Effects Of Different Irrigation Regimes Research Articles

Magnetization and oxidation of irrigation water to improve winter wheat (Triticum aestivum L.) production and water-use efficiency

Achieving optimal grain yield (GY) and water-use efficiency (WUE) is important for the sustainable development of wheat production. We evaluated the effects of different irrigation regimes on root vigor, root distribution, soil water, crop water productivity, GY, and WUE of winter wheat (Triticum aestivum L.) on the Guanzhong Plain of the Yellow River Basin. Laboratory experiments on the hydroponic cultivation of winter wheat comprised control (CK-G, CK-B), magnetization (GM, BM) and oxidation (GO, BO) groups of groundwater and brackish water. Field experiments on the growth of winter wheat included control (IG), magnetization (IGM) and oxidation (IGO) groups of groundwater irrigation. Three irrigation levels, 60, 120 and 180 mm, were used for each treatment (IGM60, IGM120 and IGM180, and IGO60, IGO120 and IGO180, respectively). Under GM and GO regimes, the surface tension and viscosity coefficient of magnetized and oxidized water decreased compared with CK-G, for up to10 hours and 8 h, respectively. The root vigor in winter wheat was 526 and 925 µg g−1 h−1 after GM and GO treatment, respectively, which was 101% and 253% higher than CK-G. Under IGM120 and IGO120 regimes, root length density at a soil depth of 0–20 cm increased by 23% and 24%, respectively, compared with IG, while the proportion of root surface area density at a depth of 20–60 cm changed by 105% and 89%. GY (11.68 ×103 kg ha−1 and 10.72 ×103 kg ha−1) and WUE (27.74 kg ha−1 mm−1 and 26.08 kg ha−1 mm−1) increased by 21% and 11%, and 21% and 14%, respectively. Between the greening and maturity growth stages, the available soil water storage in the 100–200 cm soil layer decreased by 68, 82 and 72 mm under the IG, IGM120 and IGO120 regimes, respectively. Fitted relationships between irrigation level and grain yield and the WUE indicated that 96 mm magnetized water irrigation was optimal for conserving water and increasing the efficiency of wheat irrigation on the Guanzhong Plain.

Effect of Root Canal Irrigants on Calcium Silicate Cements

Aim: The objective of the study was to compare the effect of different irrigation regimes on push out bond strength of calcium silicate cements – Biodentine and mineral trioxide aggregate (MTA). Materials and Methods: Forty-eight human teeth with single root canals were divided into three groups according to irrigation regimes. Each canal was irrigated with 5 ml of each irrigant during and after biomechanical preparation as follows: 3% sodium hypochlorite (NaOCl) and 17% ethylenediaminetetraacetic acid; 3% NaOCl during and Q mix 2 in 1 after instrumentation and distil water as the control group. Canals were filled with biodentine and MTA accordingly. A horizontal middle root section of 1.5-mm thickness was taken, and analysis was done under the universal testing machine. Statistical Analysis Used: The statistical analysis was done by the one-way analysis of variance and post hoc Tukey test. The comparative analysis was done by using the independent t-test. Results: The push-out bond strength of 3% NaOCl + Q mix 2 in 1 was highest. The least was of the control group. Conclusion: The irrigation regimes have a differential effect on root canal sealers.

Evaluation of the Effect of Different Irrigation Regimes on the Accumulation of Some Compatible Osmolytes and the Activity of Antioxidant Enzymes in Quinoa

کمبود آب باعث ایجاد محدودیت شدید زیست‌محیطی جهت تولید گیاهان زراعی می‌شود. گیاه کینوا با توجه به توانایی رشد تحت شرایط نامساعد محیطی و ارزش غذایی بالای آن در سال‌های اخیر توجه ویژه‌ای را به خود جلب کرده است. این آزمایش به‌منظور بررسی تاثیر دور آبیاری و سطوح مختلف آبیاری روی کینوا در سال 1398 در مزرعه تحقیقاتی دانشگاه کردستان واقع در دشت دهگلان به‌صورت کرت‌های خرد شده در قالب طرح بلوک‌های کامل تصادفی در 3 تکرار اجرا شد. چهار دور مختلف آبیاری شامل 4، 8، 12 و 16 روز آبیاری به‌عنوان فاکتور اول و چهار سطح آبیاری شامل آبیاری کامل (100% نیاز آبی گیاه)، 75%، 50% و 25% نیاز آبی گیاه به‌عنوان فاکتور دوم در نظر گرفته شد. نتایج حاصل از مطالعه نشان داد با کاهش آب در دسترس گیاه و افزایش فاصله دور آبیاری محتوای پرولین، گلیسین بتائین، کربوهیدرات‌های محلول و نامحلول و فعالیت آنزیم پراکسیداز و کاتالاز افزایش یافت اما عملکرد دانه کاهش یافت. افزایش فاصله دور آبیاری از 4 به 16 روز عملکرد دانه را 84/44% کاهش داد، همچنین عملکرد دانه گیاهانی که به میزان 25% نیاز آبی، آبیاری شده بودند در مقایسه با شرایط شاهد 47/56% کاهش نشان داد.

Growth responses and essential oil profile of Salvia officinalis L. Influenced by water deficit and various nutrient sources in the greenhouse.

Salvia officinalis L. is a medicinal plant extensively used in foods, traditional medicine, and the pharmacological industry. In the current study, the effects of different irrigation regimes [irrigation after 70 ± 5 (regular), 105 ± 5 (moderate drought stress), and 140 ± 5 (severe drought stress) mm evaporation] and nutrient sources (control, NPK, farmyard manure, foliar fertilizer, and hydrogel) were investigated on the growth parameters and essential oil (EO) components of S. officinalis in the greenhouse. The plants were harvested two times. The regular irrigation treatment had the most significant effect on plant height (51 cm), fresh and dry herb weight (51.5 and 18.1 g plant−1), and fresh and dry leaf weight (40.1 and 13.1 g plant−1). The highest amount of EO was observed after moderate drought stress (1.48%). The NPK treatment had the greatest effect on plant height (40 cm), branch number (19 per plant), fresh and dry herb weight (53.4 and 18.9 g plant−1), fresh and dry leaf weight (41.2 and 13.6 g plant−1), and EO content (1.67%). The 1st cutting was superior in EO amount, while the 2nd cutting had a high agronomic yield. α-Thujone (from 21.6 to 34.2%) was identified as the predominant compound. Additionally, the content of α-thujone in the 2nd cutting was higher after moderate drought stress, NPK, and hydrogel treatments. Moreover, 1,8-cineole, β-thujone, camphene, α-pinene, α-humulene, viridiflorol, borneol, and bornyl acetate were the other main compounds. As a general result, regular irrigation and NPK treatments improved the agronomic yield of S. officinalis. The plants under drought stress produced high amounts of EO. The farmyard manure also improved plant yield by providing a part of the plant's nutritional needs. Therefore, it could be concluded that it is crucial to determine the effects of limited water availability and various nutrient sources on yield and chemical compositions for medicinal and aromatic plant growth.

Effect of Irrigation Interval and Biological and Nitrogen Fertilizers on Grain Yield and Yield Components of Rice Cultivars

The effects of different irrigation regimes and the application of biological and chemical nitrogen (N) fertilizers on yield and yield components of rice cultivars in a field experiment at the Rice Research Institute of Iran, Rasht in 2018-2019 crop years were studied. The study was split-split plots based on the complete randomized block design with three replications. The main experimental factor was irrigation interval at three levels (flood irrigation and irrigation at intervals of 10 and 15 days), the second factor was fertilizer type at three levels [seedling root inoculation with Nitroxin biofertilizer, seedling root inoculation with Nitroxin biofertilizer + chemical N fertilizer to meet 50% of plant N requirement, and chemical N fertilizer (as urea) to meet 100% of plant N requirement], and the third factor was cultivar at two levels (rice varieties 'Hashemi' and 'Gilaneh'). The results showed that the combined application of the biological and chemical fertilizer (100% N) did not cause any significant differences in the yield of the rice cultivars. The flood irrigation produced 27.7% and 41.6% higher grain yield than the irrigation at intervals of 10 and 15 days, respectively. The number of unfilled grains per panicle was 20% higher in the treatment of 100% chemical N fertilizer than in the combined application of the biological and chemical fertilizers. The irrigation interval of 15 days with the combined application of the fertilizers consumed less water in both cultivars than the other treatments. The combined application of Nitroxin and chemical fertilizer not only was appropriate for yield and yield components, but it also decreased the effect of chemical N fertilizer application by 50%.

Вплив краплинного зрошення та навантаження суцвіттями на ріст і розвиток маточних кущів винограду

The high yield of grafted grape seedlings and their quality depend on many factors, including the quality of graft and rootstock components, which in turn is determined by proper care of the mother plantations of grape. Their farming techniques should be aimed at better growth and maturation of shoots. On mother bushes, the technological reception of shoot fragments is mandatory, partial removal of inflorescence is not so common in the agricultural techniques of mother plantings, but has a positive effect on the overall development of plants. Mother plantings should be irrigated if possible, as insufficient moisture supply negatively affects the condition of the bushes throughout the growing season and winter. In this work, the effect of partial removal of inflorescence (load of inflorescence 100, 75 and 50% of their total number) on mother bushes and the effect of different irrigation regimes (levels of pre-irrigation soil moisture 90, 80 and 70% of the lowest moisture capacity) on the condition of mother plantations, in particular on physiological, biochemical and biometric parameters of plants. It is shown that irrigation of bushes and reduction of inflorescence load to 50 and 75% of their total number stimulated the accumulation of chlorophyll in the leaves of mother plants, improved watering of leaf tissues, increased respiration during active growth and development of grapes. There is a positive effect of irrigation and reducing the load of inflorescence bushes to 50 and 75% on the biometrical parameters of mother grape bushes. The largest values of the total length of shoots and the degree of their maturation were in the bushes of variants with 90% the lowest moisture capacity, 50% inflorescence, 80% the lowest moisture capacity 50% inflorescence, 70% the lowest moisture capacity 50 and 75% inflorescence. Thus, effective irrigation regimes and reducing the load of inflorescence contributed to the growth of medium and strong full-fledged shoots, which are more productive.

Differential physio-biochemical and yield responses of Camelina sativa L. under varying irrigation water regimes in semi-arid climatic conditions.

Camelina sativa L. is an oilseed crop with wide nutritional and industrial applications. Because of favorable agronomic characteristics of C. sativa in a water-limiting environment interest in its production has increased worldwide. In this study the effect of different irrigation regimes (I0 = three irrigations, I1 = two irrigations, I2 = one irrigation and I3 = one irrigation) on physio-biochemical responses and seed yield attributes of two C. sativa genotypes was explored under semi-arid conditions. Results indicated that maximum physio-biochemical activity, seed yield and oil contents appeared in genotype 7126 with three irrigations (I0). In contrast water deficit stress created by withholding irrigation (I1, I2 and I3) at different growth stages significantly reduced the physio-biochemical activity as well as yield responses in both C. sativa genotypes. Nonetheless the highest reduction in physio-biochemical and yield attributes were observed in genotype 8046 when irrigation was skipped at vegetative and flowering stages of crop (I3). In genotypic comparison, C. sativa genotype 7126 performed better than 8046 under all I1, I2 and I3 irrigation treatments. Because 7126 exhibited better maintenance of tissue water content, leaf gas exchange traits and chlorophyll pigment production, resulting in better seed yield and oil production. Findings of this study suggest that to achieve maximum yield potential in camelina three irrigations are needed under semi-arid conditions, however application of two irrigations one at flowering and second at silique development stage can ensure an economic seed yield and oil contents. Furthermore, genotype 7126 should be adopted for cultivation under water limited arid and semi-arid regions due to its better adaptability.

EFFECTS OF DIFFERENT SOURCES OF IRRIGATION WATER ON THE GROWTH OF ZINNIA ELEGANS L. UNDER DROUGHT STRESS

The application of deficit irrigation water strategies to floriculture may make a significant contribution to irrigation water conservation. The purpose of this research was to evaluate the effects of different irrigation regimes for Zinnia ‘Solmar Yellow’ plants grown in an open field using different sources of irrigation water. Zinnia plants were grown in a field under three irrigation regimes, corresponding to 100% (control) of field capacity, 75%, and 50% of the irrigation needs. The water used for irrigation was derived from three sources: groundwater, distilled water, and blended water (50% ground-water + 50% distilled-water). In this investigation the vegetative growth, flower yield, pigment characteristics, ion content, leaf water potential, and leaf osmotic potential of plants exposed to these treatments were determined. Under the imposed drought conditions, the irrigation regimes with high or moderate quality water had the following effects: (i) a negative effect on the vegetative growth and flower yield, but a later flowering date; (ii) higher levels of leaf pigments in both distilled water and blended water irrigations at the 100% level; (iii) a decrease in leaf water potential and leaf osmotic potential; and (iv) a decrease in calcium, magnesium, and potassium ion contents but an increase in chloride and sodium ions under distilled water irrigation. In conclusion, irrigation with blended water (50% + 50%) at the 100% and/or 75% levels can be recommended for open field-grown Zinnia ‘Solmar Yellow’ production to enhance host plant tolerance to saline water and decrease the high cost burden of water desalinization.

Effect of irrigation regime and spraying salicylic acid on characteristics and quality of (Banzahir) lime fruits (Citrus aurantifolia B.) at harvest, marketing and some water relations.

Irrigation management is one of the most important factors for water saving, especially with limited water resources in Egypt. so, the present study was carried out during 2017 and 2018 on trees of Lime (Citrus aurantifolia), grown in sandy soil at Asyut Agriculture Research Station ARC, Asyut Governorate, Egypt, to elucidate the effect of different irrigation regimes; 100%, 80% and 60% of ETc and spraying (SA); with and without spraying on yield, fruit quality and marketability; room temperature and cold temperature. The results can be summarized as follows: irrigation with 100% ETc and spraying SA recorded the highest values of Fruit length, fruit width, Fruit weight and Yield compared with the other irrigation regimes. While, irrigation with 60% ETc and spraying SA recorded the highest values of irrigation water productivity and economic water productivity in both seasons. Also, irrigation fruits with 100% ETc and treated with SA during growth season induced the highest level of Juice weight %. Moreover, the obtained results indicated that irrigation fruits with 60% ETc and treated with SA decreased weight loss % and decay % while, increased TSS %, total acidity in fruit juice, and V.C content of mature fruit compared with the other treatments under marketability.

Effect of different irrigation regimes and fertigation levels on water requirement of turmeric

The agronomic investigation entitled, “Effect of irrigation regimes and fertigation levels on yield, quality and soil properties of turmeric (Curcuma longa L.) was undertaken during 2012-13 and 2013-14 on clay loam soil at Irrigation Water Management Project, Mahatma Phule Krishi Vidyapeeth, Rahuri. The irrigation regimes drip irrigation at 0.5 ETc was recorded maximum water use efficiency as well as higher water saving followed by irrigation regimes drip irrigation at 0.7 ET than rest of treatments.

Hay Yield and Water Use Efficiency of Alfalfa under Different Irrigation and Fungicide Regimes in a Semiarid Climate

Alfalfa is one of the most nutritive and high-yielding forage legumes planted in rotation with cereal crops across the United States. Under semiarid and arid climates with limited water resources, sustainable management of the available resources is required. The objective of this study was to investigate the effect of different irrigation regimes and fungicide applications on alfalfa in the high desert region of the Colorado Plateau of the U.S. Field experiments were conducted during the 2012–2014 period. Alfalfa was planted in fall 2012, uniformly irrigated for crop establishment and subjected to seven different irrigation regimes after the first cut in spring 2013. Alfalfa was treated by fungicide application and was harvested at 10% blooming. The maximum amounts of applied water were 350, 300, 208, and 312 mm, respectively, during the first, second, third, and fourth regrowth cycles in 2013, and 373, 282, 198, and 246 mm in 2014 for the respective regrowth cycles in 2014; the seasonal applied irrigation amount varied from 711 to 1171 mm in 2013 and from 328 to 1100 mm in 2014. The results showed non-significant effect of fungicide application on the forage yield. Alfalfa forage yield was significantly affected by the irrigation regimes and showed a third order polynomial relationship with the applied irrigation amounts during each regrowth cycle and on seasonal scale. Forage yield decreased from the first cut to the fourth cut and the annual forage varied from 10.6 to 25.7 Mg/ha for the treated alfalfa and from 11.5 to 25.6 Mg/ha for the non-treated alfalfa. Forage yield at each cut accounted for 39.6, 24.2, 17.6, and 18.6% of the 2013 season forage yield and 31.4, 23.8, 21.6, and 23.2% of the 2014 season forage yield, for the first, second, third, and fourth cut, respectively. Alfalfa water use efficiency varied from 0.06 to 3.3 kg/m3. The relationships developed in this study could be used by forage growers, crop consultants, and project managers for decision making and planning to improve the productivity of water under the semiarid and arid climate of New Mexico and the surrounding regions.

Deficit Irrigation on Guar Genotypes (Cyamopsis tetragonoloba (L.) Taub.): Effects on Seed Yield and Water Use Efficiency

For guar, a well-known drought and heat-tolerant industrial legume with a spring–summer cycle, limited research has been conducted into measuring the effects of drought on yield potential. A two-year field experiment was conducted to explore the effects of different irrigation regimes on yield, yield components and water use efficiency (WUE) on five cultivars of guar (Kinman, Lewis, Matador, Monument, and Santa Cruz) in a semi-arid Mediterranean environment. Three different water replenishment levels were used: fully irrigated (IH, 100% of the ET), and 50% (IM) and 25% (IL) irrigated. Seed yields ranged from 1.24 (IL) to 3.28 t ha−1 (IH) in 2011, and from 0.98 (IL) to 2.88 t ha−1 (IH) in 2012. Compared to IH, the two-year average seed yield reductions for IL and IM were 49% and 26%, respectively. Lewis and Santa Cruz showed significantly greater grain yields under fully-watered and water-limited conditions. The number of pods per plant achieved the highest positive direct effects on seed yield (r = 0.924***). The highest values of water use efficiency were observed in the IL water regime (1.44 kg m−3 with increments in improved water use efficiency of +34 and +95% when compared with IM and IH, respectively).

Performance of grapevine grown on reclaimed Mediterranean karst land: Appearance and duration of high temperature events and effects of irrigation

Stony karst landscape in the Adriatic coastal area has been cultivated for centuries to grow Mediterranean crops. Shallow and less fertile soils were mostly used for rain-fed grapevine and olive production. Native grapevine cultivars are, in general, well adapted to the warm and droughty climate, but a rapid drift in weather patterns characterized mostly by long-lasting high temperature events during the growing season urges the producers to apply irrigation. This research, studying the effects of different irrigation levels on Babić grapevine performance, was carried out in two growing seasons (2015 and 2016) with contrasting weather conditions in a vineyard established on a parcel of land derived from the stony surface of a limestone plateau on the very edge of the Eastern Adriatic coast. The study evaluated the effects of different irrigation regimes based on the quantification of grapevine water use (50, 75, and 100 % of crop evapotranspiration) by measuring the total leaf area, leaf gas exchange performance, and grape yield and quality. The irrigation treatments increased the total leaf area, net photosynthetic rate, average transpiration rate, and average mesophyll CO2 concentration. The yield components and grape quality were also affected by the irrigation treatments. Positive effects of irrigation in both the experimental seasons were associated with increased yield and total soluble solids (TSS), as well as synchronized TSS and phenolic ripening. Furthermore, water stress positively affected the concentrations of anthocyanins and other polyphenols in both years of the study. In 2015, extremely high temperatures reduced the grape yield, juice yield, and anthocyanin content in grapes in non-irrigated vines as well as in all irrigation treatments. Irrigation was efficient in reducing these negative effects, except in the case of the anthocyanin content.

Improving Irrigation Regimes and Plant Spacing to Maximize Rice Grain Yield and Water Productivity

Field experiments were initiated during 2017 and 2018 seasons at the Experimental Farm of Sakha Research Station, Kafr El-Sheikh, Egypt to explore the effects of different irrigation regimes and plant spacing on growth, grain yield and water productivity of Giza 179 rice cultivar. The experiments were laid out in a strip-plot design with three replications. Three irrigation treatments namely, continuous flooding (CF), irrigation every 6 (6D) and 9 days (9D) were located in the horizontal plots. However, the vertical plots were occupied by four plant spacing i.e. 15 x 20, 20 x 20, 25 x 20 and 30 x 20 cm. The main results revealed growth, grain yield and it components were significantly increased at CF and 6D compared to 9D treatment. The close spacing (15 x 20 or 20 x 20 cm) registered higher values of growth and grain yield than of wider one (30 x 20 cm). The density response gradually increased with prolonging irrigation from CF to 6D and recorded the maximum response to narrow spacing 9D treatment. CF recorded the highest amount of water usage, while the lowest amount was received by 9D treatment. Irrigation every 6 days gave similar grain yield to CF with less amount of water and gave reasonable water productivity. Generally, it could be concluded that, under the same conditions, using irrigation every 6 days with the close spacing (15 x 20 or 20 x 20 cm) leads to high values of growth, grain yield, and water productivity for Giza 179 cultivar.

Effect of Different Irrigation Regimes on Physiological Characteristics, Yield and Water Productivity of Potato Genotypes in Ardabil

Effect of Different Irrigation Regimes on Physiological Characteristics, Yield and Water Productivity of Potato Genotypes in Ardabil

Response of soil compaction to the seasonal freezing-thawing process and the key controlling factors

The seasonal freezing-thawing process can alleviate saline farmland soil compaction, and improve soil aeration and soil water retention. However, the response of soil compaction to the seasonal freezing-thawing process and the key factors affecting soil compaction are still unclear. Therefore, in this study, we conducted a regional monitoring of soil compaction and other soil physical and chemical properties before and after the 2016–2017 seasonal freezing-thawing period in Yongji Irrigation Area, Hetao Irrigation District, North China. We used a combination of genetic algorithm-projection pursuit evaluation, grey relational analysis and stepwise regression to analyze the measured soil physical and chemical properties and their variations during the freezing-thawing period. Using this method combination, we obtained one projection value to represent the whole-profile soil compaction, and found the most important influencing soil physical and chemical properties—soil water content, groundwater level and total inorganic nitrogen. Ultimately, we developed a regression model to predict soil compaction given the values of the predictive variables (soil water content, groundwater level and total inorganic nitrogen) at the same depth and time. The importance of autumn irrigation and planting structure, as well as the spatial heterogeneity of field management regime on the relationship between freezing-thawing processes and soil compaction were highlighted. Our findings provide solid foundations for regional field management policies, especially irrigation and drainage policies. Future studies are recommended to focus on the effect of different irrigation regimes, different drainage regimes and different nitrogen fertilizer application regimes on the relationship between the seasonal freezing-thawing processes and saline farmland soil compaction.

Determination of optimum irrigation and effect of deficit irrigation strategies on yield and disease rate of peanut irrigated with drip system in Eastern Mediterranean

This study aimed at examining the effects of different irrigation regimes (amount and frequency) on yield, water use, water productivity (WP), irrigation water productivity (IWP) and disease rate of drip irrigated peanut (Arachis hypogaea) during the 2014 and 2015 seasons in the Eastern Mediterranean region of Turkey. The treatments consisted of combinations of 3 irrigation frequencies (IF) (IF1: 25 mm; IF2: 50 mm; IF3: 75 mm of cumulative pan evaporation (CPE)), and 7 irrigation water levels (WL1 = 0.50, WL2 = 0.75, WL3 = 1.00 and WL4 = 1.25). WL1, WL2, WL3 and WL4 treatments received 50, 75, 100 and 125 of CPE. In addition, partial root drying (PRD) treatments WL5 = PRD50, WL6 = PRD75 and WL7 = PRD100 treatments were considered. They received 50, 75 and 100% of WL3 treatment from alternate laterals, respectively These 21 treatment combinations were arranged and analysed in a split-plot design with 4 replications. The main plots and subplots were established to irrigation frequencies (IF1, IF2 and IF3) and levels (WL1, WL2, WL3, WL4, WL5, WL6 and WL7). Both IF and WL were observed to have significantly influenced peanut yields at 1% level. In each of the experimental years, the largest and the smallest average peanut yields were acquired from the IF2WL4 and IF3WL1 treatments, respectively. Results indicated that peanut crops under PRD produced higher than those under deficit irrigation upon usage of the same volume of water amount. Significant linear relationships between irrigation – yield and evapotranspiration – yield were obtained during different irrigation frequencies in each season. The yield response factor (ky) was 0.58–0.65 in IF1, 0.65–0.70 in IF2 and 0.90–0.91 in IF3 plots in both years. Water stress raised the disease emergence in peanut markedly in the experimental years. The WP and IWP of PRD peanut were significantly greater than full irrigation and deficit irrigation (DI) treatments in both growing seasons, which demonstrated that limiting water did not reduce WP values. We conclude that DI treatments resulted in importantly lower WP (p ≤ 0.05) than PRD treatments in both years in spite of applying the same volume of water.

Modelling the Impact on Root Water Uptake and Solute Return Flow of Different Drip Irrigation Regimes with Brackish Water

Water scarcity and quality degradation represent real threats to economic, social, and environmental development of arid and semi-arid regions. Drip irrigation associated to Deficit Irrigation (DI) has been investigated as a water saving technique. Yet its environmental impacts on soil and groundwater need to be gone into in depth especially when using brackish irrigation water. Soil water content and salinity were monitored in a fully drip irrigated potato plot with brackish water (4.45 dSm−1) in semi-arid Tunisia. The HYDRUS-1D model was used to investigate the effects of different irrigation regimes (deficit irrigation (T1R, 70% ETc), full irrigation (T2R, 100% ETc), and farmer’s schedule (T3R, 237% ETc) on root water uptake, root zone salinity, and solute return flows to groundwater. The simulated values of soil water content (θ) and electrical conductivity of soil solution (ECsw) were in good agreement with the observation values, as indicated by mean RMSE values (≤0.008 m3·m−3, and ≤0.28 dSm−1 for soil water content and ECsw respectively). The results of the different simulation treatments showed that relative yield accounted for 54%, 70%, and 85.5% of the potential maximal value when both water and solute stress were considered for deficit, full. and farmer’s irrigation, respectively. Root zone salinity was the lowest and root water uptake was the same with and without solute stress for the treatment corresponding to the farmer’s irrigation schedule (273% ETc). Solute return flows reaching the groundwater were the highest for T3R after two subsequent rainfall seasons. Beyond the water efficiency of DI with brackish water, long term studies need to focus on its impact on soil and groundwater salinization risks under changing climate conditions.

Effects of Drip Irrigation Regimes Under Plastic Film on Sugar Beet Yield and Water Use Efficiency in Xinjiang

Abstract. This 2-yr study analyzed the effects of different irrigation regimes of drip irrigation under plastic film on sugar beet production in Xinjiang, China, and established a binary quadratic regression equation and normalization to describe the maximum root yield, sugar yield, and water use efficiency. Three irrigation frequencies (10, 11, and 12 d) and two irrigation water quotas (45 and 60 mm) were combined to form six treatments. Irrigation frequency had a significant effect on root yield at 1% level of significance in both years, but the effects on sugar yield and water use efficiency were nonsignificant. In both years, the sugar yield resulting from 60 mm irrigation water quota at frequency of 11 d increased by 10.8% and 6.5%, respectively, compared with that resulting from 45 mm irrigation water quota at frequency of 11 d. The regression equation based on the experimental observations indicated that in Xinjiang the optimal irrigation regime was 11 d and 55 mm which saved 21.2% irrigation water for the highest sugar beet yield. The data optimization to determine the weight of roots and evapotranspiration found that root growth exhibited a pattern similar to the aboveground crop growth, and the root growth was most rapid in the period 30 July to 10 August. Keywords: Irrigation frequency, Irrigation water quota, Optimal irrigation regime, Root growth, Root yield, Sugar yield, Water use efficiency.

Investigation the Effect of Different Irrigation Regimes on Root Development and Water Use Efficiency on Green Pepper

Investigation the Effect of Different Irrigation Regimes on Root Development and Water Use Efficiency on Green Pepper