Deep Percolation Losses Research Articles

Improving Irrigation Performance of Raised Bed Furrow Using WinSRFR Model

Agricultural productivity is intricately tied to efficient water management strategies, with raised bed furrow systems being a prevalent method for irrigation. However, the optimization of these systems remains a critical area of exploration. The border irrigation method is commonly employed in developing countries for irrigation and leads to significant water loss, reduced irrigation efficiency, and increased irrigation durations. In contrast, raised bed furrow irrigation represents an improved surface irrigation technique that optimizes water usage in irrigated systems. This study seeks to assess the irrigation performance of raised bed furrows, encompassing deep percolation loss, distribution uniformity, adequacy, and application efficiency. The evaluation will be conducted for both existing conditions and an optimized scenario achieved through the application of the WinSRFR model. Field data facilitated the numerical simulation and the model was calibrated to reflect the existing irrigation system dynamics accurately. The performance of the model was assessed by utilizing the statistical indicator of root mean square error (RMSE) and revealed good agreement between advance and recession time. Results revealed that existing raised bed furrow irrigation exhibited up to 40% deep percolation loss, 80% distribution uniformity, and 60% application efficiency. Increasing furrow length had adverse effects; decreased application efficiency and distribution uniformity; and increased deep percolation losses. In contrast, reducing the furrow length and cutoff time by up to 33% and 40%, respectively, and increasing the width and inflow rate by up to 55% and 100%, respectively, enhanced the application efficiency and distribution uniformity, and minimized deep percolation loss. Overall, improved raised bed furrow irrigation provides a more efficient option and is encouraged to adopt for irrigation.

Effect of high frequency subsurface drip fertigation on plant growth and agronomic nitrogen use efficiency of red cabbage

High emissions of nitrogen to the environment are one of the major drawbacks of modern agriculture. Subsurface drip fertigation (SDF) is a technology to apply fertilizer in small amounts continuously and directly into the root zone with the potential of mitigating deep percolation losses when accurately managed. Our study was established to analyze possible benefits of SDF, i.e. nitrate losses reduction without decrease in yield, as alternative to the conventional application of nitrogen fertilizer. In this five-year field study, effects of SDF on red cabbage (Brassica oleracea) growth, yield, root distribution and nitrogen uptake were evaluated. The experiments took place in northern Germany. Application of fertilizer in a solution with water was managed to match the needs of crops and placed directly in the root zone through permanently buried driplines. The outcomes of crop growth under SDF were compared with a control crop receiving fertilizer at one or two dates by surface broadcasting. Yield and agronomic nitrogen use efficiency were higher for crops grown under SDF. Total dry mass increase was especially high under dry conditions (34%) but as well under wet conditions with efficient management (20%). Head dry mass of crops grown under SDF had a stronger reaction to the available nitrogen than crops under conventional application, with values of 0.19 and 0.1 Mg ha-1 per kg N ha-1 respectively. Moreover, SDF treatment resulted on average ca. 14 kg ha−1 higher nitrogen uptake. In SDF plots, yield formation and nitrogen uptake was higher for plants grown directly above drip lines. Effect of the distance to nitrogen source was supported with numerical simulations. The root structure showed different distributions for the two treatments, particularly in years with low rainfall. Overall, the results showed the potential of SDF to effectively control nitrogen supply, thereby increasing yield formation of marketable plant organs.

Reducing Water, Nutrient, Pesticide, and Carbon Footprints and Costs for Drip-Irrigated Vine Crops with Compact Bed Plasticulture

Highlights Narrower and taller compact beds (CB) were designed to increase the system efficiency of drip-irrigated plasticulture. CB lowered water, fertilizer, plastic, pesticide, and fuel inputs while maintaining watermelon yield. CB reduced GHG emissions and input costs while increasing input productivity. CB are a synergistic and win-win climate-smart design to increase the sustainability of high-intensity plasticulture. Abstract. Raised bed plasticulture, used globally for producing high-value fruits and vegetables, is a high input and high intensity production system. We show that improved water and nutrient efficiency with reduced material inputs, costs, and carbon footprint is achieved with the use of taller and narrower plastic-mulched compact beds [61×30 (width × height in cm), 61×10, 46×30, and 41×30] compared to the wider and shorter conventional bed [76×20] used for growing watermelon. The primary motivation behind the compact bed design is to improve economic and environmental sustainability by reducing the bed width, to increase the fraction of the bed that is wetted by drip irrigation and to reduce the area of farmland covered under plastic. Compact beds were evaluated at two locations in South Florida with different hydrologic settings, using an ensemble of field data (inputs, plant health, yield, soil moisture, and nutrient levels) and a field-verified hydrologic model (HYDRUS). No reduction in yields was observed with compact beds, indicating no production risk for the growers. Compact beds conserve water and reduce deep percolation losses by 6 cm compared to conventional beds, thereby improving water productivity by 20%. Compact beds require less fertilizer (10%-50%) to maintain the same nutrient (N-P-K) concentrations as those in conventional beds because of smaller soil volumes. Reductions in water and fertilizer inputs provide the environmental benefit of reducing nutrient leaching to groundwater, while reduced impervious area reduces runoff losses. Compact beds reduced input (fertilizer, plastic mulch, pesticide, and diesel) costs of the system by US$720/ha and greenhouse gas emissions by 1630 kg CO2e/ha (9%) compared to conventional plasticulture. The annual cost savings create a win-win for farmers to increase profits and/or invest in conservation measures such as precision irrigation. Compact beds offer a climate change mitigation and adaptation strategy for the plasticulture system for watermelon and other similar cucurbit crops (e.g., cucumber, pumpkin, and zucchini). Keywords: Climate-Smart Agriculture, Economics, Greenhouse Gas Emissions, Nutrient Leaching, Sustainable Design, Water Conservation.

Reducing Deep Percolation Losses Using a Geotextile Layer at Different Soil Depths and Irrigation Levels for Lettuce Crop (Lactuca sativa L. var. capitata) (Limor)

Due to rising food demand and the limitation of water resources, achieving water security is essential. The lettuce crop is affected when grown under limited water supplies as it produces small heads, especially during the late growing stage. For this reason, it is important to maximize water use efficiency and crop productivity. Two successive experiments were conducted during 2021 and 2022 to reduce losses via deep percolation using a geotextile layer at different soil depths under different irrigation levels of the lettuce crop (Lactuca sativa L. var. capitata). This study aims to reduce water losses due to deep percolation and improve crop growth and yield parameters for iceberg lettuce under subsurface drip irrigation in sandy loam soil conditions. In order to achieve these aims, different amounts of irrigation (100, 80, and 60% of crop evapotranspiration “ETc”) and a geotextile layer at different soil depths (20, 30, and 40 cm from the soil surface) were used. The results revealed that the use of a geotextile layer with 20 and 30 cm depths significantly improved irrigation application efficiency and noticeably increased soil water content in the root zone. The observed results during both seasons showed that geotextile layers at 20, 30, and 40 cm depths under irrigation of 100% ETc significantly increased vegetative growth characteristics (plant height, head diameter, head circumference, head volume, plant fresh weight, and leaf area) and crop productivity compared to the control (without geotextile). In particular, the geotextile layer at a 30 cm depth under irrigation of 100% of ETc was the most statistically effective treatment in this study, with yield values of 69.3 and 67.5 t ha−1 in the two seasons, respectively. However, the treatments of geotextile layers at 20 and 30 cm depths under irrigation of 80% of ETc also recorded statistically effective results for crop growth parameters and yield in this study. In general, geotextiles can be used at different depths as an irrigation management practice to reduce deep percolation in the field.

Sustainable irrigation management in tropical lowland rice in Brazil

Drought events and water use conflicts drive the need for more efficient water management in rice-growing areas of the Brazilian Cerrado. Recent studies have shown the advantages of adopting water-saving irrigation in the region but a comprehensive assessment is needed. This study aims to model the performance of rice cultivation and water productivity in the tropical floodplains of the Cerrado biome of northern Brazil in response to irrigation management under contrasting seasonal rainfall levels. Twenty-seven scenarios of rice cultivation, resulting from the combination of three sites, three irrigation treatments, and three rainfall regimes, were simulated with the calibrated and validated hydrological model SWAP/WOFOST. The rainfall levels high (1501 mm), intermediate (952 mm), and low (510 mm) were relative to 120 days and obtained from weather stations located in the region. Two irrigation methods (flooding and water-saving irrigation) were compared against rainfed cultivation. Actual transpiration of the flooding and water-saving irrigation was 9 % and 4 % higher in the intermediate and high rainfall scenarios while it was 30 % and 20 % higher in the low rainfall scenario compared to the rainfed treatment. The largest deep percolation loss was 12700 mm per season for flood irrigation in the low rainfall scenario, whereas the lowest one was 349 mm for the rainfed treatment in the low rainfall scenario. Changing from flooding to water-saving irrigation increases water productivity by an average of 9 % and decreases relative grain yield by 5–12 %. Water productivity based on bottom flux increased on average by about five times (high rainfall scenario) to ten times (low rainfall scenario) when comparing flooding with water-saving irrigation. Results suggest that saving irrigation based on crop transpiration can reduce deep percolation losses and increase water productivity in the rice-growing areas of the Brazilian Cerrado.

Prospects of Hydrogels in Agriculture for Enhancing Crop and Water Productivity under Water Deficit Condition

In arid and semiarid regions and under rainfed conditions, water availability is one of the principal ecological constraints that hinder agriculture’s sustainability. The super absorbent polymer (agricultural) is water-absorbing and is cross-linked to absorb aqueous solutions through bonding with water molecules. It is a new approach to water management under water-stressed conditions to conserve soil moisture in the active rooting zone of crops by reducing the evaporation, deep percolation, and runoff losses. Agricultural hydrogels are water retention granules which swell their original size to numerous intervals when they come in contact with water. It can absorb and retain a huge amount of moisture under plentiful rainfall and irrigation events and release it back to the soil for mitigating crop water demand when the rhizosphere zone dries up under drought conditions. It plays multifarious roles in agriculture including soil-water retainer, nutrient and pesticide carriers, seed coating, soil erosion reducer, and food additives. It has the extraordinary ability in improving different physicochemical, hydrophysical, and biological properties of soil, simultaneously decreasing irrigation frequency, enhancing the water and nutrient use efficiencies, and increasing the yield and quality of the field, plantation, ornamental, and vegetable crops. These biodegradable materials are nontoxic to the soil, crop, and environment. Hence, the addition of the hydrogel polymer will be a promising and feasible technological tool for augmenting crop productivity under moisture stressed conditions.

English

The overall objective of this present research is assessment of rice-water requirement in Cyabayaga wetland of Nyagatare District in Rwanda. Specific objectives of this research project were to collect and analyze weather parameters, of soil physical properties, crop-water requirements and to recommend efficient water management of the study area. Research design, data collection and field observations were made during July, 2019 to January, 2020. The experiment was carried out in Cyabayaga marshland and was especially based on the assessment of rice water requirement, weather parameters and hydraulic parameters like measurement of soil infiltration rate, soil hydraulic conductivity, flow discharge in irrigation channels, water loss, conveyance efficiency and application efficiency. Evapotranspiration and irrigation needs were determined by Cropwat 8.0 software. Conveyance efficiency (Ec) was found to be 70.05% and 30% of water was lost through seepage and evapotranspiration through weeds in unlined channels. The overall deep percolation, seepage and evapotranspiration losses were found to be 25 mm/day. Considering the highest potential crop evapotranspiration (ETc) of 4.8 mm, it was indicated that huge water loss of 20.2 mm/day was caused by seepage and percolation within the soil. The application efficiency (Ea) was found to be 23.8%. Hence, the overall efficiency was 16.7%. With the current rice yield of 4.25 t/ha, a low water-use-efficiency of 0.089 kg/m3 was found.   Key words: Cropwater requirements, rice, irrigation requirements, water use efficiency and Cropwat.

Efficiency, Adequacy, and Uniformity for Normal Distribution of the Application Depths

The research aims to find a set of figures in case of the normal distribution of application depths that represent relationships for the parameters used to describe the performance characteristics of the irrigation system. Using 6010 values ​​for each of the dimensionless application depth, dimensionless cumulative area, and the coefficient of variation, with the help of the SPSS statistical program, an empirical equation was obtained to estimate the dimensionless application depth as a function of the dimensionless cumulative area and the coefficient of variation. Five figures were developed containing the relationships between dimensionless net depth of irrigation, application uniformity, coefficient of variation or uniformity coefficient, application efficiency or deep percolation losses, and storage efficiency or deficit coefficient. By knowing two of these parameters, the rest of them can be easily found from these figures.

Estimation of Irrigation Return Flow in Sandy-Loam Soil using Water-balance Approach

In this study, irrigation return flow (deep percolation) has been estimated by using water balance approach. The experimental setup consisted of two lysimeters installed at the College of Agricultural Engineering & Technology field lab, SKUAST-Kashmir, Shalimar in which pea crop was grown, simulating the natural conditions available in the vicinity of lysimeter. Regular measurements of soil moisture were made at the depths 0-20 cm, 20-40 cm, 40-60 cm, 60-80 cm and 80-100 cm using gravimetric method. The evapotranspiration estimates were determined using FAO-Penman-Monteith equation. The deep percolation was calculated using the water-balance approach. The deep percolation losses calculated by water-balance approach are comparable to the observed values of deep percolation obtained by the lysimeters. The observed and the calculated values of deep percolation have 7.65% (using water balance method) difference. Results obtained showed that locally constructed lysimeters could effectively be utilized in water balance studies of a cropped area when used in combination with root zone soil moisture monitoring devices.

IMPROVING IRRIGATION PERFORMANCE OF RAISED BED WHEAT USING THE WinSRFR MODEL UNDER EGYPTIAN CONDITIONS

Abstract: Field experiments were carried out at the Sakha Agricultural Research Station in the governorate of Kafr el Sheikh, Egypt to evaluate and optimize the irrigation performance of raised beds wheat using the WinSRFR model during 2019/2020. Raised beds (RB130 cm, and RB100 cm) were prepared using Raised bed planter. The model calibration was based on a close match between the observed and simulated curves of advance and recession time. Simulation Analysis World was used to evaluate the current irrigation performance of the raised bed furrows (RB) and the flat basin (FB) methods. The simulation analysis shows that for RB130 cm, RB100 cm, and FB irrigation systems, the application efficiencies were 80, 64, 43%, and distribution uniformities were 86, 88, 90%, and deep percolation losses were 20, 36, 56%, and adequacy were 1.07, 1.37, 2.08%, respectively. Physical Design World was used to optimize and develop different design strategies. The results showed that irrigation performance decreased with the increasing length of furrow and basin, so extremely long lengths should be avoided because they result in decreased efficiency and uniformity, as well as big deep percolation loss. Managing the inflow rate and irrigation cut-off through Operation Analysis World can increase application efficiency and reduce deep percolation losses by more than 15%, 60%, and 17%, 33%, and 23%, 17.5% respectively, for RB130 cm, RB100 cm, and FB.

Design and performance of subirrigation system in maize (Zea mays) in Kumulur farm, Trichy district, Tamil Nadu, India

Subirrigation system can furnish water to plants. The upward flux and the discharge rate must satisfy the plant’s lifesaving irrigation needs during summer. The experiment was laid out in A-block of Eastern farm, Agricultural Engineering College and Research Institute, Kumulur, Trichy, Tamil Nadu. Subirrigation system spacing was arrived using Moody's equation calculated as 10 m. The experiment was laid out in spilt plot design with three replications. Four drain spacing levels (7.5, 10, 12.5 and 15 m) were the main plot treatments and two levels of depth and diameter of drain pipes (75 cm, 60 cm & 75 mm, 63 mm) were the sub plot treatments. The highest volumetric water content was recorded in 7.5 m spacing + 45 cm soil depth + lower reach (S1T3T1). Capillary rise on water table management system under subirrigation mode was fixed as 33.5 cm and the average deep percolation loss was obtained in 0.3 cm/d at development stage of crop period. The highest maize yield (4.30 t/ha) was obtained in 7.5 m spacing + 60 cm drain depth + 75 mm diameter (S1D3). The highest water use efficiency of (0.86 kg/m3) was recorded in 7.5 m spacing + 60 cm drain depth + 75 mm drain diameter (S1D3). This subirrigation system could furnish water to plants due to upward flux and the same system also functioned efficiently under drainage modes and removed the waterlogging during wet periods.

Effect of Decision Variables on Irrigation Performance Parameters Under Different Irrigation Systems

Furrow irrigation has low irrigation performances due to inescapable irrigation water loss through runoff and deep percolation. This study was conducted under small farmers to study combined influence of furrow irrigation flow rate and irrigation systems on irrigation performance parameters. The purposes of study were to evaluate outcome of furrow irrigation flow rate and irrigation systems on application efficiency, distribution efficiency, storage efficiency and deep percolation loss using field experiment. The field experiment had two factors of three furrow irrigation system (AFI, FFI & CFI) and four furrow irrigation inflow rate (Q1, Q2, Q3 & Q4). Field experimental plot was made in randomized complete block design with factorial arrangement of twelve treatment combinations and three replications. The collected field variables were management variables (irrigation performances) and site variables (soil type, soil moisture and furrow bed slope). The results show that, influence of furrow irrigation inflow rate and irrigation systems on irrigation performance parameters were highly significant (P<0.01). However, no significant difference among irrigation systems were observed in case of distribution uniformity (Du) expect furrow inflow rate. Interaction effect of irrigation systems and furrow inflow rate on irrigation performance parameter such as Ea, Du and DP were significant (p<0.05) expect storage efficiency. The highest values of distribution uniformity were 93.45% was observed under CFIQ4 treatment combination while the least value of distribution uniformity was 81.58% was observed under AFIQ1 treatment combination. The highest values of application efficiency 68.35% was observed under AFIQ4 treatment combination and the least value of application efficiency 53.60% was observed for CFIQ1 treatment combination. However, the highest values of deep percolation loss 46.60% was obtained under CFIQ1 treatment combination and the least value of deep percolation loss 31.65% was found under AFIQ4 treatment combination. It can be concluded that best result in improving application efficiency, distribution efficiency, and storage efficiency with the reduction of deep percolation loss were obtained under Alternative furrow irrigation with maximum non erosive furrow inflow rate.

Performance of the HYDRUS-1D model for water balance components assessment of irrigated winter wheat under different water managements in semi-arid region of Morocco

The main goal of this research was to evaluate the potential of the HYDRUS-1D numerical model for estimating the soil moisture (θ) at different depths, actual crop evapotranspiration (ETa) and its components (crop transpiration, Ta and soil evaporation, Ea) as well as the deep percolation (DP) of irrigated winter wheat under different water managements in the semi-arid region of Tensift-basin (central Morocco). The HYDRUS-1D simulations were performed at daily time step during the two growing seasons: 2002/2003 and 2015/2016.The model was firstly calibrated based on one field “denoted F1” data during the 2002/2003 cropping season by using the Levenberg-Marquardt method implemented in HYDRUS-1D model for optimizing various parameters of Van Genuchten equation that provide the minimum difference between measured and simulated soil moisture at four layers of soil (0–5, 5–10, 10–20, 20–30, 30–50 cm). Afterwards, the model validation was done based on the data from four fields of wheat: two fields “denoted F2 and F3” during the 2002/2003 and two other fields “denoted F4 and F5” during the 2015/2016 cropping season. All fields were irrigated with flooding system except the field F5 where drip irrigation was undertaken. In-situ measurements of θ was carried out using Time Domain Reflectometry (TDR) and gravimetric method ETa was measured by the Eddy Covariance system Ta and Ea were monitored using a lysimeter in F5 field. The results showed that the HYDRUS-1D model simulates the θ, ETa, Ta and Ea reasonably well.Additionally, the evaluation of the irrigation system on DP losses was investigated by comparing the simulation results over flood (F4) and drip (F5) irrigated fields. It was found that about 56% and 20% of seasonal supplied water were lost by DP in F4 and F5 sites, respectively. Such unexpected high amount of DP taking place in F5 field is due to the improper use of the drip irrigation system.

Role of deficit irrigation strategies on ET partition and crop water productivity of rice in semi-arid tropics of south India

Crop water productivity (CWP) is a measure of crop yield per unit of water consumed and plays a crucial role in evaluating the role of alternate management practices for sustainable production. This study investigates the crop water and yield dynamics of rice (Oryza sativa L.) subjected to three (low, moderate, and high water stress) deficit irrigation scenarios. Factorial experiments were conducted in four paddy fields in a command area of south India during the 2017–18 growing seasons with farmers’ current irrigation practice used as the control (T1). Seasonal total and irrigation water application of rice was ranged from 803 and 175 mm for high stress to 978 and 350 mm for T1 conditions. Cumulative potential evapotranspiration (ETo) for the growing seasons was observed to be 326.65 ± 2.51 mm. The FAO-56-based SIMDualKc model was parameterized to partition the evapotranspiration (ET) fluxes and to obtain site-specific crop coefficients for each scenario. Model-simulated root zone soil moistures were in agreement with the observations for all irrigation treatments (R2 > 0.80, RMSE < 0.04 cm3 cm−3, n = 20). Stage-specific single (Kc) and basal crop (Kcb) coefficients for rice with T1 are, respectively, 1.1, 1.09, 0.79, and 0.9, 0.97, 0.57, which are slightly lower than FAO tabulated values. The calibrated soil–water balance model was further applied to simulate crop yield using a simple crop growth algorithm. Our results conclude that crop yield is sensitive to water stress during vegetation (ky = 1.14 ± 0.10) followed by transplantation (ky = 1.07 ± 0.16) and reproduction stages (ky = 1.02 ± 0.17). We observed a marginal increase in CWP (12% in 2017 and 3% in 2018) and a reduction in deep percolation losses (29% in 2017 and 14% in 2018) through controlled water-saving strategies.

Assessment of different infiltration equations for cultivated and pasture land

The measure of infiltration of water into the soil is an important indication concerning: the efficiency of irrigation and drainage optimizing the availability of the water for plant improving the yield of the crop and minimizing the erosion. By knowing proper infiltration characteristics and intake capacity of soil, deep percolation losses can be prevented and proper utilization of water may take place. Keeping the importance of infiltration characteristics in mind the study of infiltration was taken. In this study most appropriate methods for determination of infiltration under different land uses were selected among most popular methods. Some of the wellknown equations are Kostiakov equation, Modified Kostiakov equation and Horton equation. These three equations were studied for the assessment infiltration equation. Assessment of these equations was done under different lands covers such as Cultivated land cover, Pasture land cover. From the analysis of the data, it is concluded that for cultivated land cover correlation coefficients for cumulative infiltration were found to be 0.9569, 0.9687 and 0.9724 for Kostiakov, Modified Kostiakov and Horton equation, respectively. As correlation co-efficient for Horton equation is higher, this equation was found best fit for cultivated land cover. Similarly, for pasture land cover the correlation co-efficients for cumulative infiltration were found to be 0.9876, 0.9706 and 0.9891 for Kostiakov, Modified Kostiakov and Horton equation, respectively. As correlation co-efficient for Horton equation is higher, this equation was found best fit for pasture land cover.

Assessment Improving of Rainwater Retention on Crop Yield and Crop Water Use Efficiency for Winter Wheat

Storage of rainwater within the root depth zone is one of the modern ways to increase plant production. Subsurface water retention technology was applied to assess improving values of crop yield and crop water use efficiency, applying a membrane made of low-density polyethylene trough installed below the crop root zone. The goal of this paper is to assess that the retention of rainwater above the membrane can improve the crop yield and crop water use efficiency values for winter wheat. The experiment was conducted in open field, within Joeybeh Township, located in east of the Ramadi City, in Anbar Province, in winter growing season 2018-2019. Two plots T1 (with membrane trough) and T2 (without membrane) were used for the comparison and cultivated with winter wheat, where the rainwater was only the source of irrigation. At the end of the harvest stage the obtained results of crop yield and crop water use efficiency for plots T1 and T2 were; 0.35 kg/m2 and 1.66 kg/m3, and 0.28 kg/m2 and 1.28 kg/m3, respectively. The increasing value of crop yield and crop water use efficiency in plot T1 was about 25 % and 30 %, respectively more than plot T2. Benefits of the installation of membrane trough are to keep soil moisture for longer times, prevent the cracks of the soil surface and reduce the deep percolation losses.

Performance Evaluation of Sanko Small Scale Irrigation Scheme at Basketo Special Woreda in SNNPR, Ethiopia

This study conducted to evaluate the performance of Sanko small-scale irrigation scheme at Basketo Special Woreda, South Nation Nationalities Peoples Regional states. The irrigation scheme includes command area of 120 ha and 600 beneficiaries. The scheme was evaluated using internal and productivity performance indicators. From the analyses of the internal performance indicators, the conveyance efficiency of the main canal was found to be 69.3% and application efficiencies at head (61.6%), middle (63.4%) and tail (46.5%) with average application efficiency of 57.2%. A light soil with high infiltration rates favors deep percolation losses at the top of the fields, resulting in low field application efficiency in tail end part of the scheme. A deep percolation ratio and storage efficiency of the scheme was found to be 42.8% and of 78.5% respectively. Generally overall scheme efficiency of scheme was 39.6%. From the evaluation of productivity indicators, the outputs per cropped area found as at head (84,706 Birr ha-1), middle (220,690 Birr ha-1) and tail (69,686.4 Birr ha-1) and the value of the outputs per command area of scheme was 15,003,276 Birr per command area. The output per unit irrigation supply of irrigation scheme was at head (13.5 Birr m-3), middle (33.95 Birr m-3) and tail (22.12 Birr m-3). Relative water supply and relative irrigation supply; found to be 1.28, which was the same for both since there was no rainfall during study period. From the analysis result, there was lower water use efficiency (WUE) at upper head (23.37 ton/m3) as compared to middle (48.78 ton/m3) and tail (60.22 (ton/ m3) part of the scheme in relation to yield obtained. Based on the evaluation result, highest yield was obtained from at middle part of irrigation scheme and lower yield was obtained from both upper and tail end part of the scheme. The yield reduction in upper and tail part of the scheme was due to over and under irrigation. However, there is still a room for improvement at all system levels. Therefore to reduce over and under irrigate; farmers should get awareness how to use, when to use and how much water used on their fields.

Technical Performance Evaluation of Small-Scale Irrigation Scheme at Wondo Genet, Ethiopia

Expanding efficient irrigation development on various scales is one of the best alternatives to provide reliable and sustainable food security. However, many irrigation schemes in developing countries in general and particularly in Ethiopia are performing below capacity. This study was conducted to evaluate the performance of wosha soyama irrigation scheme at Wondo Genet South Nation Nationality and People Regional State, Ethiopia. The evaluation carried out using standard technical performance indicators including conveyance, application, water storage, water distribution uniformity efficiency and deep percolation loss were used at the head, middle and tail reach of the scheme. The study shows that application efficiency was very low which is 48.2% due to higher water loss through deep percolation. Conveyance efficiency, water storage, water distribution uniformity efficiency, and deep percolation loss were revealed 55.6, 89.8, 91.7 and 51.8%, respectively. The overall efficiency was also below the desired level which is 26%. Based on the above observation, adoption of water saving practices such as deficit irrigation, surge and cutoff application to improving application, frequent maintains of water conveyance system can enhance the conveyance efficiency of the scheme.

Effect of farmers’ management on movable sprinkler solid-set systems

Farmer's management is considered a key factor for efficient, cost-effective irrigation. In this study, the effect of proper irrigation management in the solid-set systems of Kurdistan province in Iran was investigated. Performance indices including Coefficient of Uniformity (CU), Potential Application Efficiency of the Low Quarter (PELQ), Wind Drift and Evaporation Loss (WDEL), Adequacy of Irrigation (ADirr), Deep Percolation Losses (DP), and Application Efficiency (AE) were measured in ten different local plots in 2007 and 2017. The performance of selected systems remained similar in 2007 and 2017. The management of the plots evaluated in 2017 was modified, taking into account the preliminary design considerations and applying changes such as irrigation scheduling and sprinkler type. These plots with improved management were re-evaluated. Results showed that CU and PELQ were improved by 29% and 82%, respectively, in all systems. In addition, deep percolation losses (DP) were reduced by more than 40%. Insufficient training for farmers and the use of unskilled labor are of the main reasons for sustained underperformance in the study area. Actions are required in farmers’ education and in public performance monitoring. Additionally, the results of this research have shown that management improvement measurements are urgently required for the satisfactory performance of the above-mentioned systems.

Hydrus-1D model for simulating water flow through paddy soils under alternate wetting and drying irrigation practice

Alternate wetting and drying (AWD) irrigation practice in paddy cultivation requires a safe soil moisture stress level in the root zone for which irrigation water savings can be maximized without compromising the yield. Determining safe soil moisture stress level in AWD practice experimentally is challenging and involves time and money. Mathematical models can be alternate tools for determining the safe soil moisture stress with least experimental data. In this study, field experiments were conducted on rice crop using thirty lysimeter plots during rabi seasons (January to April) of 2015–2016 and 2016–2017. Three irrigation treatments including irrigation under no-soil moisture stress, mild soil moisture stress (MS: 450 cm matric potential head) and severe soil moisture stress (SS: 700 cm matric potential head) were considered, and each treatment was replicated ten times. The ponding depth and matric potential head at 10, 40 and 70 cm soil depths were measured daily from all lysimeter plots. The measured field data were used to calibrate and validate Hydrus-1D model and simulate water flow under different soil moisture stress treatments. The water saving in MS and SS treatments was 23 and 27%, respectively. The deep percolation in MS and SS treatments was reduced by 27–30% and 30–35%, respectively. The safe ponding water depth required to minimize deep percolation loss in MS and SS treatments was 5 and 7 cm, respectively. The required ponding water depth was observed to be increased with the increased matric potential head.