Border Irrigation Research Articles

Optimized Border Irrigation Improved Nitrogen Accumulation, Translocation of Winter Wheat and Reduce Soil Nitrate Nitrogen Residue

We aimed to optimize field border length in the Huang-Huai-Hai Plain of China (HPC) to reduce soil inorganic nitrogen residues and increase nitrogen absorption and utilization by wheat plants using a traditional border irrigation system. In a two-year experiment (2017–2019) conducted in the HPC, four border lengths were tested: 20 m (L20), 30 m (L30), 40 m (L40), and 50 m (L50). Supplementary irrigation was implemented during jointing and anthesis stages, and control fields received treatment without irrigation. The results showed that, compared with irrigation of other border lengths, L40 irrigation significantly increased nitrogen transport in stems and leaves. In addition, L40 irrigation had the highest rate of grain nitrogen accumulation after anthesis. The risk of nitrate leaching to deep layers increased with increasing border length; however, L40 irrigation improved the plants’ capacity to absorb soil nitrogen, and the soil inorganic nitrogen residue was significantly lower than that with irrigation of other border lengths. Therefore, the grain yield and nitrogen fertilizer utilization under L40 irrigation were significantly higher than those under irrigation of other border lengths, and L40 was considered as the best border irrigation length.

The effect of drip irrigation under mulch on groundwater infiltration and recharge in a semi-arid agricultural region in China

Abstract The wide application of drip irrigation under mulch in semi-arid agricultural regions in China not only improves agricultural water efficiency, but also affects formation of groundwater and the mechanism of water infiltration to a certain extent. This paper takes the typical semi-arid agricultural region in China as the research object. The movement of soil water under the three types of underlying surface was simulated by the Hydrus-2D model for the quantitative analysis of groundwater recharge. The influence of drip irrigation under mulch on groundwater infiltration depth and cumulative infiltration amount under different level years was simulated. Taking a normal flow year as an example, the simulated results showed that the maximum infiltration depth of drip irrigation under mulch reached 250 cm, which was greater than that of border irrigation (138 cm) and bare area (158 cm). The cumulative infiltration amounts of drip irrigation under mulch at 80, 120, 140 and 200 cm were respectively 1,484.8 m3/hm2, 686.3 m3/hm2, 554.1 m3/hm2 and 238.1 m3/hm2, which were greater than that of border irrigation and bare land at the same depth. The results proved that drip irrigation under mulch could increase the infiltration depth and cumulative infiltration amount, which is beneficial to groundwater recharge in semi-arid agricultural regions of China.

High-Resolution 2D Modelling for Simulating and Improving the Management of Border Irrigation

High-Resolution 2D Modelling for Simulating and Improving the Management of Border Irrigation

Behind the Efficiency of Border Irrigation: Lesson Learned in Northern Italy

Behind the Efficiency of Border Irrigation: Lesson Learned in Northern Italy

Evapotranspiration characteristics and soil water balance of alfalfa grasslands under regulated deficit irrigation in the inland arid area of Midwestern China

Drought has been a major limiting factor affecting agricultural production in the world. Accurately quantitative analysis of the dynamic changes of evapotranspiration and soil water balance is very important for effectively managing water resources and improving water use efficiency under water scarcity. Soil water balance for perennial forage is more complex than the annuals due to stronger roots and periodic evapotranspiration. The objective was to explore the evapotranspiration characteristics and soil water balance of alfalfa (Medicago sativa L.) grasslands under border irrigation at different stand ages and irrigation treatments. A 3-yr field experiment with a full irrigation and 6 regulated deficit irrigation treatments was conducted, and growth-related indicators, soil evaporation and soil water dynamics were observed regularly. Daily evapotranspiration and soil water balance were computed using a modified dual-Kc model which is able to simulate evaporation and transpiration separately. The results showed that soil water simulated by the model and the measured value were in good agreement, and regression coefficients were higher than 0.6 and close to 1.0 in most cuts. The change trend of root zone water under deficit irrigation at single growth stages was similar to that under full irrigation. Under irrigation, the transpiration was the main water loss of alfalfa grasslands. The daily actual evapotranspiration of alfalfa in the 1st cut was higher than 8.0 mm d−1 and even over 15.0 mm d−1 at the middle and later growth stages. In contrast, in the 2nd and 3rd cut, it was always less than 10.0 mm d−1. The daily actual evapotranspiration decreased significantly and immediately after cutting, and daily actual transpiration was reduced to less than 1.0 mmd−1. The change trend of daily actual evapotranspiration under deficit irrigation at single growth stages was also similar to that under full irrigation. The seasonal evapotranspiration could reach 800 mm and was reduced by deficit irrigation. The average proportion of soil evaporation to total evapotranspiration was 18%. With the decrease of irrigation amount, the evapotranspiration, transpiration and irrigation water compensation decreased, while evaporation remained relatively stable and the ratio of evaporation to evapotranspiration increased. A lower relative evapotranspiration deficit (0.041) was obtained under moderate deficit irrigation at the budding stage than those in other deficit cases (0.086 or over). In conclusion, in the arid and semi-arid areas, deficit irrigation could be applied to alfalfa grassland at the budding stage in alfalfa production.

Ridge–furrow rainwater harvesting combined with supplementary irrigation: Water-saving and yield-maintaining mode for winter wheat in a semiarid region based on 8-year in-situ experiment

The ridge and furrow rainwater harvesting (RFRH) system has been adopted widely to improve and stabilize the productivity of dryland crops. In order to significantly reduce irrigation rate applied to fields, an 8-year (2012–2020) in-situ field experiment that RFRH combined with supplemental irrigation (RI) of winter wheat was conducted in the semiarid region of Northwest China. Border irrigation (BI) was used as the control. Under RI and BI, irrigation was applied only once (jointing–heading stage) or twice (jointing–heading and heading–flowering stage) in separate trials. Irrigation rates applied each time under RI and BI were 37.5 mm (50% of that under BI) and 75.0 mm, respectively. The results indicated that compared with BI, RI significantly increased the soil water storage in the early growth stage, net photosynthetic rate, water use efficiency (WUE), and irrigation water use efficiency, and decreased the evapotranspiration in years with different precipitation distributions. When irrigation was applied once, RI increased WUE by 13.4%, 9.1%, and 8.7% compared with BI in dry, normal, and wet years, respectively. When irrigation was applied twice, RI increased WUE by 12.6%, 8.9%, and 5.1% compared with BI in dry, normal, and wet years, respectively. Compared with BI, RI required 50% less irrigation water but it increased the grain yield by 3.3%, 2.4%, and 2.8% with once application in dry, normal, and wet years, respectively, and decreased it by 6.3%, 4.1%, and 3.2% when applied twice (P > 0.05). RI effectively maintained the yield and there was no significant difference compared with the yield under BI. Therefore, RI could be applied as a technique for significantly reducing irrigation rate consumed in semiarid and semi-humid areas.

FPGA-Embedded Smart Monitoring System for Irrigation Decisions Based on Soil Moisture and Temperature Sensors

The basic need common to all living beings is water. Less than 1% of the water on earth is fresh water and water use is increasing daily. Agricultural practices alone require huge amounts of water. The drip technique improved the efficiency of water use in irrigation and initiated the introduction and development of fertigation, the integrated distribution of water and fertilizer. The past few decades have seen extensive research being carried out in the area of development and evaluation of different technologies available to estimate/measure soil moisture to aid in various applications and to facilitate the use of drip irrigation for users and farmers. In this technology, plant moisture and temperature are accurately monitored and controlled in real time over roots in the form of droplets, by developing smart monitoring system to save water and avoid water waste using drip irrigation technology. Water is delivered to the roots drop by drop, which saves water as well as prevents plants from being flooded and decaying due to excess water released by irrigation methods such as flood irrigation, border irrigation, furrow irrigation, and control basin irrigation. Drip irrigation with an embedded intelligent monitoring system is one of the most valuable techniques used to save water and farmers’ time and energy. In this paper, we design an embedded monitoring system based in the integrated 65 nm CMOS technology in agricultural practices which would facilitate agriculture and enable farmers to monitor crops. Hence, to demonstrate the feasibility, a prototype was constructed and simulated with modelsim and validated with nclaunch the both tools from Cadence, as well as implementation on the FPGA board, was be performed.

Impacts of Irrigation Managements on Soil CO2 Emission and Soil CH4 Uptake of Winter Wheat Field in the North China Plain

The North China Plain is an important irrigated agricultural area in China. However, the effects of irrigation management on carbon emission are not well documented in this region. Due to the uneven seasonal distribution of rainfall, irrigation is mainly concentrated in the winter wheat growing season in the North China Plain. In this study, we estimated CO2 emission and soil CH4 uptake from winter wheat fields with different irrigation methods and scheduling treatments using the static chamber-gas chromatography method from April to May 2017 and 2018. Treatments included three irrigation methods (surface drip, sprinkler, and border) and three irrigation scheduling levels that initiated as soon as the soil moisture drained to 50%, 60%, and 70% of the field capacity for a 0–100 cm soil profile were tested. The results showed that both the irrigation methods and scheduling significantly influenced (p < 0.05) the cumulative CO2 and CH4 emission, grain yield, global warming potential (GWP), GWP Intensity (GWPI), GWPI per unit irrigation applied, and water use efficiency (WUE). Compared to 60% and 70% FC, 50% FC irrigation scheduling de-creased accumulated CH4 uptake 26.8–30.3% and 17.8–25.4%, and reduced accumulated CO2 emissions 7.0–15.3% and 12.6–19.4%, respectively. Conversely, 50% FC reduced GWP 6.5–13.3% and 12.5–19.4% and lower grain yield 10.4–19.7% and 8.5–16.6% compared to 60% and 70% FC irrigation scheduling in 2017 and 2018, respectively. Compared to sprinkler irrigation and border irrigation, drip irrigation at 60% FC increased the accumulated CH4 uptake 11.3–12.1% and 1.9–5.5%, while reduced the accumulated CO2 emissions from 7.5–8.8% and 10.1–12.1% in 2017 and 2018, respectively. Moreover, drip irrigation at 60% FC increased grain yield 5.2–7.5% and 6.3–6.8%, WUE 0.9–5.4% and 5.7–7.4%, and lowered GWP 8.0–9.8% and 10.1–12.0% compared to sprinkler and border irrigation in 2017 and 2018, respectively. The interaction of irrigation scheduling and irrigation methods significantly impacted accumulated CH4 uptake, cumulative CO2 amount, and GWP in 2018 only while grain yield and WUE in the entire study. Overall, drip irrigation at 60% FC is the optimal choice in terms of higher grain yield, WUE, and mitigating GWP and GWPI from winter wheat fields in North China Plain.

Simulating advance distance in border irrigation systems based on the improved method of characteristics

Improving the simulation accuracy of the advance distance based on the method of characteristics is essential to develop numerical solutions for simulating surface irrigation. Instead of volume balance in the traditional method of characteristics (T-MC), the position of critical flow is determined to simulate the advance distance in the improved method of characteristics (I-MC), which is used in border irrigation systems with rapid variation in inflow discharge in the current research. Specifically, the zones of both subcritical and supercritical flow were firstly distinguished to determine the position of the critical flow point, which was also the upstream boundary of the wetting front region, and then the advance distance was calculated by applying the diffusive wave equation in the wetting front region. The results showed that the I-MC accurately simulated the advance distance with high determination coefficients (0.984-0.998) and low errors (root mean square error of 0.35-1.56 min and coefficient of residual mass of 0.01-0.06), which performed much better than the T-MC. The I-MC provided a suitable and simple numerical simulation tool to improve the establishment of numerical surface irrigation models. Keywords: border irrigation, numerical solution, advance distance, method of characteristics DOI: 10.25165/j.ijabe.20211403.5877 Citation: Liu K H, Jiao X Y, Guo W H, Salahou M K, Gu Z. Simulating advance distance in border irrigation systems based on the improved method of characteristics. Int J Agric & Biol Eng, 2021; 14(3): 156–162.

The optimal tensiometer installation position for scheduling border irrigation in Populus tomentosa plantations

Soil matric potential (SMP) is usually monitored by a tensiometer for managing irrigation in forest plantations, so determining where to install the tensiometer is important for improving irrigation efficiency. However, such work has never been conducted for border irrigation, which is commonly used in the intensive cultivation of forest plantations. In a border irrigated Populus tomentosa plantation on sandy loam soil, we monitored the daily changes of SMP at eighteen different positions in soil wetting volume (WV) [expressed in Px y (x means distance from the trunk in cm, y means soil depth in cm)], transpiration (T), and stem growth rate (GR) in a growing season. The fine root distribution was also investigated in two successive growing seasons. The result of time stability analysis showed that, among the eighteen positions, the annual absolute mean relative difference (RD) and the standard deviation of the RD of SMP at P25 40 were not the lowest, but its root mean square error of the SMP relative deviation reached the lowest in the growing season. The root water uptake at P10 10 had the highest influence on T rate (R2 = 0.220, P < 0.01) and GR (R2 = 0.112, P < 0.05). The fine roots distribution changed greatly with the stand development, but its pattern within the WV was relatively consistent in different years. There were three dense fine roots zones located around P10 10, P40 10, and P10 50. Consequently, it was suggested to place tensiometers at two positions, i.e., P25 40 and P10 10, with the former being used for estimating irrigation amount and the latter for triggering irrigation. This recommended tensiometer placement strategy will not only help to improve the irrigation efficiency in P. tomentosa plantation but also provide a reference for the irrigation management in stands of other tree species.

Numerical and artificial intelligence models for predicting the water advance in border irrigation

The water advance time (Ta) is needed for designing and evaluating surface irrigation systems. This study employed artificial neural networks (ANNs) and gene expression programming (GEP) techniques for estimating the water advance time in the border irrigation system as a function of inflow rate per unit width (Qb), length of water advance in the border (L), longitudinal slope (So), final infiltration rate of the soil (fo) and Manning roughness coefficient (n). The techniques were tested on field measurements from agricultural farms in three different provinces of Iran. Results showed that the ANN model was superior to the GEP model for the estimation of water advance time. The performance indicators for the ANN model were R2 = 0.966, RMSE = 7.805 min and MAE = 5.090 min, MBE = 0.312 and SI = 0.181. Results of the intelligence-based models were also compared with the WinSRFR model. Both ANN and GEP models predicted the water advance time more accurately than did the WinSRFR model.

Simulation modeling of border irrigation performance under different soil texture classes and land uses

This paper aims for evaluating the border irrigation performance sensitivity including application efficiency, advance time, runoff and deep infiltration ratios to the variation of soil texture, land use, discharge, border length and soil moisture. The measurement of infiltration was done by the double-ring method in five soil texture classes and three land uses. HYDRUS-1D model was calibrated for simulating infiltration in various initial soil moisture. Next, calculated infiltration parameters by HYDRUS-1D were presented to SIRMOD for simulating border irrigation in the various lengths of the border and discharges. The result showed by decreasing the soil moisture, the variation of the performance parameters has possessed a trend of increasing, but for the runoff ratio. Therefore, by incrementing the irrigation period, application efficiency will be incremented. Under different soil textures and land uses, the deep infiltration and runoff ratios were the most and least sensitive parameters concerning soil moisture. Most variations of performance parameters were in sandy loam texture and wheat land use, however, the least variations of the parameters were in silty loam texture and fallow land use. To decrease application efficiency sensitivity to soil moisture, discharge and border length must be considered less and more for soils with great permeability than for soils with little permeability, respectively.

Irrigation management evaluation of multiple irrigation methods using performance indicators

ABSTRACT Six plots include three plots of solid-set sprinkler and three plots of border irrigation methods in Kangavar plain (Iran), were evaluated under farmers’ management standards. Wheat was grown in each of the plots and all the irrigation events were evaluated. The average values of irrigation indexes, distribution uniformity, potential application efficiency of the low quarter, application efficiency of the low quarter, application efficiency, deep percolation ratio, adequacy of irrigation, and water requirement efficiency in border-irrigated plots were 80.4%, 80.4%, 69.1%, 80.5%, 19.5%, 53.1%, and 80.8%, respectively. Those values indicated much better performance than the average values for the movable solid-set sprinkler-irrigated plots, which were 55.8%, 44.7%, 37.2%, 41.5%, 38.6%, 85.0% and 96.5%, respectively. So the system design and the farmers’ management are suitable with border irrigation in accordance with the experiences they have gained with time. That was not the case for the movable sprinkler irrigation system, in which the performance indexes are below the recommended minimum values. Therefore, the efficiency of an irrigation system is not independent of its management, and the farmer’s skill on the irrigation system is one of the most important indices for selecting a suitable irrigation system. Also, improving farmer’s management is the most appropriate way for improving irrigation performance.

Investigation of various volume–balance methods in surface irrigation

Prediction of the water advance phase and infiltration rate is of crucial importance for the design of surface irrigation. The volume–balance model is applied to specify the parameters of infiltration and advance rate. The present research aims to present a volume–balance equation for the Philip infiltration equation using the new two-point method and to compare the proposed method with seven other ones including Elliott-Walker, Ebrahimian-Shepard, Shepard, Valiantaz, Infilt, Mailapalli, and scaling method among others. To satisfy this end, the measured data for six furrows and six borders were considered. The methods described in border irrigation were more accurate than that of furrow irrigation. The results showed that the accuracy of the new two points, Elliott-Walker and Infilt methods, was higher than the other ones. The proposed new two-point’s method has been found as the most appropriate method because it does not require to calculate base infiltration. Also, it requires less input data than Infilt and Elliott-Walker. The accuracy of scaling method was less than other methods but its simplicity is superior to other methods. According to the results, if the furrow end point is used to calculate the scaling factor in the scaling method, the accuracy of this method will be significantly increased.

Optimization of the border size on the irrigation district scale – Example of the Hetao irrigation district

To improve the performance of border irrigation, this study analyzed the spatial variability characteristics of the soil particle content and bulk density, based on soil physical parameters measured at 86 sampling points in the Hetao irrigation district (HID). The soil hydraulic parameters were determined using the RETC, and HYDRUS-1D was then adopted to estimate infiltration parameters of the Kostiakov equation at different locations. The optimal layout patterns of border size were proposed under the consideration of various combinations of different typical soil textures and field slopes by WinSRFR. The results indicated that the spatial distributions of clay and silt particle contents were generally high in the middle and low at both sides of the HID, while the sand was the opposite. The results proved that the soil physical parameters are only to be measured at depths of 0–20 and 20–40 cm to meet the needs of infiltration parameter estimation which can significantly reduce the workload of soil sample collection. Moreover, two types of optimal border layouts of different combinations of the soil textures (silt loam and silt clay loam) and field slopes (no more than 1‰, 1–3‰, and 3–5‰) were proposed, which can guarantee the application efficiency and distribution uniformity no less than 85%, and be the guidance for practical field irrigation in the HID.

Effect of Drip Irrigation on Soil Water Balance and Water Use Efficiency of Maize in Northwest China

Drip irrigation (DI) has been widely utilized for crops and its water-saving effect has been confirmed by numerous studies. However, whether this technology can save so much water under the field scale during practical application is still uncertain. In order to answer this question, evapotranspiration (ET), soil water content, transpiration and evaporation over the DI and border irrigation (BI) in an arid area of NW China were continuously measured by two eddy covariance systems, micro-lysimeters, the packaged stem sap flow gauges and CS616 sensors during 2014–2018 growing seasons. The results showed that the DI averagely increased crop water use efficiency (CWUE) by 11% per year against BI. The deep drainage under DI treatment was lower than BI by 8% averagely for the five-year period. While for the ET, the DI averagely decreased ET by 7% and 40mm per year against the traditional BI. The decrease in ET was mainly due to the significant reduction in soil evaporation instead of transpiration. Oppositely, we found that DI may increase maize (Zea mays L.) transpiration in some year for the better preponderant growth of crop. Thus, the accelerating effect on transpiration of DI and its reducing effect on soil evaporation should be considered simultaneously. In our experiment, DI only improved CWUE and WUE (water use efficiency) by 11% and 15% on average in a large farmland scale, unable to always be more than a 20% improvement, as concluded by many other field experiments. Consequently, the water-saving effect of DI should not be overestimated in water resource evaluation.

Simulating advance distance in border irrigation systems based on the improved method of characteristics

Improving the simulation accuracy of the advance distance based on the method of characteristics is essential to develop numerical solutions for simulating surface irrigation. Instead of volume balance in the traditional method of characteristics (T-MC), the position of critical flow is determined to simulate the advance distance in the improved method of characteristics (I-MC), which is used in border irrigation systems with rapid variation in inflow discharge in the current research. Specifically, the zones of both subcritical and supercritical flow were firstly distinguished to determine the position of the critical flow point, which was also the upstream boundary of the wetting front region, and then the advance distance was calculated by applying the diffusive wave equation in the wetting front region. The results showed that the I-MC accurately simulated the advance distance with high determination coefficients (0.984-0.998) and low errors (root mean square error of 0.35-1.56 min and coefficient of residual mass of 0.01-0.06), which performed much better than the T-MC. The I-MC provided a suitable and simple numerical simulation tool to improve the establishment of numerical surface irrigation models. Keywords: border irrigation, numerical solution, advance distance, method of characteristics DOI: 10.25165/j.ijabe.20211403.5877 Citation: Liu K H, Jiao X Y, Guo W H, Salahou M K, Gu Z. Simulating advance distance in border irrigation systems based on the improved method of characteristics. Int J Agric & Biol Eng, 2021; 14(3): 156–162.

Modelling effect of different irrigation methods on spring maize yield, water and nitrogen use efficiencies in the North China Plain.

Conventional farming practices not only constrained food security due to low yield but also threatened the ecosystem by causing groundwater decline and groundwater nitrate contamination. A two׹ear field experiment was conducted at the research station of North China University of Water Resources and Electric Power, Zhengzhou. The WHCNS model was used to simulate grain yield, water and nitrogen fertilizer use efficiencies (WUE and FNUEs) of spring maize under border irrigation method, drip irrigation, and rainfed conditions. In addition, a scenario analysis was also performed on different dry and rainy seasons to assess the long-term impact of rainfall variability on spring maize from 2000-2017. The result showed that the model precisely simulated soil water content, N concentration, crop biomass accumulation, and grain yield. The maximum and minimum range of relative root mean squire error (RRMSE) values were 0.5-36.0% for soil water content, 14.0-38.0% for soil nitrate concentrations, 19.0-24.0% for crop biomass and 1.0-2.0% for grain yield, respectively under three irrigation methods. Both the index of agreement (IA) and Pearson correlation coefficient (r) values were close 1. We found the lowest grain yield from the rainfed maize, whereas the drip irrigation method increased grain yield by 14% at 40% water saving than border irrigation method for the two years with the 11% lower evaporation and maintained transpiration rate. Moreover, the drip irrigated maize had a negligible amount of drainage and runoff, which subsequently improved WUE by 27% in the first growing season and 16% in the second rotation than border irrigation. The drip irrigated maize also showed 24% higher FNUE. The reason of lower WUE and FNUEs under the border irrigation method was increased drainage amounts and N leaching rates. Furthermore, scenario analysis indicated that the dry season could result in a 30.8% yield decline as compared to rainy season.

Comparison of Water- and Nitrogen-Use Efficiency over Drip Irrigation with Border Irrigation Based on a Model Approach

Drip irrigation under film mulching is widely promoted to replace traditional border irrigation in order to meet water saving demand in arid and semiarid regions. Our study aims to investigate quantitatively the change in crop yield, water-use efficiency (WUE) and nitrogen-use efficiency (NUE) under film mulching drip irrigation. We conducted a 4-year contrastive experiment containing two treatments on flux measurement: (1) border irrigation (BI) under film mulching; (2) drip irrigation (DI) under film mulching. Soil water and nitrate transport and utilization in the Soil–Plants–Atmosphere Continuum system, and crop dry matter were all simulated based on an integrated model of a soil-crop system: water, heat, carbon and nitrogen simulator (WHCNS). Results showed soil water content (SWC), soil NO3−-N content, evapotranspiration (ET), and crop dry matter (Wtotal) produced by the model were in agreement with those measured. Our study showed the irrigation and nitrogen input and output were significantly changed after BI was replaced by DI. Compared with BI treatment, DI treatment decreased ET consumption by 9% annually over four years, while it increased WUE and NUE on the farmland on average by about 28% and 39% yearly. The increase of WUE and NUE were mainly due to a significant decrease of about 56% and 68% in water and nitrogen leakage loss in DI treatment, respectively, during 2014–2017. Our study confirmed the economic and environmental benefits of the DI technology and showed its improvement prospect in the research field. Meanwhile, the results contributed to the improvement and more effective application of DI in a larger region, and provided a data basis for further study on water and fertilizer saving characteristics of DI technology.

Simplified method for estimating the optimal cut‐off time of closed‐end border irrigation*

AbstractClosed‐end border irrigation has been widely used in China; however, such irrigation is usually associated with poor performance. Therefore, the performance of closed‐end border irrigation must be improved. The objectives of this study were to develop and verify a simplified method for estimating the optimal cut‐off time (Tcop) for closed‐end border irrigation. The simulated results revealed that the relationship between Tcop and the time when water advanced to 75% of the length of the border (T0.75L) can be characterized by using a power function. The comprehensive irrigation performance indicator Y (which is the geometric mean of the application efficiency and Christiansen's uniformity) obtained using the proposed method was consistent with that obtained using existing methods. The mean absolute value of the relative error and the standard error of Y between the proposed method and existing methods was 3.35 and 0.69%, respectively. This result indicates that the proposed method has high reliability. Moreover, in the proposed method, only T0.75L is required to determine Tcop for closed‐end border irrigation. Therefore, the proposed method has high practicality and can be used to improve the performance of closed‐end border irrigation.