Increasing Irrigation Efficiency Research Articles

Contrasting effects of increasing irrigation efficiency on hydrological drought based on hydrological scenario simulations

Over-exploitation of water resources leads to water scarcity and aggravation of hydrological drought. An approach to addressing the problem is to invest in increasing irrigation efficiency (IE). However, higher IE may lead to the paradox of IE, that is, after increasing IE, irrigation water consumption (IWC) could increase rather than decrease. An important cause of the paradox of IE is that increasing IE may lead to an increase in irrigation area (IA). Therefore, an improved understanding of the impacts of such practices on hydrological drought is needed. This study used the PCR-GLOBWB 2.0 model to investigate the effects of increasing IE on hydrological drought for the catchment above Bengbu in the Huaihe River Basin in central eastern China. The hydrological drought was simulated under three scenarios, i.e., a baseline scenario in which IE remains unchanged, an IE increases scenario, and an IE & IA increase scenario. The results show that increasing IE has two contrasting effects: aggravation and alleviation of hydrological drought. For instance, the increase in IE (from 0.562 to 0.601 in Henan, 0.482 to 0.544 in Anhui, and 0.464 to 0.522 in Hubei province) from 2009 to 2019 reduced standardized drought streamflow deficit (SDSD) by about 5 ∼ 60 % in the central parts of the study area, whereas in the northern edge of the study area, it intensified SDSD even by more than 80 %. When water availability (WA) is high and can meet most of the crop water demand, increasing IE will lead to a situation in which the increase of IWC is less than the decrease of irrigation water withdrawal (IWW). In this situation, increasing IE alleviates the hydrological drought as intended. However, when water resources are relatively scarce with limited WA and cannot meet most of the crop water demand, increasing IE could lead to a paradoxical situation where the increase of IWC is higher than the decrease of IWW and thereby aggravates the hydrological drought. Also, increasing IE can aggravate the hydrological drought in water-receiving areas by reducing water supply from outside water supply regions. Results show that the impact of increasing IE and IA on hydrological drought is also two-sided, but the aggravating effect is dominant because the increase in IA leads to a significant increase in IWW and IWC. However, when the irrigation system restricts the increase of IA (the IA cannot increase or only slightly), the intensification effect of increasing IE and IA on hydrological drought will be weakened, and may even alleviate the hydrological drought. These results underline the importance of considering consequences at both local and basin scales, particularly for periods during and following drought, when policy makers consider the promotion of water-saving measures at irrigation-system level.

Assessing Irrigation Efficiency Improvements in Paddy Fields Using Granular SWMM Simulations

As water scarcity intensifies due to climate change, improving the efficiency of agricultural water use has become increasingly critical. Current irrigation systems often experience significant water losses, especially in paddy fields in South Korea that largely rely on open-channel water supply networks. However, previous studies have simulated irrigation improvement strategies by aggregating multiple paddy fields into larger unites rather than modeling them individually, which limits the accurate representation of field conditions. To address this limitation, we applied a granular simulation approach, collecting detailed input data through field surveys. Using this granular model, the study evaluated strategies to enhance irrigation efficiency in paddy fields serviced by the Baekma Agricultural Reservoir in South Korea. We assessed four scenarios: the current open-channel system, conversion of open channels to closed conduits, installation of farm ponds, and a combination of closed conduits and farm ponds. These scenarios were simulated using the Strom Water Management Model (SWMM), meticulously configured to represent individual paddy fields and channel networks. The results show that converting open channels to closed conduits increased irrigation efficiency by 5.4% compared to the current open-channel system. Combining closed conduits with farm ponds achieved the highest efficiency, although the independent effect of farm ponds was minimal. These findings suggested that converting open-channels to closed conduits was a highly effective solution for reducing water losses, while farm ponds played a limited role. This study provides valuable insights into the development of precise irrigation strategies, offering a detailed assessment of real-world conditions in paddy fields.

Can Agricultural Managed Aquifer Recharge (Ag‐MAR) Recover Return Flows Under Prior Appropriation in a Warming Climate?

AbstractGroundwater return flow to streams is important for maintaining aquatic habitat and providing water to downstream users, particularly in irrigated watersheds experiencing water scarcity. However, in many agricultural regions, increased irrigation efficiency has reduced return flows and their subsequent in‐stream benefits. Agricultural managed aquifer recharge (Ag‐MAR)—where artificial recharge is conducted via irrigation canals and agricultural fields—may be a tool to recover these return flows, but implementation is challenged by water supply and water management. Using climate‐driven streamflow simulations, an integrated operations‐hydrology model, and a regional groundwater model, we investigated the potential for Ag‐MAR to recover return flows in the Henrys Fork Snake River, Idaho (USA). We simulated potential Ag‐MAR operations for water years 2023–2052, accounting for both future water supply conditions and local water management rules. We determined that Ag‐MAR operations reduced springtime peak flow at the watershed outlet by 10%–14% after accounting for return flows. Recharge contribution to streamflow peaked in July and November, increasing July–August streamflow by 6%–14% and November–March streamflow by 9%–14%. Furthermore, sites where Ag‐MAR was conducted incidental to flood irrigation had more water available for recharge, compared to sites requiring recharge rights, which are junior in priority to agricultural rights. Mean annual recharge volume for the incidental recharge sites averaged 12% of annual natural streamflow, ranged from 269 to 335 Mm3, and was largely available in April and October. We demonstrate Ag‐MAR can effectively recover groundwater return flows when applied as flood irrigation on agricultural land with senior‐priority water rights.

Adaptation measures to global change in the Serpis River Basin (Spain): An evaluation considering agricultural benefits, environmental flows, and invasive fishes

Damming and flow regulation ensure water availability during dearth periods, but they cause impacts on inhabiting biota and facilitate the establishment of Invasive Alien Species (IAS). Setting environmental flows (e-flows) has proven fundamental to ensure good ecological status of rivers, battle IAS, and sustain ecosystem services. However, ongoing climate change is further straining water resources availability and the fulfilment of e-flows in Spain, which has compelled River Basin Management Plans (RBMPs) to include specific adaptation measures. In this study, we assessed adaptation strategies addressing land use and climate change in the Serpis River (Eastern Spain), based on increasing irrigation efficiency (i.e. moving from gravity to drip irrigation). The evaluation considered two CMIP6 climate change scenarios (Shared Socioeconomic Pathways SSP1-2.6 and SSP5-8.5) for two time horizons (short term 2015–2040 and mid-term 2041–2070), together with three land use change scenarios (changes in irrigated areas and technologies). Future estimations included reservoir flow releases, e-flows fulfilment, agricultural benefits, and changes in the suitable habitat and potential competition for two native (Eastern Iberian chub Squalius valentinus and European eel Anguilla anguilla) and two invasive (common bleak Alburnus alburnus and pumpkinseed Lepomis gibbosus) fish species. Predictions indicated a decrease in the suitable habitat for eel and Eastern Iberian chub, but the established e-flows will be ensured. Although the maximum benefits will rarely be achieved, on average the modernisation expected in the RBMP would sustain agricultural incomes in the optimistic scenario (SSP1-2.6) and for the short term of the pessimistic scenario (SSP5-8.5), showing similar effects than the ongoing redistribution of agricultural plots. Habitat and competition with invasive species will experience little changes due to the strong flow regulation, although the invasive bleak would prevail in the mid-term of the most pessimistic scenario. These results highlight the necessity of proactive adaptation measures beyond those described in the RBMPs (e.g. forest management or crop substitution) to increase water availability and sustain agricultural benefits, in particular for the most pessimistic scenario. They also underscore the difficulties to counteract invasive species through streamflow management under water scarcity scenarios.

Adapting Water Resources Management to Climate Change in Water-Stressed River Basins—Júcar River Basin Case

Water scarcity will increase due to climate change, especially in basins that are currently highly stressed. The Mediterranean area is one of the most vulnerable areas in the world, with a predicted natural water resource reduction of 20% to 35% at the end of the century, due to temperature increases and a 10–20% precipitation reduction. Water scarcity indices, including gross abstraction, net abstraction, and consideration of environmental requirements, can be efficiently used to analyse the effects of climate change in water resource systems and determine the main measures to adapt these systems to climate change. Increasing the reclaimed water use, seawater desalination, irrigation efficiency, and interconnecting water resource systems are the main measures to adapt basins under water stress and reduce their vulnerability to climate change. In the Júcar River Basin District (JRBD), with a 20% reduction in natural water resources, the main measures are: increasing the reclaimed water use in agriculture from 20% to 50% (91 hm3/year to 230 hm3/year), increasing seawater desalination from 30 to 55 hm3/year, increasing irrigation efficiency from 54% to 80%, and finally, fully developing the current water interconnections between water resource systems. In highly stressed basins, moving water from downstream to upstream using energy supplied by photovoltaic systems can help adapt river basins to climate change.

Developing climate change adaptation pathways in the agricultural sector based on robust decision-making approach (case study: Sefidroud Irrigation Network, Iran).

Allocation of water in the situation of climate change presents various uncertainties. Consequently, decisions must be made to ensure stability and functionality across different climatic scenarios. This study aims to examine the effectiveness of adaptation strategies in the agricultural sector, including a 5% increase in irrigation efficiency (S1) and a shift in irrigation method to Dry-DSR (direct seeded rice) under conditions of climatic uncertainty using a decision-making approach. The study focuses on the basin downstream of the Sefidroud dam, encompassing the Sefidroud irrigation and drainage network. Initially, basin modeling was conducted using the WEAP integrated management software for the period 2006-2020. Subsequently, the impact of climate change was assessed, considering RCP2.6, RCP4.5, and RCP8.5 emission scenarios on surface water resources from 2021 to 2050. Runoff and cultivated area, both subject to uncertainty, were identified as key parameters. To evaluate strategy performance under different uncertainties and determine the efficacy of each strategy, regret and satisfaction approaches were employed. Results indicate a projected decrease in future rainfall by 3.5-11.8% compared to the base period, accompanied by an increase in maximum and minimum temperatures (0.83-1.62 °C and 1.15-1.33 °C, respectively). Inflow to the Sefidroud dam is expected to decrease by 13-28%. Presently, the Sefidroud irrigation and drainage network faces an annual deficit of 505.4 MCM, and if current trends persist with the impact of climate change, this shortfall may increase to 932.7 MCM annually. Furthermore, satisfaction indices for strategy (S2) are 0.77 in an optimistic scenario and 0.70 in strategy (S1). In a pessimistic scenario, these indices are 0.67 and 0.56, respectively. Notably, changing the irrigation method with Dry-DSR is recommended as a robust strategy, demonstrating the ability to maintain basin stability under a broad range of uncertainties and climate change scenarios. It is crucial to note that the results solely highlight the effects of climate change on water sources entering the Sefidroud dam. Considering anthropogenic activities upstream of the Sefidroud basin, water resource shortages are expected to increase. Therefore, reallocating water resources and implementing practical and appropriate measures in this area are imperative.

Analyzing hydrological alteration and environmental flows in a highly anthropized agricultural river basin system using SWAT+, WEAP and IAHRIS

Study regionZarineh River Basin, a significant contributor to Urmia Lake inflow, Iran. Study focusEmploying SWAT+, WEAP, and IAHRIS, we assess environmental flow impacts on the Zarineh River Basin through two key aspects. Firstly, we evaluate the dam-induced alteration of the hydrological regime. Secondly, we explore future implications by prioritizing water allocation for environmental flows. Our approach involves developing, calibrating, and validating a SWAT+ hydrological model, analyzing hydrological alteration indicators using IAHRIS, and calculating environmental flows using the basic flow method in the SWAT+ post-processing tool. Using the WEAP water allocation model, three scenarios are assessed: 1) status quo, prioritizing drinking water and industry over agriculture; 2) environmental flows, prioritizing regulation compliance; 3) improved irrigation efficiency, facilitating a 10% increase while maintaining environmental flow prioritization.New hydrological insights for the region: The study reveals the altered flow regime’s failure to capture seasonal variations during dry years, particularly in winter and spring. Environmental and agricultural water demands compete, posing challenges to water management in the basin. Prioritizing environmental requirements increases reliability by 56% for environmental flows but decreases it by 11% for agriculture. Balancing environmental flows and agricultural water demands is crucial. A third scenario considers increased irrigation efficiency, requiring both decreased water allocation and enhanced efficiency. This research offers policymakers insights into formulating balanced environmental flow strategies, considering water demand reliability and basin hydrology.

Water resources management scenarios and transboundary hydro-political concerns in Iran’s eastern border areas

Motives: Since the main sources of some rivers are located in neighbouring countries, hydrological issues in the eastern part of Iran are critical. The water dispute between Iran and the neighbouring Afghanistan is related to environmental issues and human health.Aim: The aim of this study was to demonstrate how transboundary water conflicts increase human vulnerability through economic issues such as reduced productivity in the agricultural sector.Results: The study’s originality lies in the application of the positive mathematical programming approach to the agricultural sector, specifically in evaluating the impact of water pricing policies on crop selection and irrigation water use. A quadratic cost function was calibrated to develop three scenarios of water resources consumption (30%, 40%, and 70% reduction for farmers in group 1, and 10%, 25%, and 75% reduction for farmers in group 2) and price increase (70%, 80%, and 100% increase). The calibration of the quadratic cost function revealed an increase in irrigation efficiency (water resources consumption) as well as an increase in the region’s irrigated area.

Are we saving water? Simple methods for assessing the effectiveness of groundwater conservation measures

Substantial storage reductions by irrigation pumping in many of the world’s major aquifers jeopardize future food production. As a result, new conservation measures are being utilized to reduce pumping and extend aquifer lifespans. The key question is how effective are these practices in attaining true water conservation (i.e., water use reduction) for a given area? Relationships between pumping and precipitation help provide an answer, as precipitation explains most of the variation in annual irrigation water use for aquifers in semi-arid to sub-humid climates when surface water supplies are limited. Our objective is to utilize correlations between radar precipitation and irrigation groundwater use at a range of spatial scales to assess the effectiveness of conservation approaches in the High Plains aquifer in the central USA. Linear regressions between pumping and precipitation for a conservation area established in 2013 in northwest Kansas indicate that water use and water use per irrigated area were over 27 % less and 25 % less, respectively, during 2013–2021 compared to the same climatic conditions during 2005–2012. Similar regressions found over a 38 % reduction and 23 % reduction in irrigation water use and use per irrigated area, respectively, during 2018–2021 compared to the same conditions during 2005–2017 in a west-central Kansas county with conservation areas. A decrease in irrigated area accounted for most of the difference between these reductions. Higher R2 values after conservation area establishment imply that irrigation tracks precipitation better due to use of soil moisture sensors and other measures as part of increased irrigation efficiency and enhanced water management. The precipitation and water use relationships, which are statistically significant for a wide range of spatial scales, have great potential for assessing the effectiveness of conservation practices in areas with high-quality water use and precipitation data.

Effects of regulated, precision and continuous deficit irrigation on the growth and productivity of a young super high-density olive orchard

Water is the main limiting factor for olive cultivation in rainfed conditions. In irrigated orchards, water availability is scarce mainly during drought periods. Thus, increasing irrigation efficiency is a key issue to improve water management, especially in semiarid conditions. The objective of this study was to assess different irrigation strategies on tree growth and production components during three years in a young super high-density olive orchard (Arbequina cv.) located in northeast Spain. Four deficit irrigation strategies were compared to a control strategy based on replenishing crop evapotranspiration. The four strategies were as follows: Continuous Deficit Irrigation (CDI), two Regulated Deficit Irrigation strategies (Moderate, MRDI, and Severe, SRDI), and a precision Irrigation strategy based on daily trunk growth (Precision). In the Precision strategy, olive oil production increased by 7% and the vegetative variables did not show significant reductions, resulting in an average yearly water savings of 31% compared to the control strategy. The Regulated Deficit Irrigation strategies also produced promising results based on the high average yearly water-saving rates of 19% and 29%. However, the SRDI strategy exhibited significant reductions in tree height, lateral branches growth, olive yield, and oil yield compared to the control. On the other hand, the MRDI strategy did not differ significantly in oil yield, tree height, and lateral branches growth compared to the control or Precision strategies. Similarly, the CDI strategy resulted in significantly lower tree height, lateral branches growth, and production compared to the control. Although the observed reduced growth in both SRDI and CDI strategies presents an interesting opportunity for managing excessive vigor in super high-density olive orchards, it is important to consider that this approach may compromise production in successive seasons.

An assessment of water management measures for climate change adaptation of agriculture in Seewinkel

To develop appropriate climate change adaptation plans, evidence of the effectiveness of adaptation measures is required. At a regional scale, however, this information is usually lacking. The region of Seewinkel in Austria was taken as a case study because of its extensive agricultural industry and its unique ecosystem of saline lakes. The goal of the study was to provide stakeholders with evidence to support their climate change adaptation process. Adaptation measures discussed by local stakeholders were analyzed to determine their efficacy. A system dynamics (SD) based model was developed to serve as a tool for the water policy analysis and to be used in place of advanced hydrological models. The model was calibrated using observational data and forced with bias-adjusted EURO-CORDEX climate data for three representative concentration pathways (RCPs) (2010–2100). Three parameters in the model were changed to simulate adaptation measures. The results showed that combined measures, increasing irrigation efficiency and changing crops could reduce water demand by an average of 40 %, 23 % and 23 %, respectively, for all RCPs. The local aquifer's level could be increased above the historical average by an average of 0.43 m by combined measures, 0.20 m by increasing irrigation efficiency, 0.20 m by changing crops and 0.06 m by artificially recharging the aquifer.

Assessment of Present and Future Water Security under Anthropogenic and Climate Changes Using WEAP Model in the Vilcanota-Urubamba Catchment, Cusco, Perú

Water is an essential resource for social and economic development. The availability of this resource is constantly threatened by the rapid increase in its demand. This research assesses current (2010–2016), short- (2017–2040), middle- (2041–2070), and long-term (2071–2099) levels of water security considering socio-economic and climate change scenarios using the Water Evaluation and Planning System (WEAP) in Vilcanota-Urubamba (VUB) catchment. The streamflow data of the Pisac hydrometric station were used to calibrate (1987–2006) and validate (2007–2016) the WEAP Model applied to the VUB region. The Nash Sutcliffe efficiency values were 0.60 and 0.84 for calibration and validation, respectively. Different scenarios were generated for socio-economic factors (population growth and increased irrigation efficiency) and the impact of climate change to evaluate their effect on the current water supply system. The results reveal that water availability is much higher than the current demand in the VUB for the period (2010–2016). For short-, middle- and long term, two scenarios were considered, “Scenario 1” (RCP 4.5) and “Scenario 2” (RCP 8.5). Climate change scenarios show that water availability will increase. However, this increase will not cover the future demands in all the sub-basins because water availability is not evenly distributed in all of the VUB. In both scenarios, an unmet demand was detected from 2050. For the period 2071–2099, an unmet demand of 477 hm3/year for “Scenario 1” and 446 hm3/year for “Scenario 2” were estimated. Because population and agricultural demands are the highest, the effects of reducing the growth rate and improving the irrigation structure were simulated. Therefore, two more scenarios were generated “Scenario 3” (RCP 4.5 with management) and “Scenario 4” (RCP 8.5 with management). This socio-economic management proved to be effective in reducing the unmet demand up to 50% in all sub-basins for the period 2071–2099.

The Crop Coefficient of Ginger (Zingiber officinale var. rubrum) during Vegetative Growth in Eastern Indonesia

Abstract Ginger (Zingiber officinale var. rubrum) is a rhizome plant that can benefit health, fitness and be used as a spice. The content contained in ginger can prevent and treat various diseases and act as an antioxidant and anti-inflammatory agent. The cultivation of ginger plants requires adequate nutrients and water for development and growth. Crop water requirements are influenced by crop coefficients which vary according to the plant growth stage. The crop coefficient values are needed for irrigation management and increasing irrigation efficiency. The main objective of the current study was to investigate the crop coefficient value of ginger by lysimeter. Lysimeter is a water balance device with the principle of mass conservation, where the input is rainfall and irrigation while the output is percolation and evapotranspiration. The rainfall during the investigated period was 0–62.82 mm·day−1, humidity 70.7–89.4%, and air temperature 23.7–32.9 °C. The crop coefficient of ginger increased during the vegetative growth period, i.e., 0.997 in the seedling stage, 1.072 in the tiller stage, and 1.138 in the advanced vegetative stage. The crop coefficient of red ginger was determined using a lysimeter quite accurately, with a coefficient of determination value (R 2) 0.950 and a significant value of F less than 0.05.

Efficient irrigation and water conservation: Evidence from South India

Widespread adoption of efficient irrigation technologies, including drip irrigation, has been proposed to limit groundwater over-exploitation, especially in water-stressed South Asia. This paper evaluates the potential productivity and water-saving benefits of smallholder drip irrigation by conducting a randomized control trial in Andhra Pradesh, India. A group of well-owners was offered a subsidy to adopt drip irrigation, while a comparable group acted as controls. After three years, the drip group shifted more into horticultural crops, enjoyed higher farm profit, and transferred (primarily through cash sales) more of its groundwater to adjacent plots. There is no difference in groundwater pumping, which is constrained by electricity rationing in this setting. The evidence thus suggests that drip adoption in South India, while increasing irrigation efficiency, will not save groundwater.

Determinants of farmers' choice to use irrigation systems: The case of northern Ethiopia

AbstractClimate change is thought to be having a negative impact on Africa's agricultural industry. Smallholder farmers who depend heavily on agriculture are more severely affected by climate change. Droughts and the depletion of water resources are two examples of how climate change affects production. Therefore, it is necessary to take steps to reduce the negative effects of climate change in Ethiopia on smallholder farmers in particular and agriculture in general. Therefore, the purpose of this analysis was to identify the factors that affect the increase in irrigation efficiency among farmers in northern Ethiopia. A total of 194 farmers were picked at random and questioned using semi‐structured questionnaires. Out of the 18 explanatory variables hypothesized to analyse the preference of farmers for using irrigation in the study area, only 13 were considered important. Of these 13 significant explanatory variables, 4 including health status, labour force members, availability of labour and perception of the advantage of using agricultural inputs were statistically significant with farmers' choice of irrigation.

Increasing Irrigation Efficiency through Maintenance of Irrigation Network Based on Dynamic Simulation

Given the increasing demand for water, it is necessary to make an effort to anticipate water scarcity through increasing efficiency in an irrigation area. Increasing efficiency requires an increase in the contribution of farmers to finance the repair of irrigation canals. The purpose of this study is to formulate a financing scheme for maintenance of irrigation networks by the state and farmer participation (contribution). Research was conducted at the Cihea Irrigation Area (Cianjur Regency). The method used is system dynamics modeling by observing the parameters studied, including; asset damage, productivity, farmer contributions, public works budget and irrigation efficiency. The results of the analysis with dynamic simulations show that the best scenario to reduce damage to Cihea Irrigation assets is scenario 2 because it reduces the damage by 10.29% and increases the irrigation maintenance index by 0.05 within 10 years. Thus, it is necessary suggest to the government and farmers to increase the contribution and budget for the improvement of the Cihea Irrigation. Keywords: Asset Damage, Efficiency, Farmer's Contribution, Government Budget, Maintenance

Global Assessment of Groundwater Stress Vis-à-Vis Sustainability of Irrigated Food Production

Due to poor water resources management, groundwater-dependent agriculture induces substantial stress on several aquifer systems worldwide, which poses a serious threat to water and food security. However, only a few studies have addressed this vital issue. This study aimed to evaluate stress on aquifers due to the overuse of groundwater for food production and explore pathways for stress reduction via improved irrigation efficiency and productivity. Groundwater stress was characterized using the ratio of water use to availability, with consideration for environmental flows. The results indicated that out of 107 countries—dependent on groundwater irrigation, about half are overexploiting groundwater, while one-fifth of these countries are extracting moderately-to heavily. Over 90% of the non-renewable groundwater abstraction occurs in 7 countries. Further, about 450 million tonnes (Mt) of global annual food production is from non-renewable groundwater exploitation. If the existing irrigation efficiency is increased to 90%, current groundwater stress would be reduced by 40%. Additionally, in unstressed regions, it would be possible to produce additional 300 Mt of food by using saved water while maintaining groundwater stress at acceptable levels. Moreover, improved water productivity in conjunction with increased irrigation efficiency could reduce the current level of unsustainable food production by 47%. These results provide important insights into the dynamics of irrigation stress on groundwater systems, and the role of managerial interventions.

The three-infrastructures framework and water risks in the Murray-Darling Basin, Australia

ABSTRACT Using a three-infrastructures (grey, soft, and green) framework, we examined key risks to water availability and quality in the Murray-Darling Basin, Australia. These risks include increased irrigation efficiency, without a quantitative knowledge of the impact on water flow pathways, particularly return flows, growth in farm dams and floodplain harvesting, and unsustainable management of salinity. Critical to mitigating these risks are the metering, monitoring, and auditing of water flows, effective linkages between evidence and analysis, and accountability of decision-makers operating in the public interest. We contend that these approaches need to be supported by innovative risk assessments, which are fit-for-purpose under the MDB Plan, wherein the ‘who, what, when and where’ are assessed in relation to cumulative, systemic, and cascading risks from human actions.

Global expansion of sustainable irrigation limited by water storage

Providing affordable and nutritious food to a growing and increasingly affluent global population requires multifaceted approaches to target supply and demand aspects. On the supply side, expanding irrigation is key to increase future food production, yet associated needs for storing water and implications of providing that water storage, remain unknown. Here, we quantify biophysical potentials for storage-fed sustainable irrigation-irrigation that neither depletes freshwater resources nor expands croplands but requires water to be stored before use-and study implications for food security and infrastructure. We find that water storage is crucial for future food systems because 460 km3/yr of sustainable blue water, enough to grow food for 1.15 billion people, can only be used for irrigation after storage. Even if all identified future dams were to contribute water to irrigation, water stored in dammed reservoirs could only supply 209 ± 50 km3/yr to irrigation and grow food for 631 ± 145 million people. In the face of this gap and the major socioecologic externalities from future dams, our results highlight limits of gray infrastructure for future irrigation and urge to increase irrigation efficiency, change to less water-intensive cropping systems, and deploy alternative storage solutions at scale.

Wetting front of soil infiltration test by real-time sensing in prototype system real-time wetting front in soil infiltration tests

Agriculture is the most water-demanding economic activity. Nevertheless, the monitoring of agricultural production systems can improve the soil water condition and contribute to soil conservation, as well as increase irrigation efficiency through quick and assertive decision-making. Thus, the objective of this work was to carry out a real-time evaluation of the wetting front (WF), the water infiltration rate in the soil, and to verify whether the system performance can affect infiltration test data in a Red Latosol with clayey and very clayey textures. The public domain prototype system consisted of a permeameter, and 10 soil moisture sensors that were calibrated by the oven drying method and inserted into a PVC pipe from 10 cm to 100 cm depth. The equipment allowed the evaluation of the wetting front and calculation of the infiltration rate and water retention and variations along the soil profile. Data were analyzed using descriptive statistics using RStudio and Excel. The results showed that the prototype system is effective to simulate the water infiltration rate in the two soil textures analyzed at low cost.