Irrigation Performance Indicators Research Articles

Irrigation Performance Indicators to Measure Wasted Irrigation Water and Their Effect on Water Sustainability: Methodology

Irrigation Performance Indicators to Measure Wasted Irrigation Water and Their Effect on Water Sustainability: Methodology

Monitoring small-scale irrigation performance using remote sensing in the Upper Blue Nile Basin, Ethiopia

Temporal and spatial irrigation performance indicators are crucial in informing decisions for improving the efficiency and sustainability of water and land resources. However, evaluating these indicators requires reliable and cost-effective data, which is challenging to obtain, particularly for small-scale irrigation schemes. This study aimed to assess the performance of a small-scale irrigation scheme using remote sensing and ground truth data for the 2021/22 and 2022/2023 irrigation seasons employing the Shimburit irrigation scheme in Northwestern Ethiopia, predominantly cultivated with wheat, as a case study. The performance indicators, including equity, adequacy, overall consumed ratio (OCR), and productivity, were assessed. The actual evapotranspiration (ET), the main input for performance assessment, was estimated using the surface energy balance for land – improved (SEBALI) model in the Google Earth Engine (GEE) platform. The results revealed good equity within the scheme, with a coefficient of variation of ETa value per field inside the scheme are 1.90 and 1.63 for the respective seasons. The water use adequacy across the fields was assessed to be very good in the two seasons. The scheme's overall consumed ratio (OCR) was 0.54 and 0.43 during the two subsequent seasons. Water productivity of wheat is 3.03 kg/m3 and 3.06 kg/m3 in the two seasons. However, due to untimely rainfall during harvest, land productivity declined from 3.25 tons/ha in the first season to 2.08 tons/ha in the second season. The study demonstrates the potential of using remote sensing to evaluate irrigation performance indicators and water productivity in smallholder irrigated fields.

Evaluation of water efficiency in agriculture: The case of the Konya closed basin

AbstractThe main goal in water efficiency in agriculture is to obtain more products with the same amount of water. In this respect, the use of irrigation performance indicators is important for increasing agricultural water efficiency. This study was conducted to evaluate agricultural water efficiency in the Konya closed basin, which is the region most affected by drought in Turkey. For this purpose, performance indicators selected for evaluating agricultural water efficiency were determined in irrigation associations taken as material for the years 2016–2020.In the research area, the following water use efficiency indicators were determined: annual amount of irrigation water distributed 1.750–517.462 million m3 yr⁻¹ (MCM yr⁻¹), annual amount of irrigation water distributed per unit area 0.529–8.688 MCM ha⁻¹, annual amount of irrigation water distributed per unit irrigated area 0.787–33.909 MCM ha⁻¹ and annual water supply ratio ranging between 0.220 and 52.600. The following agricultural water efficiency performance indicators were determined: income obtained for unit irrigation area, 127–5075 US$ ha⁻¹; income obtained per unit irrigated area, 656–12353 US$ ha⁻¹; income obtained per unit irrigation water taken into the network, 0.104–6.771 US$ m⁻3; and income obtained per unit irrigation water consumed, 0.236–37.358 US$ m⁻3. Correlation analysis was carried out to identify the significance of the relationships between the performance indicators, and the results were discussed.

Assessment of Sowing Density Impact on Water Front Advancement and Infiltration in Furrow Irrigation

This research aims to evaluate the impact of durum-wheat sowing density on wetting front advancement and water infiltration rate along the furrow length. In addition, durum wheat yield and furrow irrigation performance under the different sowing densities were assessed. For that purpose, a field experiment was conducted under semi-arid conditions in Tunisia using four durum-wheat sowing densities: SD1 (250 seeds m−2), SD2 (350 seeds m−2), SD3 (450 seeds m−2) and SD0 (bare soil). The results reveal that water front advancement tends to be inversely proportional to sowing density. In fact, under the SD3 treatment, both irrigation duration and applied water volume increased about twofold compared to those recorded under SD0, resulting in an increasing soil infiltration rate. Furthermore, the two-point method performed well in estimating water front advancement, with an R2 value close to 1. Regarding durum wheat yield, values varied between 3.5 and 4.9 t ha−1 with the highest value attributed to the SD3 treatment. Meanwhile, higher irrigation water productivity was recorded under SD1. Considering irrigation performance indicators, the results indicate that distribution uniformity (DU) increases with increasing sowing density. Moreover, the lowest application efficiency values (75%) were recorded under the SD0 and SD3 treatments as compared to 82% for SD2 and 80% for SD1.

A simulation tool to optimize the management of modernized infrastructures in collective and on-farm irrigation systems

Irrigated areas face new, pressing challenges due to escalating energy costs for pumping, increasing cost of seeds, fertilizers and agrochemicals, volatility of agricultural commodities, pressure of environmental regulations, water scarcity and mounting cost of irrigation infrastructure investments. At the same time, from the technical standpoint, farmers can chose from a wide array of irrigation design and operation alternatives for collective and on-farm systems, with variable effects on crop yield and profitability. These factors are often subjected to quick changes, complicating decision making. Simulation models have proven useful to support decision making in irrigation infrastructure, water / energy use, crop agronomy and soil management. In this research, new capacities of the Ador-Simulation software are reported, targeting comprehensive analyses of irrigation modernization. The model implements additional on-farm irrigation methods (low-pressure solid-set, center-pivot and drip irrigation); crop intensification (double cropping in the same season); and crop response to different on-farm irrigation management options (timing and frequency). Model performance was verified using a set of theoretical case studies. Finally, the model was applied to the optimization of irrigation design and management (water and energy) in the Bardenas XI project of northeastern Spain. Water application in center-pivot and drip irrigation were simulated using a normal distribution characterized by a user-defined Distribution Uniformity. In center-pivot, the application depth was randomized in every irrigation event, reproducing the random nature of wind disturbances. In drip irrigation, the application depth followed the same random distribution in all irrigation events, reproducing the deterministic effect of manufacturing and hydraulic variability. According to the literature, the effect of irrigation timing was treated differently for two key sprinkler irrigated crops: corn and alfalfa. Differences in water application and crop yield between on-farm methods resulted in different gross and net income. In the Bardenas XI project, irrigation performance indicators showed different patterns of inter-annual variability. Deep percolation was strongly affected by the amount of seasonal precipitation and by Distribution Uniformity. Indicators at the plot level were strongly determined by the on-farm irrigation method, the soil type, and the crop. In the conditions of Bardenas XI, the design option without pumping station was the most adequate. Natural pressure proved sufficient for a combination of low-pressure sprinkler irrigation, pivot and drip irrigation methods, distributed throughout the irrigated area. Escalating energy costs emphasize the need for careful assessment of pumping requirements at the design phase of irrigation projects.

Assessing Water Consumption Pattern and Delivery Irrigation Performance Indicators Using the Wapor Portal Under Data-Limited Conditions, Ethiopia

Assessing Water Consumption Pattern and Delivery Irrigation Performance Indicators Using the Wapor Portal Under Data-Limited Conditions, Ethiopia

A framework for irrigation performance assessment using WaPOR data: the case of a sugarcane estate in Mozambique

Abstract. The growing competition for finite land and water resources and the need to feed an ever-growing population require new techniques to monitor the performance of irrigation schemes and improve land and water productivity. Datasets from FAO's portal to monitor Water Productivity through Open access Remotely sensed derived data (WaPOR) are increasingly applied as a cost-effective means to support irrigation performance assessment and identify possible pathways for improvement. This study presents a framework that applies WaPOR data to assess irrigation performance indicators, including uniformity, equity, adequacy, and land and water productivity differentiated by irrigation method (furrow, sprinkler, and centre pivot) at the Xinavane sugarcane estate, Mozambique. The WaPOR data on water, land, and climate are in near-real time and spatially distributed, with the finest spatial resolution in the area of 100 m. The WaPOR data were first validated agronomically by examining the biomass response to water, and then the data were used to systematically analyse seasonal indicators for the period 2015 to 2018 on ∼8000 ha. The WaPOR-based yield estimates were found to be comparable to the estate-measured yields with ±20 % difference, a root mean square error of 19±2.5 t ha−1 and a mean absolute error of 15±1.6 t ha−1. A climate normalization factor that enables the spatial and temporal comparison of performance indicators are applied. The assessment highlights that in Xinavane no single irrigation method performs the best across all performance indicators. Centre pivot compared to sprinkler and furrow irrigation shows higher adequacy, equity, and land productivity but lower water productivity. The three irrigation methods have excellent uniformity (∼94 %) in the four seasons and acceptable adequacy for most periods of the season except in 2016, when a drought was observed. While this study is done for sugarcane in one irrigation scheme, the approach can be broadened to compare other crops across fields or irrigation schemes across Africa with diverse management units in the different agroclimatic zones within FAO WaPOR coverage. We conclude that the framework is useful for assessing irrigation performance using the WaPOR dataset.

Analysis of Water User Associations in Asi Basin with Irrigation Performance Indicators and TOPSIS Method

Bu çalışma kapsamında Asi havzasında bulunan sulama birliklerinin performansları 2013-2017 yılları verileri ile analiz edilmiştir. Analizde performans göstergeleri ve TOPSİS yöntemi ile sulama birliklerinin başarıları tespit edilmiştir. Araştırmada sulama alanına dağıtılan yıllık sulama suyu miktarı 14681-2318 m3 ha-1 arasında değişmiş, sulanan alana dağıtılan yıllık sulama suyu miktarı 17715-2678 m3 ha-1, yıllık su temin oranı 0.29-1.61 arasında hesaplanmış, sulama oranı %48–111 aralığında değişmiştir. Mali yeterlilik oranı %18-86 arasında değişirken, bakım-onarım masraflarının gelire oranı %9–181, sulama alanına düşen işletme-bakım ve yönetim masrafları 49.17-343.75 $ ha-1, su ücreti toplama performansı değeri %24-83, sulama alanına düşen enerji masrafları 0-233.96 $ ha-1, sulanan alana düşen enerji masrafları 0–394.94 $ ha-1 ve sulama suyu miktarına karşılık enerji masrafları 0–0.03494 $ m-3 olarak hesaplanmıştır. Sulama alanı üretim değeri 1509–7398 $ ha-1, sulanan alan üretim değeri 1948–11262 $ ha-1, şebekeye alınan sulama suyuna karşılık üretim değeri 0.190–2.019 $ m-3 ve bitki su ihtiyacına karşılık üretim değeri 0.203–0.950 $ m-3 olarak saptanmıştır. TOPSİS yöntemi ile analizde su kullanım başarısı %6-100, finansal başarı %15-80 ve üretim başarısı %0-100 arasında değişmiştir. Sonuç olarak sulama birliklerinin başarısında üretim değeri ve işletme bakım giderleri önemli rol oynamaktadır.

Comparison of methods used in predicting irrigation performance indicators

Decreasing availability of water and increasing consumption of it in recent years shows water management plans increase its value. Depending on water consumption in the current and previous years, it is important to predict water consumption in the coming years and make plans accordingly. Evaluation of the performance of water use in agriculture, identifying water resources that are most intensively used and prediction of the potential performance in the coming years have become increasingly important. Irrigation water management is of crucial importance for sustainable food security and needs to plan for saving water due to global warming and climate change in future. Some statistical methods such as regression and time-series to make accurate predictions are used to predict future irrigation management. However which methods are most suitable in this area is a gap in previous studies. This study aimed to determine the most accurate prediction method based on a comparison of the methods used in irrigation performance such as regression, time-series exponential smoothing and time-series ARIMA (autoregressive integrated moving average) model. In the study, Kahramanmaraş region was randomly selected and the irrigation data of 2006-2018 were used and the data of 2006-2017 were analysed to predict the data of 2018. Then, the values predicted using the methods were evaluated based on the actual values of 2018, and the method that projected values similar to the actual values was determined. The study results showed that the regression method gave the best predictions for the indicators in the water distribution dimension, while the time-series exponential smoothing method gave the best predictions for the indicators in the financial and agricultural activities dimension.

Orchard Level Assessment of Irrigation Performance and Water Productivity of an Irrigation Community in Eastern Spain

Over the last three decades, a great investment effort has been made in the modernization of irrigation in the Valencian Community (Spain). The initial change from distribution networks to pressurized ones and the shift towards drip irrigation systems was followed by improvements in irrigation scheduling, based on agrometeorological data, soil water content sensors, and remote sensing. These improvements are considered adequate for increasing irrigation water use efficiency, but it is difficult to find systematic measurements to assess its impacts on irrigation adequacy along with irrigation productivity in fruit orchards. This work presents the results of a four year assessment of irrigation water and energy use efficiency along with water productivity of a recently established irrigation community in the province of Valencia (Spain). The study was carried out at the orchard level and focused on two fruit crops: persimmon and peach trees. Six irrigation performance indicators, relative water supply (RWS), relative irrigation supply (RIS), yield performance (Yp), global water productivity (WPoverall), output per unit irrigation water (OUI), and the percent of nitrogen fertilization obtained by irrigation water, were defined and calculated for years 2017 to 2020 in 104 persimmon and peach orchards. The results showed that most of the farmers irrigated below the crop water requirements, showing RWS and RIS values less than 1, and there was great variability among farmers, especially in WPoverall and OUI indicators.

Energy balance and irrigation performance assessments in lemon orchards by applying the SAFER algorithm to Landsat 8 images

In the semiarid conditions of the São Francisco River Basin, Brazil, irrigated fruit crops are replacing natural vegetation, being lemon highlighted by incentives for the national and international markets. This paper aimed to support the rational water management of lemon orchards under different irrigation systems under these conditions. We present a methodology based on the use of the visible and near infrared images from Landsat 8 (L8) satellite together with weather and actual yield data (Ya), to assess the energy balance components and irrigation performance indicators (IPI) by applying the SAFER (Simple Algorithm for Evapotranspiration Retrieving) in six commercial farms under different irrigation systems inside the basin in the northern Minas Gerais state, Southeast Brazil. The ET rates averaged 2.7 mm d−1, 2.9 mm d−1, and 3.7 mm d−1, for drip, micro sprinkler, and pivot irrigated orchards, respectively. The evaporative fraction (latent heat flux by the available energy) reached above 1.00 for localized irrigation (drip and micro sprinkler), and 1.30 for pivots, during the lemon phenological stages from fruit growth to harvest peaks. Pivot irrigation systems were not recommended under the semi-arid conditions, due to large water direct evaporated from the soil and air close to the surface. For drip and micro sprinkler irrigated orchards, crop coefficient curves were modeled based on the accumulated degree-days (DDac) to estimate lemon crop water requirements. Drip irrigated orchards presented better water productivity levels being recommended together with deficit irrigation strategies which could allow good lemon yields with saving water savings. The most important findings of the current research are that the SAFER algorithm can be applied to estimate crop ET with satellite images without the thermal bands which together with modelled Ya data, irrigation assessments can be carried out at high spatial resolution following the principles of precision agriculture. For replication of the methods in other regions, simple calibrations of the modelling equations can be performed to infer the specific environmental conditions.

Optimizing water and nitrogen application for neglected horticultural species in tropical sub-humid climate areas: A case of African eggplant (Solanum aethiopicum L.)

African eggplant, a traditional and important nutrient-dense crop to Tanzania’s nutrition and food security. However, yields remain low as a result of sub-optimal irrigation and fertilizer practices. To reduce the yield gap, a randomized split-plot design set up with irrigation as a main and nitrogen (N) treatments as a sub-factor. The irrigation regimes were 100 % (I100), 80 % (I80) and 60 % (I60) of crop water requirements whilst nitrogen levels were 250 kg N/ha (F100), 187 kg N/ha (F75), 125 kg N/ha (F50) and 0 kgN/ha (F0). The study evaluated the effect of irrigation water and N on crop growth variables and yield, fruit quality, WUE and NUE. The study showed the importance of combining different irrigation performance indicators which responds to different levels of water and nitrogen to evaluate and assess suitable irrigation and fertilizer strategies for African eggplant. The crop growth variables (plant height and LAI) had a good correlation with fruit yield (R2 = 0.6 and 0.8). The fruit quality was best performed by 100 % water in combination with 75 % N treatment. The best WUE and NUE was attained at 80 % and 100 % levels of water in combination with 75 % N. However, minimizing trade-offs between the various indicators, the optimal application for African eggplant would likely be around 80 % of the total irrigation requirement and 75 % of the N requirement in sandy clay loam soils under tropical sub-humid conditions.

Influence of Spatial Resolution on Remote Sensing-Based Irrigation Performance Assessment Using WaPOR Data

This paper analyses the effect of the spatial assessment scale on irrigation performance indicators in small and medium-scale agriculture. Three performance indicators—adequacy (i.e., sufficiency of water use to meet the crop water requirement), equity (i.e., fairness of irrigation distribution), and productivity (i.e., unit of physical crop production/yield per unit water consumption)—are evaluated in five irrigation schemes for three spatial resolutions—250 m, 100 m, and 30 m. Each scheme has varying plot sizes and distributions, with average plot sizes ranging from 0.2 ha to 13 ha. The datasets are derived from the United Nations Food and Agricultural Organization (FAO) water productivity through open access of remotely sensed–derived data (the Water Productivity Open Access Portal—WaPOR) database. Irrigation indicators performed differently in different aspects; for adequacy, all three resolutions show similar spatial trends for relative evapotranspiration (ET) across levels for all years. However, the estimation of relative ET is often higher at higher resolution. In terms of equity, all resolutions show similar inter-annual trends in the coefficient of variation (CV); higher resolutions usually have a higher CV of the annual evapotranspiration and interception (ETIa) while capturing more spatial variability. For productivity, higher resolutions show lower crop water productivity (CWP) due to higher aboveground biomass productivity (AGBP) estimations in lower resolutions; they always have a higher CV of CWP. We find all resolutions of 250 m, 100 m, and 30 m suitable for inter-annual and inter-scheme assessments regardless of plot size. While each resolution shows consistent temporal trends, the magnitude of the trend in both space and time is smoothed by the 100 m and 250 m resolution datasets. This frequently results in substantial differences in the irrigation performance assessment criteria for inter-plot comparisons; therefore, 250 m and 100 m are not recommended for inter-plot comparison for all plot sizes, particularly small plots (<2 ha). Our findings highlight the importance of selecting the spatial resolution appropriate to scheme characteristics when undertaking irrigation performance assessment using remote sensing.

Effect of Pulse Drip Irrigation Duration on Water Distribution Uniformity

Developing an appropriate irrigation schedule is essential in order to save water while at the same time maintaining high crop yields. The standard procedures of the field evaluation of distribution uniformity do not take into account the effects of the filling and emptying phases of the irrigation system. We hypothesized that, in sloping sandy soils, when short drip irrigation pulses are applied it is important to take into account the total water applied from the beginning of irrigation until the emptying of the irrigation system. To compute distribution uniformity, we sought to characterize the filling, stable pressure, and emptying phases of a standard strawberry irrigation system. We found that the shorter the time of the irrigation pulse, the worse the distribution uniformity and the potential application efficiency or zero deficit are. This effect occurs because as the volume of water applied during filling and emptying phases increases, the values of the irrigation performance indicators decrease. Including filling and emptying phases as causes of non-uniformity has practical implications for the management of drip irrigation systems in sloping sandy soils.

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 SNNPRS, Ethiopia. The evaluation carried out using standard technical performance indicators including conveyance, application, water storage, water distribution uniformity efficiency and deep percolation ratio were used at the head, middle and tail reach of the scheme. The study shows that application efficiency was very which is 48.2% due to higher water loss through deep percolation. Conveyance efficiency, water storage, water distribution uniformity efficiency, and deep percolation ratio 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 the application, frequent maintains of water conveyance system can enhance the conveyance efficiency of the scheme. Keywords : Irrigation scheme, Performance, evaluation, and technical indicators DOI: 10.7176/JRDM/68-02 Publication date: August 31 st 2020

Modeling soil water balance and irrigation strategies in a flood-irrigated wheat-maize rotation system. A case in dry climate, China

Demand for irrigation water has been steadily increasing in arid regions where intensification of crop production is supported by flood-irrigation. An assessment of irrigation performance, water productivity, and irrigation schedules is critical to water conservation in dry climates. In this study, we conducted a field experiment to compare soil water balance in a flood-irrigated wheat-maize rotation system during the growing season of 2015–2016. We then modeled the soil water balance and improved irrigation strategies by coupling Hydrus-1D with the CROPWAT model, and using evapotranspiration calculated from climatic data. The calibrated Hydrus-1D model was used to simulate the temporal and spatial variation of evapotranspiration and deep percolation based on measured soil water distribution of soil profiles in the unsaturated zone. Results showed that using soil hydraulic parameters from inversion modeling can simulate soil water flow in multi-layer soil during a crop growing season. Simulation results indicated that about 36.6 and 40.6% (478.6 and 680.1 mm) of total water input in 2015 and 2016, respectively, was consumed by evapotranspiration. Furthermore, simulated deep percolation amounted for approximately 32.3 and 42.9% (403.9 and 696.6 mm) of the total amount of irrigation water in 2015 and 2016, respectively. These results indicated that only a small proportion of irrigation water was used by crops for transpiration. In addition, irrigation performance indicators such as relative water supply, relative irrigation supply, depleted fraction, and overall consumed ratio values indicated poor performance of irrigation practices in the study area. Particularly, crop yields did not increase with increases in irrigation water in flood-irrigated fields during the last ten years. Results of the CROPWAT model indicated that combinations of a fixed irrigation depth and timing, of 40 mm every 10 days, and 50 mm every 10 days were reasonable for wheat and maize, respectively, given the sandy soil in the study area. The improved irrigation strategies will limit water irrigation loss to 20% without significant effects on crop yields. This study provides an alternative approach for estimating deep percolation and crop water requirements supporting management efforts in water conservation in dry climates.

Optimal discharge for closed-end border irrigation under soil infiltration variability

Traditional border irrigation designs have rarely considered that soil infiltration can vary. The design of border irrigation systems can be improved by the optimization of border irrigation discharge. Therefore, the objectives of this study were (1) to expand the scope of the existing model for estimating and verifying the performance indicators of closed-end border irrigation; (2) to analyze the effect of infiltration variability on infiltration depth variability of closed-end border irrigation; and (3) to propose a method for determining the optimal discharge of closed-end border irrigation for variable soil. Physical and simulated experiments were conducted. The results revealed that for both variable and uniform soil, the estimated irrigation performance indicators were in good agreement with the measured values as well as values simulated using WinSRFR 4.1; the corresponding mean relative errors were less than 10%. The variance of infiltration variability explained a high percentage of the variance in infiltrated water depth (51.71%–95.68%). The optimal discharges were consistent for both variable and uniform soils, signifying that the optimal discharge of uniform soil can be used for the discharge design of a closed-end border irrigation system in variable soil.

Global Satellite-Based ET Products for the Local Level Irrigation Management: An Application of Irrigation Performance Assessment in the Sugarbelt of Swaziland

Remote sensing techniques have been shown, in several studies, to be an extremely effective tool for assessing the performance of irrigated areas at various scales and diverse climatic regions across the world. Open access, ready-made, global ET products were utilized in this first-ever-countrywide irrigation performance assessment study. The study aimed at identifying ‘bright spots’, the highest performing sugarcane growers, and ‘hot spots’, or low performing sugarcane growers. Four remote sensing-derived irrigation performance indicators were applied to over 302 sugarcane growers; equity, adequacy, reliability and crop water productivity. The growers were segmented according to: (i) land holding size or grower scale (ii) management regime, (iii) location of the irrigation schemes and (iv) irrigation method. Five growing seasons, from June 2005 to October 2009, were investigated. The results show while the equity of water distribution is high across all management regimes and locations, adequacy and reliability of water needs improvement in several locations. Given the fact that, in general, water supply was not constrained during the study period, the observed issues with adequacy and reliability of irrigation in some of the schemes were mostly due to poor scheme and farm level water management practices. Sugarcane crop water productivity showed the highest variation among all the indicators, with Estate managed schemes having the highest CWP at 1.57 kg/m3 and the individual growers recording the lowest CWP at 1.14 kg/m3, nearly 30% less. Similarly center pivot systems showed to have the highest CWP at 1.63 kg/m3, which was 30% higher than the CWP in furrow systems. This study showcases the applicability of publicly available global remote sensing products for assessing performance of the irrigated crops at the local level in several aspects.

Evaluation and optimization of border irrigation in different irrigation seasons based on temporal variation of infiltration and roughness

Soil infiltration and Manning’s roughness values are key parameters to determine the performance of surface irrigation. However, temporal variability in these parameters due to tillage practices, irrigation, and crop growth greatly hinders efforts to improve irrigation quality. The objective of this experiment was to evaluate effects of infiltration and surface roughness variation on irrigation water movement and irrigation performance indicators for border irrigation with three border lengths. Field experiments were conducted from 2013 to 2015 in a wheat (Triticum aestivum)-maize (Zea mays L.) rotation planting system at the Jinghui Canal Irrigation Area in Guanzhong Plain of northwest China. In this work, Manning’s equation and a surface irrigation simulation model (WinSRFR) were used to estimate Manning’s roughness values and Kostiakov soil infiltration parameters. We determined that both parameters reached moderate levels of variation for both deep and shallow tillage treatments. The impacts of temporal variation in soil infiltration and surface roughness on irrigation water movement and irrigation quality were then evaluated. Results showed that water advance times varied significantly while recession times varied much more, affecting irrigation water amounts at various distances along the length of the border. Irrigation performance indicators were significantly different over various irrigation seasons, especially for borders that were 235 m in length. Finally, considering these temporal variations during the two rotation cycles, combinations of inflow rate and cut-off ratio during different irrigation seasons were optimized, and high irrigation quality could be achieved for 80 m and 120 m borders, but not for 235 m borders. Water percolation amounts during the 2013–2014 and 2014–2015 growing periods were reduced by 55 mm and 107 mm for 235 m borders, 26 mm and 23 mm for 120 m borders, and 36 mm and 39 mm for 80 m borders, respectively. Therefore, utilizing optimal combinations of inflow rate and cut-off ratio and considering temporal variation in soil infiltration and Manning’s roughness could maintain high water application efficiency and sustainable utilization of limited water resources.

Connecting Drip Irrigation Performance to Farmers’ Practices: The Case of Greenhouse Horticulture in the Algerian Sahara

AbstractDrip irrigation is widely used in a range of different farming systems. Farmers generally adapt drip irrigation systems to their specific conditions. Irrigation performance is usually related to the hydraulic parameters of drip irrigation, and is usually expressed as a single static value. We developed a comprehensive approach to account for irrigation performance as a dynamic process, which evolves continuously due to changes in the way farmers schedule irrigation and renew irrigation equipment. The performance of drip irrigation systems used for greenhouse horticulture was evaluated in south‐east Algeria in the 2012–2013 growing season. Two indicators were evaluated—distribution uniformity and water stress level. The approach was applied to 25 greenhouses owned by 13 farmers. Results revealed that the performance of drip irrigation systems is a dynamic process. We showed that farmers have integrated certain irrigation performance indicators such as distribution uniformity and water stress levels in their practices, as they have visible effects on crop production. Conversely, the relative irrigation supply does not directly interest the farmers, and was consequently not incorporated in their irrigation practices. We conclude that measuring drip irrigation performance must be accompanied by a broader understanding of the farming systems in which drip irrigation is used. Copyright © 2018 John Wiley & Sons, Ltd.