Reduction Of Water Stress Research Articles

Rainwater harvesting through roofs and stormwater harvesting through pervious pavements: A Life Cycle Assessment and decision-making comparison

Water consumption and the building sector are among the top contributors to environmental impacts worldwide. Also, sustainable practices have been constantly encouraged in both sectors to mitigate water scarcity and provide resilience to cities. Thus, studies that provide an environmental assessment and discuss the decision-making process are essential for enabling the augmentation of sustainable practices. This research aims to contribute to the discussion on sustainability by conducting a Life Cycle Assessment (LCA) of Sustainable Urban Drainage Systems (SUDS) examples. LCA is the main methodology applied to perform environmental comparisons. First, a thorough inventory was obtained from previous works with different alternatives for water management within a university building, including drainage, paving and water supply functions. The inventory contemplates alternatives using rainwater and stormwater harvesting for non-potable water supply, including pervious pavements. Such alternatives were compared with Brazil's usual water supply systems, aiming at diminishing the total environmental burden. The methodology aspects of LCA were also regarded, such as an uncertainty assessment and a quality matrix of the processes used. Midpoint and endpoint categories were also regarded with their decision-making and uncertainty analysis. The main result is the understanding of the trade-offs between the proposed systems, with a significant reduction in water stress obtained in the alternative scenarios. However, such a decrease is accompanied by a slight increase in some impact categories. Rainwater harvesting through roofs is the most environmentally friendly alternative, although the Cultural Theory parameter definition impacts on the sustainability ranking. Alternative sustainable systems for water management still need validation in terms of LCA, while decision-making for sustainable and resilient cities also requires a robust scientific basis. Thus, in conclusion, alternative systems such as SUDS were obtained to be more sustainable than conventional paving, drainage and water supply in the case study, and the understanding of different benefits found in the LCA is important to the decision-making process.

How does virtual water influence the water stress pattern in Africa? A research perspective from the perspectives of production and trade

Northern Africa has become the first region in the world to exhaust its water resources, with a 40 % decrease in per capita water availability south of the Sahara over the past decade. While adjusting production structures and consumption can regulate the supply-demand dynamics of water resources, the extent of the impact of virtual water-induced pressure on both the regional and national levels in Africa remains largely understudied. Applying the standard Penman formula, this research calculates the water footprint of eight cereal crops in 54 African countries from 1990 to 2021. By integrating corresponding data on cereal trade, the study analyzes changes in virtual water stress. The findings indicate a decline in the per-unit production and consumption water footprints for African cereals. However, the continuous expansion of cultivation areas contributes to a rising water stress. In comparison to 1990, the water stress for soybeans, sorghum, rice, maize, and cassava increased by 149.72 %, 146.88 %, 133.89 %, 123.30 %, and 90.8 %, respectively, in 2021. Only barley showed a reduction in water stress by 23.22 %. The study underscores the growing interconnectedness of virtual water trade (VWT) among African nations from 1990 to 2021, leading to a more balanced trade distribution. VWT has reduced water stress by 7.65 %, 2.08 %, and 1.8 % in Western, Central, and Northern Africa, respectively, while increasing pressure in Southern and Eastern Africa by 10.51 % and 1.01 %. The flow of virtual water in Africa is most influenced by spatial proximity, primarily occurring between adjacent countries or regions. Forecasts for water stress under the five scenarios of SSPs-RCP8.5 have been conducted, revealing a continuous increase in water stress across Africa. Furthermore, analysis of the SSP2-RCP8.5 scenario indicates that by 2030 and 2040, African cereal crops are projected to face virtual water resource stress increases of 7 % and 18.76 %, respectively, compared to 2020 levels. During the same period, Sierra Leone is anticipated to experience a growth rate in virtual water stress of approximately 1903.38 %. Consequently, altering crop cultivation structures and enhancing VWT are poised to alleviate water resource pressure, promoting the scientific management of agricultural water resources in Africa.

Molecular and Physiological Responses to Exogenously Applied Melatonin in Spinach Under Deficit Irrigation Conditions

Melatonin, an important phytochemical, encourages plants to redirect growth in response to environmental stresses. The study aims to investigate the changes in the morphological, physiological, biochemical, and molecular properties of spinach subjected to the exogenous application of melatonin (MEL) at different doses under different water stress. The following four irrigation levels were applied: I100 (complete irrigation), I80 (20% water deficit), I60 (40% water deficit), and I40 (60% water deficit). MEL was applied through a spray on the leaves in three doses—0, 50, and 100 µM. In the present study, the application of MEL50 exhibited no significant decrease in water use efficiency (WUE) at the I80 irrigation level compared to the I100 irrigation level, while a significant decrease in the WUE was observed beyond this point. The application of MEL contributed to influencing the morphological parameters while also positively affecting the photosynthesis activity and, contribution to the antioxidant defense system. It was observed that the genes involved in the carbon metabolism of photosynthesis), the antioxidant mechanism, and the continuity of photosynthesis, all of which affect the expression of melatonin, facilitated water stress reduction in spinach. Therefore, it was inferred that the application of MEL50I80 could serve as an important irrigation strategy in semi-arid regions with limited water resources.

Water Stress Reduction Using Superstructure-Based Mathematical Model: Synthesise a Wastewater Treatment Plant Associated with Nutrient Recovery for Palm Oil Industry

Water Stress Reduction Using Superstructure-Based Mathematical Model: Synthesise a Wastewater Treatment Plant Associated with Nutrient Recovery for Palm Oil Industry

Spring barley yield and potential northward expansion under climate change in Canada

AbstractSpring barley (Hordeum vulgare L.), being a cold‐tolerant crop, may not benefit as much from a warmer climate and a lengthening of the growing season due to climate change though its suitable production area could expand further north. The objectives of this study were to assess the impact of climate change on barley yields across Canada for both current production regions and potential northern crop expansion regions in the future. Three crop models (DeNitrification and DeComposition, Decision Support System for Agrotechnology Transfer, and Simulateur mulTIdisciplinaire pour les Cultures Standard) and 18 climate scenarios (1981–2100) were used to simulate the effect of climate change on potential (non‐water and non‐nitrogen limited) and rainfed (non‐nitrogen limited) spring barley yields for 32 locations across Canada. For the currently planted spring barley regions characterized by a humid summer in Eastern Canada (growing season precipitation >500 mm), potential and rainfed yields were projected to slightly increase in the future (<+0.2 t ha−1). In western regions where precipitation amount is lower (growing season precipitation <500 mm), changes in the potential yield varied slightly (−0.1 to +0.2 t ha−1), while the rainfed yield was projected to increase (0.2–1.0 t ha−1) mainly due to a reduction in water stress under elevated CO2. Finally, in northern regions where future expansion may occur, projected yield increases were generally large (up to 2.8 t ha−1 for potential yield), but the risk of crop failure usually remained high. Our findings suggest that future climate change will present both opportunities and regionalized risks for spring barley producers with the potential to further expand barley production northward.

China's strictest water policy: Reversing water use trends and alleviating water stress

Growing water problems have promoted the Chinese government to implement the strictest water resources management system (SWRMS), the first national policy that puts into practice the concept of “safe operating space” for human water use. Here, we investigate the impact of the SWRMS on China's water use and water stress based on a newly compiled high-resolution and multi-sectoral water use dataset. Results indicate that China's total water use (TWU) increased significantly from 549 km3 yr-1 to 610 km3 yr-1 between 2000 and 2012 (i.e., the pre-SWRMS period), but decreased remarkably in the post-SWRMS period (2012–2020), reaching 565 km3 yr-1 by the year 2020. The decline in TWU was attributed to the improvements of irrigation and industrial water use efficiency (WUE), which were strictly controlled by the SWRMS at various administrative levels of China. The improved WUE has yielded about ∼90 km3 of water savings per year, freeing 17 prefectures from extreme water stress that affects 6% of China's population and 10% of its GDP. Although the improved WUE caused a significant decrease in TWU, the reduction in China's average water stress was insignificant due to the considerable influence of water availability. We further identified hotspots with great potential for water stress reduction, mainly in northwestern China, and hotspots at high risks of water security, primarily on the North China Plain. This study underscores the crucial role of the SWRMS in addressing China's water shortage and provides valuable insights to other countries grappling with water problems in defining their own “safe water operating spaces”.

Uncertainty Analysis of HYDRUS-1D Model to Simulate Soil Salinity Dynamics under Saline Irrigation Water Conditions Using Markov Chain Monte Carlo Algorithm

Utilizing degraded quality waters such as saline water as irrigation water with proper management methods such as leaching application is a potential answer to water scarcity in agricultural systems. Leaching application requires understanding the relationship between the amount of irrigation water and its quality with the dynamic of salts in the soil. The HYDRUS-1D model can simulate the dynamic of soil salinity under saline water irrigation conditions. However, these simulations are subject to uncertainty. A study was conducted to assess the uncertainty of the HYDRUS-1D model parameters and outputs to simulate the dynamic of salts under saline water irrigation conditions using the Markov Chain Monte Carlo (MCMC) based Metropolis-Hastings algorithm in the R-Studio environment. Results indicated a low level of uncertainty in parameters related to the advection term (water movement simulation) and water stress reduction function for root water uptake in the solute transport process. However, a higher level of uncertainty was detected for dispersivity and diffusivity parameters, possibly because of the study’s scale or some error in initial or boundary conditions. The model output (predictive) uncertainty showed a high uncertainty in dry periods compared to wet periods (under irrigation or rainfall). The uncertainty in model parameters was the primary source of total uncertainty in model predictions. The implementation of the Metropolis-Hastings algorithm for the HYDRUS-1D was able to conveniently estimate the residual water content (θr) value for the water simulation processes. The model’s performance in simulating soil water content and soil water electrical conductivity (ECsw) was good when tested with the 50% quantile of the posterior distribution of the parameters. Uncertainty assessment in this study revealed the effectiveness of the Metropolis-Hastings algorithm in exploring uncertainty aspects of the HYDRUS-1D model for reproducing soil salinity dynamics under saline water irrigation at a field scale.

Shared responsibility for global water stress from agri-food production and consumption and opportunities for mitigation

Understanding how agri-food consumption by individual countries contributes to their own water stress and that of other agri-food producer countries, and identifying opportunities to help reduce global water stress is important for ensuring responsible agri-food consumption and production. Assessing 26 agri-food commodities traded between 189 countries using a multi-regional input-output model (MRIO), the contribution of agri-food production to the water stress of producer countries was quantified. Then, the responsibility of consumer countries in aggravating the water stress of producer countries was assessed. Finally, an indicator of opportunity for consumer countries to target co-investment in improving the water-use efficiency of producer countries where they can achieve the highest marginal reduction in water stress was developed. The USA was the most significant contributor to global water stress, adding 42 percentage points to its own domestic water stress and 179 percentage points to the water stress of other producer countries via trade. The opportunity for reducing water stress was highest for the Dominican Republic, Qatar, and Ukraine. Production of irrigated Vegetables, fruits & nuts for export was the major contributor to the national water stress of these countries. This work can help nations reduce their contribution to global water stress through targeted investments in water-use efficiency measures across their global supply chain and help to progress towards Sustainable Development Goals 6 (Clean Water), 12 (Responsible Consumption and Production), and 17 (Global Partnerships for Sustainable Development).

Soil Drenching with Silicon Improves the Adaptive Response of Tobacco Cultivation under Excess Water Condition

Tobacco variety H382 was a cigar type tobacco that has a high economic value and potential as export trade commodity in Indonesia. The development stage of tobacco was very sensitive to water stress, like the water excess. Silicon was one of the most abundant elements in earth crust and has a role in water stress reduction to the plant. The objective of this study was to determine the response of tobacco crop variety H382 with the application of silicon fertilizer to adapt in waterlogging stress condition. This study used a factorial randomized block design with first factor was silicon fertilizer (0, 0.15, 0.30 and 0.45 ml) and second factor was excess water stress treatments (50% to 70%, 70% to 90%, 90% to 110% and 110% to 130% of field capacity). All treatments were replicated three times. The results showed that the addition of 0.45 ml silicon fertilizer to waterlogged tobacco crop could escalate the adaptive response of plant to cope with stress; seen from the increasing of the opened stomata, aerenchyma formation and the chlorophyll content of tobacco crop under excess water stress compared to control. Silicon supplementation improves the water availability in root surroundings and repairs the root architecture; thus, lead to a better hydraulic conductivity of the root for water and nutrient intake. Furthermore, authors found that the application of silicon fertilizer helped tobacco crop variety H382 improve plant adaptability to deal with excess water stress.

Water-Energy-Food-Climate Nexus in an Integrated Peri-Urban Wastewater Treatment and Reuse System: From Theory to Practice

This paper develops a framework for the identification, assessment and analysis of the water reuse-carbon-energy-food-climatic (WEFC) nexus in an integrated peri-urban wastewater treatment and reuse system. This methodology was applied to the municipal wastewater treatment plant (WWTP) of Peschiera Borromeo (Milan, Italy) and its peri-urban district to define the most possible affirmations and conflicts following the EU regulations 741/2020. Results of this work showed that transferring the WEFC nexus from theory to practice can realize sustainable resource management in the operating environment by providing a reduction in greenhouse gas (GHG) emissions, overall energy savings, reduction in water stress and optimization of agricultural practices. Particularly, it was found that if the plant configuration is upgraded to reach water quality class C for water reuse, instead of wastewater discharge, energy savings are estimated to reach up to 7.1% and carbon emissions are supposed to be reduced up to 2.7%. In addition, enhancing water quality from class C to class A resulted in increments in energy and carbon footprint of 5.7% and 1.7%, respectively. Nevertheless, higher quality crops can be cultivated with reclaimed water in class A, with bigger economic revenues and high recovery of nutrients (e.g., recovery of 154,450 kg N/y for tomato cultivation).

Reuse of treated water in European agriculture: Potential to address water scarcity under climate change

The use of reclaimed or treated water from urban wastewater treatment plants for irrigation has been proposed as an alternative water source to address water scarcity issues in Europe. In this paper using agro-economic modelling, we analyse if treated water available for agriculture has the potential to reduce freshwater abstraction and, consequently, water stress. Implementing exogenous treated water quantities as an additional water supply at NUTS 2 level in the CAPRI model, we found that treated water reuse is a possible alternative supply source to address water shortages with a very negligible effect on farmers’ income and food production in the EU. However, the actual water reuse and water stress reduction is very limited due to high costs. Even climate change effects on water availability and precipitation failed to induce higher use. The one-size-fits-all approach modelled via a flat rate water price only encourages the reuse of treated water in a limited number of EU member states. Thus, in order to maximise the potential of reused water to address water scarcity, different rates should be used so as to ensure higher treated water volumes at lower costs.

Root lateral interactions drive water uptake patterns under water limitation

The plasticity of root water uptake determines the maintenance of transpiration during periods of water limitation and drought. However, the mechanistic basis of plant water uptake, as well as the implications of water uptake strategies at the individual and ecosystem scale remain elusive. We model three-dimensional root water uptake under variably saturated conditions for a one-hectare temperate forest plot for a growing season with a pronounced mid-season dry period. Variations in root architecture, hydraulic properties, and degree of lateral interaction between root systems produce divergent local responses to water limitation and provide insights on individual and community response to meteorological conditions. Results demonstrate the plasticity of ecosystem-scale responses to surface drying, where interacting roots shift regions of active uptake to deeper soil layers with less abundant root biomass. These shifts, a product of both root system and soil hydraulic properties, illustrate intimate links between root and soil hydraulics in determining plant water sourcing. We further demonstrate that root lateral interactions are beneficial at the ecosystem-scale, even when trees compete for water. Specifically, a more spatially extensive root system facilitates access to a larger soil water reservoir, often ameliorating water limitation and reducing sharp water potential gradients. While the reduction of water stress is a benefit, it can be offset by increased root construction and maintenance costs associated with the larger rooting system. A plausible “viability” region of root communal co-existence is therefore implied where competitive pressures and root production costs are balanced by a potential water benefit.

A Review of Water Stress and Water Footprint Accounting

Production and consumption activities deplete freshwater, generate water pollution and may further lead to water stress. The accurate measurement of water stress is a precondition for sustainable water management. This paper reviews the literature on physical water stress induced by blue and green water use and by water pollution. Specifically, we clarify several key concepts (i.e., water stress, scarcity, availability, withdrawal, consumption and the water footprint) for water stress evaluation, and review physical water stress indicators in terms of quantity and quality. Furthermore, we identify research gaps in physical water stress assessment, related to environmental flow requirements, return flows, outsourcing of water pollution and standardization of terminology and approaches. These research gaps can serve as venues for further research dealing with the evaluation and reduction of water stress.

Understanding effects of genotype × environment × sowing window interactions for durum wheat in the Mediterranean basin

• Advanced sowings compared to traditional may raise durum wheat yield in Mediterranean. • Water stress reduction and longer grain filling were the major factors for yield increase. • Short-cycle cultivars were less affected by hot and dry Mediterranean conditions than medium-long cultivars. Durum wheat is one of the most important crops in the Mediterranean basin. The choice of the cultivar and the sowing time are key management practices that ensure high yield. Crop simulation models could be used to investigate the genotype × environment × sowing window (G × E×SW) interactions in order to optimize farmers’ actions. The aim of this study was to evaluate the performance of the wheat model SiriusQuality in simulating durum wheat yields in Mediterranean environments and its potential to explore the G × E×SW interactions. SiriusQuality was assessed in multiple growing seasons at seven sites located in Italy, Spain and Morocco, where locally adapted cultivars were grown. The model showed good ability in predicting anthesis and maturity date (Pearson r >0.8), as well as above ground biomass and grain yield (6 % < nRMSE < 18 %). The model was then used to find the optimal 30-day sowing window to maximize grain yields at four sites, two were located in Italy (Florence, Foggia), and the other two were in Spain (Santaella) and Morocco (Sidi El Aydi) respectively. Among the cultivars, on the average between all sowing window, Amilcar had the best performance in Foggia (+33 % compared to the traditional cultivar Simeto) and in Sidi El Aydi (+22 % compared to Karim), Karim in Florence (+19 % compared to Creso) and in Santaella (+6 % compared to Amilcar). Instead Creso and Simeto showed the lowest production at all locations. The results showed that an earlier sowing window compared to the traditional one would have a positive effect on wheat yields in all environments tested, because of increased maximum leaf area index, grain number and size, and grain filling duration. Moreover, with earlier sowing, grain filling coincides with higher soil water availability, reducing the water stress and increasing the accumulation of dry mass in grains. In cooler and wetter locations, cultivars characterized by higher leaf area index and radiation use efficiency had the higher number of grains, while in the hottest and driest locations, short-cycle cultivars with high grain dry matter potential (e.g. through enhanced “stay green” capacity) should be preferred.

Parameterization of the water stress reduction function based on soil–plant water relations

Rational parameterization of the soil water stress reduction function in root water uptake model is crucial for accurate description of root water uptake and simulation of soil water dynamics in a soil–plant system. In this study, we propose three improvements to a popular transpiration-based approach to parameterize the water stress reduction function in a widely used macroscopic root water uptake model. The improvements are based on the interdependent relationships between soil and plant water status and consideration of effects of (1) relative distribution of soil water to roots on transpiration; (2) differences in growth levels of plants exposed to different levels of water stresses on potential transpiration; and (3) hysteresis of water stress on parameter optimization through identifying and discarding the data involved in the recovery periods when the discrepancy between soil and plant water availability is significant. Lysimetric experiments with winter wheat planted alternatively in greenhouse soil columns and in a field were conducted to test the proposed improvements. Through minimizing the residuals between the measured and estimated actual transpiration, the optimized parameterization was used to set up the root water uptake model. Thereupon, actual transpiration and relative transpiration were estimated and soil water content distributions were simulated. The estimated actual (RMSE ≤ 0.09 cm day−1) and relative (RMSE = 0.06) transpiration agreed well with the measurements. The simulated soil water content distributions also matched the measured values well for both experiments (RMSE ≤ 0.023 cm3 cm−3). Omitting any of the three proposed improvements reduced the estimation accuracy of relative transpiration, as the individual contribution ratio for each improvement was between 21.2 and 51.2%. The improvements should be reasonable in providing rational parameter estimation for the water stress reduction function, from which root water uptake models can be established to accurately evaluate plant transpiration and simulate soil water flow in a soil–plant system. The parameterization strategy for the water stress reduction function of root water uptake not only benefits accurate evaluation of plant transpiration under drought conditions but also contributes to further study and description regarding the apparent hysteresis of root water uptake after re-watering.

Aplicação de extrato etanólico de própolis em doenças da cultura da soja

The application of fungicides is the main management of soybean diseases, but due to the environmental appeal and the emergence of resistant fungi, there is a need for studies with alternative products. The objective of this work was to verify the effect of ethanolic propolis extract (EPE) on the management of fungal diseases, on growth, reduction of water stress and soybean yield. The experimental design was a randomized complete block design (DBC), with five replications in a 4 × 2 factorial scheme. The first factor was four EPE doses: 0, 106, 212, 318&nbsp;g of crude propolis ha‑1&nbsp;and the second with two levels: without and with the sequential application of fungicides (two applications of fungicides trifloxystrobin + prothioconazole and one of mancozeb). The foliar application of EEP reduced the severity of the target spot with the greatest efficacy at the concentration of 212&nbsp;g&nbsp;ha‑1. Water content and vegetative growth increase with the application of EEP. The application of fungicide management increases the yield of soybean grains by 12%. The application of EEP increases soybean productivity by up to 23%, due to the reduction of the target spot severity and increase in the water content in the plant tissues.

Reduction in Water Stress for Tree Saplings Using Hydrogels in Soil

The effect of soil amendment with hydrogel on reducing water stress was tested for Siberian elm (Ulmus pumila) and silver maple (Acer saccharinum) saplings. The trees were planted in soils with one of two concentrations of hydrogel (0.5% or 1% dry weight) as compared to the control soil (0% of hydrogel) and watered either daily, weekly, or bi-weekly. Growth was monitored by measuring height and stem diameter. Stress was monitored by measuring SPAD readings and normalized difference vegetation index (NDVI), as proxy measures of chlorophyll content and photosynthetic activity, respectively. Water stress decreased NDVI (p < 0.05) but did not have a significant effect on SPAD readings. Soil with 0.5% concentration of hydrogel was positively associated with greater height and NDVI (p < 0.01) for both maple and elm trees. Hydrogels had a species-specific effect on SPAD readings. The interaction between hydrogel concentration and the watering regime had a significant effect on the height and NDVI (p < 0.01) of elms, but not maples. The improved performance of water-stressed tree saplings in hydrogel-amended soils was presumably due to the ability of hydrogels to absorb and then gradually release water and nutrients. This is of special interest for urban foresters, because water stress and nutrient deficiency are two important growth-limiting factors for street trees.

Role of Potash Fertilization in Reduction of Water Stress in Moonbean (Vigna radiata L.) and Yield Components

The field study is conducted during two autumn seasons of 2012 and 2013 at Al-Anbar province to determine the actual water use by mungbean crop (Vigna radiata L.) under water stress conditions and potassium fertilizer, as well as the assessment of crop and growth characteristics. Four treatments of irrigation are used (I1 watering when %50 of available water used (treatment measure), I2 watering when %25 of treatment measure used, I3 watering when %50 of treatment measure used and I4 watering when %75 of treatment measure used) and three levels of potassium Sulfate fertilizer (41.5% K) (40, 80 and 120 kg. ha-1) in addition to the control (K0) are used, it is given K1, K2 and K3 to the potassium levels respectively. A split plot in randomized complete block design was used with three replications to do this experiment. Treatments of irrigation are used as main plots while potassium fertilizer levels are used as a sub-plot. Least significant difference (LSD) at 5% probability is used to compare the means. The treatment of I1 and I2 significantly gives the highest mean for yield and yield components without significant difference between them. I1 treatment gives the means( 35.26 and 33.83 pods. plant-1 ), the length of pod (7.49 and 7.41 cm), (7.35 and 6.62 seed. pod-1), 100-seed weight (4.07 and 3.78 gm), (1080.10 and 909.80 kg. ha-1) for the first and second seasons respectively, but I2 treatment has given the mean (34.09 and 32.64 pods. plant-1 ), (7.26 and 6.52 seed. pod-1), 100-seed weight (3.95 and 3.61 gm), (1047.10 and 881.60 kg. ha-1) for the first and second seasons respectively. Moreover K3 treatment significantly gives the highest means for yield and yield components (31.39 and 29.05 pods. plant-1 ),(6.88 and 6.04 seed. pod-1), 100-seed weight (4.03 and 3.67 gm), (895.30 and 743.10 kg. ha-1) for the first and second seasons respectively, The interaction among I1K3, I2K3 and I1K2 significantly gives the highest means for all plant characteristics without significant differences.

Role of Potash Fertilization in Reduction of Water Stress in Mungbean (Vigna radiata L.) and Vegetative Growth Characteristics

A field study has been conducted during two autumn seasons of 2012 and 2013 at Al-Anbar province to determine the actual water use by mungbean crop (Vigna radiata L.) under water stress conditions and potassium fertilizer, as well as the assessment of crop and vegetative growth characteristics. Four treatments of irrigation are used (I1 watering when %50 of available water used (treatment measure), I2 watering when %25 of treatment measure used, I3 watering when %50 of treatment measure used and I4 watering when %75 of treatment measure used) and three levels of potassium Sulfate fertilizer (41.5% K) (40, 80 and 120 kg. ha-1) in addition to the control (K0) are used, it is given K1, K2 and K3 to the potassium levels respectively. A split plot in randomized complete block design is used with three replications to do this experiment. Treatments of irrigation are used as main plots while potassium fertilizer levels are used as sub-plot. Least significant difference (LSD) at 5% probability is used to compare the means. The results showed superiority of the treatment of irrigation I1 in all characteristics (plant height and number of branches per plant, number of leaves per plant and leaf area and leaf area index) in the first and second seasons, respectively, do not differ significantly for the treatment of irrigation I2 and all the characteristics and two seasons, respectively. While fertilization treatment K3 showed its superiority in all characteristics, do not differ significantly for the treatment of fertilization K2 in leaf area in the first season, the number of branches and number of leaves per plant in the second season. The interaction among I1K3, I2K3 and I1K2 significantly give the highest means for all plant characteristics without significant differences.

How anthropogenic disturbances affect the resilience of a keystone palm tree in the threatened Andean cloud forest?

To conserve tropical forests, it is crucial to characterise the disturbance threshold beyond which populations of tropical trees are no longer resilient. This approach is still not widely employed, especially with respect to the effects of moderate disturbances. Compensation effects, such as positive interactions among plants, are addressed even more rarely. We attempt to identify the extents to which the distribution of the keystone palm tree Ceroxylon echinulatum is regulated by various regimes of deforestation in a threatened tropical montane cloud forest in the North-West Andes of Ecuador. The demographic structure of this palm tree was examined in three habitats: old-growth forest, forest disturbed by selective logging, and deforested pasture. Patterns were related to stand structure, microclimate, and soil composition. Seedling desiccation owing to severe aboveground water stress led to the absence of juvenile palms in pastures, and thus was predictive of a near extinction of the species in this habitat. However, shade provided by dominant bunchgrass in pastures considerably reduced above- and belowground water stress by diminishing light intensity. Selective logging resulted in a higher density of individuals in disturbed forests than in old-growth forests, but was associated with a spoiled spatial structure. Therefore, the protection of residual old-growth forests is a prerequisite for the conservation of C. echinulatum, although secondary forests might act as provisional refuges that promote its resilience. The reduction of water stress by nurse grasses in pastures represents a promising approach to promote the resilience of tropical tree species and their associated communities after deforestation.