Subsurface Drip Irrigation System Research Articles

Sub-Surface Drip Irrigation in Associated with H2O2 Improved the Productivity of Maize under Clay-Rich Soil of Adana, Turkey

Maize being sub-tropical crop is sensitive to water deficit during the early growth stages; particularly clay-rich soil, due to the compaction of the soil. It is well-documented that potential sub-surface drip irrigation (SDI) (Full irrigation; SDIFull (100% field capacity (FC)), Deficit irrigation; SDIDeficit (70% FC)) improves water use efficiency, which leads to increased crop productivity; since it has a constraint that SDI excludes soil air around the root-zone during irrigation events, which alter the root function and crop performance. Additionally, in clayrich soils, the root system of plants generally suffers the limitation of oxygen, particularly the temporal hypoxia, and occasionally from root anoxia; while SDI system accomplishes with the aerating stream of irrigation in the rhizosphere could provide oxygen root environment. The oxygen can be introduced into the irrigation stream of SDI through two ways: the venturi principle, or by using solutions of hydrogen peroxide through the air injection system. Therefore, the application of hydrogen peroxide (H₂O₂; HP) can mitigate the adverse effect of soil compactness and also lead to improving the growth, yield and yield attributes of maize in clay-rich soil. Considering the burning issue, a field study was conducted in consecutive two seasons of 2017 and 2018; where hybrid maize was cultivated as a second crop, to evaluate the effect of liquid-injection of H₂O₂ (HP) into the irrigation stream of SDI on the performance of maize in a clay-rich soil field of Adana, Turkey. When soil water content decreased in 50% of available water, irrigation was performed. The amount of water applied to reach the soil water content to the field capacity is SDIFull (100% FC) and 70% FC of this water is SDIDeficit (70% FC). In the irrigation program, hydrogen peroxide (HP) was applied at intervals of 7 days on average according to available water with and without HP: SDIFull (100% FC) + 0 ppm HP with full SDI irrigation; SDIFull (100% FC) + 250 ppm HP with deficit SDI irrigation; SDIDeficit (70% FC) + 0 ppm HP, SDIDeficit (70% FC) + 250 ppm HP and SDIDeficit (70% FC) + 500 ppm HP. Deficit irrigation (SDIDeficit (70% FC)) program was started from tasseling stage and continued up to the physiological maturity stage with sub-soil drip irrigation. H₂O₂ was applied 3 times during the growing season. Two years’ results revealed that the liquid-injection of H₂O₂ into the irrigation stream of SDI improved the growth and yield-related attributes and grain yield of maize. Based on the obtained results, during the extreme climatic condition in the year 2017, SDIFull (100% FC) + 250 ppm HP was more effective than SDIFull (100% FC) + 0 ppm HP on all traits for relative to full irrigation. While, during the favourable climatic condition in the 2018 season, SDIFull (100% FC) + 250 ppm HP was more effective than full irrigation with SDIFull (100% FC) + 0 ppm HP for the grain yield, grains, and SPAD value. Accordingly, the most effective treatment was SDIFull (100% FC) + 250 ppm HP, as it gave the highest growth and yield-related attributes and grain yield of maize followed by SDIDeficit (70% FC) + 250 ppm HP. Therefore, SDIFull with 250 ppm H₂O₂ using as liquid-injection may be recommended to mitigate the adverse effect of soil compactness particularly water-deficit stress in clay-rich soil for the sustainability of maize production.

Re-designing irrigated intensive cereal systems through bundling precision agronomic innovations for transitioning towards agricultural sustainability in North-West India

A study was conducted to design productive, profitable, irrigation water¸ nitrogen and energy use efficient intensive cereal systems (rice-wheat; RW and maize-wheat; MW) in North-West India. Bundling of conservation agriculture (CA) with sub-surface drip irrigation termed as CA+ were compared with CA alone and conventional tillage based and flood irrigated RW rotation (farmer’s practice; ScI). In contrast to conventional till RW rotation which consumed 1889 mm ha−1 irrigation water (2-yr mean), CA+ system saved 58.4 and 95.5% irrigation water in RW and MW rotations, respectively. CA+ practices saved 45.8 and 22.7% of irrigation water in rice and maize, respectively compared to CA with flood irrigation. On a system basis, CA+ practices saved 46.7 and 44.7% irrigation water under RW (ScV) and MW (ScVI) systems compared to their respective CA-based systems with flood irrigation (ScIII and ScIV). CA+ in RW system recorded 11.2% higher crop productivity and improved irrigation water productivity by 145% and profitability by 29.2% compared to farmers’ practice. Substitution of rice with maize (MW system; ScVI) recorded 19.7% higher productivity, saved 84.5% of irrigation water and increased net returns by 48.9% compared to farmer’s practice. CA+ RW and MW system improved energy productivity by 75 and 169% and partial factor productivity of N by 44.6 and 49.6%, respectively compared to ScI. The sub-surface drip irrigation system saved the fertilizer N by 20% under CA systems. CA+ in RW and MW systems recorded ~13 and 5% (2-yr mean) higher profitability with 80% subsidy on installing sub-surface drip irrigation system and similar profitability without subsidy scenario compared with their respective flood irrigated CA-based systems.

Subsurface Drip Lateral Line Depths to Protect against Root Intrusion

Root intrusion into emitters poses a threat to the lifespan of subsurface drip irrigation systems. In an attempt to address this problem, an experiment was conducted on spring wheat (Mengmai 30) grown in soil columns installed in a greenhouse to study the effects of lateral line depths to reduce root intrusion into emitters. The soil columns are rectangular containers, and the dimensions were 15 cm, 60 cm, 100 cm. The soil matric potential at a 20 cm depth immediately over (lateral line depth <20 cm), under (lateral line depth >20 cm), or next to (lateral line depth = 20 cm) the drip emitters was used to schedule the subsurface drip irrigation regime. Five different lateral line depths, with depths of 10, 20, 30, 40, and 50 cm, were maintained. The lateral line depths influenced the spring wheat root distribution, emitter flow rate, root intrusion, and spring wheat yield and quality. Results indicated that the shallower the lateral line depth, the more root was distributed in the surface layer. Root density values increased with soil depth. The emitter flow rate (eventual flow rate divided by the initial flow rate) increased as the lateral line depth decreased. All the treatments had root intrusion except 50 cm treatment. Root intrusion increased as the lateral line depth decreased. The lowest root intrusion rate (0%) was achieved with a lateral line depth of 50 cm. The greatest relative yield was achieved with a lateral line depth of 30 cm. After root intrusion and yield were both considered, the lateral line depth of 30–40 cm was a better choice.

Predicting Wetting Patterns in Soil from a Single Subsurface Drip Irrigation System

Soil wetted pattern from a subsurface drip plays great importance in the design of subsurface drip irrigation (SDI) system for delivering the required water directly to the roots of the plant. An equation to estimate the dimensions of the wetted area in soil are taking into account water uptake by roots is simulated numerically using HYDRUS (2D/3D) software. In this paper, three soil textures namely loamy sand, sandy loam, and loam soil were used with three different types of crops tomato, pepper, and cucumber, respectively, and different values of drip discharge, drip depth, and initial soil moisture content were proposed. The soil wetting patterns were obtained at every thirty minutes for a total time of irrigation equal to three hours. Equations for wetted width and depth were predicted and evaluated by utilizing the statistical parameters (model efficiency (EF), and root mean square error (RMSE)). The model efficiency was more than 95%, and RMSE did not exceed 0.64 cm for three soils. This shows that evolved formula can be utilized to describe the soil wetting pattern from SDI system with good accuracy. 

Estimación de la evapotranspiración de maíz forrajero apoyada con sensores remotos y mediciones in situ.

Irrigated agriculture requires better estimates of crop water demand. The aim of this study was to estimate the evapotranspiration (ETc) in forage corn through vegetation indices obtained in situ and estimated with remote sensing in the Comarca Lagunera, Mexico. The research was carried out in 2011 and 2012 in four 900 m2 plots irrigated with a subsurface drip irrigation system. Normalized Difference Vegetation Index (NDVI) and crop coeff icient (Kc) during crop development were determined. The initial, maximum and f inal NDVI values were 0.13, 0.79 and 0.63 for both methods and in both cycles. The maximum Kc values were obtained 54 and 48 days after sowing (DDS) with GreenSeeker, and at 61 and 59 DDS with satellite images in 2011 and 2012, respectively. The results showed a good relationship between ETc estimated in situ and ETc estimated with remote sensing (r = 0.98) for both years. Although the variation of ETc using both methods was 1.2 mm day‑1, early in the cycle and 7.4 mm day-1 to flowering start-milky grains. Water needs of forage corn were estimated with similar precision using remote sensing and in situ measurements. Therefore, both methods can be used to improve irrigation scheduling and preserve water resources in agriculture.

ENERGY CONSUMED, WATER PRODUCTIVITY AND VITAMIN (C) CONCENTRATION OF ORANGE CROP UNDER DIFFERENT IRRIGATION SYSTEMS

Food and water consider the key to life. The aim of this study is to increase water productivity and enhancing the quality of the orange crop (Citrus sinensis Osbeck L.). To a chive that aim, four irrigation systems (conventional surface irrigation (SI), furrow irrigation (FI), surface drip irrigation (SDI) and subsurface drip irrigation (SSDI) under heavy soil (clay) at the north of delta Egypt. Soil water content (SWC), soil temperature and soil EC were measured during the growing season under irrigation systems. At the end of the growth season yield and vitamin C were measured for three randomized samples for each treatment. Also, the energy consumed was estimated for each irrigation system. The results shown that the highest values of soil water content at depth 10 cm and along the distance of 200 cm from steam of tree were achieved under SSDI and SDI which increased SWC by 1.7 % and 1.2 % than SI, respectively and the lowest values of SWC was obtain at FI which decreased by 13.2 % than SI, while, at depth 50 cm the highest values of SWC were under SI, applying FI, SSDI and SDI systems decreased the SWC by 16.9 %, 14.7 % and 7.3% than FI, respectively. At depth 100 cm the highest value of SWC was 31.9 (cm3 cm 3) under FI, which increased by 40.2 % than SI, followed by SSDI and SDI by values 27.9% and 7.7%, respectively. Moreover, the results shown that, subsurface drip irrigation system (SSDI) gave the highest orange yield (6.1 Mg fed-1), followed by the surface drip irrigation (SDI) system of 6 Mg fed-1, while the lowest yield was obtained under SI system (5.2Mg fed -1). FI resulted in the higher yield compared with SI (5.4 Mg fed-1) but at the same time, the lower yield as compared with both the SSDI and SDI systems. On the other hand, SSDI system increased the yield by 40.1 %, followed by SDI by 25.8 % and FI by 8.6 % than SI. The highest concentration of vitamin C was 23.4 mg / 100g under SSDI, followed by values 16.83 and 14.52 (mg/ 100g) under SDI and FI, respectively and the lowest concentration was 12.11 under SI. The highest value of consumptive energy was 1044.4 (kwh / fed. season) achieved under SI, followed by 696.3 (kwh / fed. season) under FI and the lowest values were 613.1 and 642.3 (kwh / fed. season) under SSDI and SI, respectively.

Developing a centralized automatic control system to increase flexibility of water delivery within predictable and unpredictable irrigation water demands

Irrigation districts modernization has become a key strategy to address unreliable water resources and improve water use efficiency in irrigated regions. However, improving water use efficiency will be achieved when off-farm water distribution systems are integrated with on-farm practices within irrigation districts. In the present study a modernization alternative for irrigation canal operation, a centralized automated control system, was designed to handle both of known and unknown patterns of demanded water dictating by different irrigation systems in the farms. This alternative was developed in response to on-farm water management transitions from traditional, surface irrigation methods, to modern irrigation systems including the pressurized systems. The capability of Centralized Model Predictive Control (CMPC) was investigated for dealing with a set of complex water distribution test scenarios including predictable and unpredictable ±50% demand variations through the irrigation canal. Altus canal of the Lugert-Altus Irrigation District in southwest Oklahoma, USA is selected as the test case due to the recent challenges occurred in water distribution management in the Altus canal. The transition from traditional irrigation methods (i.e., furrow irrigation) to modern pressurized systems of subsurface drip irrigation (SDI) systems in large regions of the district caused the mentioned challenges. The results showed that when the demands were predictable, the controller successfully regulated water levels so that no off-take within the entire canal suffered from inadequate water delivery. Although the changes in the demand were considerable, stable canal operation was provided using the CMPC for this scenario. The designed controller also had an outstanding performance in dealing with extreme, unpredictable irrigation water taking test scenarios. The controller performed well with a quick hydraulic response to the changes, especially in the downstream canal reaches. The developed system started storing extra water within the canal reaches and employed it as a local inline reservoir to compensate delay times of water traveling within the irrigation canal. The stored water within the canal was entirely used after a sudden increase in any unknown demands.

Effect of Deficit Irrigation, Air injection and Nitrogen Fertilization on Water Productivity of Carrot under Subsurface Drip Irrigation System.

A field study was conducted in 2017-2018 to evaluate the effect of deficit irrigation, air injection and nitrogen fertilization on yield and water productivity of carrot under subsurface drip irrigation system. Experimental treatments were three levels ofdeficit irrigation (60%, 80% and 100%) of full crop water requirements and three types of nitrogen fertilizer(nitric acid(HNO3)48 % N, urea CO(NH2)2 46% N and ammonium nitrate(NH4NO3)33.5% N, with air injection treatment (12% air by volume of water). The results show that the yield and water productivity as well as the length of carrot root significantly increased for air injection treatments. On the other hand, the carrot diameter increase was not significant. The highest value of the carrot root yield (19.487 ton/fed) was obtained due to deficit irrigation 60% (I60%) and ammonium nitrate(NH4NO3)with air injection. Also, treatment of deficit irrigation (I80%) and urea fertilization CO(NH2)2 with air injection resulted 17.437 (ton/ fed) carrot roots which was significantly higher than that of non-air injection treatments. Also,the highest values of water productivity of carrot were 185.189 and 101.376 kg/m3obtained due to(I60%) with (NH4NO3)and co(NH2)2underair injection treatments, respectively. The highest lengths of carrot (cm) were 19.800 and 19.000 (cm)obtained due to (I80%) with CO(NH2)2and (I100%) with (NH4NO3), under air injection treatments, respectively. The highest values of carrotdiameter were 42.153 and 41.260 (mm) obtained due to treatment of full irrigation(I100%) and(NH4NO3) fertilizer withoutair injection and the treatment (I80%) and CO(NH2)2 fertilizer with air injection, respectively. Data from this study indicate that carrot yield and its water productivity can be improved byaerated sub surface drip irrigation system(SSDI).

Assessing Hydrus-2D Model to Investigate the Effects of Different On-Farm Irrigation Strategies on Potato Crop under Subsurface Drip Irrigation

The objective of this paper was to assess the performance of Hydrus-2D model to simulate the effects of different on-farm irrigation strategies applied on potato crop. The ability of the model to simulate the stress coefficient (Ks), obtained as the ratio between actual and maximum transpiration, and to define the productive function of potato crop under the semi-arid conditions of central Tunisia were also evaluated. Experiments were carried out on potato crop under full (FI) and deficit irrigation (DI) and two different water qualities supplied by means of a subsurface drip irrigation system. Results evidenced that the model, despite some discrepancies locally observed, can fairly accurately predict soil water contents and electrical conductivity around buried emitters. Furthermore, under water and salt stress conditions, “measured” Ks, based on crop water stress index (CWSI) obtained on thermal images, resulted in a good correlation with the corresponding estimated by the model (R2 = 0.8). The database collected during the three growth seasons also allowed the definition of the crop productive function represented by a linear relationship between the relative yield loss and Ks. This function represents a useful guidelines for the sustainable use of irrigation water in countries characterized by a semi-arid climate and a limited availability of water for irrigation.

Evaluation of aerated subsurface drip irrigation on yield, dry weight partitioning and water use efficiency of a broad-acre chickpea (Cicer arietinum, L.) in a vertosol

Chickpea is susceptible to water logging and responds to soil aeration. Oxygen deficiency at both a temporal and spatial scale could occur for a subsurface drip irrigated crop, particularly in heavy clay soils. Use of aerated water irrigation (oxygation) to overcome hypoxia in the rhizosphere was evaluated in broad-acre chickpea crops in 2006 and 2007, in a heavy clay soil of central Queensland, Australia. The injection of 12% by volume air into subsurface drip irrigation water (oxygation) to two consecutive broad-acre chickpea crops resulted in a beneficial effect on yield (gains of 27% and 10% for 2006 and 2007, respectively), but the effect of irrigation regimes at deficit and full irrigation (85 and 100% ETc) was not significantly different. Chickpea yield with aerated subsurface drip irrigation was much higher (3.24 and 2.05 t ha-1) compared to the 7-year (2008–2015) national average yield (1.13 t ha-1). The aerated irrigation resulted into significantly higher gross production water use index (GPWUI) and irrigation water use index (IWUI) particularly in the year when the crop was planted early in the season. There was no significant difference in response to either of these water use efficiency (WUE) indicators between irrigation treatments, with the exception of a significantly enhanced IWUI with the 85% ETc in the first season. These results were consistent with those for cotton on the same site, providing further justification for the capital investment required for oxygated subsurface drip irrigation (SDI) system.

Response of(Vitis vinifera L.)cv. Fantasy Seedless to water deficit treatments: Phenolic compounds and physiological activities

This paper describes an investigation on the effects of deficit irrigation treatments on phenolic compounds and physiological activities of Fantasy Seedless table grape variety. Research was conducted in Viticultural Research Institute of Manisa, located in Aegean Region of Turkey, during two consecutive years (2016–2017). Three irrigation treatments were assayed; namely full irrigation (T-F), deficit irrigations (T-35 and T-65). In T-F, soil water deficit in the 90 cm within the one week intervals was completed to the field capacity. T-35 and T-65 treatments received 35% and 65% of water applied to T-F. Sub-surface drip irrigation system was used in the research and soil water content was measured by MobiCheck probe while vine water status was monitored through midday leaf water potential before the irrigations. Results showed that water deficit treatments (T-35 and T-65) affected berry composition particularly individual phenolics [Gallic acid, (+)(−) Catechine, (−)-Epigallocatechin gallate, (−)-Epicatechin gallate, Caftaric acid, Chlorogenic acid, Caffeic acid, p-Coumeric acid, Ferulic acid, Sinapic acid, Trans-Resveratrol, Myricetin, Quercetin hydrate, Kaempferol, Oenin Chloride, Delphinidin Chloride, Cyanidin Chloride, Malvidin Chloride] differently. The highest Catechine content in the samples was obtained from T-65, T-35 and T-F treatments, respectively. Furthermore it was determined that DI treatments did not change the Myricetin and Quercetin hydrate contents in 2017. On the other hand minimum Ψmdvalue was observed from the T-35 treatment in both years. Last of all, our findings show a strong relationship between the amount of water and berry composition values especially individual phenolics which are benefical to health.

Modelación de la humedad del suelo para garantizar profundidad y espaciamiento adecuados mediante riego por goteo subterráneo en alfalfa

Introduction: A major design issue in implementing a subsurface drip irrigation (SDI) system is determining the appropriate drip tape placement depth to allow basic farming operations while still providing adequate water to the crop. Objective: To determine the appropriate placement depth of the SDI tapes using modeling techniques and classical soil mechanics theory. Methodology: The HYDRUS-2D program was used to determine the wetting pattern, after 12 h of irrigation, of a SDI emitter installed at 50 cm depth in three soil types: sandy clay loam (SCL), clay loam (CL) and loam (L), and classical soil mechanics theory was used to calculate the increase in soil stress at different depths. Results: The vertical capillary rise above the dripline was 27, 30 and 22 cm for SCL, CL and LF soils, respectively. The minimum dripline placement depth to avoid failure is 40 cm in SCL and L soils, and 35 cm for CL soil. Study limitations: The physical properties and hydraulic parameters of the soil were obtained from the literature, and the soil mechanics theory results were not calibrated with field measurements. Originality: This is the first study in which soil mechanics is used to determine the spacing and installation depth of SDI system tapes. Conclusions: This type of study is helpful in determining the SDI dripline placement depth to ensure adequate trafficability under these irrigation system

Using the step by step models to evaluate field application uniformity of subsurface drip irrigation systems

Compared to other irrigation methods, drip irrigation systems (DI) are considered one of the most efficient form of irrigation. Subsurface drip irrigation allowed reducing water losses by evaporation, runoff, and deep percolation comparing to other irrigation systems supplying water on soil surface. Field evaluation of Uniformity of water applications and its stability, however, are still a matter of controversy and deserve more investigation, since the collection of water discharged needs to excavate the soil around the emitters. Experiments carried out at the Department of Rural and Agrifood Engineering of Polytechnic University of Valencia allowed describing a methodology to assess the performance of drip irrigation through hydraulic characterizations and an emission uniformity coefficient, using the step by step models. Calculations evidenced that operating pressures on emitters ranged between 127.6 kPa and 131.7 kPa, whereas the corresponding flow rates varied from 4.00 L/h and 4.07 L/h, with an average value of 4.02 L/h. Variability in the emitters’ flow rate resulted very limited due to the short length of the lateral (25.6 m). However, more attention should be paid to this for a longer field dimensions. Consequently, the value of emission uniformity coefficient was equal to 96.3%, testifying the uniform water distribution within the sub-plot.

Corn and Sorghum ET, E, Yield, and CWP as Affected by Irrigation Application Method: SDI versus Mid-Elevation Spray Irrigation

Abstract. Greater than 80% of the irrigated area in the Southern High Plains is served by center-pivot irrigation, but the area served by subsurface drip irrigation (SDI) is increasing due to several factors including declining well yields and improved yields and crop water productivity (CWP), particularly for cotton. Not as well established is the degree to which the reduced soil water evaporation (E) in SDI systems affects the soil water balance, water available to the crop, and overall water savings. Grain corn ( L.) and sorghum ( L. Moench) were grown on four large weighing lysimeters at Bushland, Texas, in 2013 (corn), 2014 and 2015 (sorghum), and 2016 (corn). Evapotranspiration (ET) was measured using the lysimeters and using a neutron probe in the surrounding fields. Two of the lysimeters and surrounding fields were irrigated with SDI, and the other two were irrigated with mid-elevation spray application (MESA). The lysimeter-measured evaporative losses were 149 to 151 mm greater from sprinkler-irrigated corn fields than from SDI fields. When growing sorghum, the lysimeter-measured evaporative losses were 44 to 71 mm greater from sprinkler-irrigated fields than from SDI fields. The differences were affected by plant height and became smaller when plant height reached the height of the spray nozzles, indicating that the use of LEPA or LESA nozzles could decrease the evaporative losses from sprinkler-irrigated fields in this region with its high evaporative demand. Annual weather patterns also influenced the differences in evaporative loss, with increased differences in dry years. SDI reduced overall corn water use by 13% to 15%, as determined by neutron probe, while either not significantly affecting yield (2016) or increasing yield by up to 19% (2013) and increasing CWP by 37% (2013) to 13% (2016) as compared with MESA full irrigation. However, sorghum yield decreased by 15% and CWP decreased by 14% in 2014 when using SDI compared with MESA full irrigation due to an overly wet soil profile in the SDI fields and deep percolation that likely caused nutrient losses. In 2015, there were no significant sorghum yield differences between irrigation methods. Sorghum CWP was significantly greater (by 14%) in one SDI field in 2015 compared with MESA fully irrigated sorghum. Overall, sorghum CWP increased by 8% for SDI compared with MESA full irrigation in 2015. These results indicate that SDI will be successful for corn production in the Texas High Plains, but SDI is unlikely to benefit sorghum production. Keywords: Corn, Crop water productivity, Evaporative loss, Evapotranspiration, Irrigation application method, Sorghum, Water use efficiency, Weighing lysimeter.

UTILIZATION CHEMIGATION TO REDUCE PEAS CONTAMINATION WITH PESTICIDE IN NEW RECLAIMED LANDS

the aim of this study is to reduce Peas contamination with herbicide by applying chemigation in new reclaimed lands through drip irrigation systems. The herbicide (butralin) was injected with recommended rate (2.5 Kg/Fed) through subsurface and surface drip irrigation systems with two flow rates of 8 and 12 l/h/m tube under sandy soil conditions in winter and summer seasons 2016. The results showed that the highest productivity of the peas was (5570 kg / Fed) with water use efficiency (WUE) of (2.31 Kg / m3) and more uniformity under the following conditions: the subsurface drip irrigation system at an flow rate of 8 l / h/m – tube (dripper flow rate of 4 l/h) and 50 cm emitters spacing, injection of the herbicide (butralin). It is wearthly to mention that no (butralin) residues were found in Pea yield produced under subsurface drip irrigation systems (10 cm depth), 50 cm emitters spacing and 8 l/h/m flow rate under the manured sandy soil.

Registration of Seven Upland Cotton Germplasm Lines (PSLC‐U01, PSLC‐U02, PSLC‐U03, PSLC‐U04, PSLC‐U05, PSLC‐U06, and PSLC‐U07) for the Texas High Plains Possessing Superior Fiber Traits and Good Yield

Seven upland cotton (Gossypium hirsutum L.) germplasm lines—PSLC‐U01 (Reg. No. GP‐1038, PI 687031), PSLC‐U02 (Reg. No. GP‐1039, PI 687032), PSLC‐U03 (Reg. No. GP‐1040, PI 687033), PSLC‐U04 (Reg. No. GP‐1041, PI 687034), PSLC‐U05 (Reg. No. GP‐1042, PI 687035), PSLC‐U06 (Reg. No. GP‐1043, PI 687036), and PSLC‐U07 (Reg. No. GP‐1044, PI 687037)—were developed by the USDA–ARS and jointly released with Cotton Incorporated in 2017. The plant stress laboratory cotton (PSLC) germplasm lines originated from the cross of two distinct commercial cultivars from different cotton growing regions of the United States, ‘Phytogen 72’ (PHY 72 [female] far west [PVP #200100115]) and ‘Stoneville 474’ (STV 474 [male] mid‐south [PVP# 9400152]). The PSLC‐U01 to PSLC‐U07 lines were originally selected from a total of 137 F7 recombinant inbred lines in 2014; each line derived from a single seed or plant decent (F1:7). In 2014 and 2016, at the USDA–ARS Plant Stress and Germplasm Development Research Unit, Lubbock, TX, 137 and 27 lines were evaluated in a randomized complete block design with three and four single 6.1‐m‐plot replications under two irrigation regimes (regular and reduced by half using subsurface drip irrigation system), respectively. In 2016, 7 lines of the 27 advanced breeding lines (PSLC‐U01, PSLC‐U02, PSLC‐U03, PSLC‐U04, PSLC‐U05, PSLC‐U06, and PSLC‐U07) were selected for release on the basis of good overall agronomic performance and superior fiber quality properties in these tests when they were compared with original parents and four upland commercial check cultivars.

Response of micro-irrigation systems on growth, yield and WUE of Pomegranate (Punica granatum L.) in semi-arid regions of India

The effects of various micro-irrigation systems on some parameters of Pomegranate (Punica granatum L. cv. Bhagwa) i.e. physiological, yield, fruit qualities, root density, water use and water use efficiency parameters studied in the field experiments. Six types of micro-irrigation treatments with four replications were applied: 4-subsurface and 2-surface micro-irrigation were presented along with the 1-inline lateral at dripper spacing 30 cm, 2-inline laterals at drippers spacing 30 x 30 cm, 2-inline laterals at drippers spacing 40 x 40 cm; 2-inline laterals at drippers spacing 50 x 50 cm; 1-online lateral with 2-drippers (2D) and 2-online laterals with 4-drippers (4D), respectively. Maximum plant height, steam diameter, leaf area index, flowers, nutrient status and yield was recorded in subsurface drip irrigation system (SDI) with 2-inline laterals (30 x 30 cm) followed by (40 x 40 cm), (50 x 50 cm), surface drip irrigation (DI) with 2-laterals and 4drippers, 1-inline lateral at dripper spacing 30 cm and 1-online lateral with 2drippers. Soil moisture withholding was also higher in the SDI with double inline laterals (30 x 30 cm). The total average quantities of water used ranged from 2520.20 to 8340.60 Lbahar−1 t−1 and water use efficiency was found to be ranged from 1.98 to 4.01 kg m-3 in micro-irrigation systems. The biophysical advantages are low canopy humidity and fewer diseases and weeds. The results showed that 30 x 30 cm inline double lateral enhanced the flowering intensity, yield, root density and water use efficiency of pomegranate.

Evaluation of Drip Irrigation System for Water Productivity and Yield of Rice

Core Ideas Drip irrigation improved the aerobic rice yield and water savings by 29 and 50%, respectively. The subsurface drip laid out at 0.8 m lateral distance with 1.0 L per hour dripper discharge irrigation system performed better in rice growth, physiology, and yield. Drip irrigation favored the root oxidizing power, canopy photosynthesis, and dry matter partitioning. There is a twofold increase in water productivity of aerobic rice under drip irrigation system. The use of drip irrigation in upland rice (Oryza sativa L.) cultivation is a contemporary water‐saving strategy. However, inadequate evidence is available related to consequential changes in water productivity on rice yield. The effects of distinctive drip irrigation treatments, namely differences in lateral distances (0.6, 0.8, and 1.0 m), dripper discharge rates (0.6 and 1.0 L per hour, Lph), irrigation methods (surface and subsurface), and the conventional aerobic rice production system (control) on, physiology and water productivity of rice were studied during the summer of 2012 and 2013. Grain yield significantly increased in the subsurface drip irrigation method laid out at 0.8 m lateral distance and in 1.0 Lph discharge rate (5389 kg ha−1) compared with control irrigation method (4181 kg ha−1). This treatment mounts up dry matter partitioning, leaf photosynthesis as well as root oxidizing power. In addition, drip irrigation in aerobic rice production system had twice the water productivity and stimulates longer roots with higher density compared with control irrigation method. The subsurface drip irrigation system with drippers/laterals of 0.8‐m distance with flow rate 1.0 Lph, in aerobic rice production system is a cost‐effective method and had the potential to save water (27.0%) without compromising grain yield in comparison to control irrigation method. This could be the promising technology to be recommended for aerobic rice production system.

IRRIGATION MANAGEMENT OF PEPPER CROP UNDER SURFACE AND SUB-SURFACE DRIP IRRIGATION SYSTEMS BY USING EXPERT SYSTEM, IRRIMET AND CROPWAT

The scarcity of water in Egypt need for hard work to solve it. One of the best solutions is good management of limited water, therefore, this paper aims to provide farmers and decision-makers with a new accurate and cheap technique for water management. The experimental work was carried out in the farm of Faculty of Agriculture, Benha University (300 21/ 26.24// N and 310 13/ 15.89// E) during the summer seasons of 2016 and 2017. Three irrigation management tools (Expert system (ES), IRRIMET model (IM) and Cropwat model (CW)) were applied with surface and sub-surface drip irrigation systems. The results showed that the highest values of water saving were achieved by IM model followed by ES tool. Also, the estimated values of reference evapotranspiration (ETo), single crop factor (Kc) and crop evapotranspiration (ETC)under ES were very close to that obtained under IM model while under CW model the corresponding values were far from that under IM model especially the ETc values. Yield were achieved under subsurface drip irrigation system (SSDI). On the other hand, the IM model gave the highest values of pepper yield, water productivity (WP) and nutrient use efficiency (NUE) (6.86 ton h-1, 1.59 kg m-3 and 21.17 kg kg-1, respectively, with SSDI and 6.71 ton h-1 , 1.64 kg m-3 and 20.75 kg kg-1, respectively, with SDI), followed by ES (6.02 ton h-1 , 1.3 kg m-3 and 17.28 kg kg-1, respectively with SSDI and 4.31 ton h-1 , 1.09 kg m-3 and 13.76 kg kg-1, respectively with SDI. However, the differences between the values resulted from using ES and IM were not significant. The lowest values of pepper yield, WP and NUE were achieved with the management based on CW model outputs.

INFLUENCE OF DEFICIT IRRIGATION AND PARTIAL DRY OF ROOT ZONE ON SQUASH CROP YIELD AND WATER USE EFFICIENCY

The main objectives of this research were to study the effects of sustained deficit irrigation (SDI) and partial drying of root zone (PRD) on yield and water use efficiency of squash (Cucurbita Pepo, L. Oto) crop. To fulfill these purposes, a field study was conducted in the experimental farm of Faculty of Agriculture, at Moshthor, Benha University, Egypt, for the two successive seasons of late summer (2016 and 2017), under both drip surface (DSI) and subsurface irrigation (SSDI) systems. Five irrigation treatments were undertaken. The first (FI-100%) was corresponding to full crop water requirements (FWR), and soil water deficit was replenished to field capacity when 50% of the available water was exhausted, depending on root depth which was predicted by a root depth model. The second treatment was corresponding to 80% of the FWR (SDI-80%), the third one was corresponding to 70% of FWR (SDI-70%), the fourth one was corresponding to 70% of the FWR and partial drying of root zone (SDI-70%+PRD), and in the last treatment (SDI-50%), the crop was irrigated at 50% of full water requirement FWR. In the treatment (SDI-70%+PRD), the root zone was irrigated partially but from alternate laterals. The results show that surface drip irrigation (DSI) resulted in lower WUE and lower yield of squash than the sub-surface drip irrigation (SSDI), although with the subsurface drip irrigation system water consumption is less than with the surface drip irrigation by 5 %. The treatment (FI-100 %) resulted in both the highest WUE and squash yield either with surface or sub-surface. The treatment SDI-80% resulted in WUE and yield not significantly different from FI-100%. SDI-70%+PRD resulted in WUE and yield almost equal to those achieved with SDI-80%.