Water Availability For Agriculture Research Articles

A probabilistic assessment of agricultural water scarcity in a semi-arid and snowmelt-dominated river basin under climate change

Water resources planning and management is crucial and challenging in semi-arid regions to minimize water scarcity. Potential impacts due to climate change are a concern to water managers and stakeholders in semi-arid river basins with limited water availability. This study provides a probabilistic assessment of climate change impacts on water scarcity in the Sevier River Basin of Utah, which has a snowmelt-driven water supply and high agricultural water demands, using a decision-scaling framework. The methodology consists of a bottom-up approach that uses climate response functions, together with projections from 31 general circulation models (GCMs), to assess vulnerability to water scarcity for 2000–2099. Water scarcity is defined using an index comparing water availability to crop water demand predicted by the AquaCrop model from the Food and Agriculture Organization. Results showed that off-season precipitation is the most sensitive factor affecting water scarcity in the basin, followed by precipitation and temperature during the growing seasons. The GCM projections of temperature and precipitation suggest an increasing availability of water for agriculture in the basin. Still, a considerable risk probability of agricultural water shortage was found in years 2025 through 2049 with the emission scenario RCP4.5, suggesting the need for adaptation and mitigation strategies. The bottom-up decision scaling approach used here with a wide range of GCMs was practical to explore climate risk to agricultural water scarcity given the simplicity and minimal computational requirement.

Two-Stage Stochastic Chance-Constrained Fractional Programming Model for Optimal Agricultural Cultivation Scale in an Arid Area

AbstractIn the agricultural irrigation system, agricultural water availability and demand are significantly affected by seasonal variations. Additionally, agricultural land use in arid regions larg...

An Ancient Irrigation Canal in the Pampa Tamarugal (Chile)

ABSTRACTSouthwest of Tarapacá Valley, in the Pampa Tamarugal of northern Chile, the remains of a canal were discovered running south for more than 6 km. Mapping and excavations indicated that this narrow (about 3 m) and shallow (about 0.5 m) construction was intended to divert water from the perennial Tarapacá River, combine this with occasional run-off from the mountains to the east, and irrigate a system of agricultural fields in a depression on the pampa. Several piles of rocks (cairns) and cleared lines (geoglyphs) were seen in the vicinity of the canal. The recovered pottery sherds were identified as belonging to the Pica-Charcollo tradition (800–1500 c.e.), while four radiocarbon dates from excavated wood and charcoal clustered around 1400–1600 c.e. This places the canal around the time of the colonization of the area by the Inka Empire, which made Tarapacá Valley into a regional center for mining and marine resources. The rationale behind its construction is likely a combination of the need to mitigate fluctuations in the availability of water for agriculture and the production of a larger food surplus.

Водные ресурсы и продовольственная безопасность: партнерство России и стран Азии

The volume of renewable water resources and specific water availability in countries of Asia is shown. It has been found that at present more than 1.7 billion people live in the conditions of water stress and scarcity. Volumes of fresh water withdrawal for various purposes in Asian countries for 1980–2010 and predominant role of agrarian sector have been shown. Some measures aimed at the water availability for agriculture have been presented. Forecasts of increase of the global demand for grain and cattle-breeding products by 2050 is given and it has been found that Asia will play the leading role in global agriculture trends formation. It has been shown that Russia could become one of the leaders on the market of water-consuming agricultural products as it possesses enormous reserves for grain production increase. Problems with pure drinking water supply in Asian countries have caused drastic increase of bottled water consumption. Bottled water markets in Asian countries are the most rapidly growing in the world. Possibilities of Russia’s cooperation with its Asian neighbors in bottled water supply are shown.

Perceptions of Present and Future Climate Change Impacts on Water Availability for Agricultural Systems in the Western Mediterranean Region

Many Mediterranean countries have experienced water shortages during the last 20 years and future climate change projections foresee further pressure on water resources. This will have significant implications for irrigation water management in agricultural systems in the future. Through qualitative and quantitative empirical research methods carried out on a case study on four Mediterranean farming systems located in Oristano, Italy, we sought to understand the relationship between farmers’ perceptions of climate change (i.e., increased temperature and decreased precipitation) and of present and future water availability for agriculture as forecasted by climatic and crop models. We also explored asymmetries between farmers’ perceptions and present and future climate change and water scenarios as well as factors influencing perceptions. Our hypotheses were that farmers’ perceptions are the main drivers of actual water management practices and that sustainable practices can emerge from learning spaces designed from the understanding of the gaps between perceptions and scientific evidences. Results showed that most farmers perceived that climate change is occurring or will occur in their area. They also perceived that there has been an increased temperature trend, but also increased precipitation. Therefore, they are convinced that they have and will have enough irrigation water for agriculture in the near future, while climate change projections foresee an increasing pressure on water resources in the Mediterranean region. Such results suggest the need for (i) irrigation management policies that take into account farmers’ perceptions in order to promote virtuous behaviors and improve irrigation water use efficiency; (ii) new, well-designed learning spaces to improve the understanding on climate change expectations in the near future in order to support effective adaptive responses at the farm and catchment scales.

Projected Impact of Climate Change on Hydrological Regimes in the Philippines.

The Philippines is one of the most vulnerable countries in the world to the potential impacts of climate change. To fully understand these potential impacts, especially on future hydrological regimes and water resources (2010-2050), 24 river basins located in the major agricultural provinces throughout the Philippines were assessed. Calibrated using existing historical interpolated climate data, the STREAM model was used to assess future river flows derived from three global climate models (BCM2, CNCM3 and MPEH5) under two plausible scenarios (A1B and A2) and then compared with baseline scenarios (20th century). Results predict a general increase in water availability for most parts of the country. For the A1B scenario, CNCM3 and MPEH5 models predict an overall increase in river flows and river flow variability for most basins, with higher flow magnitudes and flow variability, while an increase in peak flow return periods is predicted for the middle and southern parts of the country during the wet season. However, in the north, the prognosis is for an increase in peak flow return periods for both wet and dry seasons. These findings suggest a general increase in water availability for agriculture, however, there is also the increased threat of flooding and enhanced soil erosion throughout the country.

What information do policy makers need to develop climate adaptation plans for smallholder farmers? The case of Central America and Mexico

Scientific and technical information can increase the ability of policy makers to make strategic decisions. However, climate change policy is often formulated without significant input from science. We examine whether the availability and accessibility of information related to climate change is a major barrier for policy action on climate change adaptation for smallholder farmers. We also investigate whether scientific information related to climate change is available and used in policy making in Central America and Mexico. Our online survey of 105 decision makers indicated that a lack of scientific and technical information hinders policy makers from developing policies to help smallholder farmers adapt to climate change. Specific needs include information on the impacts of climate change on water availability for agriculture and the areas that are or will be prone to flooding, droughts or landslides. Information about the location of the farmers who are most vulnerable to climate change, the projected temperature and precipitation in agricultural areas and the expected impacts of climate change on crop yields or animal productivity, is also needed. Despite high interest in having scientific information guide policy making, many respondents indicated that policy makers rarely use this information in adaptation planning. In addition to ensuring that relevant information is available to inform policy making, technical and scientific information must be published in venues that are readily accessible for policy makers, easy to understand, and written in a format that is policy-relevant. It is also critical that scientific articles provide specific recommendations for achieving desired policy outcomes.

Agriculture under changing climate conditions and adaptation options in the Koshi Basin

Using biophysical and social analysis methods, this paper evaluated agricultural practices under changing climate in the Koshi Basin and assessed adaptation options. Agricultural trend analysis showed that in the recent three to four decades, the total cultivated area had declined in all parts of the basin except in the Nepal Mountain Region. Household survey results also confirmed such decline and further revealed shifts towards non-agricultural activities. Climate trend analysis showed changes in the frequency of wet and dry days in study districts, implying an increasing chance of flood and drought events. Household surveys further revealed that, in general, people perceived a decline in agricultural water availability and an increase in drought and flood events. The direct impacts of these changes were reduced crop yield, increased fallow lands, displacement of people from settlement areas, sedimentation of cultivable land and damage to properties. Household surveys showed that despite the perceived impacts on agriculture and livelihoods, only limited adaptation options are currently practised. Adaptation efforts are constrained by several factors, including: finance; technical knowledge; lack of awareness about adaptation options; lack of collective action; unclear property rights; and ineffective role of state agencies.

Uncertainty of wheat water use: Simulated patterns and sensitivity to temperature and CO2

Projected global warming and population growth will reduce future water availability for agriculture. Thus, it is essential to increase the efficiency in using water to ensure crop productivity. Quantifying crop water use (WU; i.e. actual evapotranspiration) is a critical step towards this goal. Here, sixteen wheat simulation models were used to quantify sources of model uncertainty and to estimate the relative changes and variability between models for simulated WU, water use efficiency (WUE, WU per unit of grain dry mass produced), transpiration efficiency (Teff, transpiration per kg of unit of grain yield dry mass produced), grain yield, crop transpiration and soil evaporation at increased temperatures and elevated atmospheric carbon dioxide concentrations ([CO2]). The greatest uncertainty in simulating water use, potential evapotranspiration, crop transpiration and soil evaporation was due to differences in how crop transpiration was modelled and accounted for 50% of the total variability among models. The simulation results for the sensitivity to temperature indicated that crop WU will decline with increasing temperature due to reduced growing seasons. The uncertainties in simulated crop WU, and in particularly due to uncertainties in simulating crop transpiration, were greater under conditions of increased temperatures and with high temperatures in combination with elevated atmospheric [CO2] concentrations. Hence the simulation of crop WU, and in particularly crop transpiration under higher temperature, needs to be improved and evaluated with field measurements before models can be used to simulate climate change impacts on future crop water demand.

WATER DISTRIBUTION UNIFORMITY FOR MINI-SPRINKLER IRRIGATION SYSTEM

The change of world climate and its attendant effect on scarce water resources have further reduced the availability of water for agriculture. Under this circumstance, the use of pressurized irrigation systems can be an option of enhancing the efficiency of water consumption. This study was therefore conducted to evaluate the performance of mini-sprinkler irrigation system and to determine optimum operating conditions that achieve high coefficient of uniformity (CU). An experiment was conducted on the experimental farm of faculty of Agricultural, Suez Canal Univ. Egypt. Four different commercially available makes of mini-sprinklers MSP1, MSP2, MSP3 and MSP4 of different nozzle sizes 0.85, 1.35, 1.5 and 2.0 mm, respectively were tested at 75 cm stake height for their hydraulic performance in terms of pressure-discharge, pressure-wetting diameter and pressure-average precipitation rate of single mini-sprinkler head relationships. The experiment was conducted at six different operating pressures of 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 bar. Polynomial equation of the form Q = aP2 + bP + C were developed for all types of four mini-sprinklers to describe the pressure-discharge relationship. On the basis of this relationship MSP4 was found to be superior over other three nozzles. Pressure- wetting diameter relationships was very well established by polynomial type equation of the form WD = aP2 + bP + C and MSP4 was to be superior over other three nozzles. Average precipitation rate was found to be decreases with increase in operating pressure. For all tested operating pressures and nozzle size, the CU increased with increased operating pressure until its maximum at 2.0 bar.

Impacts of land cover dynamics and shallow groundwater abstraction on sustainability of Hakwatuna Oya irrigation system

Deforestation, expansion of agriculture and over abstraction of groundwater in watersheds can influence the water yield. Hakwatuna Oya watershed area in Deduru Oya basin also faces a similar situation due to rapid land use/cover changes and associated impacts. This study was conducted to identify the land use change dynamics and their possible impacts on the inflow to the Hakwatuna Oya reservoir. Land use mapping was done using 1:50,000 topographic maps and Landsat TM, ETM+ and OLI satellite images of 1994, 2003 and 2014 and the changes were assessed using GIS. Measured pump discharges rates and duration of pumping was used to calculate the total groundwater abstraction per month based on the average hours of irrigation and the duration of cultivation. Secondary data on rainfall, evaporation, reservoir storage and water issues were used to calculate the inflow using a water balance study. Assessment identified that forest, home gardens and agricultural area changes are the most prominent during 1986 to 2014. Proliferation of agro-well irrigation was observed as a result of agricultural activities with an agro-well diffusion of 71/100 farmers and agro-well density of 110/km2 of agricultural land area; exceeding the recommended value of 100/km 2 . No statistically significant change was observed in reservoir inflow with time. Although the temporal changes of reservoir inflow was not statistically significant, even a slight reduction of inflow can have a considerable impact to the farmers due to sensitivity of water availability for agriculture. Therefore, it is important to manage the watershed area of Hakwatuna Oya to preserve the ecosystems and to maintain the water yield for the sustainability of the downstream irrigation system.

Agricultural watershed modeling: a review for hydrology and soil erosion processes

ABSTRACT Models have been used by man for thousands of years to control his environment in a favorable way to better human living conditions. The use of hydrologic models has been a widely effective tool in order to support decision makers dealing with watersheds related to several economic and social activities, like public water supply, energy generation, and water availability for agriculture, among others. The purpose of this review is to briefly discuss some models on soil and water movement on landscapes (RUSLE, WEPP, GeoWEPP, LASH, DHSVM and AnnAGNPS) to provide information about them to help and serve in a proper manner in order to discuss particular problems related to hydrology and soil erosion processes. Models have been changed and evaluated significantly in recent years, highlighting the use of remote sense, GIS and automatic calibration process, allowing them capable of simulating watersheds under a given land-use and climate change effects. However, hydrology models have almost the same physical structure, which is not enough for simulating problems related to the long-term effects of different land-uses. That has been our challenge for next future: to understand entirely the hydrology cycle, having as reference the critical zone, in which the hydrological processes act together from canopy to the bottom of aquifers.

The Need for Agricultural Water Management in Sub-Saharan Africa

This paper discusses the current and future conditions that affect water resources and the constraints of water (agricultural) management in sub-Saharan Africa and suggests remedial measures to be considered by policy makers. The pressure on the quantity and quality of water resources is rising in sub-Saharan Africa due to the increased demand of water for agriculture and other purposes as a result of increase in population and food demand. The availability of water is also under threat from changing climate and as a result, water scarcity is expected in many countries in sub-Saharan Africa. On the other hand, the availability of water for agriculture is expected to further shrink due to the increasing demand of water for other purposes like industry, manufacturing and environmental requirement. The current poor efficiency rate of irrigation systems and massive expansion of irrigated area is expected to further exacerbate the water scarcity. Hence, a water management policy focused on maximization of water use efficiency and water productivity should be prioritized in order to meet the food demand of the growing population and cope with water scarcity problems. Engineering and management intervention integrated with strong society awareness and participation is considered very crucial in enhancing water use efficiency and crop water productivity.

Causes and trends of water scarcity in food production

The insufficiency of water resources to meet the needs of food production is a pressing issue that is likely to increase in importance in the future. Improved understanding of historical developments can provide a basis for addressing future challenges. In this study we analyse how hydroclimatic variation, cropland expansion and evolving agricultural practices have influenced the potential for food self-sufficiency within the last century. We consider a food production unit (FPU) to have experienced green–blue water (GBW) scarcity if local renewable green (in soils) and blue water resources (in rivers, lakes, reservoirs, aquifers) were not sufficient for producing a reference food supply of 3000 kcal with 20% animal products for all inhabitants. The number of people living in FPUs affected by GBW scarcity has gone up from 360 million in 1905 (21% of world population at the time) to 2.2 billion (34%) in 2005. During this time, GBW scarcity has spread to large areas and become more frequent in regions where it occurs. Meanwhile, cropland expansion has increased green water availability for agriculture around the world, and advancements in agronomic practices have decreased water requirements of producing food. These efforts have improved food production potential and thus eased GBW scarcity considerably but also made possible the rapid population growth of the last century. The influence of modern agronomic practices is particularly striking: if agronomic practices of the early 1900s were applied today, it would roughly double the population under GBW scarcity worldwide.

Genetic Variation of Morphological Traits and Transpiration in an Apple Core Collection under Well-Watered Conditions: Towards the Identification of Morphotypes with High Water Use Efficiency.

Water use efficiency (WUE) is a quantitative measurement which improvement is a major issue in the context of global warming and restrictions in water availability for agriculture. In this study, we aimed at studying the variation and genetic control of WUE and the respective role of its components (plant biomass and transpiration) in a perennial fruit crop. We explored an INRA apple core collection grown in a phenotyping platform to screen one-year-old scions for their accumulated biomass, transpiration and WUE under optimal growing conditions. Plant biomass was decompose into morphological components related to either growth or organ expansion. For each trait, nine mixed models were evaluated to account for the genetic effect and spatial heterogeneity inside the platform. The Best Linear Unbiased Predictors of genetic values were estimated after model selection. Mean broad-sense heritabilities were calculated from variance estimates. Heritability values indicated that biomass (0.76) and WUE (0.73) were under genetic control. This genetic control was lower in plant transpiration with an heritability of 0.54. Across the collection, biomass accounted for 70% of the WUE variability. A Hierarchical Ascendant Classification of the core collection indicated the existence of six groups of genotypes with contrasting morphology and WUE. Differences between morphotypes were interpreted as resulting from differences in the main processes responsible for plant growth: cell division leading to the generation of new organs and cell elongation leading to organ dimension. Although further studies will be necessary on mature trees with more complex architecture and multiple sinks such as fruits, this study is a first step for improving apple plant material for the use of water.

Non-Parametric and Parametric Analysis of Runoff in Satluj River Basin, Himachal Pradesh, India

Testing the significance of observed trends in hydrological time series has received a great attention recently, especially in connection with climate change. The changing pattern of runoff deserves urgent and systematic attention over a basin for planning, development, utilisation and management of water resources. Therefore, one large catchment i.e. Indian part of Satluj River Basin is selected for the present study. The daily data of runoff were converted to monthly and then computed to seasonal and annual series. The missing values in the data were computed by using average method. For better understanding of the observed trends, data were computed into standardised runoff indices (SDI). These standardised data series were plotted against time and the linear trends observed were represented graphically. The records of runoff were subjected to trend analysis by using both non-parametric (Mann-Kendall test) and parametric (linear regression analysis) procedures.Trend analysis results of runoff show that out of 8 annual trends 2 (25%) are statistically insignificant increasing and 6 (75%) are decreasing in nature where 2 (25%) are statistically significant at 95% confidence level. Apart from annual, the changes were investigated for the four seasons: winter (December-March), pre-monsoon (April-June), monsoon (July-September) and post-monsoon (October-November). The analysis of annual as well as seasonal runoff for the Satluj River Basin indicates significant changes from 1984 to 2010. There is a clear contrast in the runoff pattern of river between the high altitude mountainous region and the lower reaches where it changes as a result of contribution from rainfall, especially during monsoon season. Although the runoff at majority of stations showed decreasing trend, but very few are statistically significant. Such studies help us to resolve potential issues associated with availability of water for agriculture, industry, hydropower, domestic use etc.

Non-Parametric and Parametric Analysis of Runoff in Satluj River Basin, Himachal Pradesh, India

Testing the significance of observed trends in hydrological time series has received a great attention recently, especially in connection with climate change. The changing pattern of runoff deserves urgent and systematic attention over a basin for planning, development, utilisation and management of water resources. Therefore, one large catchment i.e. Indian part of Satluj River Basin is selected for the present study. The daily data of runoff were converted to monthly and then computed to seasonal and annual series. The missing values in the data were computed by using average method. For better understanding of the observed trends, data were computed into standardised runoff indices (SDI). These standardised data series were plotted against time and the linear trends observed were represented graphically. The records of runoff were subjected to trend analysis by using both non-parametric (Mann-Kendall test) and parametric (linear regression analysis) procedures.Trend analysis results of runoff show that out of 8 annual trends 2 (25%) are statistically insignificant increasing and 6 (75%) are decreasing in nature where 2 (25%) are statistically significant at 95% confidence level. Apart from annual, the changes were investigated for the four seasons: winter (December-March), pre-monsoon (April-June), monsoon (July-September) and post-monsoon (October-November). The analysis of annual as well as seasonal runoff for the Satluj River Basin indicates significant changes from 1984 to 2010. There is a clear contrast in the runoff pattern of river between the high altitude mountainous region and the lower reaches where it changes as a result of contribution from rainfall, especially during monsoon season. Although the runoff at majority of stations showed decreasing trend, but very few are statistically significant. Such studies help us to resolve potential issues associated with availability of water for agriculture, industry, hydropower, domestic use etc.

Using a choice experiment to estimate the social benefits from improved water supply services

Efficient and sustainable future investments in water infrastructure and improved water services should be based on a thorough understanding of public preferences and values. This paper examines the welfare effects of improved water supply services in a characteristic coastal area, where water policy makers should address both water quality and water quantity problems. A choice experiment method was designed and conducted in order to evaluate public preferences for alternative levels of water supply attributes: i.e. water quality, frequency of water supply interruptions and water availability for agriculture. Primary data were collected using a structured questionnaire from a sample of residents in the study area (Municipality of New Propontida, Greece). The results show a significant willingness to pay (WTP) for drinking water quality improvements and a lower yet important WTP to avoid interruptions in water services. In a cost-benefit framework, those findings may serve as a reference for sustainable water resources planning, aiming at deriving reliable estimates of social benefits from selected water management decisions.

English

The population in India is expected to stabilize around 1640 million by the year 2050, as a result, gross per capita water availability will decline from 1820 m3/year in 2001 to as low as ~ 1140 m3/year in 2050. Thus, the growing concern about water scarcity challenges us to think of alternative solutions to avoid the current problem of water scarcity. The micro-watershed development, which ensures availability of water for agriculture and domestic purpose and the roof-top rain water harvesting measures, which provide water for domestic consumption are often suggested as solutions for overcoming water shortage in drought prone areas of India. This article presents the success story of rooftop rain water harvesting program in Renavi village in Sangli District of Maharashtra, India. The potential assessment of the village revealed that, approximately 20 lakh liters of water collected from rooftops, will satisfy the demand of a population of 1300 for at least 78 days. This estimation is as per the United Nations standard, which prescribes the requirement of 20 liters of water (cooking and domestic uses) per person per day in India.                Key words: Roof top, rain water harvesting, water scarcity.&nbsp

Assessing Climate Change Impacts on Water Resources and Colorado Agriculture Using an Equilibrium Displacement Mathematical Programming Model

This research models selected impacts of climate change on Colorado agriculture several decades in the future, using an Economic Displacement Mathematical Programming model. The agricultural economy in Colorado is dominated by livestock, which accounts for 67% of total receipts. Crops, including feed grains and forages, account for the remainder. Most agriculture is based on irrigated production, which depends on both groundwater, especially from the Ogallala aquifer, and surface water that comes from runoff derived from snowpack in the Rocky Mountains. The analysis is composed of a Base simulation, designed to represent selected features of the agricultural economy several decades in the future, and then three alternative climatic scenarios are run. The Base starts with a reduction in agricultural water by 10.3% from increased municipal and industrial water demand, and assumes a 75% increase in corn extracted-ethanol production. From this, the first simulation (S1) reduces agricultural water availability by a further 14.0%, for a combined decrease of 24.3%, due to climatic factors and related groundwater depletion. The second simulation (S2-WET) describes wet year conditions, which negatively affect yields of irrigated corn and milking cows, but improves yields for important crops such as non-irrigated wheat and forages. In contrast, the third simulation (S3-DRY) describes a drought year, which leads to reduced dairy output and reduced corn and wheat. Consumer and producer surplus losses are approximately $10 million in this simulation. The simulation results also demonstrate the importance of the modeling trade when studying climate change in a small open economy, and of linking crop and livestock activities to quantify overall sector effects. This model has not taken into account farmers’ adaptation strategies, which would reduce the climate impact on yields, nor has it reflected climate-induced shifts in planting decisions and production practices that have environmental impacts or higher costs. It also focuses on a comparative statics approach to the analysis in order to identify several key effects of changes in water availability and yields, without having a large number of perhaps confounding assumptions.