Consumptive Water Use Research Articles

Managing irrigation under increasing water scarcity

AbstractWith rising physical and economic scarcity of water, increasing or sustaining agricultural production while limiting or reducing consumptive water use is an urgent challenge. This article examines the case of four countries—India, China, western United States, and Israel—where there is a long history of irrigated agriculture with significant public and private investments, to identify key themes for managing irrigation under increasing physical and economic water scarcity. The focus of irrigation management has expanded from investing in irrigation infrastructure to reforming institutions; strengthening policies pertaining to irrigation prices and rights; using incentives to reward reductions in irrigation application; and improving irrigation efficiency. However, this may not be sufficient to reduce consumptive use of water in agriculture. Reducing freshwater use in agriculture will require cost‐effective harnessing of other water sources through processes such as desalination and wastewater reuse, which may be difficult to implement in most geographies. Changes to policies in other sectors will likely be needed, especially in food procurement and land‐use, which require balancing water security with food security, and supporting potential losses in livelihoods and incomes from such changes. Finally, reductions in agricultural water use in a country will likely have implications for water use in other countries, through imports.

Rising agricultural water scarcity in China is driven by expansion of irrigated cropland in water scarce regions

Rising agricultural water scarcity in China is driven by expansion of irrigated cropland in water scarce regions

Featured Collection Introduction: Severe Sustained Drought Revisited: Managing the Colorado River System in Times of Water Shortage 25 Years Later — Part I

Featured Collection Introduction: Severe Sustained Drought Revisited: Managing the Colorado River System in Times of Water Shortage 25 Years Later — Part I

Evapotranspiration estimates of soybean using surface renewal: Comparison with crop coefficient approach

Evapotranspiration (ET) is widely considered the main consumptive water use in agricultural production and its accurate determination enables crop producers to make informed decisions. Field experiments were conducted in KwaZulu-Natal, South Africa to estimate soybean ET from sensible and latent heat flux obtained using the surface renewal (SR) method. Two versions of the SR method (SR2) were used. One version combines SR analysis with Monin-Obukhov similarity theory (MOST), hereinafter referred to as SRMOST. The other is a combination of SR analysis and dissipation theory (DT) referred to as SRDT. The ET estimated using SRMOST and SRDT (ETSRMOST and ETSRDT respectively) were compared to the ET obtained using the standard crop coefficient (Kc) approach (ETKc). During flowering, pod formation and seed filling, both SRMOST and SRDT methods slightly overestimated ET obtained using Kc approach with an average normalised root mean square error (NRMSE) of 23.4% and an average normalised mean absolute error (NMAE) of 10.1% for SRMOST and 21.7 and 9.4% for SRDT respectively. During senescence and at maturity, SRMOST and SRDT slightly underestimated ET compared to Kc approach. The average statistical measures for SRMOST were NRMSE = 21.0% and NMAE = 9.2%. Correspondingly, the statistics for SRDT were 17.5 and 7.1% respectively. Both SR2 methods estimated the minimum ET more accurately compared to the maximum. The SRDT method was more in agreement with Kc approach. Surface renewal is robust, less expensive than other micrometeorological techniques and a reliable method for deriving evapotranspiration of soybean when crop coefficients are problematic.

Effects of activated water irrigation on the growth, water consumption and water use efficiency of winter wheat

Effects of activated water irrigation on the growth, water consumption and water use efficiency of winter wheat

Comparison between organic and conventional farming systems using Life Cycle Assessment (LCA): A case study with an ancient wheat variety

Assessing the environmental impact of agriculture is a key factor towards reducing human impacts on the food production chain. Because of the growing consumer interest in healthy foods cultivated with low-impact approach, a study assessing the impacts of ancient wheat variety in organic and conventional farming appears to be of great importance. Thus, this study was aimed at assessing and comparing the environmental impacts and resources consumptions of organic and conventional farming practices on an ancient soft wheat variety (var. Verna) in Tuscany, Italy. The fact that Verna wheat falls within the PDO bread specification, one of the few at the European level, increases the importance of this work. A cradle-to-grave life cycle assessment (LCA) from raw material extraction, through to industrial processing, field utilization, grain harvesting and finally transportation to storage centres was carried out. This study analysed data sampled over a five-year period (2014/2015 to 2018/2019) derived from five organic and conventional farms, respectively. The impact categories considered included: global warming, freshwater ecotoxicity, seawater ecotoxicity, terrestrial ecotoxicity, human toxicity, acidification, eutrophication, photo-oxidant formation, non-renewable energy resource consumption, renewable energy resource consumption, water consumption and land use. In almost all the impact categories, organic farming was shown to have lower environmental impacts, while conventional farming had a lower impact on land use. Results relating to acidification, photo-oxidant formation, ozone layer depletion and non-renewable energy resource consumption were considered similar for the two cultivation systems. Normalization of the results showed that seawater ecotoxicity had the greatest impact among all impact categories (> 99%) for both cultivation systems. Moreover, major environmental problems in conventional farming and organic farming were the use of synthetic N fertilizers and low yields, respectively. Results showed that 192 ×106 hectares of organic farming would be needed to maintain current wheat production in the EU, compared to just 99 ×106 hectares cultivated with the conventional farming. Accordingly, yield increase in organic farming, and reduction of nutrient losses/emissions from conventional farming, are the two most promising strategies towards maintaining a high agricultural production with concomitant reductions in the related environmental impact.

Effect of Depth of Sowing and Mulching on Rainfed Chickpea (Cicer arietinum) in Red and Lateritic Belt of West Bengal

Background: Availability of soil moisture is a serious bottleneck for successful growing of post monsoon crops in red and lateritic soil. Hence, soil moisture conservation is crucial for post monsoon crops. In this aspect using mulches for conservation of moisture and optimum depth of sowing for proper germination and seedling emergence are important crop management practices in red and lateritic soil. Methods: The experiment was laid out in split plot design with three depths of sowing as main-plot treatments and four mulching practices as subplot treatments replicated thrice. Measured growth parameters were plant height (cm), number of branches plant-1, dry matter accumulation (g m-2) and leaf area index (LAI); yield attributes such as effective branches m-2, number of mature pods branch-1, number of seeds pod-1 and seed index; grain and stalk yield. Economics of cultivation was assessed in terms of cost of cultivation, gross and net return and net return per invested. Result: Chickpea sown planted at 7.5 cm depth of sowing recorded maximum yield, consumptive water use efficiency and profitability. Application of 7.5 t ha-1 straw mulch registered significantly higher yield of chickpea, consumptive water use efficiency and profitability.

Growth, Yield and Water Use Efficiency of Sweet Sorghum [Sorghum bicolor (L.) Moench] Affected by Drip Irrigation and Nitrogen Levels through Fertigation

An experiment entitled “Growth, yield and water use efficiency of sweet sorghum [Sorghum bicolor (L.) Moench] affected by drip irrigation and nitrogen levels through fertigation” was carried out on clayey and slightly alkaline soil during rabi season of 2019-20 and 2020-21 at the Instructional Farm, Department of Agronomy, College of Agriculture, Junagadh Agricultural University, Junagadh. The experiment was laid out in split plot design with four replications. There were nine treatment combinations. The main plot treatments viz; (I1) drip irrigation at 0.6 PEF, (I2) drip irrigation at 0.8 PEF and (I3) drip irrigation at 1.0 PEF; and sub plot consist of three nitrogen fertigation levels viz; (N1) 75% RDN through fertigation, (N2) 100% RDN through fertigation and (N3) 125% RDN through fertigation (RDF for sweet sorghum is 90-40-40 N, P2O5 and K2O kg ha-1). The results revealed that drip irrigation scheduling at 1.0 PEF enhance consumptive use of water and nitrogen use efficiency which ultimately resulted in higher grain and fodder yields of sweet sorghum. The results indicated that 125% RDN through fertigation significantly increased water use efficiency, which eventually recorded higher grain and fodder yields of sweet sorghum. Based on the results of two years experimentation, it can be concluded that for getting higher grain and fodder yields, sweet sorghum should be applied two common surface irrigation each of 50 mm depth followed by scheduling drip irrigation at 0.8 PEF (operating pressure: 1.2 kg cm-2 and lateral spacing: 120 cm) at alternate day and crop should be fertilized with 100% RDN through drip fertigation out of which, 50% RDN as basal and remaining 50% RDN in five equal splits at 10 days interval through fertigation started from 35 DAS.

Dietary environmental impacts relative to planetary boundaries for six environmental indicators – A population-based study

The environmental impact of Swedish diets was assessed for six indicators (greenhouse gas [GHG] emissions, cropland use, nitrogen application, phosphorus application, consumptive water use and extinction rate), using self-reported food intake within two population-based cohorts of men and women, 56–96 years of age. The dietary environmental impact was assessed in relation to per capita planetary boundaries, overall and by population subgroups, addressing the relative importance of specific foods and food groups. The total average dietary impact exceeded the planetary boundaries by 1.6 to 4-fold for five of the six environmental indicators; consumptive water use did not exceed the boundaries. Comparing the highest with lowest quintiles of the population impact showed >2.5-fold differences across all environmental indicators. Of the diet's total average environmental impact, animal-based, plant-based and discretionary foods accounted for 28–83%, 8–40% and 9–37%, respectively, across the six indicators. Animal-based foods dominated the impact on GHG emissions, cropland use and nitrogen and phosphorus application, while plant-based and discretionary foods contributed more to consumptive water use and extinction rate. Environmental impact was driven predominantly by consumption of red meat, dairy, fresh fruit and coffee. The findings show major challenges in affluent countries that have to be addressed to achieving sustainable food production systems and diets. They provide guidance on critical food groups, environmental indicators and population subgroups to prioritize in future efforts to reduce the environmental impact.

Agricultural Adaptation to Reconcile Food Security and Water Sustainability Under Climate Change: The Case of Cereals in Iran.

In this study, we simulate the crop yield and water footprint (WF) of major food crops of Iran on irrigated and rainfed croplands for the historical and the future climate. We assess the effects of three agricultural adaptation strategies to climate change in terms of potential blue water savings. We then evaluate to what extent these savings can reduce unsustainable blue WF. We find that cereal production increases under climate change in both irrigated and rainfed croplands (by 2.6-3.1 and 1.4-2.3 million t yr-1, respectively) due to increased yields (6.6%-78.7%). Simultaneously, the unit WF (m3 t-1) tends to decrease in most scenarios. However, the annual consumptive water use increases in both irrigated and rainfed croplands (by 0.3-1.8 and 0.5-1.7 billion m3 yr-1, respectively). This is most noticeable in the arid regions, where consumptive water use increases by roughly 70% under climate change. Off-season cultivation is the most effective adaptation strategy to alleviate additional pressure on blue water resources with blue water savings of 14-15 billion m3 yr-1. The second most effective is WF benchmarking, which results in blue water savings of 1.1-3.5 billion m3 yr-1. The early planting strategy is less effective but still leads to blue water savings of 1.7-1.9 billion m3 yr-1. In the same order of effectiveness, these three strategies can reduce blue water scarcity and unsustainable blue water use in Iran under current conditions. However, we find that these strategies do not mitigate water scarcity in all provinces per se, nor all months of the year.

Single irrigation at the four-leaf stage in the spring optimizes winter wheat water consumption characteristics and water use efficiency

Water scarcity is a key constraint to crop production in North China Plain (NCP), which produces the majority of the country’s winter wheat (Triticum aestivum L.). The objective of this three-year field study was to see whether and when irrigation one-time in spring improved grain productivity and water use efficiency. Four sets of irrigation were established at the 3-leaf visible stage (L3) and the L4, L5, and L6 stages. When irrigation time was postponed, the spike number, 1000-grain weight, and water consumption increased progressively, whereas grain yield, grain number, dry matter, harvest, and WUE grew, then dropped, and peaked at L4. The increased grain number can be attributed to the L4's higher daily water consumption and water consumption percentage throughout the jointing-anthesis stages compared to the L3, L5, and L6. The cumulative (37 days), whereas it was longer in L3, L5, and L6(40, 42, and 43 days, respectively). Furthermore, flag leaf senescence was postponed in L4 with a higher post-anthesis leaf area index, photosynthetic rate, chlorophyll content, higher superoxide dismutase activity, and lower malondialdehyde concentration. As a result, single irrigation at the 4-leaf visible stage optimized water deficit and consumption before and after anthesis, resulting in higher yield and WUE in the NCP.

Water saving potential for large-scale photovoltaic power generation in China: Based on life cycle assessment

While large-scale photovoltaic is regarded as a water saving generation technology, it comes with direct water consumption and embodied indirect water consumption associated with the manufacture of system equipment and building materials during construction. However, few studies have quantified the water consumptive use for photovoltaic generation from a life cycle perspective. In this context, this paper carefully calculated the life cycle water consumption for large-scale photovoltaic power generation in China and identified the hot spots in its supply chain. The results show the life cycle water consumption per kW installed capacity of large-scale photovoltaic plants is 20,419 L. Photovoltaic panel production and the Balance of System together make up over 85% of the total. The application of recycling technologies to the photovoltaic system is promised to cut down the total water consumption by another 13%. Then the water consumption intensity of large-scale photovoltaic power generation in China is presented at the provincial resolution in the range of 0.45–1.52 L/kWh, which is significantly lower than that of current power generation in China. In addition, considering the power generation structure in China in recent years, the water saving potential under the maximum photovoltaic scenario in China during the year 2015–2017 could reach 3.75%, 4.04%, and 4.27% of China's national water supply. Finally, the regional water stress index is also introduced to explore the influence of water consumption on locally available water resources. This study could enable policymakers to better relate the development of large-scale photovoltaics to water saving strategies.

Is the Subsurface Drip the Most Sustainable Irrigation System for Almond Orchards in Water-Scarce Areas?

The expansion of irrigated almond orchards in arid and semi-arid areas with scarce water available raises key issues related to the sustainability of the water resources. A 3-year field experiment was conducted on a commercial young almond orchard located in the southeast of Spain to study the effect of two drip irrigation systems (surface, DI and subsurface, SDI) on almond crop growth and their physiological responses under fully-irrigated conditions. Crop evapotranspiration (ETc) and its components (crop transpiration, Tc and soil evaporation, Es) were monitored as well as the irrigation water and nitrogen productivities. To estimate ETc, a simplified two-source energy balance (STSEB) approach was used. Although a lower irrigation water amount was applied in SDI compared to DI (differences between 10% and 13.8%), the almond crop growth and physiological responses as well as the yield components and kernel yield showed no significant differences. The ETc estimates resulted in small differences for spring and fall periods (0.1–0.2 mm day−1) for both treatments, while differences were significant during higher ETo periods (May–August), being 1.0–1.3 mm day−1 higher for the DI treatment than for the SDI treatment. The irrigation water productivity (IWP) was significantly higher in the SDI treatment than in the DI treatment. However, no significant differences between the two treatments were observed for nitrogen productivity. It can be concluded that the SDI system is a suitable strategy for irrigating almond crops, reducing consumptive water use and increasing IWP.

Design and Construction of a Small Scale Combined Weighing and Non-Weighing Lysimeter

A field experiment was conducted to study the consumptive use of water leaf (Talinum triangulare) on a constructed small scale combined weighing and non-weighing Lysimeter. This study considered the design and construction of a small scale lysimeter that combined the characteristics of a weighing and non-weighing. The main components of the lysimeter facility are mild steel, load cell, Arduino nano, micro secure digital (Micro SD) card, liquid crystal display (LCD) screen, real time clock (RTC) with model DS1307, moisture sensor, inner cylinder and outer cylinder. The installation depth of 0.4572 m with a known rectangular floor was constructed to house the outer cylinder height of 167.8 mm with a diameter 309.4 mm, inner cylinder height of 355.6 mm with a diameter 304.8 mm and a hole of 2 mm perforated at the bottom of the inner cylinder for easy drainage. The results on the data logged shows how much water is required for plant root extraction at various irrigation rates. The combined weighing and non-weighing lysimeter serve the purposes of determining the soil-water balance and water consumptive use of crops.

Changes to California Alfalfa Production and Perceptions during the 2011–2017 Drought

California experienced a severe multiyear drought stretching from 2011 through 2017, significantly reducing surface water supply for ecosystems, agriculture, and humans and prompting coordinated conservation efforts. Given that agriculture is the largest consumptive use of water in the state, one anticipated response to a severe drought would be to decrease production of low-value, high-water-use crops such as alfalfa. In this article we use a multimethod approach to examine both spatial distribution and public perceptions of alfalfa production in California over the course of the 2011 through 2017 drought. We find that although California alfalfa production did decline at the state level, it persisted and even increased in specific areas of the state. We also find that alfalfa persisted even though discourses and understandings that were critical of alfalfa production emerged in public forums during this time. We situate these findings within a broader context of California’s water management system, which meant that in practice, infrastructure and water rights allocation practices left many growers with little incentive to change growing practices, even in the face of serious meteorological drought.

Failure to achieve recommended environmental flows coincides with declining fish populations: Long‐term trends in regulated and unregulated rivers

Abstract Dams can be operated to mimic components of the natural flow regime to minimise impacts on downstream ecosystems. However, infrastructure, societal needs, water management, and catchment runoff constrain which and when flow regime attributes can be mimicked. We compared fish assemblage responses, including native and non‐native species, over 2 decades of managed environmental flows to those in a river retaining a relatively unaltered flow regime. Both of these arid‐land rivers are within the overallocated Colorado River basin and have experienced declines in catchment runoff over the past 20 years. We predicted that fish–flow relationships would be conserved across time and between managed and unmanaged rivers. Declines in flow in both rivers coincided with declines in some native fishes, and more native and non‐native fish species exhibited declines in the managed river than in the unmanaged river. Our ability to detect previously documented native fish–flow relationships diminished in the managed river system because established environmental flow targets were not met due to water management, but we detected these fish–flow relationships in the unmanaged river. Our results suggest declining catchment runoff and increased consumptive water use could reduce the effectiveness of environmental flows that have lower priority in most years.

A Review on Evapotranspiration Estimation in Agricultural Water Management: Past, Present, and Future

Evapotranspiration (ET) is a major component of the water cycle and agricultural water balance. Estimation of water consumption over agricultural areas is important for agricultural water resources planning, management, and regulation. It leads to the establishment of a sustainable water balance, mitigates the impacts of water scarcity, as well as prevents the overusing and wasting of precious water resources. As evapotranspiration is a major consumptive use of irrigation water and rainwater on agricultural lands, improvements of water use efficiency and sustainable water management in agriculture must be based on the accurate estimation of ET. Applications of precision and digital agricultural technologies, the integration of advanced techniques including remote sensing and satellite technology, and usage of machine learning algorithms will be an advantage to enhance the accuracy of the ET estimation in agricultural water management. This paper reviews and summarizes the technical development of the available methodologies and explores the advanced techniques in the estimation of ET in agricultural water management and highlights the potential improvements to enhance the accuracy of the ET estimation to achieve precise agricultural water management.

Consumption, Extraction, Recharge and Availability of Water in the Main Subsectors of the Mexican Manufacturing Industry, Regional Levels

If the consumptive use of water in agriculture, domestic, thermoelectric plants and service enterprices does not decrease, will the water be available for consumption in the manufacturing industries? There is no certainty of the availability of this resource in the medium or long term. Aquifer recharge depends on temperature-precipitation cycles and desalination processes, where appropriate. Using gray forecast models, linear and non-linear regression, the main sustainability indicators were calculated considering the subsectors that most demand water, to obtain a medium-term vision, applying scenarios to 2030 of status of resource at the national level, (administrative) water region and federative entity, as well as, by surface or underground source. Pollutant aspects or water quality were not considered. The results show the urgent decision-making to ensure the availability of water.

Searching for Sustainable-Irrigation Issues of Clementine Orchards in the Syrian Akkar Plain: Effects of Irrigation Method and Canopy Size on Crop Coefficients, Transpiration, and Water Use with SIMDualKc Model

Citrus is one of the most valuable crops in Syria, with the largest production areas in the Tartus and Latakia provinces. Water-saving policies have been adopted to modernize the irrigation systems and increase water productivity. Following dedicated research, this study aimed to evaluate the water balance in clementine trees irrigated with diverse methods and schedules using the SIMDualKc software model. Two experiments are reported: one with 10–14 years old trees irrigated with different methods (2007−2011) and the other with the same trees but now 18−20 years old, irrigated with different schedules (2015−2019). The SIMDualKc model successfully simulated the soil water contents measured in the various field plots, with root mean square error values lower than 0.004 m3 m−3 and modeling efficiencies up to 0.83. The model-calibrated standard basal crop coefficients (Kcb) were approximately constant throughout all growing stages, assuming values of 0.54−0.55 for the mature trees having smaller height (h) and fraction of ground cover (fc), and 0.64 for older trees with larger canopies, i.e., larger h and fc. With drip irrigation, single Kc had a higher value (1.14) at the end, non-growing, and initial stages, and a lower value (0.75–0.76) during mid-season (Kc mid), because precipitation was lesser then, contributing less to soil evaporation. On the other hand, Kc values were nearly constant with micro-sprinkler and surface irrigation techniques because the ground was fully wetted. The Kcb values derived from the fraction of ground cover and height (A&P approach) were similar to those obtained from the model, thus showing that the A&P approach represents a practical alternative to estimate Kcb in the practice of irrigation management. The soil water balance further revealed a large weight of the terms corresponding to the non-beneficial water consumption and non-consumptive water use when the fraction wetted was large and the application efficiencies were low. These terms were reduced, namely, evaporation losses when drip irrigation was used. This study, thus, provides a valuable tool for improving the irrigation management, water saving, and water productivity of Syrian citrus production systems.

Magnetized Water and Proline to Boost the Growth, Productivity and Fruit Quality of ‘Taifi’ Pomegranate Subjected to Deficit Irrigation in Saline Clay Soils of Semi-Arid Egypt

Water scarcity is becoming a global problem. The shift from traditional irrigation systems to deficit irrigation increased soil salinity, particularly in clay soils. The use of magnetized water (MW) and biostimulants can induce plant resistance to drought and salinity stress. To assess the role of MW and proline (P) on ‘Taifi’ pomegranate shrubs’ growth, productivity, and fruit quality under such conditions, a split-plots experiment was conducted for two seasons using three irrigation levels (100%, 75%, and 50%), based on the crop water requirements (CWR), and four treatments including foliar spray of tap water (control) and P, irrigation with MW, and MW + P. The most pronounced effect was referred to MW + P at 75% CWR that improved shrubs’ chlorophyll content and nutritional status, reduced endogenous proline content, and enhanced vegetative growth with minimum consumptive water use (CWU), optimum water use efficiency (WUE), maximum water productivity (WP), utmost yield and average fruit weight, lowest percentage of fruit cracking, and fairly good total soluble solids (TSS), vitamin C and anthocyanin contents. Overall, MW + P at 75% CWR improved the resistance mechanism of pomegranate shrubs in saline clay soils, plus improving the growers’ net profit. MW generally reduced soil salinity, expressed as reduced pH, EC, Na+, and Ca2+ values.