Depletion Of Available Water Research Articles

Effect of Foliar Seaweed and Different Irrigation Levels on Water Consumption, Growth and Yield of Wheat

This experiment was carried out using the RCBD randomized complete block design in the Yusufiya district in Baghdad governorate during the agricultural season 2020/2021. The experiment included three spraying levels of seaweed extract of 2,4,8 ml L−1 and three levels of depletion of available water 25,50,75%, with three replicates for each treatment. Some plant tests and some water calculations were conducted, as the results indicated that there were significant differences between spray levels of marine algae extract in plant height, number of branches, leaf surface area, grain yield and biological yield. The spray level of 8 ml L−1 exceeded the levels of 2 and 4 ml L−1. It was also found that treatment 25% was significantly superior according to the different levels of depletion of the available water, as the treatment and for all the studied traits, and there was a significant superiority for the water consumption according to the level of spraying and the level of depletion, and the values ranged from 548.5 to the depletion treatment 25% and at a seaweed extract level of 8 ml L−1 to 404.5 for 75% depletion treatment and at a seaweed extract level of 2 ml L−1, As for the productivity of crop and field water, its values ranged from 1.16 and 1.54 kg m3, respectively, for 50% depletion treatment of the available water and spray level of 8 ml L−1 to 0.87 and 1.13 kg m 3 respectively, for 75% depletion treatment of available water and spray level of 2 ml L−1.

Effect of Soil Moisture Level and Nutrient Management on Yield, Bio-Chemical Properties and Water Productivity of Black Cumin

A field experiment was conducted at the Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur farm during rabi season of 2017-2018 to evaluate the effects of soil moisture levels and nutrient management on yield, bio-chemical properties and water productivity of black cumin (cv. BARI Kalozira-1) in the Shallow Red-Brown Terrace Soil of Salna series under AEZ-28 (Madhupur Tract). The experiment was set up in a Randomized Complete Block Design (factorial) with three replications comprising 9 treatment combinations having 3 soil moisture levels (Irrigation at 10%, 20% and 30% depletion of soil available water at field capacity) and 3 nutrient management packages: 100% RDF (80-45-50-20-5-2 kg ha-1 of N-P-K-S-Zn-B), 75% RDF + 25% N from cowdung and 50% RDF + 50% N from cowdung. The highest seed yield (1027 kg ha-1), biomass yield (2303 kg ha-1), thymoquinone (3286 mg kg-1 seed), thymol (149 mg kg-1 seed), fixed oil (28.7%), essential oil (0.85%), total consumptive use of water (112 mm) and water productivity (20.5 & 9.14 kg ha-1 mm-1, on the basis of biomass & seed yield, respectively) were obtained from irrigation at 10% depletion of available water along with 75% RDF + 1.98 t ha-1 cowdung. The application of irrigation water at 10% depletion of available water (112.22 mm) with N, P, K, S, Zn and B @ 60, 45, 50, 20, 5 and 2 kg ha-1, respectively + 1.98 t ha-1 cowdung (for supplementing 25% N requirement) appeared to be the best suited treatment package for black cumin cultivation in the study area.
 Bangladesh J. Agril. Res. 47(3): 309-321, September 2022

Foliar-applied zinc enhances sesame physiological and yield attributes under different irrigation regimes

Arid-semiarid regions are characterized by calcareous soils that are often deficient in micronutrients at least in a form that can be easily taken up by the plants. Sesame (Sesamum indicum L.) is an ancient oilseed crop with scanty data on its response to Zn. The purpose was, thus, to examine physiological attributes such as photosynthesis and water relations, grain and oil yield, and dry mass of five S. indicum genotypes under foliar Zn treatment, as exposed to two irrigation regimes. Two field studies were conducted under different climatic conditions, each consisting of two levels of ZnSO4 solution (0 and 3 g kg–1), five S. indicum genotypes and two irrigation regimes, i.e. irrigation after 45–55% (control) and 75–85% depletion (drought) of available soil water. Drought led to up to 55–60% increases in proline, malondialdehyde, and H2O2 concentrations but decreases in chlorophyll concentration, net photosynthetic rate, leaf area index, relative water content, plant height, branching, and consequently 16–30% and 37–48% decreases in grain yield and dry mass, respectively, of different genotypes. Foliar-applied Zn resulted in enhancement in chlorophyll concentration, leaf area index, grain Zn, plant height and branching, net photosynthetic rate and, hence, 6–9%, 6%, and 10–30% increases in grain yield, oil concentration, and dry mass, respectively, of both drought-stressed and non-stressed S. indicum. Results revealed that drought imposes alterations to plant water status, physiological, photosynthetic, growth functions, and yield attributes, but foliar application of Zn is beneficial to these attributes and this benefit is not limited to either drought or non-stress circumstances.

How nano‐iron chelate and arbuscular mycorrhizal fungi mitigate water stress in Lallemantia species: A growth and physio‐biochemical properties

AbstractBackgroundWater deficit can seriously affect the growth, yield, and biochemical properties of plants; however, the application of nano‐iron chelate and arbuscular mycorrhizal fertilizers in water deficit has been considered one of the most promising methods to improve plant growth and enhance drought tolerance.AimsThis study aimed to investigate the effects of nano‐iron chelated (nFe) fertilizer and arbuscular mycorrhizal fungi (AMFs) on the growth, yield, root colonization, mycorrhizal dependency, water use efficiency (WUE), physio‐biochemical properties, and seed biochemical properties of Lallemantia iberica and Lallemantia royleana species under drought stress.MethodsA split‐factorial experiment was conducted using a randomized complete block design with three replications. The main plot consisted of three drought stress levels (according to the depletion of soil available water) of 30% (I1; without stress), 60% (I2; mild stress), and 90% (I3; severe stress). The subplots were the factorial combination of fertilizers (F) (without fertilizer, nano‐iron chelate [nFe], and AMFs) and plant species (S) of Lallemantia (L. iberica and L. royleana).ResultsA decrease in the irrigation regime caused a reduction in growth, seed yield, WUE, chlorophyll content, nutrient uptake, seed oil, and mucilage content, as well as an increase in lipid peroxidation and hydrogen peroxide. Compared with nFe, AMF significantly increased root colonization by mycorrhizal fungi in both species across irrigation regimes. Furthermore, AMF inoculation enhanced nutrient uptake, mucilage, oil, and fatty acids by increasing the WUE. Higher mycorrhizal dependency in inoculated plants played an important role in increasing proline and antioxidant activities in the leaves of the host plant. The water stress and fertilization treatments resulted in the highest root colonization, mycorrhizal dependency, proline content, and antioxidant enzyme activities in L. royleana, as well as the highest WUE, accumulation of fatty acids, and nutrient uptake was observed in L. iberica. Interestingly, the mycorrhization potential of Lallemantia sp. is clearly defined.ConclusionsThe results highlighted that AMFs can promote Lallemantia to increase seed mucilage and oil under water stress. Overall, we found that both Lallemantia species responded well to AMF inoculation under water deficit conditions, where nFe was found to be less effective.

Assessment of trunk microtensiometer as a novel biosensor to continuously monitor plant water status in nectarine trees.

The objective of this work was to validate the trunk water potential (Ψtrunk), using emerged microtensiometer devices, as a potential biosensor to ascertain plant water status in field-grown nectarine trees. During the summer of 2022, trees were subjected to different irrigation protocols based on maximum allowed depletion (MAD), automatically managed by real-time soil water content values measured by capacitance probes. Three percentages of depletion of available soil water (α) were imposed: (i) α=10% (MAD=27.5%); (ii) α=50% (MAD=21.5%); and (iii) α=100%, no-irrigation until Ψstem reached -2.0 MPa. Thereafter, irrigation was recovered to the maximum water requirement of the crop. Seasonal and diurnal patterns of indicators of water status in the soil-plant-atmosphere continuum (SPAC) were characterised, including air and soil water potentials, pressure chamber-derived stem (Ψstem) and leaf (Ψleaf) water potentials, and leaf gas exchange, together with Ψtrunk. Continuous measurements of Ψtrunk served as a promising indicator to determine plant water status. There was a strong linear relationship between Ψtrunk vs. Ψstem (R2 = 0.86, p<0.001), while it was not significant between Ψtrunk vs. Ψleaf (R2 = 0.37, p>0.05). A mean gradient of 0.3 and 1.8 MPa was observed between Ψtrunk vs.Ψstem and Ψleaf, respectively. In addition, Ψtrunk was the best matched to the soil matric potential. The main finding of this work points to the potential use of trunk microtensiometer as a valuable biosensor for monitoring the water status of nectarine trees. Also, trunk water potential agreed with the automated soil-based irrigation protocols implemented.

Fatty Acid Composition and Eco-agronomical Traits of Lallemantia Species Modulated upon Exposed to Arbuscular Mycorrhizal Fungi and Nano-iron Chelate Fertilizers under Water Deficit Conditions

The main objectives of the current study were to investigate the effect of arbuscular mycorrhizal fungi (AMF) and nano-iron chelate fertilizer under water deficit conditions on grain yield, root colonization, leaf chlorophyll concentration, oil percentage, and fatty acid profile of Lallemantia species. The experiment was carried out as a factorial based on a complete randomized block design consisting of three factors of irrigation levels of 30, 60, and 90% depletion of available soil water (ASW)), fertilizer levels of control (without fertilizer), AMF inoculation, and nano-iron chelate, and plant species of Lallemantia (L. iberica and L. royleana). The results showed that increasing water deficit stress significantly decreased the above traits, while applying nano-iron and AMF fertilizers significantly increased them across water treatments. AMF fertilizer inoculation significantly improved yield of both Lallemantia species. Higher root colonization by AMF inoculation enhanced seed oil production with all major fatty acid moieties improved. In contrast, applying nano-iron chelate by increasing chlorophyll concentration in any irrigation regime could enhance seed oil of L. royleana and some fatty acids such as palmitoleic acid. Water deficit stress and application of fertilizers had different effects on both species. L. iberica, compared with L. royleana, had the most tolerance to water deficit stress and the highest dependence on AMF inoculation. Overall, these results demonstrated that the application of AMF could improve major features of Lallemantia species under irrigation deficit conditions, especially at the 60% depletion of ASW.

Application of zeolite improves water and nitrogen use efficiency while increasing essential oil yield and quality of Salvia officinalis under water-deficit stress

Soil moisture and nitrogen (N) are two of the most important factors affecting the production of medicinal plants. So, the management strategy of these factors is critical and to be identified. In order to study the application of zeolite (Z) (0 and 10 ton ha−1) in S. officinalis culture medium under different irrigation regimes (30 % depletion of available soil water (ASW)) and 60 % depletion of ASW) and N (0, 75 and 150 kg N ha−1) a split-factorial experiment was carried out with three replicates in 2018. The highest fresh and dry weight were achieved at irrigation after 30 % depletion of ASW while using 150 kg N ha−1 and 10 ton Z ha−1. Maximum water use efficiency (WUE) (22.10 g.L-1) was obtained after 60 % depletion of ASW and 150 kg N ha−1 and 10 ton Z ha−1. Besides, the maximum nitrogen use efficiency (NUE) was obtained after 60 % depletion of ASW and 75 kg N ha−1 and 10 ton Z ha−1 (14.25 kg.kg-1N). Maximum essential oil (EO) content (1.06%) and cis-Thujone were obtained from plants subjected to 60 % depletion of ASW and, application of 75 kg N ha−1 and 10 ton Z ha−1. Applying Z with N, in different irrigation regimes did improve soil conditions for achieving higher, WUE and NUE, increased the EO content and yield while decreasing the negative effects from water-deficit stress and has provided a direction towards a stable system.

Water use efficiency of green gram (Vigna radiata L.) impacted by paddy straw mulch and irrigation regimes in north-western India

A multilocation field experiment was conducted at Students’ Research Farm, Department of Agronomy, Punjab Agricultural University (PAU), Ludhiana and PAU, Regional Research Station (RRS), Bathinda, during summer 2019. The experiment was conducted in RCBD with 15 treatment combinations with 3 replications. The treatments comprised of 3 mulch levels i.e., M0, M6, and M12 i.e., no mulch, 6 and 12 t ha−1, respectively, and 5 irrigation schedules i.e., I10, I20, I30, and I40 with 10%, 20%, 30% and 40% depletion of available soil water (ASW), respectively, and IR (PAU recommendation as 4 irrigations). The growth parameters (plant height, dry matter accumulation and leaf area index), yield attributing characters namely pods per plant, number of seeds per pod and thousand-grain weight, seed and straw yield were significantly higher in M12 than M6 and no mulch (M0). The growth parameters, yield attributes, seed and straw yield were significantly higher for I10 due to increased irrigation frequency (5–6 irrigations). Both M0I10 (seven irrigations without mulch) and M6I30 (3 irrigations with straw mulch (6 t ha−1)) treatments observed comparable seed yield (1.06 t ha−1). Therefore, the substantial increase in seed yield with lower crop water use with the usage of straw mulch saves a considerable amount of water. Subsequently, the use of 6 t ha−1 of straw mulch with 3 irrigations (30% depletion from available soil water) facilitated a higher seed yield. The crop water use (CWU) was highest for M0 as due to bare soil, resulted in more evapotranspiration. The bio-physical productivity (BPWP) and water use efficiency was found to be maximum for mulch treatments. The I10 reported maximum CWU, whereas, Bio-physical water productivity (BPWP) were higher for I40 treatment where only one irrigation was given in this treatment. The WUE was maximum in I30 treatment at Ludhiana and in I20 at Bathinda location.

Using of Potassium Silicate to Alleviate Drought Stress Effect on Peanut as Grown in Sandy Soil

Two field Experiments were conducted at Abd El-Maneim Ryad, South Tahrir, El- Beheira Governorate, Egypt, during the summer growing seasons of 2017 and 2018 to study the role of foliar application of potassium silicate for alleviating drought stress effect on peanut grown in sandy soil. This experiment carried out in a split plot design with three replicates where the drought stress treatments (irrigation after depletion of 40%, 55%, 70% and 85% Available soil water were occupied main plot, while potassium silicate concentration (control, 500, 1000 and 1500mg/l silicate) was allocated in sub main plot. Results revealed that irrigation after depletion of 55% available soil water recorded the highest mean values of yield and yield components i.e. (100-pods weight, no. of pods/plant, pods yield/fed, biological yield/fed and straw yield/fed during both seasons, while, the irrigation after depletion of 40% available soil water recorded the highest mean values of harvest index percentage during both seasons). Foliar application of potassium silicate at 1500 mg/l silicate recorded the maximum 100- pods weight, no. of pods/plant, pods yield/fed, biological yield/fed and straw yield/fed, while, control treatment recorded the highest mean values of harvest index percentage during both seasons. Chemical compositions i.e. (oil percentage and oil yield/fed) recorded the best values with irrigation after depletion of 40% available soil water, while, proline content recorded the highest mean values at irrigation after 85% depletion of available water; in addition, potassium silicate at 1500 mg/l silicate recorded the highest percentages of oil and oil yield/fed, while, proline content recorded the best values with control treatment, during both seasons. Water use efficiency recorded the highest mean value with irrigation after depletion of 85%available soil water during both seasons; with regard, potassium silicate at 1500 mg/l silicate gave the highest mean values of water use efficiency as compared with control treatment which recorded the lowest mean values of WUE during both seasons

Self-organizing map estimator for the crop water stress index

Crop water stress index (CWSI) is a reliable, economic and non-destructive method of monitoring the onset of water stress for irrigation scheduling purposes. Its application, however, is limited due to the need of obtaining the baseline canopy temperatures. This study developed a self-organizing map (SOM) based model to predict the CWSI using microclimatic variables, namely air temperature, canopy temperature and relative humidity. The canopy temperature measurements were made from Indian mustard crop grown in a humid sub-tropical agro-climate during the 2017 and 2018 cropping seasons. Eight levels of irrigation treatments (I1 – I8) based on maximum allowable depletion of available soil water were considered in the study. The CWSI for treatments I2 – I7 was computed using the empirical approach based on the experimentally measured baseline canopy temperatures from treatments I1 and I8. The number of data points used was 1260 and 1350 for model training and testing, respectively. The developed SOM model was evaluated using the error indices Nash-Sutcliffe efficiency (NSE), bias error (BE), absolute error (AE), and coefficient of determination (R2). The SOM predicted CWSI presented a good agreement with the baseline computed CWSI values during model training (R2 = 0.98, NSE = 0.97, AE = 0.018, BE = 0.0004) and testing (R2 = 0.98, NSE = 0.98, AE = 0.018, BE = 0.002). Treatment specific analysis was conducted to evaluate the performance of SOM predicted CWSI for different irrigation levels. Results indicated that the presence of zero CWSI values in a significant proportion in the dataset impacted the model prediction performance at low CWSI (<0.1) values, with an R2 of 0.71 during testing. Nonetheless, the model performed exceptionally well in predicting CWSI values between 0.1 and 0.6 (R2 = 0.93–0.98, NSE = 0.92–0.98, AE = 0.013–0.015, BE = −0.002–0.004), which is the commonly observed CWSI range for irrigation scheduling in field crops. For better understanding, the developed SOM model was also analysed through the component planes, U-matrix, clusters and high-low bar planes in the cluster features.

Severe depletion of available deep soil water induced by revegetation on the arid and semiarid Loess Plateau

Revegetation-induced water deficits in the deep soil (>100 cm) on the arid and semiarid Loess Plateau threaten the sustainability of its ecosystems. However, quantifying changes in deep-soil water status at the regional scale remains challenging. This study represents the first attempt to integrate meta-analysis with the digitization of map data from previous research to evaluate the effects of revegetation on the deep soil water status. A total of 4906 observations from 94 peer-reviewed publications related to soil water changes to a depth of 500 cm in planted forests, planted shrublands, natural grasslands and croplands were synthesized, and two regional-scale evaluation criteria, the stable field capacity (SFC) and the permanent wilting point (PWP), were developed by digitizing the map data. The results indicated that (1) compared with cropland, revegetation more severely depleted the deep soil water availability, and planted forest revegetation resulted in the most serious depletion; (2) the extent of soil water changes was influenced significantly by the tree species planted; Platycladus orientalis was better able to maintain the deep soil water availability than Robinia pseudoacacia and Pinus tabuliformis; (3) the soil water status worsened with time after restoration, particularly at 20 years after restoration; (4) contrary to expectations, deep soil water depletion in forests and shrublands even increased in areas of high rainfall zones (>550 mm) compared to drier zones.; and (5) natural restoration (i.e., grasslands) was a better option than revegetation due to the resultant higher, more stable soil water availability. These results indicate that changes in deep soil water availability must be considered when planning revegetation initiatives.

"Evaluation of The Performance of Genotypes of Bread Wheat ( Triticum Aestivum L.) for Drought Tolerance Using Drought Indexes and Analysis of Multiple Variables "

"ltural Research Ministry of Agriculture several drought indexes have been used to determine the best genotypes of (Triticum eastivum L.) for drought tolerance in the central region of Iraq, Determination of the efficacy of drought indexes for knowledge the genotypes of drought-tolerant and susceptibility and interpretation of the relationship between drought index used by primary component analysis, cluster analysis and rank sum. experiment was conducted to investigate water stress effect for the some traits of selected genotypes, using split plot arrangement within RCBD with 3 replications. The main plots included 2 levels of water stress (20% and 80%) depletion of available water while, the 9th selected genotypes and the control variety IPA99 occupied sub plots. The use of the best index of drought tolerance, MP, GMP and STI, led to the diagnosis of tolerant and stress-sensitive genotypes due to their association with grain yield in both stress and irrigation (YS and YP), The results of drought tolerance index showed that genotypes 186, 179 and 45 were the most tolerant of drought, while genotypes IPA 99, 117, 27 and 17 were the most sensitive to water stress and the other genotypes 44, 129, 147, middle tolerance or water stress sensitivity, Therefore, we recommend the cultivation of genotypes 186, 179 and 45 in the central region as they are most resistant to drought"

Irrigation Management Effects on Crop Water Productivity for Maize Production in the Texas High Plains

Corn (Zea mays L.) was grown under full and deficit irrigation in two research field locations near Bushland, TX, in 2018 to compare seasonal water use of two irrigation management approaches. Full irrigation was achieved in both fields by allowing no more than 55% depletion of plant available soil water. However, irrigation depth and frequency were different in each field. The USDA-ARS Conservation and Production Research Laboratory (CPRL) weighing lysimeter fields were generally irrigated twice weekly using irrigation depths ranging from 19 to 32 mm. The Texas A&M AgriLife Research Emeny field was irrigated only once per week, having greater application depths ranging from 35 to 42 mm. Deficit irrigation treatments of 75% of full irrigation were also performed in both research fields. Yield and crop water productivity values for the 100 and 75% lysimeter field irrigation treatments were greater than corresponding values for the Emeny field. Emeny field yields may have been slightly reduced by heat stress incurred between irrigations during early grain fill whereas more frequent irrigations on the lysimeter fields may have reduced heat stress during that period. Results from this study suggest that evaporative losses associated with the more frequent, smaller application depth irrigations on the lysimeter fields did not contribute to appreciably lower CWP values, as losses were likely mitigated by the rapid development of the corn canopy. These findings suggest that corn yield is principally dependent upon seasonal water inputs and losses from frequent, smaller depth irrigations are minimal outside of incomplete canopy conditions.

COMPARISON OF THE PERFORMANCE OF MOBILE DRIP IRRIGATION AND SUB-SURFACE DRIP IRRIGATION USING NANOTECHNOLOGY IN THE GROWTH AND YIELD BROAD BEEN (VICIA FABA L.)

A field study was carried out in clay loam soil that classified into Typic Torrifluret in Ramadi city (College of Agriculture- University Of Anbar) during the fall season of 2018 in order to compare mobile drip irrigation with under surface drip irrigation by using Nano-Root guard drippers and their effects in physical properties and water consumption of bean as well as, the study targeted determination of water use efficiency using Najeeb Kharoofa equation depending on crop coefficient that obtained from recent researches and weather data of experiment location. All agricultural practices were done as recommended and the experiment was laid out as RCBD with three replications of each irrigation system. Seeds of bean (cv. Veto) were sown in 20th of October 2018 and the harvest time was in 13th of March 2019. Irrigation dates were at 50% depletion of available water according to evaporation pan Bean productivity was significantly increased at under surface drip irrigation with 7.71-ton ha-1 in comparison with 6.32-ton ha-1 that obtained from mobile drip irrigation. The difference were significant between water use consumption values that were calculated according to Najeeb Kharoofah equation and between data collected from evaporation pan, however it was 148.48 mm by Najeeb Kharoofah equation while it was 446 mm according to evaporation pan data. Regarding the method of irrigation, they were affected. The effect was clear in the mobile drip irrigation compared to sub-surface drip irrigation as the evaporation rate was higher. However, the average of soil water content average for the three replications along growing season was 21.75% while it was 24.96% in the sub-surface drip irrigation.

Simulating Maize Yield Response to Depletion of Available Soil Water and Nitrogen Management under Drip Irrigation with the FAO AquaCrop Model

Crop simulation models of different complexity have been developed for predicting the effects of soil, water and nutrients on growth and water productivity of different crops. These models are calibrated and validated for a given region using the data generated from field experiments. Therefore, AquaCrop model was calibrated and validated for grain maize (Single Cross 260) under varying irrigation and nitrogen levels. The experiment was conducted at the research farm of the agricultural college, Islamic Azad University, Shiraz during summer season 2011 and 2012. Irrigation treatments consisted of different levels of depletion of available soil water. The four levels of moisture depletions considered in the study were 20, 40, 60 and 80 percent. Nitrogen application levels were 150 (N1), 200 (N2), 250 (N3) and 300 kg ha–1. Root Mean Square error (RMSE), Prediction error (Pe), coefficient of determination (R2) and normalized root mean square error (RMSEn) were used to test the model performance. The model was calibrated for simulating maize grain and biomass yield for all treatment levels with the prediction error 4 < Pe < 5 per cent, 0.64 < R2 < 0.81 and 469 < RMSE < 786 t ha–1. Upon validation, Pe between 10 and 6; R2 between 0.65 and 0.76 and RMSE between 1062 and 1293 for grain and biomass yield, respectively. The highest and the lowest accuracy to predict yield and biomass under all nitrogen levels was obtained at I1 (MAD: 20%) and I4 (MAD: 80%) treatments, respectively. The results of the present study show that the AquaCrop model simulates aboveground biomass more accurately than grain yield. Also, model cannot provide satisfactory results under severe water stress conditions.

GGE biplot tool to identify melon fruit weight stability under different drought conditions

ABSTRACT It is difficult to identify superior muskmelon (Cucumis melo L.) genotypes due to their interaction in different irrigation regimes, but assessing their interaction with drought is important in identifing stable genotypes. Muskmelon genotypes, procured from the National Plant Gene Bank of Iran, were assessed for response to irrigation level on stability of fruit weight. Irrigation treatment consisted of: 25 (mild), 50 (moderate) and 75% (severe) depletion of available soil water which was indicated as the computational component environment. Performance of genotypes was evaluated as change in fruit weight. Additive main effects and multiplicative interaction (AMMI), genotype main effect and genotype × environment interaction (GGE) were used to evaluate genotypes. The AMMI analyses indicated significant GGE for fruit weight. The AMMI stability value indicated genotypes 33, 11, 23 and 28 are stable. The GGE-biplot models indicated irrigation regimes belonged to 1 mega-environment. The GGE indicated genotypes 11 and 28 as the most stable and can be used in creation of hybrids. Based on 75% water depletion, genotype 28 was identified as best due to its stability and yield and would be suitable for crossing and breeding. This methodology uses a biplot to indicate factors genotype main effect and genotype × environment interactions important in genotype evaluation and the interaction of genotypes under different irrigation depletion can be monitored. This method can be used to identify stable genotypes that can be used in arid zones to increase production.

Improving growth and phenolic compounds of Echinacea purpurea root by integrating biological and chemical resources of phosphorus under water deficit stress

The global viewpoint toward crop production is to increase the quantitative and qualitative yield of medicinal plants through management techniques such as the use of bio-fertilizers and the reduction of chemical fertilizers consumption. Improving the growth and phenolic compounds in E. purpurea root by combining the phosphorous fertilizer with biological resources at different irrigation intervals was the research proposes in this study. A split-plot experiment was performed in a randomized complete block design with three replications. The main plots consisted of soil irrigation at 25, 50, and 75 % of available water depletion (AWD) to retain field capacity moisture. The subplots were six different treatments to supply phosphorus (P) for plant growth (control without P fertilizer, 100 % plant required P from triple super-phosphate, sole application of mycorrhizal arbuscular fungi (AMF) and Pseudomonas fluorescens bacteria (PFB), and AMF or PFB combination with 50 % of the plant's P requirement. Results showed that 75 % of AWD decreased root biomass and increased root cichoric and caftaric acid. The highest root colonization was observed when P fertilizer and AMF were applied together. Complete supply of plant phosphorus from triple superphosphate (100 kg/ha) increased root biomass and echinacoside yield by 57 % and 47 %, respectively compared to control (P < 0.05). Moreover, the use of phosphorus with PFB significantly increased chlorogenic and caftaric acid content by 29 % and 62 %, respectively. In 25 % of AWD, the highest root cynarin (0.583 mg/g dry matter) was observed in the joint application of phosphorus + AMF. Root colonization with beneficial soil microorganisms partially increased drought stress tolerance in E. purpurea through root development. The incorporation of chemical P with bio-fertilizers also played a vital role in the synthesis of secondary compounds in E. purpurea.

Effects of water deficit on shoot, root and some physiological characteristics in some greenhouse grown potato cultivars

A greenhouse experiment was conducted to evaluate the response of ten potato cultivars to two levels of soil water in terms of contents of total chlorophyll (Chltot), chlorophyll florescence (Fv/Fm), shoot fresh weight (SFW), shoot dry weight (SDW), root fresh weight (RFW), root dry weight (RDW), mean root length (MRL), root length density (RLD), special root length (SRL), root volume (RV), ascorbate peroxidase (APX), peroxidase (POX) and proline content. Plants were grown under two irrigation levels (30 and 80% depletion of available soil water). Greenhouse test plots were arranged in a randomized complete block design with four replications. Under control level of irrigation, the maximum and the minimum shoot dry weight were achieved for cultivars Satina (12.7 g/plant) and Sante (4.7 g/plant) and root dry weight for Marfona (2.95 g/plant) and Milva (1.17 g/plant), respectively. SDW and RDW were decreased in all cultivars under 80% depletion of available soil water. Based on the biplot analysis cultivars Agria, Satina and Marfona were hence identified as preferable cultivars for 80% depletion of available soil water conditions. However, this investigate has been able to gather evidence that water deficit increased the activities of antioxidant enzymes and proline content in all tested potato cultivars. Also, our results revealed the pivotal role of proline in response of potato plants to water deficit and biomass production.

Effect of Zeolite on Nitrogen Use Efficiency and Physiological and Biomass Traits of Amaranth (Amaranthus hypochondriacus) Under Water-Deficit Stress Conditions

In the present study, the interactive effect of irrigation and nitrogen (N) on biomass and physiological characteristics of amaranth and the influence of zeolite in this interaction were investigated. A 2-year field experiment was conducted as split-plot factorial in a randomized complete block design in three replicates. The main factor consisted of different levels of deficit irrigation (DI) such as irrigation after 40 (DI1), 60 (DI2), and 75% (DI3) depletion of soil available water. The subplots derived from a combination of different factors including nitrogen rates (zero (N0), 80 (N1), 160 (N2), and 240 (N3) kg urea ha−1) and zeolite levels (zero (Z0) and 10 (Z1) ton ha−1). Reduction of soil moisture resulted in a decrease in the amount of chlorophylls, carotenoids, protein, maximum quantum yield of photosystem II (Fv/Fm ratio), and biomass of amaranth. In contrast, it resulted in the increase of antioxidant enzyme activity, soluble carbohydrates, and proline. However, nitrogen application led to an increase in the contents of chlorophyll, carotenoids, protein, antioxidant enzyme activity, Fv/Fm ratio, and biomass of amaranth and a decrease in the soluble carbohydrates and proline. Zeolite treatment by increasing the content of chlorophylls (16%), carotenoids (19%), protein (25%), Fv/Fm ratio (11%) as well as enchantment of soluble carbohydrate content and antioxidant enzyme activity and by decreasing the proline content (40%) moderated the adverse consequences of water-deficit stress and improved biomass of amaranth. In general, the use of zeolite along with the lowest rate of nitrogen fertilizer (80 kg urea ha−1) reduced the harmful effects of the oxidative stress caused by water scarcity and improved the growth conditions for the plant and thus produced maximum biomass of amaranth plant under moderate and severe deficit irrigations.

To what extent arbuscular mycorrhiza can protect chicory (Cichorium intybus L.) against drought stress

Water deficiency is one of the most significant limiting factors resulting in severe crop yield reduction. This study hypothesizes that the inoculation of arbuscular mycorrhiza (AM) minimize the detrimental effects of drought in chicory (Cichorium intybus L.). The objective was to evaluate how AM inoculation affects agro-biochemical traits of chicory under different irrigation rates. Field experiments were conducted in 2017 and 2018 in north of Iran and designed as a factorial combination of three irrigation rates [40, 65 and 90 % of maximum allowable depletion of available soil water (IR1, IR2 and IR3, respectively)], two AM inoculations [inoculated and not inoculated (AM+ and AM−, respectively)] and two chicory ecotypes [Sefid Isfahan and Siyah Shiraz (E1 and E2, respectively)]. Crop growth, pigments and minerals content, carbon exchange rate, transpiration rate and stomatal conductance were evaluated. The data showed that the mycorrhizal colonization increased chicory growth performance by 12.4 %, 16.1 % and 21.0 %, under I1, I2, and I3 water regime, respectively. The mineral content and photosynthesis parameters decreased as irrigation water decreased, irrespective of whether plants were inoculated or not. Similarly, AM+ plants had higher inulin percentage and the mean inulin degree of polymerisation than AM− plant under all of irrigation levels. Furthermore, inoculated chicory plants under drought stress showed an enhanced activity of the antioxidant system, such as superoxide dismutase, peroxidase, ascorbic acid and glutathione, while the accumulation of hydrogen peroxide and the oxidative damage were reduced. The two ecotypes tended to respond similarly to irrigation and AM treatments for all growth and quality parameters measured in the experiment, even if ecotype Siyah Shiraz performed better than ecotype Sefid Isfahan. The improved plant performance and inulin content in the inoculated plants demonstrate that AM has the potential to minimize the detrimental effects of drought stress on chicory under semi-arid conditions.