 ± 0.8 PgC/yr/Tt H2O using observations and the emergent constraint methodology. However, the long-term tropical land carbon-climate feedback uncertainties in the latest models can no longer be directly constrained by interannual variability compared with previous models, given that additional important processes are not well reflected in interannual variability but could determine long-term land carbon storage. Our results highlight the limited implication of interannual variability for long-term tropical land carbon-climate feedbacks and help isolate remaining uncertainties with respect to water limitations on tropical land carbon sink in Earth system models.

Machine learning-based estimation of fractional snow cover in the Hindukush Mountains using MODIS and Landsat data

Accurate estimation of snow-covered area (SCA) is vital for effective water resource management, especially in snowmelt-dependent regions like the Kabul River Basin (KRB). It serves as a reference point for comparing expected variations in water availability driven by climate change, particularly in arid and semi-arid regions like the KRB. In this study, fractional snow cover (FSC) was estimated across the KRB using Landsat and moderate resolution imaging spectroradiometer (MODIS) datasets. For this purpose, 34 Landsat-8 and MODIS image-pairs were acquired covering the snowfall period from 01 October 2018 and 31 March 2021. The training dataset consisted of 31 image-pairs, while the remaining three were used as an independent test dataset. Sample sizes and training strategies (i.e., full, semi, and trimmed-models), three each, were evaluated to understand the relevance of the predictor variables. The full-model incorporated MODIS surface reflectance bands (SRB) 1–7 spectral indices, topography and landcover while the semi-model included MODIS SRB 1–7 and indices. The trimmed-model only utilized SRB 1–7. Random Forests (RF) facilitated FSC mapping with Landsat-8 data as a reference. The findings indicated comparable performance between full and semi models, whereas the trimmed-model exhibited weaker performance. The correlation coefficient (R) of the full, semi and trimmed models ranged from 0.83 to 0.92, 0.83–0.92 and 0.82–0.87 respectively. The models performed strongly in grassland regions (R = 0.89–0.90), but moderately in forested areas (R = 0.43–0.53). This approach results in improved MODIS-based SCA-mapping in the Hindukush Mountains, facilitating better water resource management in the region.

Divergent Impacts of Evapotranspiration by Plant CO2 Physiological Forcing on the Mean and Variability of Water Availability

AbstractVegetation responses to rising atmospheric CO2 levels can significantly affect water availability (defined as precipitation minus evapotranspiration (ET)). While this effect has long been recognized and assessed for the mean state, its influence on interannual variability, which is more closely associated with extreme events, has yet to be comprehensively quantified. In this study, our primary focus is to evaluate the impacts of ET by plant physiology (denoted as ETPhy) on the mean and interannual variability of water availability under elevated CO2 using multiple CO2 sensitivity experiments from the coupled model intercomparison project phase 6. We show that the contribution of vegetation physiological effects to the mean water availability varies among regions, while it consistently contributes to variability by about 33%. Considering CO2 physiological effects alone, ETPhy exerts a more significant influence on the mean state than on variability, particularly in humid regions. Consequently, ETPhy contributes less than 5% to the variability of water availability in humid regions under rising CO2, whereas it accounts for about 20% of the mean state. This distinction could be attributed to the different mechanisms governing the mean and variability of ETPhy. Specifically, evaporation from CO2 physiological forcing is the most critical contributor to the variability of ETPhy in most regions while showing minimal impacts on the mean state. Our findings identify the divergent effects of ETPhy on the mean state and interannual variability of water availability under elevated CO2, as important in future climate projections.

Long-Term Impacts of Glacier Retreat on Downstream Water Availability in Ethiopia

Purpose: The aim of the study was to examine Long-Term Impacts of Glacier Retreat on Downstream Water Availability in Ethiopia. Methodology: This study adopted a desk methodology. A desk study research design is commonly known as secondary data collection. This is basically collecting data from existing resources preferably because of its low cost advantage as compared to a field research. Our current study looked into already published studies and reports as the data was easily accessed through online journals and libraries. Findings: The study revealed that as glaciers continue to shrink due to climate change, the hydrological systems in mountainous regions of Ethiopia, such as the Simien Mountains and Bale Mountains, face disruptions in water supply, affecting both local communities and downstream users. The reduction in glacial meltwater contributes to decreased streamflow, altered river regimes, and increased variability in water availability, exacerbating water stress in a country already prone to droughts and water scarcity. Moreover, glacier retreat affects ecosystems, biodiversity, and livelihoods dependent on freshwater resources, further amplifying socio-economic vulnerabilities in the region. Unique Contribution to Theory, Practice and Policy: Climate Change Theory, Hydrological Cycle Theory & Systems Theory may be used to anchor future studies on Long-Term Impacts of Glacier Retreat on Downstream Water Availability in Ethiopia. Implement cutting-edge technologies for real-time monitoring of glacier melt and downstream water flow. Use satellite imagery, remote sensing, and IoT sensors to gather data that can inform water management practices in real time. Develop and enforce policies that ensure sustainable water use and prioritize the maintenance of water quality and ecosystem health. This includes setting limits on water withdrawals based on sustainability criteria and enhancing the legal frameworks protecting water rights.

Construction of the water balance model for the Bontanga irrigation dam in Northern Ghana

ABSTRACT Freshwater resources are essential for the sustenance of all living things, for crop production and socio-economic activities. The objective of this study was to construct a water balance model aimed at optimizing reservoir management by analyzing variations in water availability in the reservoir. This model will help dam operators to adopt water allocation strategies, timing of water releases and storage decisions. An echo sounder was used to measure the depth of water. Crop water requirements were computed using FAO CROPWAT 8 software, and the InVEST-SDR model was used to estimate sediments exported downstream of the watershed. Model construction utilized multiple linear regression, and the results were tested at a level of significance α = 0.05. Model performance was evaluated using a coefficient of determination (R2) and the ratio of the root mean square error to the standard deviation of measured data (RSR). The results revealed a coefficient of determination (R2) of 0.743 and a ratio of the root mean square error to the standard deviation of measured data (RSR) of 0.67. The constructed model will provide essential information to stakeholders on drought preparedness and mitigation, including water conservation measures and the management of water releases during critical periods.

Impact of Salinity Fluctuations on Dunaliella salina Biomass Production

The utilization of microalgae as a green carbon source for chemical production has attracted attention for its potential use in sustainable and climate-friendly solutions. This study investigates the growth of Dunaliella salina, a unicellular green microalga, in response to salinity variations and water and seawater addition to compensate for evaporation in open cultures. The impact of continuous and non-continuous water addition, as well as seawater addition, on the growth of D. salina was analyzed though tank tests. The results showed that different water-addition methods did not significantly influence cell concentrations, indicating the organism’s resilience to salinity changes. Continuous water addition maintained stable salinity levels at 12%, but required continuous monitoring, while non-continuous addition reduced the intervention frequency. The overall results showed that a salinity range between 12 and 15% did not affect microalgae growth, suggesting flexibility in evaporation-loss compensation methods based on cultivation-system specifics and resource availability. Maintaining consistent biomass regardless of the water-addition method used suggests sustainable production within the tested salinity range, with seawater addition making microalgae cultivation more adaptable to regions with varying water availability. Further research, including outdoor pilot tests, is recommended to validate and extend these findings to natural environments.

INDUCTION OF DROUGHT RESISTANCE IN MELON (Cucumis melo L.) M15 WITH HORMOPRIMING BRASSINOSTEROID BASED ON MORFOLOGY, ANATOMY, AND PHYSIOLOGY ASPECTS

Melon productivity in Indonesia has been declining. Global climate change is affecting the productivity of melons. Long-term droughts have contributed to a reduction in plant growth and development. Hormopriming is an alternative to increase the germination and growth of melon plants by soaking seeds in a solution of plant growth regulators. Brassinosteroid can enhance germination and plant tolerance under drought conditions. The objective of this research is to examine the impact of brassinosteroid hormopriming treatment on the germination and growth of melon plants subjected to various degrees of drought stress. The study utilized a two-factor fully randomized design. The brassinosteroid concentrations used were 0, 0.05, 0.10, and 0.15 ppm. Media with different water capacities of 75%, 50%, and 25% Space Capacity (SC) were used to test drought stress resistance. Water capacities were examined using the gravimetric method. This study's findings suggest that treating melon plants with brassinosteroid variations can induce drought resistance in M15 melons. A brassinosteroid concentration of 0.15 ppm is the best concentration, as it can increase all parameters of plant growth and adaptation under each variation of water availability provided. The findings of this study can serve as a reference for melon cultivators constrained by dry land conditions to increase the efficiency of cultivation.

The vegetation–topography heterogeneity coupling in the Loess Plateau, China

As a result of adaptation to the environment, the great environmental spatial heterogeneity leads to the high spatial heterogeneity of vegetation status. This coupling may be more apparent in water-limited drylands, where topography is the main determinant of small-scale variation in water availability and energy. Metrics describing this coupling may contribute to the detection of the extension of vegetation reshaped by human intervention and other driven forces. In this study, the heterogeneity index of coupling (HIC) was developed to indicate the coupling between spatial heterogeneity of vegetation status (Hv) and the spatial heterogeneity of topography (HT) in the Loess Plateau in northern China. The 16-day composed MODIS normalized vegetation index (NDVI) with a resolution of 250 m and SRTM DEM were employed to quantify the heterogeneity of vegetation status and the topographical heterogeneity. The results show that HIC varies among geomorphic zones, land cover types, and land cover change categories. Among all land cover types, HIC of sandy areas was the largest, followed by the HIC of the forest, shrub, farmland, and grassland. Among geomorphic zones, the highest HIC value appeared in plains with dense residential areas, followed by sandy land that is frequently reshaped by wind, rocky mountainous areas, hilly and gully loess plateaus, and loess tableland. It was revealed that the alternation of vegetation by human activities and natural disturbances shaped greater HIC. Results of this study approved the effectiveness of the HIC in reflecting the coupling of the vegetation status with topography at regional scale.

Analysis of the Growth Response of Cassava Plants (Manihot Esculenta) to Variability in Water Availability

In recent decades, there has been a very pronounced climate change on earth. Reduced rainfall and the occurrence of long droughts are direct impacts that can trigger other problems in the agricultural sector such as crop failure and weakening food security. This will also have an impact on the process of growth and agricultural production in the Lampung Province area, especially on cassava plants. Water often limits the growth and development of cultivated plants. The response of plants to lack of water can be seen in their metabolic activity, morphology, growth rate, or productivity. Cell growth is the function of plants that are most sensitive to water shortages. Lack of water will affect cell turgor so that it will reduce cell development, protein synthesis, and cell wall synthesis. The cassava clones used in this study were Garuda Clones with 5 treatment levels, namely the first treatment (P1) 0L, the second treatment (P2) 0.5L, the third treatment (P3) 1L, the fourth treatment (P4) 1.5L, the fifth treatment (P5) 2L. The result of this study is that there is a cassava growth response to water availability in each treatment except for the variable number of shoots. In the variable plant height, significant response variations are obtained, and it is known that the availability of water needed is directly proportional to the response to plant height growth that also increases.

A river runs through it: Robust automated mapping of riparian woodlands and land surface phenology across dryland regions

Riparian woodlands in drylands are critically important to human society, global biodiversity, and regional water and energy budgets. These sensitive ecosystems have experienced substantial degradation over the last several decades from climatic change and direct human activity. Nevertheless, quantifying long-term change in dryland riparian woodlands remains a major challenge, and much uncertainty exists in their remaining extent, historical breadth, and likely future trajectories. Dryland landscapes show large, fine-scale spatial heterogeneity in seasonal greenness patterns, driven in part by spatial variation in water availability. Riparian woodlands occur where water is concentrated in the landscape, either as aboveground streamflow or subsurface groundwater. In arid and semi-arid climates, this renders them phenologically distinctive from upland ecosystems. However, despite their importance and distinctiveness, there are currently no automated methods for delineating dryland riparian woodlands across regional extents in the cloud. Here we designed and implemented a cloud-based algorithm to retrieve dryland land surface phenology patterns from multispectral satellite imagery and conducted sensitivity analyses using real and simulated data to demonstrate that the approach is robust for MODIS, Sentinel-2, and Landsat over realistic ranges of noise and cloud cover. We then designed a series of random forest vegetation classifiers that integrate phenological and spectral information, vegetative structure from LiDAR, and topography from LiDAR or the Shuttle Radar Topography Mission. We implemented classifiers for three local study sites and then generalized our model to run regionally across the southwestern United States, with balanced accuracy for the riparian woodland class ranging from 94.5% to 97.5% when validated with local to regional datasets. Generally, phenological information proved more important than any other data source for mapping riparian woodlands, which showed more stability in interannual phenology than did upland vegetation types. To our knowledge, ours is the first regional, annual, automatically-generated and updated approach for mapping dryland riparian woodlands in the southwestern United States, paving the way for improved modeling and management efforts on watershed to regional scales. We also provide one of the first operational, exclusively cloud-based methods to extract dryland land surface phenology patterns using Landsat, Sentinel-2, MODIS, or other sensors, providing a framework for future studies investigating other aspects of long-term or spatial variation in dryland vegetative seasonality across the globe.