Combined effects of border irrigation and super-absorbent polymers on enzyme activity and microbial diversity of poplar rhizosphere soil.

Fast-growing poplar plantations are considered a great benefit to timber production, but water availability is a key factor limiting their growth and development, especially in arid and semi-arid ecosystems. Super-absorbent polymers facilitate more water retention in soil after rain or irrigation, and they are able to release water gradually during plant growth. This study aimed to examine the effects of reduced irrigation (60% and 30% of conventional border irrigation) co-applied with super-absorbent polymers (0, 40 kg/ha) on root exudates, enzyme activities, microbial functional diversity in rhizosphere soil, and volume increments in poplar (Populus euramericana cv. 'Neva'). The results showed that 60% border irrigation co-applied with super-absorbent polymers significantly increased the content of organic acids, amino acids and total sugars in the root exudates, and the activities of invertase, urease, dehydrogenase, and catalase in the rhizosphere soil in comparison to conventional border irrigation without super-absorbent polymers. Meanwhile, this treatment also enhanced the average well-color development, Shannon index, and McIntosh index, but decreased the Simpson index. Additionally, the average volume growth rate and relative water content of leaves reached their maximum using 60% irrigation with super-absorbent polymers, which was significantly higher than other treatments. However, using 30% irrigation with super-absorbent polymers, had a smaller effect on rhizosphere soil and volume growth than 60% irrigation with super-absorbent polymers. Therefore, using an appropriate water-saving irrigation measure (60% conventional border irrigation with super-absorbent polymers) can help to improve enzyme activities and microbial diversity in the rhizosphere soil while promoting the growth of poplar trees.

Efficiency dynamics among onion growers in Maharashtra: a comparative analysis of drip irrigation adopters and non-adopters.

BACKGROUND: Onions are economically and nutritionally important vegetable crops. Despite advances in technology and acreage, Indian onion growers face challenges in realizing their full productivity potential. This study examines the technical efficiency of onion growers, the factors influencing it, and the constraints faced by those adopting drip irrigation in the Ghod river basin of western Maharashtra. A sample of 480 farmers including those practicing drip irrigation and those not practicing it, was selected from Junnar, Shirur, Parner, and Shrigonda blocks of the basin. The primary data was collected through semi-structured interviews. Analytical tools such as the Cobb-Douglas production function (represents technological relationship between multiple inputs and the resulting output), a single-stage stochastic frontier model, the Tobit model, and descriptive statistics were used to assess the technical efficiency of onion production at the farm level. RESULTS: According to the maximum likelihood estimates of the stochastic frontier analysis, drip adopters exhibited a mean technical efficiency of 92%, while for non-adopters it was 65%. It indicates that the use of drip irrigation technology is associated with higher technical efficiency. The association of technical efficiency and socio-economic characters of households showed that education, extension contacts, social participation, and use of information sources had a positive influence on technical efficiency, while family size had a negative influence on the drip irrigation adopters. For non-drip adopters, significant positive effects were observed for landholding, extension contact, and information source use. The major constraints faced by drip system adopters included a lack of knowledge about the proper operating techniques for drip systems and the cost of maintenance. CONCLUSION: The differences with inputs associated with two irrigation methods showed that the response of inputs to increase onion yield is greater for farmers who use drip irrigation than for farmers who do not, and are a result of the large differences in the technical efficiencies. These inefficiencies and other limitations following the introduction of drip irrigation, such as lack of knowledge about the proper operations, need to be addressed through tailored training for farmers and further interventions.

Modelling the impact of different irrigation regimes and mulching on strawberry crop growth and water use in the arsenic-contaminated Bengal basin.

Replacement of water-intensive winter rice with strawberry (Fragaria × ananassa Duch.) may restrict groundwater extraction and improve water productivity and sustainability of agricultural production in the arsenic-contaminated Bengal basin. The potential of strawberry cultivation in terms of yield obtained and water use efficiency need to be evaluated under predominant soil types with mulch applications. Water-driven model AquaCrop was used to predict the canopy cover, soil water storage and above-ground biomass of strawberry in an arsenic-contaminated area in the Bengal basin. After successful calibration and validation over three seasons, AquaCrop was used over a range of management scenarios (nine drip-irrigation × three soil types × four mulch materials) to identify the best irrigation options for a drip-irrigated strawberry crop. The most appropriate irrigation of 176 mm for clay loam soil in lowland and 189 mm for sandy clay loam in medium land rice areas and the use of organic mulch from locally available jute agrotextile improved 1.4 times higher yield and 1.7 times higher water productivity than that of without mulch. Strawberry can be introduced as an alternative crop replacing rice in non-traditional upland and medium land areas of the arsenic-contaminated Bengal basin with 88% lower groundwater extraction load and better economic return to farmers.

Water reuse of treated domestic wastewater in agriculture: Effects on tomato plants, soil nutrient availability and microbial community structure.

The reuse of treated wastewater (TWW) in agriculture for crop irrigation is desirable. Crop responses to irrigation with TWW depend on the characteristics of TWW and on intrinsic and extrinsic soil properties. The aim of this study was to assess the response of tomato (Solanum lycopersicum L.) cultivated in five different soils to irrigation with TWW, compared to tap water (TAP) and an inorganic NPK solution (IFW). In addition, since soil microbiota play many important roles in plant growth, a metataxonomic analysis was performed to reveal the prokaryotic community structures of TAP, TWW and IFW treated soil, respectively. A 56-days pot experiment was carried out. Plant biometric parameters, and chemical, biochemical and microbiological properties of different soils were investigated. Shoot and root dry and fresh weights, as well as plant height, were the highest in plants irrigated with IFW followed by those irrigated with TWW, and finally with TAP water. Plant biometric parameters were positively affected by soil total organic carbon (TOC) and nitrogen (TN). Electrical conductivity was increased by TWW and IFW, being such an increase proportional to clay and TOC. Soil available P was not affected by TWW, whereas mineral N increased following their application. Total microbial biomass, as well as, main microbial groups were positively affected by TOC and TN, and increased according to the following order: IFW > TWW > TAP. However, the fungi-to-bacteria ratio was lowered in soil irrigated with TWW because of its adverse effect on fungi. The germicidal effect of sodium hypochlorite on soil microorganisms was affected by soil pH. Nutrients supplied by TWW are not sufficient to meet the whole nutrients requirement of tomato, thus integration by fertilization is required. Bacteria were more stimulated than fungi by TWW, thus leading to a lower fungi-to-bacteria ratio. Interestingly, IFW and TWW treatment led to an increased abundance of Proteobacteria and Acidobacteria phyla and Balneimonas, Rubrobacter, and Steroidobacter genera. This soil microbiota structure modulation paralleled a general decrement of fungi versus bacteria abundance ratio, the increment of electrical conductivity and nitrogen content of soil and an improvement of tomato growth. Finally, the potential adverse effect of TWW added with sodium chloride on soil microorganisms depends on soil pH.

Investigating foliar application of bulk and nanoparticles titanium dioxide on fennel productivity to mitigate the negative effects of saline irrigation water.

BACKGROUND: Fennel essential oils are fragrance compounds used in food and pharmaceutical sectors. One of the major impediments to expansion of fennel farming in Egypt's reclamation areas is saline water. Titanium dioxide (TiO2) or TiO2 nano particles (TiO2NP) can be utilized to boost the yield of aromatic plants cultivated under saline irrigation water. Saline water, particularly which contains sodium chloride can harm fennel plant; consequently, it was predicted that fennel production would fail in Egypt's reclaimed area, where the primary source of irrigation is groundwater consisting sodium chloride. This study sought to help fennel respond to sodium chloride by applying Ti forms to their leaves in order to reduce the detrimental effects of sodium chloride on them for expanding their production in the newly reclamation areas as a natural source of essential oil. Ti forms were applied as foliar application at 0, 0.1, 0.2 TiO2, 0.1 TiO2NP, and 0.2 TiO2NP, mM under irrigation with fresh water (0.4 dS m-1), or saline water (51.3 mM or 4.7 dS m-1). RESULTS: Plants exposed to 0.1 mM TiO2NP under fresh water resulted in the maximum values of morphological characters, estragole, oxygenated monoterpenes and photosynthetic pigments; while those subjected to 0.1 mM TiO2NP under saline water gave the greatest values of essential oil, proline, antioxidant enzymes and phenols. The greatest amounts of soluble sugars were recorded with 0.2 mM TiO2NP irrigated with saline water. Plants subjected to 0 mM TiO2 under saline water produced the greatest values of flavonoids, hydrogen peroxide and malondialdehyde. CONCLUSION: To mitigate the negative effects of salty irrigation water on fennel plant production, TiO2NP application is suggested as a potential strategy.

A comprehensive and molecular level evaluation of treated wastewater reusing via drip systems: Interactions of dissolved ions and hydraulic shear stresses on calcium carbonate scaling.

To overcome the global water shortage, the treated wastewater is increasingly utilized in agricultural irrigation, and thus reducing freshwater consumption and increasing the water sustainability. Drip irrigation technology is the most appropriate irrigation method to utilize these water sources. However, its operating performance is negatively affected by calcium carbonate (CaCO3) scaling, which is one of the most dominant precipitations and also closely related to dissolved ions and the hydraulic characteristics inside irrigation systems. Thus, the effects of eight common dissolved ions (K+, Mg2+, Mn2+, Zn2+, Fe3+, NO3-, SO42-, and PO43-) in these water sources and four hydraulic shear stresses (0, 0.2, 0.4, and 0.6 Pa) on CaCO3 scaling formation were assessed in this study. Results showed that CaCO3 scaling was primarily formed of calcite and aragonite. Fe3+ would significantly accelerate the CaCO3 scaling accumulation, as it reduced the unit cell volume and chemical bonds of calcite, enhancing calcite adhesion and stability. On the other hand, Mg2+, Mn2+, NO3-, SO42-, and PO43- significantly inhibited CaCO3 scaling. Among them, Mg2+, Mn2+, and PO43- followed the typical water chemical precipitation rule, while NO3- increased water molecule diffusion rate and thus decreased the possibility that Ca2+ and CO32- to precipitate. SO42- grabbed the binding point belonging to CO32- and was adsorbed on the calcite crystal, which inhibited crystal growth. However, those treatments under K+ and Zn2+ did not reach a significant level due to their solubleness. During the precipitation of CaCO3, there were significant (p < 0.01) interactions between dissolved ions and hydraulic shear stresses. When hydraulic shear stresses varied, the effects of Fe3+ and SO42- on the CaCO3 scaling were relatively weakened, while that of Mg2+ was relatively strengthened. In return, dissolved ions affected the effect of hydraulic shear stresses on CaCO3 scaling. Overall, the results obtained could provide theoretical reference for high-efficiency utilization of treated wastewater for agricultural irrigation through the management of CaCO3 scaling.

Effect of magnetized water irrigation on Cd subcellular allocation and chemical forms in leaves of Festuca arundinacea during phytoremediation.

The application of an external magnetic field has been shown to improve the Cd phytoremediation efficiency of F. arundinacea by leaf harvesting. However, the influencing mechanisms of the promoting effect have not yet been revealed. This study evaluated variations in the Cd subcellular allocation and fractions in various F. arundinacea leaves, with or without magnetized water irrigation. Over 50 % of the metal were sequestered within the cell wall in all tissues under all treatments, indicating that cell wall binding was a critical detoxification pathway for Cd. After magnetized water treatment, the metal stored in the cytoplasm of roots raised from 33.1 % to 45.3 %, and the quantity of soluble Cd in plant roots enhanced from 53.4 % to 59.0 %. The findings suggested that magnetized water mobilized Cd in the roots, and thus drove it into the leaves. In addition, the proportion of Cd in the organelles, and the concentration of ethanol-extracted Cd in emerging leaves, decreased by 13.0 % and 47.1 %, respectively, after magnetized water treatment. These results explained why an external field improved the phytoextraction effect of the plant through leaf harvesting.

Research progress in parameterizing irrigation and fertilization in land surface model.

Under the context of global climate change and growing population, irrigation and fertilization have become important ways to ensure food production, with consequences on water cycling, energy flow, and materials cycling in terrestrial ecosystems. In the land surface model (LSM), coupling irrigation and fertilization schemes are of great importance for clearly understanding the land-atmosphere interactions to ensure food security. We reviewed the expression methods of three key parameters, namely, the applied method, usage, and time in the parameterization process of irrigation and fertilization (nitrogen fertilizer) in LSM. We found that the ways to irrigate and ferti-lize in LSM are different from the ways used in actual practice due to the limitation of the high resolution of spatio-temporal data, which makes it difficult to understand the actual influences of irrigation and fertilization on grain yield, environment, and local climate. Finally, we proposed future works: 1) taking the differences of crop water demand into account and making the different irrigation thresholds for different crops to properly evaluate the total and intensity of water consumption of different crops; 2) using the field records and the regional grid data of fertilization and irrigation developed in recent years to develop parameterized schemes that are more in line with actual agricultural operations, which can accurately reveal their economic, ecological, and climatic effects; 3) developing fertilization diagnosis scheme considering crop type, phenological stage, and soil basic fertility as the supplementary scheme in LSM, to improve the applicability and simulation accuracy of LSM in the areas without nitrogen fertilizer data.

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.

Assessment of antibiotic-resistant infection risks associated with reclaimed wastewater irrigation in intensive tomato cultivation.

Agricultural irrigation using reclaimed urban wastewater (RWW) represents a sustainable practice to meet the ever-increasing water stress in modern societies. However, the occurrence of residual antibiotics and antibiotic resistant bacteria (ARB) in RWW is an important human health concern. This study applied for the first time a novel Simple-Death dose-response model to the field data of Escherichia coli and Pseudomonas spp. collected from three greenhouses for cultivation of tomatoes irrigated with RWW. The model estimates the risk of infection by enteropathogenic E. coli associated with consumption of tomatoes and the risk of eye-infection caused by Pseudomonas aeruginosa in cultivation soil through hand-to-eye contacts. The fraction of antibiotic resistant (AR)-E. coli measured in irrigation water and AR-Pseudomonas spp. in soil was incorporated in the model to estimate the survival of ARB and antibiotic susceptible bacteria in the presence of trace level of antibiotics in human body. The results showed that the risk of E. coli infection through consumption of tomatoes irrigated with RWW is within the WHO and USEPA recommended risk threshold (<10-4); Pseudomonas aeruginosa eye-infection risk is at or below the acceptable risk level. The presence of residual antibiotic in human body reduced the overall risk probabilities of infections but selectively enhanced the survival of ARB in comparison to their susceptible counterparts, which resulted in antibiotic untreatable infection. Therefore, the outcomes of this study call for a new risk threshold for antibiotic untreatable infections and highlight the key importance of adopting work safety measures for better human health protection.

Optimizing irrigation and nitrogen addition to balance grassland biomass production with greenhouse gas emissions: A mesocosm study.

Achieving a balance between greenhouse gas mitigation and biomass production in grasslands necessitates optimizing irrigation frequency and nitrogen addition, which significantly influence grassland productivity and soil nitrous oxide emissions, and consequently impact the ecosystem carbon dioxide exchange. This study aimed to elucidate these influences using a controlled mesocosm experiment where bermudagrass (Cynodon dactylon L.) was cultivated under varied irrigation frequencies (daily and every 6 days) with (100 kg ha-1) or without nitrogen addition; measurements of net ecosystem carbon dioxide exchange, ecosystem respiration, soil respiration, and nitrous oxide emissions across two cutting events were performed as well. The findings revealed a critical interaction between water-filled pore space, regulated by irrigation, and nitrogen availability, with the latter exerting a more substantial influence on aboveground biomass growth and ecosystem carbon dioxide exchange than water availability. Moreover, the total dry matter was significantly higher with nitrogen addition compared to without nitrogen addition, irrespective of the irrigation frequency. In contrast, soil nitrous oxide emissions were observed to be significantly higher with increased irrigation frequency and nitrogen addition. The effects of nitrogen addition on soil respiration components appeared to depend on water availability, with autotrophic respiration seeing a significant rise with nitrogen addition under limited irrigation (5.4 ± 0.6 µmol m-2 s-1). Interestingly, the lower irrigation frequency did not result in water stress, suggesting resilience in bermudagrass. These findings highlight the importance of considering interactions between irrigation and nitrogen addition to optimize water and nitrogen input in grasslands for a synergistic balance between grassland biomass production and greenhouse gas emission mitigation.

Effects of irrigation scheduling on the yield and irrigation water productivity of cucumber in coconut coir culture.

Optimum irrigation scheduling is important for ensuring high yield and water productivity in substrate-cultivated vegetables and is determined based on information such as substrate water content, meteorological parameters, and crop growth. The aim of this study was to determine a precise irrigation schedule for coconut coir culture in a solar greenhouse by comparing the irrigation, evapotranspiration (ET), substrate water content (VWC), as well as the crop growth indices and yield of cucumber, and irrigation water productivity (IWP) under three irrigation schedules: the soil moisture sensor-based method (T-VWC), the accumulated radiation combined with soil moisture sensor-based method (Rn-VWC), and the crop evapotranspiration estimated method using the hourly PM-ETo equation with an improved calculation of Kc (T-ETc). The results showed that the daily irrigation and evapotranspiration amount were the highest under T-VWC treatment, while the lowest under T-ETc treatment. In different meteorological environments, the change in irrigation amount was more consistent with the ET,and the VWC was relatively stable in T-ETc treatment compared with that under T-VWC or Rn-VWC treatments. The plant height, leaves number, leaf area, and stem diameter of T-VWC and Rn-VWC treatments were higher than those of the T-ETc treatments, but there was no significant difference in cucumber yield. Compared with the T-VWC treatment, total irrigation amount under Rn-VWC and T-ETc treatments significantly decreased by 25.75% and 34.04%, respectively ([Formula: see text]). The highest IWP values of 25.07 kg m[Formula: see text] was achieved from T-ETc treatment with significantly increasing by 44.33% compared to the T-VWC treatment (17.37 kg m[Formula: see text]). In summary, the T-ETc treatment allowed more reasonable irrigation management and was appropriate for growing cucumber in coconut coir culture.

Impacts of irrigation with treated livestock wastewater on the accumulation characteristic of ARGs in the farmland soil: a case study in Hohhot, China.

Irrigation with treated livestock wastewater (TWW) is a promising strategy for reusing resources. However, TWW irrigation might introduce antibiotic resistant genes (ARGs) into the soil, posing environmental risks associated with antibiotic resistance. This study focuses on investigating the influence of irrigation amounts and duration on the fate of ARGs and identifies key factors driving their changes. The results showed that there were 13 ARGs in TWW, while only 5 ARGs were detected in irrigated soil. That is some introduced ARGs from TWW could not persistently exist in the soil. After 1-year irrigation, an increase in irrigation amount from 0.016 t/m2 to 0.048 t/m2 significantly enhanced the abundance of tetC by 29.81%, while ermB and sul2 decreased by 45.37% and 76.47%, respectively (p < 0.01). After 2-year irrigation, the abundance of tetC, ermB, ermF, dfrA1, and total ARGs significantly increased (p < 0.05) when the irrigation amount increased. The abundances of ARGs after 2-year irrigation were found to be 2.5-34.4 times higher than 1 year. Obviously, the irrigation years intensified the positive correlation between ARGs abundance and irrigation amount. TetC and ermF were the dominant genes resulting in the accumulation of ARGs. TWW irrigation increased the content of organic matter and total nitrogen in the soil, which affected microbial community structure. The changes of the potential host were the determining factors driving the ARGs abundance. Our study demonstrated that continuous TWW irrigation for 2 years led to a substantial accumulation of ARGs in soil.

Long-term saline water irrigation has the potential to balance greenhouse gas emissions and cotton yield in North China plain.

Saline water has proven to be one of the alternative sources of freshwater for agricultural irrigation in water-scarce areas. However, the changes in farmland ecology caused by saline water irrigation remain unclear. In this study, six irrigation water salinities (CK: 1.3 dS m-1, S1: 3.4 dS m-1, S2: 7.1 dS m-1, S3: 10.6 dS m-1, S4: 14.1 dS m-1, S5: 17.7 dS m-1) were set in a three-year (2019, 2021-2022) experiment to investigate their effects on soil environment and greenhouse gas emissions in cotton fields under long-term saline water irrigation. Results show that soil salinity in the same layer increased as increasing water salinity. Soil moisture of S3-S5 increased significantly by 4.99-12.94%. There was no significant difference in soil organic matter content between CK and S1. Saline water irrigation increased soil ammonium nitrogen content by 0.57-49.26%, while decreasing nitrate nitrogen content by 1.43-32.03%. Soil CO2 and N2O emissions and CH4 uptake were lower in S1-S5 than in CK at different cotton growth stages. In addition, saline water irrigation reduced the global warming potential by 6.93-53.86%. A structural equation model was developed to show that soil salinity, moisture, and ammonium nitrogen content were negatively correlated with global warming potential, while organic matter and nitrate nitrogen had positive effects on global warming potential. Considering the comprehensive perspectives of gas emissions and cotton yield, irrigation water with salinity less than 10.6 dS m-1 could effectively reduce greenhouse gas emissions from cotton fields while maintaining stable cotton yields in the experimental area and similar region.

Soil Water Movement and Groundwater Recharge Under Different Land Uses in a Flood-Irrigated Area.

The water shortage in agriculture area in China requires to reduce the consumption of excessive water in flood irrigation. Therefore, the dynamics of soil water regime is needed to investigate and water-saving irrigation is necessary to alleviate water shortage. This study investigated the impact of flood irrigation on soil water movement and recharge to groundwater in the Yellow River irrigation area of Yinchuan Plain, China. Combining comprehensive field observation, stable isotopic techniques and water balance simulation, we described the soil water mechanism in vadose zone covered with bare soil in 2019 and planted with maize in 2020. The soil layers affected by precipitation infiltration and evaporation were mainly 0-50 cm, while the soil influenced by irrigation was the entire profile in the mode of piston flow. The maize root took up the soil water up to the depth of 100 cm during the tasseling period. The infiltration and capillary rise in 2020 were similar with those in 2019. However, the total deep percolation was 156.5 mm in 2020 which was about 50% of that in 2019 because of the maize root water uptake. The leakage of ditch water was the major recharge resource of groundwater for the fast water table rise. Precise irrigation is required to minimize deep percolation and leakage of ditch water and reduce excessive unproductive evapotranspiration. Therefore, understanding the soil water movement and groundwater recharge is critical for agricultural water management to improve irrigation efficiency and water use efficiency in arid regions.

Cleaner tillage and irrigation options for food-water-energy-carbon synergism in wheat-maize cropping systems.

The conventional wheat-maize systems in the North China Plain are energy and water intensive with high carbon emissions. It is imperative to find cleaner production technologies for sustainable food-water-energy-carbon synergism. Here, a three-year field experiment was performed to explore the effects of two tillage modes and four irrigation regimes during wheat season on crop yield, economic profile, water use efficiency, energy utilization, and carbon footprint in typical wheat-maize cropping systems in the North China Plain. Pre-sowing irrigation resulted in the lowest crop yield and benefit profile. Pre-sowing + anthesis irrigation decreased economic benefit and water use efficiency with higher carbon footprint. Pre-sowing + jointing + anthesis irrigation led to the greatest energy consumption and greenhouse gas emissions. However, pre-sowing + jointing irrigation increased yield by 2.3-8.7%, economic benefit by 4.0-11.1%, water use efficiency by 7.4-10.9%, and net energy by 6.5-12.0% but reduced carbon footprint by 9.8-14.3% compared to pre-sowing + anthesis irrigation and pre-sowing + jointing + anthesis irrigation. The corresponding metrics in rotary tillage improved by 9.6%, 13.9%, 7.0%, and 14.2%, respectively, relative to subsoiling, whereas carbon footprint decreased by 12.4-17.2%. Besides, rotary tillage coupled with additional jointing irrigation obtained the highest value based on a Z-score method, which was recommended as a cleaner management practice to improve benefit return and water use efficiency with lower energy consumption and carbon footprint. This work provides valuable insights into food-water-energy-carbon nexus for ensuring food security and achieving environmental sustainability in the wheat-maize cropping systems.

The water-energy-food-ecosystem nexus in the Danube River Basin: Exploring scenarios and implications of maize irrigation.

The Water-Energy-Food-Ecosystem (WEFE) nexus concept postulates that water, energy production, agriculture and ecosystems are closely interlinked. In transboundary river basins, different sectors and countries compete for shared water resources. In the Danube River Basin (DRB), possible expansion of agricultural irrigation is expected to intensify water competition in the WEFE nexus, however, trade-offs have not yet been quantified. Here, we quantified trade-offs between agriculture, hydropower and (aquatic) ecosystems in the DRB resulting from maize irrigation when irrigation water was withdrawn from rivers. Using the process-based hydro-agroecological model PROMET, we simulated three maize scenarios for the period 2011-2020: (i) rainfed; (ii) irrigated near rivers without considering environmental flow requirements (EFRs); (iii) irrigated near rivers with water abstractions complying with EFRs. Maize yield and water use efficiency (WUE) increased by 101-125 % and 29-34 % under irrigation compared to rainfed cultivation. Irrigation water withdrawals from rivers resulted in moderate to severe discharge reductions and, without consideration of EFRs, to substantial EFR infringements. Annual hydropower production decreased by 1.0-1.9 % due to discharge reductions. However, the financial turnover increase in agriculture (5.8-7.2 billion €/a) was two orders of magnitude larger than the financial turnover decrease in hydropower (23.9-47.8 million €/a), making water more profitable in agriculture. Irrigation WUE was highest for EFR-compliant irrigation, indicating that maintaining EFRs is economically beneficial and that improving WUE is key to attenuating nexus water competition. Current maize production could be met on the most productive 35-41 % of current maize cropland under irrigation, allowing 59-65 % to be returned to nature without loss of production. Maize priority areas were on fertile lowlands near major rivers, while biodiversity priority areas were on marginal cropland of highest biodiversity intactness. Our quantitative trade-off analysis can help identifying science-based pathways for sustainable WEFE nexus management in the DRB, also in light of climate change.

Water rights reform and water-saving irrigation: evidence from China.

As a market-based water resource management, the water rights reform (WRR) will allocate water rights to water users and allow water users to trade water rights, which can realize the reallocation across water users. In this context, the adoption of water-saving irrigation (WSI) is an important technical form to adapt to the reform. Based on this, this paper studies the impacts of the WRR on WSI using the difference-in-differences (DID) strategy. The results show that the WRR could increase the land area for WSI by an average of 13.63%. The WRR could promote the expansion of high-efficiency irrigation mainly because the WRR could promote the expansion of spray and drip irrigation areas, and micro-irrigation land areas, which are high-efficiency water-saving irrigation technologies. In addition, the WRR also could improve agricultural production by increasing agricultural water productivity and planting area (including the sown area of grain crops and cash crops), but the WRR does not reduce agricultural water extraction. Therefore, the WRR could increase agricultural production without increasing agricultural water extraction.

Assessment of heavy metal accumulation and health risk in three essential edible weeds grown on wastewater irrigated soil.

The main problem facing Egypt recently is the shortage of available water resources. Therefore, farmers resort to use wastewater for irrigation. So, the present work aims to assess the impacts of wastewater irrigation on the productivity of three edible weeds (Cichorium endivia, Sonchus oleraceous and Beta vulgaris) and its effect on the nutritional value of plants and its risk on human health. This study will focus on Shibin Al Kanater region, and the physicochemical characteristics of drainage water, canal water, drainage water-irrigated soils and canal-irrigated soils were estimated. The vegetative and traits of edible weeds were determined including their photosynthetic pigments, organic and inorganic nutrients content, and heavy metals content. The health risk index (HRI) associated with consumption of polluted plants was created using the estimated exposure factor of a crop to the oral reference dosage of the toxic metal. The main results showed that biomass productivity of S. oleraceous, B. vulgaris and C. endivia increased due to drainage water irrigation with increasing percentage as 27.9, 19.6, and 19.1%, respectively. Irrigation with drainage water significantly increased the photosynthetic pigments of edible weeds. Irrigation with drainage water increased carbohydrate content, crude protein, total soluble sugar, and gross energy in all studied weeds. C. endivia, S. oleraceus and B. vulgaris plants irrigated with canal and drainage water could accumulate Fe, Zn, Cu, and Co in their roots. C. endivia, S. oleraceus and B. vulgaris plants irrigated with canal water indicated HRI more than the unit for Mn, Cu, Pb, and Cd. This research advises that regulation be put in place to prohibit irrigation using untreated drainage and to restrict the discharge of industrial, domestic, and agricultural wastewater into irrigation canals.

Changes in phytochemical properties and water use efficiency of peppermint (Mentha piperita L.) using superabsorbent polymer under drought stress.

Water consumption management and the application of advanced techniques in the agricultural sector can significantly contribute to the efficient utilization of limited water resources. This can be achieved by improving soil texture, increasing water retention, reducing erosion, and enhancing seedling germination through the use of superabsorbent polymers. This study aimed to investigate the effect of Aquasource superabsorbent (AS) on the morphological characteristics, phytochemical properties, antioxidant content, and water use efficiency of peppermint. It was conducted under different irrigation management and using different superabsorbent levels. Therefore, a 3 × 4 factorial design was used to determine the effects of irrigation intervals (2-, 4-, and 6-day) and different levels of AS amount (zero [control], 0.5, 1, and 2 wt%). The effects of these factors on various parameters (morphological characteristics, essential oil percentage, nutrient, protein, proline, carotenoid, antioxidant, and chlorophyll content, leaf area index, relative water content, and water use efficiency [WUE]) were evaluated. The results showed that morphological characteristics and essential oil percentage decreased significantly under drought stress (increasing the irrigation intervals). However, the addition of 0.5 (wt%) AS improved plant growth conditions. Increasing the amount of superabsorbent used to 1 and 2 (wt%) decreased the measured traits, which indicates the creation of unsuitable conditions for plant growth. AS application improved the growth of the root more than the leaf yield of peppermint. A 0.5 (wt%) addition of AS resulted in root length increases of 3, 13, and 15%, respectively, at irrigation intervals of 2, 4, and 6 days, respectively. Additionally, at 0.5 (wt%) AS, root weight increased by 8, 15, and 16% in 2-, 4-, and 6-day irrigation intervals, respectively. Also, the height of the plant increased by 3, 5, and 17% at 2-, 4-, and 6-day irrigation intervals when 0.5 (wt%) of AS was used compared to the control. As well, essential oil percentage increased by 2.14, 2.06, and 1.63% at 2-, 4-, and 6-day irrigation intervals. The nutrient and protein contents decreased as irrigation intervals and AS usage increased, indicating a similar trend. However, compared with the control, the addition of 0.5 (wt%) of AS resulted in some improvements in nutrients and protein. The highest WUE (3.075 kg m-3) was attained in the 4-day irrigation interval and 1 wt% AS addition. This was followed closely by the 2-day irrigation interval with 1 wt% AS addition at 3.025 kg m-3, and the 4-day irrigation interval with 0.5 wt% AS addition, which reached 2.941 kg m-3. Overall, the use of AS in appropriate amounts (0.5 wt%) can reduce water consumption and enhance essential oil yield and WUE in peppermint cultivation in water-scarce arid and semi-arid regions.