Improving Irrigation Efficiency Research Articles

Macroplastic Fragment Contamination of Agricultural Soils Supports a Distinct Microbial Hotspot

Agricultural plastics support crop production and quality by reducing weeds, improving irrigation efficiency, and regulating soil conditions, but can also become a soil pollutant. While microplastic effects on soil function are increasingly well-understood, the impacts of agricultural macroplastic (>5 mm) contamination on soils are poorly documented. Prolonged exposure to plastic macrofragments may alter microbial decomposer community structure and function, since plastic can directly affect edaphic factors while leaching novel compounds. To better characterize how plastic contamination influences the soil habitat, we sampled three farms characterized by agricultural plastic pollution in Monterey County, CA, United States. Using a randomized block design, we collected surface soil samples from the fields (“bulk PC soil”) to compare with soil directly in contact with the remaining polyethylene (PE) mulch and polyvinyl chloride (PVC) dripline fragments (“plastic-associated soil”). Soil directly associated with plastic fragments was hypothesized to have reduced microbial biomass and decomposer activities relative to the bulk soil, due to a greater likelihood of toxicity. In contrast to our expectations, we found that both PE and PVC macrofragments support a distinct microbial habitat that hosts a larger, more efficient microbial biomass with greater labile nutrient pools than the surrounding bulk soil. Because of the scope of macroplastic pollution likely occurring in agricultural soils, our findings suggest that this novel plastisphere habitat may significantly alter ecological functions critical to agricultural soils over time by encouraging microbial colonization within plastic debris.

Understanding and promoting adoption of irrigation efficiency practices in Paso Robles, California vineyards: The importance of farm typology and grower sustainability networks

Groundwater depletion and water scarcity are significant global risks facing humanity. Improved irrigation efficiency is a key strategy for achieving sustainable management of groundwater resources. In 2021, we surveyed vineyard managers in the Paso Robles (California) American Viticultural Area, assessing the level of, and barriers to, adoption of six irrigation efficiency best management practices (BMPs). BMP adoption was relatively low overall, with the use of flow meters most widespread (55%) and plant tissue sampling to schedule irrigation least prevalent (32%). Financial expense to implement and manage was the most cited barrier and UC Cooperative Extension was the most trusted information source for water management concerns. There was a clear relationship between BMP adoption and the vineyard and vineyard manager characteristics included in the study. Participation in Sustainability in Practice (SIP) certification and its related grower-to-grower network activities emerged as the single most important determinant of BMP adoption. A vineyard typology of three types (small, medium and large-scale) was also constructed to understand the relationship between BMP adoption, vineyard type and other vineyard and vineyard manager characteristics. There were sharp differences between vineyard types in BMP adoption, barriers to adoption, and trusted information sources. The analysis concludes with targeted outreach recommendations to improve BMP adoption that include financial and technical assistance. Our approach of assessing adoption, characterizing barriers, identifying opportunities, and formulating an outreach strategy informed by farm typology is relevant to other irrigated agricultural regions facing water scarcity and groundwater depletion and could be extended to other irrigation BMPs as well as to other crops.

Are multiscale water–energy–land–food nexus studies effective in assessing agricultural sustainability?

Several studies have highlighted the need for multiscale water–energy–land–food (WELF) nexus studies to ensure sustainable food production without endangering water and energy security. However, a systematic attempt to evaluate the efficiency of such multiscale studies has not yet been made. In this study, we used a data-intensive crop water requirement model to study the multiscale WELF nexus in southern India. In particular, we estimated the groundwater and energy consumption for cultivating five major crops between 2017 and 2019 at three distinct spatial scales ranging from 160 000 km2 (state) to 11 000 km2 (district) to 87 km2 (block). A two-at-one-time approach was used to develop six WELF interactions for each crop, which was used to evaluate the performance of each region. A gross vulnerability index was developed at multiple scales that integrated the WELF interactions to identify vulnerable hotspots from a nexus perspective. Results from this nexus study identified the regions that accounted for the largest groundwater and energy consumption, which were also adjudged to be vulnerable hotspots. Our results indicate that while a finer analysis may be necessary for drought-resistant crops like groundnut, a coarser scale analysis may be sufficient to evaluate the agricultural efficiency of water-intensive crops like paddy and sugarcane. We identified that vulnerable hotspots at local scales were often dependent on the crop under consideration, i.e. a hotspot for one crop may not necessarily be a hotspot for another. Clearly, policymaking decisions for improving irrigation efficiency through interventions such as crop-shifting would benefit from such insights. It is evident that such approaches will play a critical role in ensuring food-water-energy security in the coming decades.

Assessing effects of climate change on irrigation water demand in the Lombok River Basin, Indonesia

Irrigation water demand in the command area is affected by rainfall and climate conditions in the river basin. In climate change conditions, rainfall and temperature are predicted to increase and projected to impact irrigation water requirements significantly. Therefore, understanding the climate change effects on irrigation demand in the command area is significant to the river basin manager and planner for managing water resources effectively. This study aims to predict the impact of climate change and irrigation efficiency improvement on the irrigation water requirement in 2032-2040. This study used the CropWat model to estimate irrigation water requirements in 1995-2005 and 2032-2040. Irrigation water demand in the Dodokan watershed as a part of the Lombok river basin was computed using the historical rainfall and climate data from observation stations. Further, the observed data from 2006 to 2014 were projected into climate change in 2032-2040 as an input for the model to predict the demand in corresponding years. Result suggests that the change of annual irrigation water demand in the Dodokan watershed was expected to rise by 1.61% in 2032-2040 compared with 1995-2005, and irrigation efficiency improvement effort would decrease the demand -18.18% in the climate change period.

Assessment of improving irrigation efficiency for tomatoes planted in greenhouses in Lam Dong Province, Vietnam

This study was conducted to investigate the developmental processes of tomato plants in greenhouses covered with polyethene agricultural film that applied a smart irrigation system. The study tested applying different irrigation water levels (IWLs) of 60, 80, 100, and 120% of crop evapotranspiration (ETc). Based on the findings for the tomato rows sampled to collect information about leaf area, biomass, and yield, maximal growth of tomatoes varied from 80 to 90 days after transplanting (DAT) for all IWLs. Among the applied IWLs, approximately 80% of ETc was recorded as the most appropriate for the crop growth rate (CGR), leaf area index (LAI), and yield, while the IWLs with 60%, 100%, and 120% of ETc also gave an equivalent output. The results of this work can provide useful information for farmers to make the right decisions about the amount of irrigation water to use.

Early almond harvest as a strategy for sustainable irrigation, pest and disease management

Almonds (Prunus dulcis (Mill.) D. A. Webb) are one of the most economically important agricultural commodities in California. As production in the state continues to increase, growers seek sustainable methods to manage agricultural water use and pests that are affordable and environmentally sustainable. The primary objectives of this research were to test the efficacy of hull split regulated deficit irrigation in combination with early harvest of almonds (Prunus dulcis (Mill.) D. A. Webb) for improved irrigation efficiency and control of navel orangeworm (NOW) (Amyelois transitella (Walker)) and hull rot (HR) (Rhizopus stolonifer (Ehrenb:Fr.) Vuill.; Monilinia fructicola (G. Wint.) Honey). Standard Harvest (SH) timing was compared to Early Harvest (EH) timing at approximately three to four weeks earlier in two California almond orchards using a randomized complete block design at each orchard. Stem water potential (SWP) measurements were used to monitor tree water status and manipulate irrigation to prepare trees for EH treatments. Trees were maintained at -1400 to -1800 kPa SWP for two to three weeks leading up to both EH and SH. There were significantly lower HR strikes in EH treatment trees than in SH treatment trees, and significant reductions in the percentage of kernels infested with NOW when EH was employed. There were no significant kernel yield, marketable yield, or shaker efficacy differences between the two treatments. Although 83.3 and 40.9 mm less water was applied to EH trees than SH trees at the Denair and Woodland sites respectively, the trees from both treatment regimes at both sites returned to the same water status after SH and recovered from the induced moderate water stress by the same date after harvest. With further development of complementary harvest and processing strategies, early harvest of almonds shows promise as a strategy for improved water use efficiency and pest and disease control in almond orchards.

Irrigation efficiency and renewable energy powered desalination as key components of Pakistan's water management strategy

Pakistan is reported to be one of the top ten, most water stressed, countries in the world. In this research, the potential to use renewable energy-based seawater desalination and improved irrigation systems to overcome the water stress in Pakistan is evaluated. It was observed that increasing the country's overall irrigation efficiency to 90% by 2050, results in a 54% and 80% reduction in total water and desalination demand, respective to a business as usual scenario. In a moderate scenario, where the maximum increase in irrigation efficiency is 1% per year, the 2050 total water and desalination demand are reduced by 21% and 40% respectively. The projected desalination demand growth, across the three scenarios, can be powered solely by renewables by 2050, at an average cost of water production of 0.6 €/m3. This includes the cost of water transportation in Pakistan and is reported to be an attractive water cost for farmers. Solar photovoltaics and battery storage drive the low cost electricity generation production in Pakistan. Thus, the results show how Pakistan can use improved irrigation efficiency systems and the low cost renewable electricity to achieve water security for the country.

Irrigation Supply and Demand, Land Use/Cover Change and Future Projections of Climate, in Indus Basin Irrigation System, Pakistan

Sustainable management of canal water through optimum water allocation is the need of the modern world due to the rapid rise in water demand and climatic variations. The present research was conducted at the Chaj Doab, Indus Basin Irrigation System (IBIS) of Pakistan, using the WEAP (Water Evaluation and Planning) model. Six different scenarios were developed, and the results showed that the current available surface water is not sufficient to meet crop water demands. The Lower Jhelum Canal (LJC) command area is more sensitive to water scarcity than the Upper Jhelum Canal (UJC). The future (up to 2070) climate change scenarios for RCP 4.5 and 8.5 showed a decrease in catchment reliability up to 26.80 and 26.28% for UJC as well as 27.56 and 27.31% for LJC catchment, respectively. We concluded that scenario 3 (irrigation efficiency improvement through implementation of a high efficiency irrigation system, canal lining, reduction and replacement of high delta crops with low delta crops) was sufficient to reduce the canal water deficit in order to optimize canal water allocation. Improvement in the irrigation system and cropping area should be optimized for efficient canal water management.

Decomposition Analysis of Global Water Supply-Demand Balances Focusing on Food Production and Consumption

Food production and consumption require large amounts of freshwater. There is no literature on the decomposition analysis of the intensities of water supply-demand balances (water balance intensities) for each country worldwide. The aim of this study is to evaluate the water balance intensities and elucidate the promoting factors and offset factors of water balance intensities for each country worldwide, focusing on food supply-demand balances and considering food trade balances on a global scale. The modified Laspeyres index method is applied to both a production-based water balance index (WBIPB) and a consumption-based water balance index (WBICB). The major promoting factor for the WBIPB is the renewable freshwater resources, whereas the major offset factor is the produced item preference. The major promoting factor for the WBICB is the consumed item preference, whereas the major offset factor is the producing area preference. Improving irrigation efficiencies of rice and cereals is effective because rice requires the largest blue water footprint intensities, considering irrigation efficiency on a calorie content basis in all of the items, whereas cereals are the largest share of calorie-based production quantities in all of the items worldwide. This study provides the foundation for decreasing water balance intensities regarding food production and consumption.

The Climate Challenge in Managing Water: Evidence Based on Projections in the Mahanadi River Basin, India

This study analyzes the long-term changes in the rainfall and surface hydrology of the upper and middle sub-basins of Mahanadi, an inter-state river basin in eastern India that experiences climate-induced hydrological extremes, and draws implications for the sustainability of irrigation and drinking water supplies. The likely impacts of rainfall changes on surface flow were also modeled. A Water Evaluation and Planning (WEAP) model was set up (beginning June 2009 and ending May 2050) to analyze the future water balance of the basin for the expected changes in socio-economic conditions. The model was also run for future scenarios that considered different water management interventions, and hydrological consequences of climate variability and change. The model results showed that there would be a water deficit, about 2,182 million cubic meters (MCM) by 2050 (20% of the demand) even under the business-as-usual scenario. The gap is expected to widen to 5,005 MCM (25% of the demand) under a high growth scenario. Further, the water demand management interventions in agriculture would be able to reduce the overall demand for water in the basin to some extent, while it would also reduce the supplies slightly due to a reduction in return flows occurring as a result of irrigation efficiency improvement. The water deficit under this scenario will reduce to about 2,773 MCM in 2050. Under the predicted changes in climate, the water deficit is expected to reduce further (will be 1,684–2,373 MCM in 2050) due to an increase in supplies owing to an increase in the catchment yields resulting from higher rainfall. While there will be a significant amount of outflow from the two sub-basins in all the scenarios in most future years (ranging from 25,286 MCM to 28,697 MCM in 2050), during drought years, the water deficit in the upper basin areas will increase slightly, but with a significant reduction in the outflows to the lower sub-basin areas by 2046–47 (will be about 11,311 MCM). These results indicate that there is a need for building more water storage/diversion infrastructure to detain floodwaters during wet years that can provide buffer storage for the dry years.

Improvement of Irrigation Efficiency by Developing on Farm Irrigation System

The experiments were Carried out in Biahmu Village at Al-Fayoum Governorate, Egypt during the two winter seasons of 2018/2019 and 2019/2020, on wheat crop to (cv. Gemmiza 11) evaluate the traditional surface irrigation system TSIS and the improved surface irrigation system ISIS(terrace), under laser leveling with two slops (S1≈ zero% and S2 ≈ 3%). The evaluation parameters included; reduction in land loss LL, the roughness coefficient of marwa-walls, water efficiencies (i.e., water conveyance efficiencies WCE, water application efficiencies WAE and water storage efficiencies WSE), yield productivity Yp, total applied water and water required, irrigation water productivity IWP and times of water advance, recession and opportunity. The results concluded that improving traditional marwa, led to reduction in land loss by 49.46% from the area of marwa, and WCE increased by 83.17% in improved Marwa IM the compare to Traditional Marwa It was observed that on the efficiency of water added to the field irrigated by TM. The highest level of water productivity (1.79kg wheat/m3 water) was achieved in IM at a level of 3%. Advanced time T.Adv (min) decreased at 50, 50.77, 27.6, 20.75, and 17.17% and 30.9, 40.51, 22.8, 10.89 and7.05% for TL and IL by sloping to S2.

Assessing the Impact of Irrigation Efficiency Projects on Return Flows in the South-Eastern Murray–Darling Basin, Australia

Improving irrigation efficiency (IE) is an approach used globally to help meet competing demands for water and facilitate reallocation of water between sectors. In the Murray–Darling Basin in Australia, the Australian government has invested heavily in IE projects to recover water for the environment. However, this approach has been seriously questioned, out of concerns that improved IE would reduce irrigation return flows to rivers and therefore offset water recovery. In this study, we use a water balance model to assess the impact of the IE projects on return flows and highlight sensitivities and uncertainties. The model enables the impact on return flows to be assessed on specific IE projects and regional characteristics. Overall, reductions in return flows are estimated to be less than 20% of the total proposed IE savings. The history of IE in the southern MDB has meant that most of the current reductions are in ground return flows. Our estimate is much lower than two previous studies, mainly due to different assumptions being used on groundwater connectivity between irrigation areas and major streams. While the IE projects significantly reduce seepage to groundwater (with off-farm and on-farm projects reducing seepage by 19% and 53% of total savings respectively), not all seepage reductions will translate to a reduction in ground return flows to rivers. A lower estimate is consistent with existing monitoring and groundwater modeling studies. In this paper, the study results are discussed in a broader context of impacts of IE projects on volumes and salinity of streams and groundwater resources.

The optimal tensiometer installation position for scheduling border irrigation in Populus tomentosa plantations

Soil matric potential (SMP) is usually monitored by a tensiometer for managing irrigation in forest plantations, so determining where to install the tensiometer is important for improving irrigation efficiency. However, such work has never been conducted for border irrigation, which is commonly used in the intensive cultivation of forest plantations. In a border irrigated Populus tomentosa plantation on sandy loam soil, we monitored the daily changes of SMP at eighteen different positions in soil wetting volume (WV) [expressed in Px y (x means distance from the trunk in cm, y means soil depth in cm)], transpiration (T), and stem growth rate (GR) in a growing season. The fine root distribution was also investigated in two successive growing seasons. The result of time stability analysis showed that, among the eighteen positions, the annual absolute mean relative difference (RD) and the standard deviation of the RD of SMP at P25 40 were not the lowest, but its root mean square error of the SMP relative deviation reached the lowest in the growing season. The root water uptake at P10 10 had the highest influence on T rate (R2 = 0.220, P < 0.01) and GR (R2 = 0.112, P < 0.05). The fine roots distribution changed greatly with the stand development, but its pattern within the WV was relatively consistent in different years. There were three dense fine roots zones located around P10 10, P40 10, and P10 50. Consequently, it was suggested to place tensiometers at two positions, i.e., P25 40 and P10 10, with the former being used for estimating irrigation amount and the latter for triggering irrigation. This recommended tensiometer placement strategy will not only help to improve the irrigation efficiency in P. tomentosa plantation but also provide a reference for the irrigation management in stands of other tree species.

Robust climate change adaptation pathways in agricultural water management

Analysis of climate change impacts as well as conscious decision-making and long-term planning in complex water resources systems require use of innovative approaches under conditions of deep climate uncertainty. This research aims to design and evaluate robust adaptable plans under deep climate uncertainties in the agricultural sector. For this purpose, a combination of the Adaptation Pathways (AP) approach in conjunction with the Soil and Water Assessment Tool (SWAT) model is used to evaluate the robustness of adaptation actions and to design robust adaptation pathways under future climate uncertainties in the Hablehroud River Basin, Iran. Deep climate uncertainties are specified as plausible climate scenario combinations according to the average precipitation and temperature changes in Representative Concentration Pathways (RCPs) 4.5 and 8.5, 2020–2080. According to the results, changes in cropping patterns represent the most robust adaptation action across various combinations of climate scenarios. Other adaptation actions, including deficit irrigation, changes in crop planting dates, and improving irrigation efficiency, are fairly robust in the specific time period from 2020 to 2080. Sequencing of these adaptation actions based on their robustness and expiry date results in designing adaptation pathway maps under RCPs 4.5 and 8.5. Finally, different preferred pathways are identified based on the expiry date of each robust adaptation action. Changes in cropping patterns can be selected as the most robust adaptation pathway (robustness greater than 80) under deep climate uncertainty among these different pathways. Suggesting other preferred pathways can be helpful to select reasonable pathways for implementation.

Modelling net irrigation water requirements using FAO-CROPWAT 8.0 and CLIMWAT 2.0: a case study of Tina Plain and East South ElKantara regions, North Sinai, Egypt

ABSTRACT The present study aims at estimating net and gross water requirements of eight major irrigated crops in the agro-ecological regions Tina Plain (AER 1), and East South ELKantara (AER 2) in Egypt using FAO-CROPWAT 8.0 and its attached meteorological parameters CLIMWAT 2.0 model. Historical weather data at Ismailia and Port Said stations for 40 years (1975 to 2014) were recalled from the CLIMWAT 2.0. The net irrigation requirements for berseem clover, barley and cotton in AER 1 were computed at 612 mm, 283 mm and 901 mm, respectively, while, in AER 2, the corresponding values were 738 mm, 287 mm and 1113 mm showing a 19% increase. District water balance scenarios show for crop pattern with maximum net and gross irrigation water requirement, and irrigation efficiencies 40% and 60% in AER 1 and AER 2, respectively, indicates 22.1% increase above the licensed water limit, crop pattern with minimum net and gross irrigation requirements indicates 23.1% saving of allocation water limit, and the current crop pattern indicates 8.1% saving. Therefore, better water management should be adapted to focus on improving irrigation efficiency and cultivating crops with lower water need, such as green beans, wheat, barely, sugar beet, and tomato.

Hydrologic modeling of reach scale fluxes from flood irrigated fields

Agricultural water is of considerable interest to water managers and policymakers as irrigation—particularly flood irrigation—accounts for the largest portion of freshwater use. However, characterization of how and when flood applied water contributes to storage and adjacent surface water bodies via return flow remains limited, particularly relative to the volume of studies addressing surface processes. This study focuses on improving our understanding of return flow paths and explicitly quantifying subsurface return flow contributions using hydro-geophysical observations coupled with a vadose zone transport flow model. Our approach, which simulates return flow in agricultural fields in a small, heavily instrumented field site in northern Wyoming, leverages daily measured values of evapotranspiration obtained from a large aperture scintillometer and atmospheric conditions, and uses seismic data to characterize heterogeneous structure of the soil profiles at field scale. We use these high-resolution, site specific datasets to parameterize a process-based vadose zone flow model that quantifies hydrologic response to flood irrigation along the stream reach, allowing us to identify return flow fluxes out of the fields. Using our approach, we found that the majority of applied irrigation water (60%) left the fields through subsurface flow paths, while only 13% was consumed by vegetation. Subsurface runoff over less-permeable soil layers, governed by the subsurface structural characteristics, was identified as the dominant subsurface flow process contributing to fluxes out of the fields. Importantly, our findings about the importance of subsurface return flow paths nuance previous research which has emphasized surface flow paths. By improving our understanding of return flow processes through a high- resolution vadose zone model that leverages climatological, geophysical, and hydrological observations, this study advances our understanding of return flow processes. Understanding how subsurface characteristics influence return flow generation in semi-arid agriculturally productive regions will help managers and policy makers balance desires for improved irrigation efficiency against concerns about irrigation-dependent ecosystem services.

Barriers and measures to improve adoption of irrigation technologies: A case study from the Bundaberg region in Queensland, Australia*

AbstractAustralia is the driest continent and is largely reliant on irrigation for efficient agricultural production. Irrigation uses significant volumes of water, and in recent decades many initiatives have been undertaken to improve efficiencies of irrigation systems and management practices. This paper analyses the perceptions and barriers to adoption of irrigation technologies and management practices in agriculture based on a field study undertaken in the Bundaberg region in Queensland, Australia. Overall, most farmers surveyed rated the efficiency of their irrigation systems very highly; nonetheless, more than half the farmers surveyed recognized that their systems and practices had the potential for further improvement through automation. Financial constraints and uncertainty around the economic viability of investing in certain agricultural technologies emerged as major barriers to adoption of available and emerging technologies that could improve irrigation efficiency. This is occasioned by insufficient evidence of the benefits of adopting these innovations. Issues suggested by the respondents for further extension, development and research align closely to known barriers to adoption of agricultural innovations. A key finding and recommendation of this study is that farm‐specific cost–benefit analyses of new irrigation technologies and practices are required to facilitate the decision‐making process for the improvement of irrigation efficiency.

Assessment of deficit irrigation efficiency. Case study: Middle Sebou and Innaouene downstream

Abstract Future projection shows that the availability of freshwater per capita will decrease to 560 m3/year by 2030 in Morocco. In this realm of adopting efficient irrigation, alternatives become a priority to overcome water shortage. The presented study aims to investigate theoretically the likelihood of improving irrigation efficiency at the plot level of the Middle Sebou and Innaouene downstream perimeter using 75% of the total irrigation water requirement (IWR), based on the successful results obtained by the Moroccan National Institute for Agronomic Research. The methodology consists of the extraction of monthly evaporation data from MODIS16A2 and process it under Google Earth Engine (GEE); data that are used in the second part of the study, which aims to assess the efficiency of deficit irrigation on a plot of 2,500 olive tree, using three main indexes; olive three height (cm), Stomatal conductance (mmol H2O m−2 s−1), and olive tree growth (cm). The results show that 0.75 of full irrigation could save 17% of the total water used, reducing the water irrigation supply by an average of 5 Mm3, with a slight decreasing of the olive production, estimated as 0.5 t/ha. Furthermore, water use efficiency and water productivity have been enhanced under deficit irrigation by respectively 0.25 kg/m3 and 0.54 Dh/m3. In economic terms, the result shows that with deficit irrigation, the decision-maker, or the farmer, could save about 5 million m3 per year, which is a boost to the global economy if the method is transposed and applied to other Moroccan regions and also a support for the new agricultural strategy called Generation Green.

Root distribution with the use of drip irrigation on layered soils at greenhouses crops

Greenhouse cultivation has proven to be an efficient solution to extra-early horticultural production, allowing the cycle of vegetable production to be closed throughout the year. This efficient solution depends on many factors, perhaps the main one being the localized irrigation system. On the other hand, the availability of water for irrigation will be one of the most limiting factors for the development of this agricultural practice. The permanent search for improving irrigation efficiency must be considered as one of the great challenges of sustainable agriculture and in the interest of environmental conservation. In this study, the distribution of the roots of the two main horticultural crops, tomato (Solanum lycopersicum L.) and peppers (Capsicum annuum L.), has been analyzed with the localized irrigation system. In addition, they have been studied for layered soils, which represent an advance in terms of resources, since they are artificial soils, where the natural soil does not allow a horticultural crop. It has been found for these stratified soils, that in pepper crop 90% of the root density is in the soil layer 0 to 9 cm. However, for tomato crops 90% of the root density is in the soil layer from 0 to 11 or 15.5 cm according to the type of soil, in other words filling almost all the added soil. The results obtained in this research allow the Hydrus 3D model for stratified soils to be calibrated. This work allows opening new perspectives in the efficient management of adding soils for new greenhouse construction and for localized irrigation of horticultural crops in general, tomato, and peppers in particular.

A copula-based stochastic fractional programming method for optimizing water-food-energy nexus system under uncertainty in the Aral Sea basin

Abstract A copula-based stochastic fractional programming (CSFP) method is developed for optimizing water-food-energy nexus (WFEN) system, which can tackle random variables under conflicting objectives and analyze the interrelationship between marginal benefit and system-failure risk. Then, a CSFP-WFEN model is formulated for the Aral Sea basin and multiple scenarios with individual- and joint-probabilistic risks related to water resources, arable land, and hydropower generation are examined. Synthesizing the results under all scenarios, hydropower generation would decrease by 11.9% and crop area would increase by 12.4% by 2035 under severe water scarcity. Agricultural water would decrease with time (from 69.1% in 2021 to 53.9% in 2035), and the share of wheat farmland would increase by 16.4% for food security. Compared with the traditional stochastic fractional programming (SFP) and copula-based stochastic programming (CSP) methods, the marginal benefit from CSFP would be improved 1.7% and water would be saved 9.2%. To support sustainable development of the study basin, some suggestions can be derived from the results: (i) since agriculture is still the largest water user in the future, it is desired to reduce its water consumption through improving irrigation efficiency and adjusting crop planting structure; (ii) effectively reducing Uzbekistan’s water consumption can improve water allocations to other countries and relieve regional conflicts caused by water shortage; (iii) compared to the single management pattern, the integrated optimization of water, food and energy nexus not only has higher efficiency of resources allocation and utilization, but also allows an increased robustness in controlling system-failure risk under joint probabilistic constraints.