Irrigation Levels Research Articles

The effect of melatonin on physiological, biochemical, and enzymatic properties and the expression of antioxidant genes under different irrigation regimes in wheat

A split-plot experiment was conducted based on a randomized complete block design with four replications in two years to study the effect of melatonin on the biochemical properties and the gene expression related to antioxidant enzyme activity in bread wheat. Irrigation levels (normal (FC = 80%)), mild stress (FC = 60%), and severe stress (FC = 40%)) were assigned to the main plots, and melatonin foliar applications (zero, 50, 100, 150, and 200 μM) were assigned to Subplots. Results showed that, with the intensification of water stress, the 1000 kernel weight decreased, and the activity of ascorbate peroxidase enzyme and flavonoid content increased. Also, the level of 100 μM melatonin had the highest 1000 kernel weight, flavonoid content, and ascorbate peroxidase enzyme activity. In this study, the highest number of grains per spike, biological yield, grain yield, chlorophyll a, chlorophyll b, carotenoids, and the lowest amount of malondialdehyde recorded for foliar treatment with 50 μM of melatonin under normal irrigation conditions and the highest proline content, total phenol, superoxide dismutase, and catalase were allocated to the 100 μM melatonin foliar treatment under severe water stress conditions. The synergistic effect of water deficit stress and melatonin foliar application increased the activity and expression level of genes related to antioxidant enzymes. So, the content of superoxide dismutase (21.30% and 65.16% respectively) and catalase (50.60% and 54.44% respectively) enzyme activity increased significantly under 100- and 150-mM melatonin foliar application in water severe water stress compared to the corresponding control treatment. Furthermore, mentioned melatonin levels increased the gene expression levels of superoxide dismutase (16.67% and 38.19% respectively), ascorbate peroxides (73.76% and 47.57% respectively), polyphenol oxidase (39.32 and 51.15%) and catalase (39.95% and 50.0% respectively) under an extreme water shortage compared with corresponding control treatment. In general, the application of 100- and 150-mM melatonin induced resistance to water deficit stress in wheat by increasing the expression of antioxidant genes.

Influence of Biochar and Irrigation Levels on Productivity of Marjoram (Origanum majorana L.) under Sandy Soil Conditions

A field experiment designed as a split-plot experiment based on a randomized complete block design with three replications was conducted during two summer successive seasons 2021 and 2022 at the Experimental Farm of EL-Quassasin Horticultural Research Station, Ismailia Governorate; Egypt, to investigate the influence of biochar at rates of 0, 2, 4, and 6 tons/fed. at three irrigation levels (1, 1.5, and 2 hours/day) using a drip irrigation system on the growth, essential oil (productivity and constituents), as well as some chemical constituents of marjoram (Origanum majorana L.) plant grown in sandy soil. The obtained results revealed that both irrigation and biochar levels affected all the above-mentioned traits. It was clear that plant growth parameters increased as long as increasing irrigation levels and biochar rate. Considering the interaction, it was clear that generally the highest values in vegetative growth (plant height, number of branches, and herb fresh & dry weights/ plant), essential oil yield/plant, N%, and K% were attained from the treatment of irrigation at 1.5 hours/day combined with biochar at the rate of 6ton/fed. On the other hand, the highest values of essential oil%, essential oil components (p-cymene, trans-Sabinene hydrate, α-terpineol), as well as proline, were recorded in stressed plants (received 1h/ day irrigation and 0 biochar). The existing outcomes show that biochar application might increase water use efficiency and produce a high yield of marjoram. Subsequently, it could be a viable option to alleviate the severity effect of water deficit in marjoram growth, which opens opportunities for cultivating arid regions.

Optimizing Rabi Chilli Production: Examining the Impact of Fertigation and Drip Irrigation Levels in the Context of Mulching Practices on Yield and Quality

The field investigation was carried out to evaluate the influence of fertigation levels, mulch and drip irrigation levels on yield and yield quality at WTC fields, PJTSAU, Rajendranagar, Telangana during 2020-21 and 2021-22. The study was consisted of 12 treatment combinations viz. 75%, 100% (300-60-120 kg ha-1 N-P2O5-K2O & 125% RDF, drip irrigation levels (0.8 Epan & 1.0 Epan) imposed under factorial combination of mulch (M1) and no mulch (M0) conditions. An investigation was undertaken during rabi season. Among the fertigation levels, 100% RDF (31.15 t ha-1, 195.04 mg 100 g-1, 10.33% & 0.94%, respectively) recorded the higher fresh fruit yield, ascorbic acid content, oleoresin content and capsaicin content in pooled data. With regards to mulch, the M1 has recorded the maximum values for fresh fruit yield (37.56 t ha-1), ascorbic acid content (224.43), oleoresin content (11.11%) and capsaicin content (0.74%) in pooled data.

Zinc and amino acids improve the growth, physiological, and biochemical attributes of corn under different irrigation levels

The global challenge of food security is threatened by drought stress. Exogenous application of zinc and amino acids could alleviate the negative impacts of water shortage on the growth, physiological, and biochemical attributes of plants. Based on this hypothesis, a field study was conducted to assess the effects of chelated zinc applied through irrigation systems and foliar amino acids on the growth, physiological and biochemical attributes of corn, under three irrigation levels at the recommended irrigation level (100%), and at 75% and 50% of the recommended rate. The treatments were arranged in randomized complete block design in triplicate. Treatment effects on yield varied with intensity and duration of water stress. An irrigation level of 100% means the normal supply of recommended water. In results, the implementation of irrigation levels on corn led to varying impacts on yield, depending on the intensity and duration of the water stress. Plants responded by reallocating nutrient accumulation within their tissues, which played a crucial role in mitigating the negative effects of water stress. The application of zinc and amino acids individually showed positive effects on corn improvement, as these promoted antioxidant defense systems and enhanced corn yield. However, the combined application of foliar amino acids and soil-applied zinc, particularly under the 75% irrigation level, had a tremendous effect on various examined parameters. There was an increase in catalase by 65.9%, superoxide dismutase by 17.1%, and peroxidase by 15.1%, resulting in improved corn yield by 114.6% and decreased hydrogen peroxide contents by 74.2% compared to control. In conclusion, adopting 75% of the applied water and treating corn plants with a combination of zinc and amino acids resulted in the highest yield, nutrient accumulation, antioxidant enzymes, chlorophyll contents, relative water contents, and carbohydrate levels.

Responses of Tomato Crop and Water Productivity to Deficit Irrigation Strategies and Salinity Stress in Greenhouse

Saudi Arabia faces water scarcity and inadequate sustainable sources, particularly in agriculture, necessitating efficient irrigation water management to improve productivity amidst rising demand. The study investigated the impact of irrigation levels and water salinity on tomato plants in greenhouses, covering four irrigation levels (100%, 80%, 60%, and 40% of ETc) and three water sources (FW (0.9 dS·m−1), SW (3.6 dS·m−1) and MW (2.25 dS·m−1)). Salinity impacts crop yield, physiological responses, and fruit quality. The photosynthesis, stomatal conductance, transpiration, and chlorophyll content decrease with MW and SW, negatively affecting morphological characteristics. For MW, it was recommended to apply 60% deficit irrigation with a yield of 98 kg·ha−1, and water productivity (WP) improved to 21.93 kg·m−3 compared to 13.65 kg·m−3 at full irrigation (FI). In SW, 80% irrigation was suggested, as there was no significant difference in yield compared to FI. For FW, 60% deficit irrigation produced the best water conservation (104.58 kg·ha−1 yield and 23.19 kg·m−3 WP), while FI produced the highest yield per unit area (123.48 kg·ha−1 yield and 16.51 kg·m−3 WP). Nonetheless, greater water and salinity stress was associated with increased fruit quality measures such as total acidity, vitamin C, and soluble solids. The results show that implementing deficit irrigation with salinity strategies in greenhouse tomatoes could improve crop adaptability, yield, and water productivity in the face of water scarcity and salinity variability.

Comparative effect of different irrigation levels and soil amendments on cabbage productivity in semi‐arid Central Namibia

AbstractIn semi‐arid Central Namibia, poor sandy soils limit sustainable crop production. We assessed cabbage performance in two split‐plot field experiments. In Experiment 1, treatments comprised two irrigation levels: full irrigation (watered 3 days a week) and reduced irrigation (watered 2 days a week) as the main plot factor and six soil amendments (biochar; compost; zeolite; nitrogen, phosphorus potassium [NPK]; Be‐Grow boost [L] hydrogel; and hoof and horn + bone [HHB] meal) as subplot factors in three replications. Full irrigation produced a significantly higher yield (21.1 t ha−1), head weight (0.958 kg) and larger head girths (42.1 cm). Biochar produced the highest marketable heads (24,884 heads ha−1), water use efficiency (76.0 kg ha−1 mm−1) and the largest head girths (42.7 cm). In Experiment 2, water was applied 5 and 4 days a week for full and reduced irrigation; the application rates of compost, HHB meal, Be‐Grow boost (L) hydrogel and NPK were modified. The interaction of Be‐Grow boost (L) hydrogel, NPK and biochar with full irrigation and HHB meal with reduced irrigation produced more marketable heads (28,935, 28,009, 27,546 and 28,703 heads ha−1, respectively). Therefore, full irrigation with these amendments could be used for resilient cabbage production in Central Namibia.

Intermediate irrigation with low fertilization promotes soil nutrient cycling and reduces CO2 and CH4 emissions via regulating fungal communities in arid agroecosystems

The field practices, including irrigation and fertilization, strongly affect greenhouse gas emissions and soil nutrient cycling from agriculture. Understanding the underlying mechanism of greenhouse gas emissions, soil nutrient cycling, and their impact factors (fungal diversity, network characteristics, soil pH, salt, and moisture) is essential for efficiently managing global greenhouse gas mitigation and agricultural production. By considering abundant and rare taxa, we determine the identities and relative importance of ecological processes that modulate the fungal communities and identify whether they are crucial contributors to soil nutrient cycling and greenhouse gas emissions. The research is based on a 4-year field fertigation experiment with low (300 kg/ha P2O5 with 150 kg/ha urea) and high (600 kg/ha P2O5 with 300 kg/ha urea) fertilization level and three irrigation levels, that is, low (200 mm), medium (300 mm), and high (400 mm). The α-diversity (richness and Shannon index) of fungal subcommunities was significantly higher under medium irrigation (300 mm) and low fertilization (300 kg/ha P2O5 with 150 kg/ha urea) than under other treatments. Intermediate irrigation with low fertilization treatment yielded the most significant higher multinutrient cycling index and the lowest CO2 and CH4 emissions. The null model indicated that abundant taxa are mainly regulated by stochastic processes (dispersal limitation), and rare taxa are mainly regulated by environmental selection, especially by soil salinity. The co-occurrence network of rare taxa explained the changes in the entire fungal network stability. The abundant taxa played vital roles in regulating soil nutrient status, owing to the stronger association between their network and multinutrient cycling index. Furthermore, we have confirmed that soil moisture and fungal network stability are crucial factors affecting greenhouse gas emissions. Together, these results provide a deep understanding of the mechanisms that reveal fungal community assembly and soil fungal-driven variations in nutrient status and network stability, link fungal network characteristics to ecosystem functions, and reveal the factors that influence greenhouse gas emissions.

Effects of Post-Anthesis Irrigation on the Activity of Starch Synthesis-Related Enzymes and Wheat Grain Quality under Different Nitrogen Conditions.

To develop optimal management strategies for water and nitrogen fertilizer application in winter wheat cultivation, we conducted a potted experiment to investigate the effects of different irrigation levels and nitrogen fertilizer treatments on the activity of starch synthesis-related enzymes and the grain quality of winter wheat. The potted experiment consisted of three irrigation levels, with the lower limits set at 50-55% (I0), 60-65% (I1), and 70-75% (I2) of the field capacity. In addition, four levels of nitrogen fertilizer were applied, denoted as N0 (0 kg N hm-2), N1 (120 kg N hm-2), N2 (240 kg N hm-2), and N3 (300 kg N hm-2), respectively. The results revealed the significant impacts of irrigation and nitrogen treatments on the activities of key starch-related enzymes, including adenosine diphosphoglucose pyrophosphrylase (ADPG-PPase), soluble starch synthase (SSS), granule-bound starch synthase (GBSS), and starch branching enzymes (SBE) in wheat grains. These treatments also influenced the starch content, amylopectin content, and, ultimately, wheat yield. In summary, our findings suggest that maintaining irrigation at a lower limit of 60% to 65% of the field capacity and applying nitrogen fertilizer at a rate of 240 kg hm-2 is beneficial for achieving both high yield and high quality in winter wheat cultivation.

Deficit Irrigation on Fruit Yield and Quality of Sweet Pepper

Background: Deficit irrigation is an approach to use less water in crop growth in places where water resources are the limiting factor for agricultural production, to maximize the production per unit of volume of water available. Objective: The study aimed to evaluate the effect of four levels of irrigation applied to replenish soil moisture depletion on the growth and yield of two sweet pepper cultivars. Methods: The experiment was performed on field conditions from January to June 2020 in a randomized block experimental design with three repetitions arranged in divided plots, the main plot was the four irrigation depths, and the sub-plots were the two cultivars (Tres Filos and Pepón) for a total of eight treatments. The irrigation depths applied corresponded to 60%, 80%, 100%, and 120% of the crop evapotranspiration. Results: The ANOVA (analysis of variance) of the main factors indicates that for the irrigation treatment factor, the number of fruits per plant for the two varieties is statistically equal when irrigation is applied at 120, 100 and 80% of the crop evapotranspiration (ETc) and greater than the one obtained with irrigation at 60% of ETc. For the cultivars factor, the number of fruits per plant and the fruit yield (g plant-1) in the different irrigation treatments was higher in the cv Tres Filo, but the weight of the fruit was higher in the cv Pepón. Conclusion: The application of irrigation at 60% of the ETc represents a saving of 40% of the volume of water compared to the application at 100% of ETc. The reduction in the number of fruits per plant, fruit weight, and average yield (g plant-1) of both cultivars was only 4.21%, 7.47%, and 11.95%, respectively. Therefore, if the limiting factor for agricultural production is water availability, it is advisable to irrigate at 60% of the ETc and increase the surface for irrigation to increase total production.

Exogenously applied 5-aminolevulinic acid modulates growth, yield, and physiological parameters in lentil (Lens culinaris Medik.) under rain-fed and supplemental irrigation conditions

Lentils are a significant source of plant protein and are cultivated across Asia, Europe, and North Africa. Plants are subjected to various environmental stresses, which can hinder growth, yield, and productivity. 5-aminolevulinic acid (ALA) is a compound that acts as a precursor in the biosynthesis of tetrapyrroles and can increase plant tolerance to different abiotic stressors. However, the effects of exogenously applied ALA on lentil growth, yield, and physiological parameters under rain-fed and supplemental irrigation conditions are not well-known. In this study, a split plot experiment was conducted to investigate the impact of ALA foliar application and supplemental irrigation on lentil (Lens culinaris Medik.). The experiment was designed based on a randomized complete block with three replications. The main plot included four levels of supplemental irrigation [(supplementary irrigation in the flowering and early seed-filling stages, supplementary irrigation in the flowering stage, supplementary irrigation in the early seed-filling along with rain-fed conditions (no irrigation)]. The subplot considered foliar application of ALA at varying levels [(0 (control), 50 and 100 ppm)]. The results showed that water regimes and foliar spray with ALA significantly (P ˂ 0.01) affected plant height, number of pods per plant, pod weight, number of seeds per pod and weight of 1000 seeds, biological yield, seed yield, and harvest index. The highest total chlorophyll content was observed in plants that were subjected to supplementary irrigation in flowering and early seed filling stages and foliar sprayed with 100 ppm ALA. The study also found that exogenous ALA improved drought tolerance in lentil plants under rain-fed conditions mainly by regulating antioxidant enzymes, which ultimately protected the cellular membranes against overproduction of H2O2. Furthermore, ALA application increased total carbohydrate contents at all supplemental irrigation levels, but the rate was higher in complementary irrigation conditions during flowering and early seed-filling stages. Malondialdehyde (MDA), H2O2, and proline contents were increased in field-grown plants under rain-fed conditions without exogenous ALA application. In conclusion, this study sheds light on the effects of ALA foliar spray and supplemental irrigation on lentil growth, yield, and physiological parameters. The findings suggest that exogenous ALA can improve plant tolerance to various abiotic stressors and enhance plant growth, yield, and physiological parameters.

Essential oil profiles, improvement of enzymatic and non-enzymatic antioxidant systems in different populations of Salvia subg. Perovskia by irrigation management

Salvia subg. Perovskia is an aromatic medicinal plant from the Lamiaceae family. Essential oil (EO) content and composition, along with enzymatic and non-enzymatic antioxidants, were evaluated in 18 plant populations under three levels of irrigation for two consecutive years. Based on the GC-MS analysis, the main components of EO were borneol (1.18–36.53%), followed by camphor (0.54–32.17%), 1,8-cineole (12.44–29.26%), δ-3-carene (0.39–21.20%), myrcene (0.59–16.28%), and α- pinene (0.79–12.87%) in the studied treatment. Except for malondialdehyde and hydrogen peroxide in leaves and roots, all the examined parameters showed lower values in the first harvest year compared to those of the second year. The activities of antioxidant enzymes, total phenolics, and flavonoids of the extracts were substantially enhanced as stress intensified to reach maximum values in leaves under severe stress and in roots under moderate stress conditions. The maximum root tanshinones content was observed under moderate water deficit conditions, while the highest EO content was obtained in plants exposed to severe stress conditions. Taking into account the evidence provided by this study, it can be inferred that the use of water deficit stress can serve as an effective method to stimulate and improve antioxidant properties, as well as the quantity and quality of secondary metabolites in Salvia subg. Perovskia.

Effect of Water Stress and Selenium Spraying on Vegetative and Yield Indicators of Garlic Allium sativum L.

A field trial was carried out at the research station of the Faculty of Agriculture - University of Kufa, Iraq, during the growing season in September 2022 to evaluate the effect of water stress and spraying with selenium on the growth and yield of garlic. Three irrigation levels (100%, 80%, and 60%) of the water required for garlic and three concentrations of selenium (0, 10, and 20) mg.L-1. A strip-plot system was set up within a randomized complete block design with three replicates, where irrigation levels were placed in the main plots and selenium concentrations were designated in the subplots. Plant height, number of leaves, total chlorophyll content, shoot dry weight, number of cloves, bulb weight, and bulb yield were recorded as the agro-physiological traits. Furthermore, analysis of variance exhibited significant differences between both factors and their interactions for all traits measured. The results showed significant differences in all the aforementioned traits when irrigation levels were reduced from 100% to 60% of the water requirement. Spraying selenium at 20 mg.L-1 achieved the highest values in most of the above-mentioned characteristics in comparison with the absolute control, which gave the lowest values. The interaction treatment (100% watering + 20 mg.L-1 selenium) provided the highest mean for plant height, number of leaves, number of cloves, bulb weight, and yield compared with the other treatments.

Response of Jasmine rice to different levels of irrigation and organic fertilization under SRI cultivation method

Maintaining a certain level of rice production must coincide with maintaining soil fertility, reducing pollution to the environment, and reducing water consumption. A field experiment was carried out during the 2020 summer growing season in a spot of Al-Issa county-Abbasiya district in the province of Najaf, in order to study the effect of different levels of irrigation and organic fertilizers on the growth, yield and components of the local rice variety Jasmine. The experimental plants were planted on June 17, according to the rice intensification system (SRI) method, by seedling method, at distances of 25 cm between seedlings and lines, with one seedling in the hole. Weeds were removed by hand three times. It was designed as a factorial experiment using a randomized complete block design (RCBD) with three replicates, where the irrigation levels (daily, 3 or 7 days irrigation intervals) as the main factor, while the organic fertilizers at two levels (10 and 5 ton.hˉ¹) were the secondary factor. The results showed that irrigation at 3 days intervals in clay soil mixed with the use of 10 ton.h-1 of organic fertilizers in SRI gave the highest rates of growth characteristics and yield components of Jasmine rice. In the case of irrigation and soil conditions in the study site, SRI is recommended to reduce water consumption and maintain an acceptable level of soil fertility, taking into account maintaining a level of production.

English

Drought is a highly important abiotic stress that affects crops around the world and especially under the Mediterranean climate. This study is focused on strawberry, an important species around the Mediterranean that is suitable for family-owned smallscale businesses. This study aimed to determine the effects of conventional deficit irrigation and fixed partial root drying techniques on the evapotranspiration (ET), yield and quality of Rubygem strawberry species. Strawberry seedlings were planted in the greenhouse in a double row at a planting distance of 30×30 cm. Irrigation was carried out by drip irrigation. The control - full irrigation was based on measurements taken from an A-Class Evaporation Pan. Three conventional deficit irrigation (DI80, DI60 and DI40) and four fixed partial root drying (FPRD100, FPRD80, and FPRD60 FPRD40) were examined. Irrigation water quantities were applied at the 100% (FPRD100/FULL), 80% (DI80 and FPRD80), 60% (DI60 and FPRD60) and 40% (DI40 and FPRD40) levels. The amount of irrigation water ranged between 199.17 and 452.92 mm. It was found that the various water levels affected the ET and the yield (Y). In general, as the amount of water decreased, the ET also decreased. The ET, Y, water use efficiency (WUE) and irrigation water use efficiency (IWUE) were significantly affected by irrigation treatments (LSD 5%). The yield values are ranked from high to low as FULL > FPRD100 > FPRD80 > DI80 > DI60 > FPRD60 > FPRD40 > DI40. As expected, WUE and IWUE values were higher under deficit irrigation levels i.e., DI80, DI60, DI40, FPRD80, FPRD60, and FPRD40. Fruit quality parameters (width, height and average weight) increased with the increase in the amount of applied irrigation water. In addition, fruit firmness values and total phenolic compounds were significantly affected by irrigation level. The results showed that different irrigation levels (100%, 80%, 60% and 40%) affected the yield and yield parameters of strawberry plants. In general, it has been found that, the yield and quality are negatively affected with increases in water deficit (DI40 and FPRD40 treatments). However, the results showed that the fixed partial root drying technique is superior to conventional deficit irrigation applications. As a result of the research, mainly FPRD80 and then DI80, DI60 and FPRD60 are recommended for strawberry cultivation, especially in arid and semiarid regions, depending on the availability of water

Foliar Spray with Selenium to Mitigate the Impact of Water Stress on Chemical, Enzymatic, and Hormonal Parameters of Garlic Allium sativum L.

The current research explored the beneficial role of selenium (Se) in alleviating the negative impacts of water stress on the chemical, enzymatic, and hormonal parameters of garlic plants via manipulating chemo-physiological mechanisms. A field experiment was executed at the research station of the Faculty of Agriculture, University of Kufa, Iraq in September 2022 using a randomized complete block design with three replicates based on a strip-plot system. Three water levels (100%, 80%, and 60%) were set up in the whole plots while foliar application of selenium (Se) with three concentrations (0, 10, and 20) mg.L-1 were assigned to the subplots. Our findings revealed a significant increase in the leaf content of free proline acid, sulfur, and ABA, as well as an increase in the activity of the antioxidant enzymes SOD and CAT when reducing irrigation levels from (100% to 60%) of the water requirement. While there was a significant decline in the plant hormones GA3 and IAA content in garlic leaves @ (60%) level of irrigation. The plants treated with foliar selenium @ (20 mg.L-1) enhanced most of the studied characteristics of garlic plants grown at different water levels. Moreover’ the full water requirement in combination with foliar Se @ (20 mg.L-1) provided the highest values of GA3 and IAA which were both comparable to the interaction treatment of water level @ (80%) and foliar Se @ (20 mg.L-1).

Interactive Effect of Deficit Irrigation and Water Quality on Yield and Water Use Efficiency of Red Cabbage (Brassica oleracea var. capitate L.) under Drip Irrigation

Deficit irrigation is emerging as a promising management practice to reduce water use with marginal loss in crop yield. Further, limited studies are available on the combined effect of water deficit and water quality on the water use efficiency of leafy vegetables like red cabbage in the semi-arid climate of Kirkuk. Therefore, this study was initiated to unveil the combined effect of varying deficit irrigation levels (0.5, 0.75, 1, and 1.2 of full irrigation) and two types of water quality (fresh and saline water) on water use efficiency of red cabbage under drip irrigation with two types of emitters. The results indicated that there is a steady increase in fruit yield with an increase in the level of irrigation with saline water over the entire range of applied water. The highest water efficiency was achieved under the combined effect of fresh water and GR and Turbo emitter when the level of applied water at full irrigation was reduced by a factor of 0.5 (20.31 kg/m3)(21.96kg/m3) respectively Furthermore, crop response factor analysis revealed that the red cabbage can tolerate deficit irrigation and produce satisfactory under both fresh and saline water were GR emitter with fresh and saline water given best value (0.627) (0.703) compeer with Turbo emitter with fresh and saline water given (0.292)(0.566)respectively. Additionally, further research is proposed to study the water productivity of red cabbage with saline water and take into account the yield of the same piece of land when the experiment is repeated for several years.

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.

Interactive Effects of Emitter Type, Water Salinity, and Deficit Irrigation on Red Cabbage (Brassica Oleracea L) with Evaluating Drip Irrigation System

Field research was carried out at Kirkuk Governorate (Altun Kopri district) near the village of Hasar Al- Kabeer for the agricultural season of 2022 to compare two types of GR and Turbo emitter and two levels of water salinity on yield (0.55 EC dSm-1), (4.40 EC dSm-1), with four levels of deficit irrigation (ETc 120%), (100% full irrigation) (75% ETc), and(0.50% Etc). The results were analyzed with a factorial split-split plot design, and the F-test and Duncan’s test determined the differences between factories and averages. The system was evaluated at the beginning of the experiment in comparison between GR and turbo emitter performance. Results were shown to outperform the GR emitter on the Turbo emitter in four qualities: coefficient of manufactured variety (% CV), uniformity of emitter flow (% Eu), uniformity field emission F.EU%, and absolute uniformity field emission F.Eua% with results of 0.01% 9.45% %,99.09%and 99.87 % The system was also evaluated in the middle of the experiment in comparison between fresh water and saline water in same qualities parameter. The results were shown by the superiority of fresh water over saline water as the results were (0.0379%), (0.0932%), (98.83%), (97.16%),(98.28),(98.93), and(99.85),(99.87)respectively. The most important results showed the superiority of the GR emitter interference treatment with freshwater at water stress level (100% ETc) in the total yield Mg ha-1 and plant height cm for red cabbage were 26.50 Mg ha-1 and 35.00 cm. Turbo emitter with saline water at 50% water stress given the best value (24.20 leaf plant -1).

Screening some pine species from North America and dried zones of western Asia for drought stress tolerance in terms of nutrients status, biochemical and physiological characteristics

Drought due to climate change or reduced precipitation is one of the main factors limiting the growth and establishment of plants and is one of the most critical challenges facing humans. To investigate the effect of different levels of drought stress on some pine species, this research was carried out as a factorial experiment using two factors and a completely randomized design. It included five populations of four pine species (Pinus brutia Ten. var. eldarica, P. nigra Arnold, P. mugo, and P. banksiana Lamb (including populations 8310055 and 8960049), and three levels of irrigation (100%, 75%, or 50% FC, denoted as normal, mild or intense drought stress, respectively) with three replicates. The findings showed that, photosynthetic pigments, relative water content, visual quality, the content of nutrients, protein content, and fresh and dry weight all decreased significantly when plants were exposed to intense drought stress. However, raised proline levels, electrolyte leakage percentage, soluble sugars levels, and antioxidant enzyme activity. We detected a decline in most growth traits when comparing mild drought stress conditions to normal irrigation, yet acceptable quality seedlings when compared to intense drought stress. Intense drought stress had a substantial impact on many pine seedlings. PCA results showed that among different pine species, the level of resistance to drought is as follows: P. mugo> P. brutia var. eldarica> P. nigra> P. banksiana 8310055> P. banksiana 8960049. Our novel finding was that, P. mugo is a resistant species in arid and semi-arid regions, and P. banksiana species, especially its population of 8960049, is sensitive.

Parameters of nitrogen use efficiency of Kentucky bluegrass cultivars at different N levels under deficit irrigation

AbstractIncreasing N use efficiency (NUE) is desirable in turfgrass management. Traditional definition of NUE in turfgrass is essentially the inverse of nitrogen concentration in the clippings and is often evaluated once in a growing season. In this experiment, we followed the Brenderse and Aerts' definition of NUE as the product of mean residence time (MRT) and nitrogen productivity (NP). The objective of this experiment was to identify NP changes over time in Kentucky bluegrass cultivars at different N levels under deficit irrigation. Nine Kentucky bluegrass (Poa pratensis L.) and two hybrid bluegrass cultivars from 10 phenotypic classes were tested under N rates of 10 and 40 g m−2. Deficit irrigation at 60% of the evapotranspiration was imposed. The results showed interaction effects on NP from N level, irrigation, and cultivar. Low‐N treatment resulted in higher NP values as compared to high‐N for ‘Merit’ and ‘Martha’. No NP difference existed between N or irrigation levels for ‘Blue ghost’, ‘Geronimo’, ‘Heidi’, ‘Bandera’, ‘Impact’, ‘Fielder’, ‘Jackrabbit’, and ‘Park’. ‘Rhythm’ showed lower NP values in high‐N combined with full irrigation compared to other treatments. In general, increasing N levels resulted in lower NP, but higher nitrate reductase activity (NaR) and higher net photosynthesis. No N by irrigation interaction effect was detected for effective quantum yield or NaR. In conclusion, leaf‐level NP was shown to be an effective parameter for in‐season monitoring of the above‐ground NUE of Kentucky bluegrass, which provided more dynamic information than clipping yields or a one‐time NUE calculation based on traditional definition.