High Irrigation Research Articles

English

Furrow irrigation systems are one of the dominant methods for growing cotton in the North China Plain and in other parts of the word. Many attempts have been made to improve furrow irrigation performance by selecting an optimal cut off time. The objective of this study is to determine the appropriate control point position for the estimation of the optimal cutoff time in a field situation with a closed-end furrow irrigation system. The experiments were conducted in a cotton field at the EcoAgricultural Experimental Station in Wuqiao, Hebei Province, North China Plain. Simulations employing two optimization strategies were used for determining the optimal cutoff time. These strategies were selected based on the irrigation system properties (total water applied depth and field characteristics), aiming to maximize application efficiency or requirement efficiency. The results show that the optimal cutoff time could be selected based on the relationship between the cutoff time and the advance time to a particular control point downstream. The position of this control point depends on the range of the inflow rate. The recommended control point position for estimating the optimal cutoff time was set at 0.9 of a furrow length for inflow rates less than 1.6 l/s and at 0.8 and 0.7 for inflow rates ranging between 1.6 and 2.0 l/s and 2.0 and 2.6 l/s, respectively. The results also show that to achieve a high irrigation performance when the inflow rate is high, it is better to reduce the requirements of irrigation and increase the number of irrigations. Determining the appropriate position of the control point helps to select the optimal cutoff time without requiring knowledge of the other irrigation system properties (i.e., soil water content, etc.). Keywords: Closed-end

IRRIGATION UNIFORMITY OPTIMISATION OF A MINI-CENTRE PIVOT SYSTEM

In El Oued, southern Algeria, the traditional Mini-Centre Pivot System (MCPS) is widely used for the irrigation of agricultural crops, and its use has been growing continuously. However, these systems have a constant nozzle diameter along the lateral pipe, which affects productivity directly, besides decreasing both the quantity and quality of agricultural products by irrigation heterogeneity. Therefore, optimising the design of the MCPS nozzles is linked strongly to the desired uniform irrigation. This study aims to determine the optimal configuration of nozzles for high irrigation uniformity. To achieve this goal, a genetic algorithm was used for maximising the uniformity of MCPS-mediated irrigation. The optimisation is carried out according to water distribution modelling, calculation of the Heermann and Hein uniformity coefficient (CUH), and existing nozzle diameters. To verify the accuracy of the proposed model, three existing MCPS (60 m, 50 m, and 46 m in length) are investigated experimentally. The developed code findings in terms of CUH are in agreement with those obtained by experimental tests. The analysis indicated that the nozzle diameter should vary from 5 to 15 mm along the lateral pipe. In these optimal conditions, the CUH was improved by 29.77%, 33.99%, and 19.36%, respectively, for the existing 60, 50, and 46 m irrigation systems. The most obvious findings to emerge from this study is that using a genetic algorithm to optimise the design based on the nozzle size improves water application uniformity by more than 19% in terms of the CUH.

Impact of Drought and Changing Water Sources on Water Use and Soil Salinity of Almond and Pistachio Orchards: 2. Modeling

California is increasingly experiencing drought conditions that restrict irrigation deliveries to perennial nut crops such as almonds and pistachios. During drought, poorer quality groundwater is often used to maintain these crops, but this use often results in secondary salinization that requires skilled management. Process-based models can help improve management guidelines under these challenging circumstances. The main objective of this work was to assess seasonal soil salinity and root water uptake as a function of irrigation water salinity and annual rain amounts. The manuscript presents a comparison of three-year experimental and numerically simulated root zone salinities in and below the root zone of almond and pistachio drip-irrigated orchards at multiple locations in the San Joaquin Valley (SJV), California, with different meteorological characteristics. The HYDRUS-1D numerical model was calibrated and validated using field measurements of soil water contents and soil solute bulk electrical conductivities at four root zone depths and measured soil hydraulic conductivities. The remaining soil hydraulic parameters were estimated inversely. Observations and simulations showed that the effects of rain on root zone salinity were higher in fields with initially low salinities than in fields with high salinities. The maximum reduction in simulated root water uptake (7%) occurred in response to initially high soil salinity conditions and saline irrigation water. The minimum reduction in simulated water uptake (2.5%) occurred in response to initially low soil salinity conditions and a wet rain year. Simulated water uptake reductions and leaching fractions varied at early and late times of the growing season, depending on irrigation water salinity. Root water uptake reduction was highly correlated with the cumulative effects of using saline waters in prior years, more than salt leaching during a particular season, even when rain was sufficient to leach salts during a wet year.

Effect of Irrigation Regime on the Cultivation of Five Wild Colocynth[Citrullus colocynthsis (L.) Schrad.] Ecotypes in Terms of Their Growth, Seed Yield and Oil content

The objective of this research was to evaluate the response of five wild colocynth (an important medicinal plant) ecotypes toirrigation regime as a basic input of cultural practices. The research was laid out in a split plot design with three replications. Treatments were two irrigation regimes (Q1= 100 % Etc and Q2= 50 % Etc) and five wild colocynth ecotypes (G, SF, SD, GD and NK). The experiment was run for two seasons (2014 and 2015). Parameters measured were days to 50 % flowering, number of fruits per plant, number of seeds per fruit weight of 1000 seeds, seed yield and oil content of seeds. Days to 50 %flowering were not significantly affected by watering regimes for the two seasons; however, ecotypes were significantly effective in the first season only. Number of fruits per plant was not significantly affected by watering regimes in both seasons; yet, ecotypes were significantly affected in the first season only. The highest number of fruits/plant wasproduced by ecotype G in the first season and by NK in the second season. The lowest number was produced by ecotype SD in both seasons. Number of seeds per fruit was not significantly different between the watering regimes in both seasons; it was, however, significantly different among ecotypes in both seasons. There was no significant difference in seed yields between watering regimes in both seasons. Ecotype GD produced the highest seed yield in both seasons.The two watering regimes and ecotypes were significantly different regarding weight of 1000 seeds in the first but not in the second season.Mean oil percent of seeds resulting from irrigated ecotypes (15.2%) was higher than that of seeds collected from the wild (12.1%).Moreover, mean oil percent from seeds produced by high and low irrigation was individually higher than that of seeds from the wild habitat. In the wild habitat, SD produced the highest (16.0%) oil percent and NK the lowest (6.4%). When irrigated, ecotypes showed differential positive response. In conclusion, wild colocynth ectypes responded positively to irrigation regarding oil content of seeds, which is the most important product, indicating possibility of inclusion of colocynth in the existing cropping system thereby ensuring its conservation and economic use. More research, however, is needed todetermine, precisely, the irrigation water requirement for colocynth seed production.

Irrigation Rationalization Boosts Wheat (Triticum aestivum L.) Yield and Reduces Rust Incidence under Arid Conditions.

Under changing climate, water scarcity and frequent incidence of diseases like stripe rust pose the biggest threat to sustainable crop production which jeopardizes nutritional security. A study was executed to rationalize crop water requirement and evaluate wheat (Triticum aestivum L. cv. Bohoth 3) yield losses by stripe rust infection under irrigated conditions. Seven water treatments included three irrigations in three stages/season (S3), four irrigations (S4), and five irrigations (S5) at the different sensitive growth stages, full (F), and two deficit irrigation levels including D1 = 80% of field capacity (FC) and D2 = 70% (FC) along with farmers' practice of irrigation as control (C). Results revealed that F and D1 boosted grain yield by 31 and 14%. Overall, F irrigation regime resulted in the highest grain production (2.93 ton/ha) as well as biomass yield (13.2 ton/ha). However, D2 had the highest value of grain protein (15.9%) and achieved the highest application efficiency (AE) at midseason (54.6%) and end season (59.6%), and the lowest AE was under S3. Also, halting irrigation at the milky stage (S5) led to a significant decrease in irrigation water use efficiency as compared to D1. However, cutting irrigation at the end of seedling, heading, and milky stages (S3) caused a significant reduction in Ea, crop water use (ETa), and 1000 grain weight in comparison with all other treatments. Regarding yellow rust, S3 irrigation regime resulted in the lowest incidence of yellow rust infection. The highest irrigation and water use efficiency values were recorded under D1 (0.79 and 0.59 kg/m3), and the lowest values were obtained for control. Hence, the deficit irrigation treatment D1 could be recommended as the best appropriate strategy to save more water and to improve the water productivity under Yemeni agroclimatic conditions.

Thermal effects of thulium: YAG laser treatment of the prostate\u2014an in vitro study

PurposeTo objectively determine whether there is potential thermal tissue damage during Tm:YAG laser-based LUTS treatment.MethodsOur experimental model was comprised of a prostatic resection trainer placed in a 37 °C water bath. In a hollowed-out central area simulating the urethral lumen, we placed a RigiFib 800 fibre, irrigation inflow regulated with a digital pump, and a type K thermocouple. A second thermocouple was inserted 0.5/1 cm adjacently and protected with an aluminum barrier to prevent it from urethral fluid. We investigated continuous and intermittent 120 W and 80 W laser application with various irrigation rates in eight measurement sessions lasting up to 14 min. Thermal measurements were recorded continuously and in real-time using MatLab. All experiments were repeated five times to balance out variations.ResultsContinuous laser application at 120 W and 125 ml/min caused a urethral ∆T of ~ 15 K and a parenchymal temperature increase of up to 7 K. With 50 ml/min irrigation, a urethral and parenchymal ∆T of 30 K and 15 K were reached, respectively. Subsequently and in absence of laser application, prostatic parenchyma needed over 16 min to reach baseline body temperature. At 80 W lower temperature increases were reached compared to similar irrigation but higher power.ConclusionsWe showed that potentially harming temperatures can be reached, especially during high laser power and low irrigation. The heat generation can also be conveyed to the prostate parenchyma and deeper structures, potentially affecting the neurovascular bundles. Further clinical studies with intracorporal temperature measurement are necessary to further investigate this potentially harming surgical adverse effect.

MP65-03 DOES THE NOVEL THULIUM LASER GENERATE MORE HEAT THAN THE CONVENTIONAL HOLMIUM LASER?

You have accessJournal of UrologyStone Disease: Surgical Therapy V (MP65)1 Sep 2021MP65-03 DOES THE NOVEL THULIUM LASER GENERATE MORE HEAT THAN THE CONVENTIONAL HOLMIUM LASER? Joshua D. Belle, Nathaniel Srikureja, Natalie Chen, Mohamed Keheila, Akin S. Amasyali, Jenna Lee, Mohammad Hajiha, and D. Duane Baldwin Joshua D. BelleJoshua D. Belle More articles by this author , Nathaniel SrikurejaNathaniel Srikureja More articles by this author , Natalie ChenNatalie Chen More articles by this author , Mohamed KeheilaMohamed Keheila More articles by this author , Akin S. AmasyaliAkin S. Amasyali More articles by this author , Jenna LeeJenna Lee More articles by this author , Mohammad HajihaMohammad Hajiha More articles by this author , and D. Duane BaldwinD. Duane Baldwin More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002105.03AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The novel thulium fiber laser (TFL) has been shown to break stones more rapidly than the traditional holmium:YAG laser (HL). However, some evidence suggests that the TFL may generate comparatively more heat. The purpose of this study is to compare ureteral temperatures generated by these lasers during flexible ureteroscopic laser lithotripsy in a benchtop model. METHODS: A 1-cm BegoStone (CaOx monohydrate consistency) was manually impacted in the proximal ureter of a 3D printed kidney-ureter model and submerged in 35°C saline. Lithotripsy was performed with a flexible ureteroscope and a 200 μm laser fiber without a ureteral access sheath. Three lasers were compared (Dornier 30W HL, Olympus 100W HL, and Olympus 60W TFL). A needle thermocouple to measure temperature was inserted 2 mm from the laser tip. Irrigation was maintained at 35cc/min at room temperature using the Thermedx FluidSmart System. Intraluminal temperature was continuously recorded for 60 seconds of laser activation. Time was given between each trial for the intraureteral fluid to return to room temperature. 5 trials were performed for each of 4 different power settings: 3.6, 10, 20, and 30 Watts. ANOVA and Mann-Whitney U tests were performed, with p<0.05 considered significant. RESULTS: Intraureteral fluid temperature increased as laser power settings increased for all lasers trialed (p<0.05, table 1). The TFL produced significantly higher temperatures at both 3.6W (26.36°C vs. 24.57°C (Dornier) and 23.23°C (Empower); p<0.05) and 30W (41.76°C vs. 37.28°C (Empower); p<0.05). There was no difference in intraureteral temperature between lasers at the 10W and 20W settings. At 30W, the TFL generated supraphysiologic intraluminal temperature. CONCLUSIONS: The TFL generated significantly more heat at both the 3.6W and 30W settings. Supraphysiologic ureteral temperatures may be generated by the TFL with extended use at high energy settings and low irrigation rates. Understanding the heat generation properties of both the Holmium and Thulium lasers during ureteroscopy could help improve the safety of ureteroscopic laser lithotripsy. Source of Funding: None © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e1119-e1119 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Joshua D. Belle More articles by this author Nathaniel Srikureja More articles by this author Natalie Chen More articles by this author Mohamed Keheila More articles by this author Akin S. Amasyali More articles by this author Jenna Lee More articles by this author Mohammad Hajiha More articles by this author D. Duane Baldwin More articles by this author Expand All Advertisement Loading ...

An Agent-Based Model for Simulating Irrigated Agriculture in the Samambaia Basin in Goiás

Agriculture is one of the main economic activities in Brazil. The intensive use of water for irrigated agriculture leads to water rise demand contributing to increase water stress. Agent-based models help assess this problem with promising applications entailing an organizing principle to inform us of how to view a real-world system and effectively build a model. In this work, agent-based modeling is applied to simulate water usage for irrigation in agricultural production in the Samambaia river basin in the municipality of Cristalina in the Goias state of Brazil. The use of real data enables analysis of resource availability in a scenario with high demand irrigation, allowing a greater understanding of the needs of the parties involved.

SIMULATING THE EFFECT OF CLIMATE CHANGE ON WINTER WHEAT PRODUCTION AND WATER / NITROGEN USE EFFICIENCY IN IRAQ: CASE STUDY

The objective of this study was to investigate the capability of modifying the irrigation and nitrogen application rates as an adaptation to climate change, especially, increasing air temperature, using the Root Zone Water Quality Model (RZWQM2). Field experiments were conducted in the winter wheat season of 2015-2016 and 2019-2020 at the Rasheed County, south of Baghdad, Iraq. The effect of increasing air temperature on the water use efficiency, nitrogen use efficiency, and grain yield of wheat was assessed under different irrigation deficits and nitrogen application rates. Three levels of water depletion: 30, 50, and 70 of available water and four N application rates (0, 140, 200, and 260 kg N ha−1) were applied for winter wheat. Two temperature scenarios in the RZWQM2 were created for the study purpose. The first scenario was to add 2Co to the normal temperature, and the second scenario was to add 4Co to the normal temperature. Results showed that high irrigation levels presented better results than the low levels under projected temperature scenarios. However, all applied nitrogen rates presented similar results under projected temperature (2Co and 4Co scenarios). Therefore, modifying irrigation requirements is a workable adaption strategy to the increased temperature.

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

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

Opportunities to reduce nitrous oxide emissions from horticultural production systems in Canada

Horticultural systems, specifically vegetable production systems, are considered intensive agricultural systems as they are characterized by high nitrogen (N) fertilizer application rate, frequent tillage, and irrigation operations. Accordingly, horticultural production in temperate climates is prone to N losses — mainly during post-harvest (during fall and winter) or pre-plant (spring) periods — such as N2O emissions and nitrate leaching. The risk for N losses is linked to low crop N use efficiency (NUE) combined with a narrow C:N and high N content of crop residues. Here we reviewed the studies conducted in Canada and similar climates to better understand the risk of N2O emission and potential agronomic management strategies to reduce N2O emissions from horticultural systems. Current knowledge on N2O emissions from horticultural systems indicate that increasing crop NUE, modifying the amount, type, time, and rate of N fertilizer inputs, and adopting cover crops in crop rotations are some of the effective approaches to decrease N2O emissions. However, there is uncertainty related to the efficiency of the existing N2O mitigation strategies due to the complex interactions between the factors (soil characteristics, type of plant species, climatic conditions, and soil microbial activity) responsible for N2O production from soil. Little research on N2O emissions from Canadian horticultural systems limits our ability to understand and manage the soil N2O production processes to mitigate the risk of N2O emissions. Thus, continuing to expand this line of research will help to advance the sustainability of Canadian horticultural cropping systems.

Impact of crop management and environment on the spatio-temporal variance of potato yield at regional scale

• We determine and quantify the main drivers of potato yield variability under irrigated conditions. • We used correlation analysis, decomposition of variability sources and maps to assess potato yield variability. • Using APSIM, three planting dates × four irrigation strategies were simulated. • Crop management factors explained the greatest potato yield variability when compared to environmental factors. • We identified a need to discriminate the drivers of potato yield variability regionally. The uncertainties associated with crop model inputs can affect the spatio-temporal variance of simulated yields, particularly under suboptimal irrigation. The aim of this study was to determine and quantify the main drivers of irrigated potato yield variance; as influenced by crop management practices as well as climate and soil factors. Using a locally calibrated crop model (APSIM), three planting dates × three irrigation strategies (plus a non-water limited treatment) were simulated using 30 years of historical weather data across potato production areas in Tasmania, Australia. We used (i) correlation analysis, (ii) variance decomposition and (iii) maps to visualise the spatial decomposition of variance of potato yield. Our results showed that the implementation of potential irrigation compensated for the impact of planting date on climate drivers of simulated yield and changed the most important yield driving factors from irrigation and planting date to global solar radiation (r = 0.69−0.81). Under early-planting, we found positive correlations of simulated yield vs. global solar radiation (r up to 0.75 under high and medium irrigation) and between the simulated yield and rainfall (r up to 0.55 under low irrigation). In general, a mix of negative and positive correlations were found for minimum and maximum temperature depending on soil type. Using variance decomposition analysis, we found that crop management factors explained the greatest yield variance depending on soil type related to plant available water capacity (PAWC). For soils with high PAWC (>200 mm), most variance was explained by global solar radiation (56–62 %) followed by planting date (43–47 %). However, when PAWC values decreased from 242 mm to 94 mm, the contribution of global solar radiation and planting date were reduced from 62 % to 5.8 % and from 47 % to 4.4 %, respectively, and the contribution of irrigation strategy increased from 0.4%–32.5%. We identified a need to quantify and differentiate the variance contribution of environmental and crop management factors on crop yield and within these factors, discriminate the key drivers of yield variance at regional scale.

Changes in secondary metabolites and fiber quality of cotton (Gossypium hirsutum) seed under consecutive water stress and in silico analysis of cellulose synthase and xyloglucan endotransglucosylase.

Global warming has led to severe drought conditions. The selection of plant varieties that can withstand drought and produce increased yields are of utmost importance. In the current study, secondary metabolites, seed trait and fiber characteristic of cottonseeds (Gossypium hirsutum) exposed to double and third water stress exposure was investigated. Total phenol and tannin content in W1S33 increased significantly after third water stress exposure. Accumulation of wax was enhanced in seeds of W3S33 and W3S34 that were subjected to third water stress. Fiber quality parameters decreased when cottonseeds were rainfed. High irrigation resulted in fragile and delicate fiber. Seeds grown under 66% FC irrigation saved water and produced seeds that had the potential of producing high quality fibers. In silico analysis was performed on cellulose synthase A (CesA) and xyloglucan endotransglycosylase (XET) enzymes present in Gossypium hirsutum. The intracellular locations of the CesA and XET1 enzymes are the plasma membrane and cell wall, respectively. Proline is conserved in the C-terminal of the CesA enzyme and plays an important role in enzyme functionality. This study provides a better understanding as to the mechanisms by which the plant can tolerate and combat water stress conditions as well as reduce water consumption. In order to grow cotton seeds with desirable morphometric characteristics and optimal fibers under water stress exposure and in dry areas, it is better to use seeds that are irrigated under optimal irrigation conditions, ie 66% FC.

Impact of Lateral Depth and Irrigation Frequency on Inorganic Nitrogen Distribution, Yield, and Quality of Asparagus Lettuce Utilizing Sewage Effluent under Drip Irrigation

ABSTRACT The utilization of wastewater for agricultural irrigation has been widely accepted in China and other arid and semi-arid regions around the world. Effects of lateral depth and irrigation frequency on inorganic nitrogen yield and quality of Lactuca sativa var. augustana (asparagus lettuce) under drip irrigation with sewage effluent was examined in a solar-heated greenhouse in North China Plain amid two growing seasons of 2014 and 2015. Three pan coefficients of 0.6, 0.8, and 1.0 and three lateral depths of 0, 10, and 20 cm were tested during the 2014 season. In contrast, three irrigation intervals of 4, 8, and 12 days and three lateral depths similar to the 2014 season were utilized in the 2015 season. The groundwater control experiment was applied for treatments with a pan coefficient of 0.8 (2014) and irrigation intervals of 8 days (2015). A higher irrigation frequency increased the yield of asparagus lettuce, while a lower frequency was favorable to the quality parameters of vitamin C and soluble sugar. Generally, compared with surface drip irrigation, subsurface drip irrigation increased inorganic nitrogen distribution in the subsurface soil layer, and also increased the yield, vitamin C, and soluble sugar of asparagus lettuce. When asparagus lettuce was buried laterally 10 cm below the soil surface, highest yield was observed. Sewage irrigation increases the accumulation of nitrogen in the soil, and asparagus lettuce yield is higher compared to groundwater irrigation. Additionally, compared with groundwater irrigation, no destructive effect of sewage irrigation on the quality of asparagus lettuce was found.

Substrate Stratification: Layering Unique Substrates within a Container Increases Resource Efficiency without Impacting Growth of Shrub Rose

Nurseries rely on soilless substrates to provide suitable growing media for container grown crops. These soilless substrates have been developed to readily drain water to prevent issues with waterlogging and associated soil-borne disease. A negative consequence of high porosity and subsequent drainage throughout the container profile is the required high or frequent irrigation rates with poor retention of applied nutrients. Substrates with relatively high levels of moisture and nutrient retention placed on top of a coarse and freely draining substrate could further optimize water and nutrient retention, while allowing for needed gas exchange for plant establishment and growth. Containerized Red Drift® rose (Rosa ‘Meigalpio’ PP17877) plants were grown under 16 mm or 12 mm daily irrigation, utilizing a traditional pine bark substrate or stratified substrates with either a conventional bark, bark fines, or a bark–peat mixture on top of a coarse bark within a container. The stratified substrates received 20% less controlled-release fertilizer; however, the fertilizer in the stratified treatments was concentrated in the upper strata only. During the first growing phase or season, plants grown in stratified substrates outperformed those grown in conventional, non-stratified bark substrates under normal irrigation. The stratified substrates did not reduce growth under reduced irrigation regimes. Overall, crop growth was equal or superior for stratified substrates when compared to the non-stratified controls, even with a 20% reduction of fertilizer. This research suggests that stratified substrate systems can be used to reduce fertilizer and irrigation rates while producing crops of similar or superior quality to conventionally grown containerized crops.

Influence of irrigation regimes on yield, pomological parameters and population development of Tetranychus cinnabarinus Boisd. (Acari: Tetranychidae) in strawberry

In this study, the effect of full (IR100), 50% (IR50), 75% (IR75) and 125% (IR125) irrigation levels on population development of the carmine spider mite (CSM) as well as on yield and some pomological properties of ‘Fortuna’ strawberry cultivar grown in high tunnels were evaluated in two consecutive growing seasons (2016–2017 and 2017–2018). The numbers of CSM were significantly lower on strawberry leaves which were irrigated by IR50 and IR75 in both growing seasons. Full (IR100) and highest (IR125) irrigation levels were the most favorable for the development of CSM populations. On the other hand, in the CSM thriving period (2017), the fruit weight was generally high in the plots with the highest irrigation (IR125) level. Although there was no interaction with the CSM population, fruit acidity (%) increased in the IR100 and IR125 irrigation levels, possibly due to stress in plants, when CSM population was highest (in March). In the absence of CSM, fruit acidity was significantly high in the plots where water stress was experienced. While no significant interaction was found between the pomological characters and the CSM population, the mites affected the yield significantly in that plants were more productive under IR 75 even when there was a CSM population. This study suggests that the application of IR75 level in Fortuna strawberry is related to lower CSM population growth and significantly higher yields.

Synergistic and antagonistic interactions of soil water potential and osmotic potential linked to nitrogen fertilization on spinach traits and water use efficiency

Few studies have attempted to investigate the combined effects of soil matric potential (Ψm) and osmotic potential (Ψs) on plant production and water use efficiency (WUE). The purpose of this study is to evaluate the synergistic and antagonistic effects of Ψm and Ψs associated with nitrogen (N) fertilization on spinach (Spinacia oleracea L.) growth traits and WUE. Five levels of salinity (1, 4, 7, 9, 11 dS m−1), three levels of water use amounts including deficit-irrigation (W–), full-irrigation (W0) and over-irrigation (W+), and four levels of N application rates (0, 50, 75, and 100% of N requirement) were applied. A new parameter namely "WUEθ" is suggested based on soil water content (θ). Results showed that water deficit combined with high saline irrigation water caused the most reduction in the plant biomass, leaf area index (LAI) and evapotranspiration (ET). The acquired plant yield coefficient (Ky) of 1.003 indicates that the spinach is a moderately salt-sensitive vegetable. The highest WUE was observed under deficit-irrigation and intermediate salinity conditions, which was attributed to an adaptation mechanism in the plant. However, WUEθ (R2 > 0.98) was a better predictor of the plant yield than WUE (R2 > 0.48). Nitrogen use efficiency (NUE) decreased with increasing salinity and water deficiency. Also, Ψm and Ψs had a synergistic interaction on yield and ET, while their effect on WUE and WUEθ was antagonistic. Salinity greater than drought reduced yield, while both had equal reducing effects on ET. Furthermore, WUE and WUEθ were more influenced by Ψm than Ψs. Research Highlights The new parameter WUEθ is a better predictor of the spinach plant yield than WUE. WUE and WUEθ are more influenced by water potential (Ψm) than osmotic potential (Ψs). Synergistic interaction of Ψm and Ψs on yield and ET, but antagonistic effect on WUE and WUEθ. Salinity greater than drought reduces yield, while both have equal reducing effects on ET. Ψm shows negative effects on yield and ET, but positive effects on WUE and WUEθ.

A novel water-saving and drought-resistance rice variety promotes phosphorus absorption through root secreting organic acid compounds to stabilize yield under water-saving condition

More than 70% of global rice production depends on irrigation water, which has brought on a progressive reduction in the groundwater table. Further groundwater withdrawal are unsustainable for future rice production. Sustainable rice production calls for the use of resource-saving and environmentally friendly rice varieties. This study investigated the morphological and physiological mechanisms of biomass and tissue phosphorus accumulation in a water-saving and drought-resistance rice variety (Hanyou73) and a normal paddy rice variety (Hyou518) under different water management regimes. The two rice cultivars were grown in pot experiments carried out with factorial combinations of three water regimes, conventional irrigation (high irrigation rate, HR), 60% of conventional irrigation (medium irrigation rate, MR), and 20% of conventional irrigation (low irrigation rate, LR) for four-years. While the grain yield of Hanyou73 was similar as Hyou518 under HR, it was significantly higher than Hyou518 under MR and LR. Under deficit irrigation, the tissue-specific biomass of Hanyou73 was higher than that of Hyou518, and the total P accumulation of Hanyou73 was 70% greater than that of Hyou518. Meanwhile, the root growth, root oxidation activity, and absorption area of Hanyou73 under the MR and LR treatments were significantly higher than those of Hyou518. Analysis of root exudate metabolites revealed an abundance of organic acids produced by the Hanyou73 roots under, which may account for its higher P uptake. Overall, the findings of this study indicate that Hanyou73 promoted P uptake to maintain higher yields under deficit irrigation. The higher P uptake by Hanyou73 may be related to its altered root physiology, which may be the mechanism by which Hanyou73 adapts to water saving irrigation conditions and maintains its yield traits.

Yield and morphology of forage cactus cultivars under drip irrigation management based on soil water matric potential thresholds

The recent increase of irrigation practices in forage cactus crops makes appropriate irrigation management criteria necessary. In this study, the morphological and yield characteristics of forage cactus cultivars were evaluated for some soil-based irrigation management criteria. Five experiments were carried out simultaneously under semiarid conditions in a randomized block design, with forage cactus cultivars Orelha de Elefante (OE), IPA-Sertânia (IPA), Doce (DC), Gigante (GG), and Orelha de Onça (OO). For each cultivar, irrigation management was performed using four upper thresholds of matric potential (−0.2, −0.33, −1, and −3 atm), as well as a non-irrigated (rainfed) treatment. Forage cactus crop yield was evaluated after 12 months and responded positively and similarly to irrigation management using any of the thresholds, with a significant increase in the cladode area and, overall, a positive effect on growth and yield parameters. Very high irrigation water productivity up to 75 kg m−3 was obtained especially in the −3 atm threshold treatment, whereas an increase of the threshold potential caused a sharp reduction of water productivity. We conclude that irrigation management of forage cactus grown in semi-arid climates is highly beneficial and that unconventionally low matric potential thresholds may be used.

Modelling water consumption, N fates and maize yield under different water-saving management practices in China and Pakistan

Excessive water and fertilizer input in conventional farming practices not only lead to low production but also damaged the ecosystem by causing groundwater decline and groundwater nitrate contamination. The two-year field experiments were conducted at Zhengzhou of China and TandoJam of Pakistan sites, respectively. The WHCNS (soil-water-heat-carbon-nitrogen-simulator) model was used to simulate soil water dynamic, nitrogen (N) fate and maize yield under different irrigation practices, including farmer-based full flood irrigation (FI), drip irrigation (DI) and rainfed (RF) at the Zhengzhou site. Treatments of the TandoJam site were full flood irrigation (F100), moderate deficit irrigation (F75) and high deficit irrigation (F50) to meet the 100%, 75% and 50% crop evapotranspiration, respectively. Results showed that the model precisely simulated water consumption, fates of N, crop growth, and yield at both sites. In Zhengzhou site, we found the lowest grain yield in the RF system, whereas the DI increased average grain yield by 9.8%, decreased 62.5% water consumption compared to FI for the two years. Moreover, the DI had a negligible amount of drainage, runoff, and N leaching, which subsequently improved water use efficiency (WUE) up-to 24.5% and 9.1% fertilizer N use efficiency (FNUE). In TandoJam site, compared to F100, the F75 produced almost equal grain yield with 25.1% water-saving, reduced 42.5% drainage and 11.8% runoff, 57% N leaching, enhanced 4.1% WUE and 14.9% FNUE. Furthermore, results suggested that too deficit irrigation, for example, F50, could cause serious yield loss or complete crop failure, because the weather condition of the TandoJam site is very hot.