Agricultural Water Use Research Articles

Water Conservation Challenges and Solutions to Preserve National Food Security

Political security, economic security, social security, and national security have a close relationship to food security. Thus, we focus on water conservation to ensure and support national food security. Here, we also systematically summary the irrigation area and agricultural water use in our country, and analyze the challenges of food security in the view of the relationship between water resources and grain-production arrangement, agricultural water use efficiency, and farmland water conservancy investment. In light of that, we also propose some solutions and suggests, which may lay theoretic foundations for national food security.

Influence of anthropogenic nitrogen inputs and legacy nitrogen change on riverine nitrogen export in areas with high agricultural activity

Increased riverine nitrogen (N) concentrations due to human activities is one of the leading causes of water quality decline, worldwide. Therefore, quantitative information about the N exported from watershed to the river (TN exports) is essential for defining N pollution control practices. This paper evaluated the changes in net anthropogenic N inputs (NANI) and the N stored in land ecosystems (legacy N) in the Jianghan Plain (JHP) from 1990 to 2019 and their impacts on TN exports. Moreover, an empirical model was developed to estimate TN exports, trace its source, and predict its future variations in 2020–2035 under different scenarios. According to the results, NANI exhibited a rise-decrease-rise-decrease M-shaped trend, with N fertilizer application being the dominant driver for NANI change. In terms of the NANI components, non-point-source was the primary N input form (96%). Noteworthy is that the correlation between NANI and TN exports became weaker over time, and large differences in changing trends were observed after 2014. A likely cause for this abnormal trend was that the accumulation of N surplus in soil led to N saturation in agricultural areas. Legacy N was also an important source of TN exports. However, the contribution of legacy N has rarely been considered when defining N pollution control strategies. An empirical model, incorporating legacy N, agricultural irrigation water use, and cropland area ratio, was developed. Based on this model, legacy N contributed a large proportion (15–31%). Furthermore, the results of future predictions indicated that legacy N had a larger impact on future TN exports changes compared to other factors, and increased irrigation water would increase rather than decrease TN exports. Therefore, an integrated N management strategy considering the impact of NANI, legacy N, and irrigation water use is crucial to control N pollution in areas with intensive agriculture.

Circular economy and the resource nexus: Realignment and progress towards sustainable development in Saudi Arabia

Resources such as water, energy, and arable land represent bottlenecks with regard to achieving key sustainability paradigms such as the circular economy (CE). They exhibit vital inputs and outputs for economic development, and they are closely linked to the environmental challenges to the protection of ecosystems, emissions reduction, and sustainable resource use. In the Kingdom of Saudi Arabia (KSA), aridity, large environmental footprints and the reliance on carbon fuels accentuate the importance of the water and energy sectors. This paper analyzes the resource nexus in KSA using the lens of the CE. It examines the relevance of the CE paradigm, and presents current progress, interventions and policy initiatives to promote this paradigm in natural resource sectors and subsectors such as desalination, electricity production, urban mobility, and agricultural water use. The current directions in KSA show a heightened engagement with sustainability issues, including significant projects related to the CE. Guided by the KSA (SAV 2030), several interventions exist in the energy-related sectors aimed at promotion of renewables, decarbonization of electricity production, energy efficiency in the built environment, carbon capture, and sustainable mobility. Similarly, the water sector has been progressing towards sustainable (and solar) desalination, water reuse and ecosystems-based solutions. However, the current efforts should be better embedded within larger policies such as the SAV 2030, the Green Middle East Initiative, and the Circular Carbon Economy. Moreover, explicit and more targeted CE strategies are needed in order to develop a comprehensive and more participatory approach towards promoting the CE, particularly in prominent areas such as water and energy. The paper provides best practices and highlights key policies for enhancing CE and resource-use sustainability and for moving towards a low-carbon and circular production in KSA or other carbon-exporting countries.

Cropland fallow reduces agricultural water consumption by 303 million tons annually in Gansu Province, China

The high-intensity utilization of global cropland causes water shortage and food crisis, which seriously affects the realization of SDG 2 (zero hunger), SDG 6 (clean water and sanitation) and SDG 15 (life on land), and threatens the sustainable social, economic and ecological development. Cropland fallow can not only improve the quality of cropland and maintain ecosystem balance, but also have a significant water-saving effect. However, in most developing countries, such as China, cropland fallow has not yet been widely promoted, and there are few reliable fallow cropland fallow identification methods, making it even more challenging to assess the water-saving effect. To remedy this deficit, we propose a framework for mapping cropland fallow and evaluating its water savings. First, we used the Landsat series of data to interpret the annual land use/cover changes in Gansu Province, China from 1991 to 2020. Subsequently, the spatial-temporal variation of cropland fallow in Gansu province (giving up farming for one to two years) was mapped. Finally, we evaluated the water-saving effect of cropland fallow using evapotranspiration, precipitation, irrigation maps, and crop-related data, instead of actual water consumption. The results showed that the mapping accuracy of fallow land in Gansu Province was 79.50 %, which was higher than that of most known fallow mapping studies. From 1993 to 2018, the average annual fallow rate in Gansu Province, China, was 10.86 %, which was at a low level in arid/semi-arid regions worldwide. More importantly, from 2003 to 2018, cropland fallow reduces annual water consumption of 303.26 million tons in Gansu Province, accounting for 3.44 % of agricultural water use in Gansu Province and equivalent to the annual water demand of 655,000 people in Gansu Province. Based on our research, we speculate that the increasing pilot projects of cropland fallow in China can bring significant water-saving effects and help achieve China's Sustainable Development Goals.

Multi-layer multi-objective cooperative regulation of agricultural water resources in large agricultural irrigation areas based on runoff prediction

Reasonable and optimal allocation of irrigation water is of great significance to improve agricultural water use efficiency for large-area agricultural irrigation systems. To solve the problems of large agricultural production scale, unreasonable water distribution structure, many rivers in the region and large changes in runoff volume, this paper takes the Sanjiang Plain in Heilongjiang Province, China, as the research object to develop an efficient and accurate water optimal allocation method. First, the runoff volume of many rivers in the region was obtained through the ARIMA-SVM-BP combined runoff prediction model, based on which a ‘regional-irrigation district-farmland’ multilayer multiobjective water resource cooperative deployment system model was established to achieve the synergistic enhancement of farmers' interests and the economic-social and regional economic-engineering volume of the irrigation district. The joint optimization method, fuzzy mathematical planning, and large system decomposition-coordination coupling were used to solve the multilayer multiobjective regulation system. The results show that the optimal agricultural water allocation volumes for the current year (2020) and the forecast year (2025) of 37 irrigation districts in the Sanjiang Plain are 3.61 × 109 m3 and 3.89 × 109 m3, saving 17% of water and resulting in a 24% decrease in the agricultural water use ratio compared with the actual situation, respectively. In the process of repeated coordination of the large system, the water distribution error is controlled within 1%. The fairness of water distribution in the multilayer system was improved by 34.7% while obtaining high economic benefits. The method proposed in this study helps the coordinated regulation and planning of multiple water sources in large agricultural irrigation areas, improves the ability of water distribution in irrigation areas to cope with different levels of incoming water, and promotes the sustainable development of regional irrigated agriculture.

Relationship between Indigenous Knowledge Development in Agriculture and the Sustainability of Water Resources

The relationship between agricultural knowledge and water management is very important. Indigenous knowledge in agriculture can improve the water crisis situation and alleviate water stress from dry and semi-arid areas. Therefore, the combination of these two impacts can improve the agricultural sector and reduce the effects of drought. The purpose of this study was to investigate the factors affecting indigenous knowledge and the sustainable management of water resources for optimal water use in agriculture in the Sistan region of Iran. Alongside field research and interviews with 40 indigenous experts and experts from the Jihad-e-Agriculture sector of the Sistan region, the required information was collected by means of a questionnaire. Using the fuzzy hierarchy process (FAHP), the factors affecting indigenous knowledge and the sustainable management of water resources for optimal water use in the Sistan region were ranked. The final rankings of the factors influencing indigenous knowledge for optimal agricultural use of water resources indicate that the educational-extensional factor, with a final weight of 0.37, is the first priority, while social factors, government support, economics, farmers’ knowledge, and information, with weights of 0.24, 0.21, 0.13, and 0.03, respectively, are the next priorities. It is recommended that the indigenous knowledge of local authorities be augmented, and that farmers be encouraged to use modern irrigation techniques to optimize the agricultural irrigation of water.

Exploring the Influences of Water-Saving Practices on the Spatiotemporal Evolution of Groundwater Dynamics in a Large-Scale Arid District in the Yellow River Basin

Water-saving practices (WSPs) have been recognized as an effective measure for reducing agricultural water use and alleviating regional water shortages in arid irrigation districts. However, WSPs have also reduced groundwater recharge, thereby causing the depth to groundwater table (DGT) to increase. Therefore, characterizing the impact of WSPs on the spatiotemporal variability in the DGT is of paramount importance for protecting limited groundwater resources. Based on monthly DGT observation data collected from 1990 to 2015 at 206 observation wells in the Hetao Irrigation District (HID), located in Northwest China with an arid climate, the spatiotemporal variations in DGT before and after the application of WSPs were analyzed using the empirical orthogonal function (EOF) method, and the major driving factors of the spatiotemporal DGT changes were also identified using comprehensive approaches. The EOF method revealed four major spatiotemporal DGT patterns both before and after WSPs were applied; these patterns explained 71.39% and 73.99% of the total variability in the HID before and after WSPs application, respectively. In addition, the main controlling factors affecting the DGT dynamics were different before and after WSPs were applied. In terms of the associations of the DGT with the impacting factors, the meteorological factors had the strongest impact on the DGT changes on the long-term scale of 64 months; however, irrigation played a leading role at the seasonal and semiannual scales, especially after WSPs application. The soil texture significantly impacted the spatial DGT patterns, particularly at depths above 150 cm. This study provides a scientific basis for the rational development of local groundwater resources and the scientific management of water-saving irrigation measures.

Projection of net primary production under changing environment in Xinjiang using an improved wCASA model

Net Primary Productivity (NPP) is an important component of the carbon cycle of terrestrial ecosystems and plays an important role in the evaluation of vegetation growth. Among all the factors, wind also plays a vital role in modeling vegetation productivity. However, none of the current models have considered the impact of wind on the process of productivity estimation. An in-depth study was conducted on the temporal and spatial distribution and internal relations between wind speed and NPP. By introducing the influence factor wind, the Carnegie-Ames-Stanford model (CASA) based on the land-surface water index was modified and named as wCASA model. The estimation and prediction results of wCASA model considering the influence factor wind were better than that of the CASA model. The modified wCASA model was applied in Xinjiang, China. The simulation results were improved with the coefficient of determination (R2) increased by 9.59%, the root mean square error (RMSE) decreased by 13.78%, and the residual of prediction deviation (RPD) improved by 12.08% as compared to CASA model. The optimal model was used to simulate and predict the NPP of cropland and grassland for 2022–2050 under three climate scenarios, SSP126, SSP245, and SSP585, respectively, based on the CMIP6 dataset. The wCASA model can accurately estimate and predict NPP, which provides scientific basis for efficient agricultural water use and food production.

Complex Policy Mixes are Needed to Cope with Agricultural Water Demands Under Climate Change

The divergence between agricultural water use and the annual supply of water resources (water gap) has been increasing for decades. The forecast is that this water gap will continue to widen, compromising the water security of a large share of the global population. On the one hand, the increase in demand is attributed to an ever-growing population that, in addition, is adopting a high-water consumption per capita lifestyle (e.g., meat-rich diet, increased use of biofuels and of irrigated agriculture). On the other hand, climate change is increasing aridification and the spatio-temporal heterogeneity of precipitation worldwide. The water gap is particularly acute in drylands, where development and food security has been based on the massive exploitation of water resources, particularly groundwater. Here we analyze the mechanisms underlying this water gap, which is mainly driven by water use in agriculture, and suggest suitable solutions that can help to close it. Using causal diagrams, we show how population generates different demands that create a water gap that prevailing supply-side solutions cannot close. Indeed, it has been widening over the years because water consumption has grown exponentially. This behaviour is explained by a series of mechanisms that it is necessary to understand to realize the complexity of water scarcity problems. For solving the water gap, we propose and exemplify eight lines of action that can be combined and tailored to each territory. Our analyses corroborate the urgent need to plan an integral management of water resources to avoid widespread scenarios of water scarcity under future climatic conditions.

Water resource management for irrigated agriculture in China: Problems and prospects

AbstractAgriculture underpins the continuous development and progress of society. As water resources impose a major constraint on economic and social development, strengthened management and scientific allocation of water resources for agricultural purpose has become a hot issue of concern for countries around the world. This is particularly important for China, a large, populous country, to safeguard its food security. In 2010, irrigation, on which China's crop production is highly dependent, contributed 32.4% of the national grain yield. With rapid economic development, however, agriculture has always faced competition for water with nonagricultural sectors. Given water and land shortage and growing rigid grain demand in China and based on the decoupling theory, this paper analyses the relationship between grain yield and irrigation water use from 2000 to 2020. The paper examines the impacts on grain yield brought by such factors as irrigation water use, effective irrigation area, fertilizer application and labour input and explores China's agricultural water security mechanism. The results show that grain yield has been significantly affected by irrigation water use, but such dependence is gradually reducing at this stage. China tries to guarantee agricultural water use by developing farmland water conservation and water‐saving irrigation, but future agricultural water use will be affected by a variety of factors, including the intensified constraint of adversely distributed water and land resources, poor operation and management of irrigation works, transfer of water rights from agriculture to industry and potential conversion of irrigated areas. This calls for red lines that define the lower and upper limits of agricultural water use to ensure agricultural water security.

Key performance indicators for small and medium-sized urban water systems in a semi-arid region: a case study of Okanagan Valley, Canada

ABSTRACT Drinking water, wastewater, and stormwater are three components of an Urban Water System. Maintenance of these components requires evaluation of the existing performance of the water system. The evaluation becomes more significant in small and medium-sized water systems because these systems wrestle with various constraints, such as insufficient funds, inadequate infrastructure and water governance. In this study, Key Performance Indicators (KPIs) are identified for each UWS component considering six performance criteria. A questionnaire was distributed to water utilities across the Okanagan Valley. KPIs were identified by combining Delphi technique and Preference Ranking Organization Method for Enrichment Evaluation methods. Ninety-six KPIs were identified with 39, 30, and 27 KPIs for drinking water, wastewater, and stormwater. Based on the available literature, agriculture water use, low impact development implementation (LID), average annual life cycle investment, and swimming advisories are a few notable KPIs that are unique to the Valley.

Fully Distributed Water Balance Modelling in Large Agricultural Areas—The Pinios River Basin (Greece) Case Study

Robust assessments of variations in freshwater availability are essential for current and future water resource management in the Pinios River Basin (PRB), which is one of the most productive basins of Greece in terms of agriculture. To support sustainable water resources management in the PRB, we set up and calibrated the mGROWA hydrological model at a high spatial (100 m) and temporal (daily) resolution for the period 1971–2000, with particular attention given to deriving crop-specific irrigation requirements. We developed and implemented a comprehensive methodological framework to overcome data scarcity constraints in the PRB, thus enabling the derivation of high-resolution spatially continuous estimates of many input variables required for the mGROWA model. We generated estimates of spatiotemporal variations in the water balance components actual evapotranspiration, irrigation requirements, total runoff, and groundwater recharge for the PRB. In addition, through the calculation of indices, such as the potential irrigation to groundwater recharge ratio (PIQR), we demonstrate a way to identify potential unsustainable water use in irrigated agriculture. The established mGROWA model can be used both as a hydrological reference model providing continuous decision support for water resources management, focusing on irrigation water use, and a basis for climate impact studies for the PRB.

Seasonal water sources at irrigated urban vegetable production sites in Ghana

AbstractStudies on water use in urban agriculture in developing countries have largely focused on wastewater reuse and its associated health concerns. However, there is some heterogeneity in the choice of water sources of urban farmers in a developing country such as Ghana, where agricultural infrastructure is not fully developed. Therefore, this study explores the choice of water sources during the rainy and dry seasons by urban farmers since it has implications for food security in urban areas and beyond. Using chi‐square and multinomial logit regression, this paper assesses urban farmers’ choices for different water sources in Ghana during the rainy and dry seasons and examines the associated factors driving these choices. The results show that most urban farmers use rainwater and wastewater during the rainy and dry seasons, respectively, but small lakes/rivers are the least used during both seasons. Also, the choice of water sources at different locations is influenced by farm and non‐farm characteristics. The paper concludes that there is heterogeneity in the choice of water sources among urban farmers at different locations during different seasons. We recommend that stakeholders involved in promoting and sustaining urban agriculture must help in building a solid infrastructure for sustainable irrigation.

Predictive Modelling of Reference Evapotranspiration Using Machine Learning Models Coupled with Grey Wolf Optimizer

Mismanagement of fresh water is a primary concern that negatively impacts agricultural productivity. Judicious use of water in agriculture is possible by estimating the optimal requirement. The present practice of estimating crop water requirements is using reference evapotranspiration (ET0) values, which is considered a standard method. Hence, predicting ET0 is vital in allocating and managing available resources. In this study, different machine learning (ML) algorithms, namely random forests (RF), extreme gradient boosting (XGB), and light gradient boosting (LGB), were optimized using the naturally inspired grey wolf optimizer (GWO) viz. GWORF, GWOXGB, and GWOLGB. The daily meteorological data of 10 locations falling under humid and sub-humid regions of India for different cross-validation stages were employed, using eighteen input scenarios. Besides, different empirical models were also compared with the ML models. The hybrid ML models were found superior in accurately predicting at all the stations than the conventional and empirical models. The reduction in the root mean square error (RMSE) from 0.919 to 0.812 mm/day in the humid region and 1.253 mm/day to 1.154 mm/day in the sub-humid region was seen in the least accurate model using the hyperparameter tuning. The RF models have improved their accuracies substantially using the GWO optimizer than LGB and XGB models.

Question 63: What role is played by multidisciplinary dialogue to achieve sustainable development goals?

AbstractCongress Question 63 ‘What role is played by multidisciplinary dialogue to achieve sustainable development goals?’ sought to explore how a multidisciplinary approach can be enhanced with improved interactions and new layers to engage in the attainment of sustainable development goals (SDGs) more effectively. In addressing these questions, some 39 papers summarized findings from about 24 countries representing substantially different economic situations, climate, farming systems and water resources. The papers illustrated the potential of irrigated agriculture to help end poverty (SDG 1), end hunger (SDG 2), to promote collaboration and investments (SDG 17) and sustain water‐related ecosystems (SDG 14 and SDG 15). The papers highlight the need for increased, and improved, exchange of information among multiple stakeholders involved in agricultural production systems, from field level, through the supply chain, to the consumers of the food and fibre created. Furthermore, a continued focus on capacity development among stakeholders in the sector is essential with improved communication of the value and challenges of agricultural water management beyond the immediate stakeholders (farmers, system operators, water sector regulators, etc.). As greater attention is directed towards the role of agricultural water use in the management of water resources and related ecosystems, the irrigation and drainage profession must communicate more effectively with the broader society to maintain a ‘social license to operate’.

Receiving Robust Analysis of Spatial and Temporary Variation of Agricultural Water Use Efficiency While Considering Environmental Factors: On the Evaluation of Data Envelopment Analysis Technique

With accelerated urbanisation, continued growth in water demand and the external pressure of water demand from the South–North Water Transfer Project, agricultural water use in Jiangsu is facing a critical situation. Therefore, it is important to explore the spatial and temporal variation in agricultural water use efficiency in order to clarify the pathway for improving agricultural water use efficiency. Firstly, the Super-Slacks-Based Measure (SBM) model was utilized to measure agricultural water use efficiency in Jiangsu Province, China, from 2011 to 2020, and secondly, a fixed-effects model was used to investigate agricultural water use efficiency and the factors influencing it in 13 prefectures in Jiangsu Province in both time and space. The results show that (1) the overall value of agricultural water use efficiency in Jiangsu Province is below 1, which means that agricultural water use efficiency in Jiangsu Province is low and far from the effective boundary, and there is more room for improvement in agricultural water use efficiency; (2) a total of 92% of prefectures in Jiangsu Province have input redundancy, which seriously inhibits the progress of agricultural water use efficiency in Jiangsu Province, among which the redundancy of total agricultural machinery power and agricultural water use is the highest; (3) Regarding total factor productivity and its decomposition index for agricultural use in Jiangsu Province, in the time dimension, the number of professional and technical personnel inputs has a positive impact on agricultural water use efficiency. In the spatial dimension, the number of professional and technical personnel inputs, industrial structure and arable land area have a positive impact on improving regional agricultural water use efficiency, among which the industrial structure has a smaller contribution to agricultural water use efficiency.

Effects of multidimensional urbanisation on water footprint self-sufficiency of staple crops in China

Rapid urbanisation in developing countries has exerted ever-increasing pressure on food and water resource systems. Existing studies mostly focus on impacts of population urbanisation on agricultural water use, disregarding the multidimensional characteristics of urbanisation. Accounting for four dimensions of urbanisation: population, economy, spatial distribution, and society, we assessed the impact of multidimensional urbanisation on the water footprint self-sufficiency rate (WFSS) of three staple crops, that is, the ratio of the water footprint (WF) of crop production to the WF of crop-related consumption, through the case for China over 2000–2017. The socio-economic driving factors and spatial heterogeneity of crop WFSS were further tested. Results show that <30% of high-crop WFSS provinces supplied more than 70% of low-crop WFSS provinces. Social urbanisation and economic urbanisation were the governing positive and negative driving factors of the rice WFSS, respectively. Population urbanisation was the dominant factor attenuating wheat WFSS during the study period, while playing a reverse role in maize WFSS. Impacts of different dimensions of urbanisation on crop WFSS were heterogeneous and even contradictory depending on the crop type, the different processes of urbanisation, and the water endowment and economic level of the provinces. The quantile regression results further indicate that population urbanisation, spatial urbanisation and social urbanisation had greater impact on the higher WFSS (i.e., resulted in virtual water export) of rice and wheat. The current analysis challenges the conventionally monotonous urbanisation-water relationships, and suggests that additional dimensions of urbanisation should be considered when assessing the effects of urbanisation on agricultural water use.

Modern issues of the organizational and legal basis improving of land reclamation

The article deals with topical issues of the development of the organizational and legal framework for water use in land reclamation. Land reclamation based on a developed reclamation and water management complex largely determines the increase in the efficiency of agriculture, ensuring the country's food security, meeting the needs of the rural population and the agro-industrial complex in water resources. At present, the provision of water resources is complicated by modern climate changes, which cause an increase in the aridity of the climate in the south of the European part of Russia. The performed zoning of the territory confirmed insignificant renewable water resources and high anthropogenic pressure on water bodies of the Stavropol and Krasnodar Territories, the Republic of Kalmykia and the Rostov Region, which affects not only the volume of water resources available for irrigation, but also the quality. Significant physical deterioration of the structures of the reclamation and water management complex, reaching 80% or more, low values of the efficiency of reclamation systems determine significant unproductive water losses during irrigation. To normalize agricultural water use, ensure accident-free and uninterrupted supply of water of the required quantity and quality to the population and agricultural producers, develop and improve the efficiency of irrigated agriculture, it is important to improve the organizational and legal framework for water use in land reclamation. The principal directions of legal regulation of the development of land reclamation and water management of the country and regions are determined by the need to legally consolidate the transition to integrated water resources management in agriculture, improve existing legislative acts, standardize the rights and obligations of water users, determine the role of the state in the implementation of measures to modernize the water management complex. For the transition to a new technological level of management of the reclamation and water management complex of the agro-industrial complex, the introduction of water accounting systems and control over the use of water resources, the improvement of organizational principles for managing the operation mode of reservoirs to take into account the requirements of agriculture in the zone of insufficient moisture, audit of reclamation systems to assess their effectiveness and long-term planning of agricultural development based on land reclamation and other activities.

Can the use of magnetized water affect the seedling development and the metabolite profiles of two different species: Lentil and durum wheat?

Seedlings of durum wheat and lentil were utilized to investigate the efficiency of magnetic water on growth and metabolic epicotyl profile. Tap water was passed through a magnetic device with a flow rate of max. 12900 - 13200 Gauss (G). Seeds and plantlets were grown on sand-free paper soaked by magnetized water, with unmagnetized tap water used in a control group. The growth parameters were collected at three time points (48, 96, and 144 hours after treatment), the same times at which metabolomic analysis was conducted on seeds, roots, and epicotyls. Although the effects varied with the species, tissues, and time point considered, compared with tap water (TW), the use of magnetized water treatment (MWT) led to higher root elongation in both genotypes. On the contrary, epicotyl length was not affected by treatment both in durum wheat and lentil. The results indicate that the use of magnetized water in agriculture can be considered a sustainable technology to promote plant development and quality with reduced and more efficient water usage, leading to cost-saving and environmental protection.

Optimized border irrigation delays winter wheat flag leaf senescence and promotes grain filling.

Border irrigation is still the main irrigation method in the Huang-Huai-Hai Plain of China (HPC), and the suitable irrigation border length for water saving and high yield under traditional irrigation is still unclear. Therefore, a 2-year traditional border irrigation experiment (2017-2019) was conducted on the HPC. Four border lengths were tested: 20m (L20), 30m (L30), 40m (L40), and 50m (L50). These treatments were given supplementary irrigation at jointing and anthesis. An exclusively rainfed condition formed the control treatment. Compared with other treatments, the activities of superoxide dismutase antioxidant and sucrose phosphate synthetase, and the contents of sucrose and soluble proteins after anthesis were higher in the L40 and L50 treatments, while the content of malondialdehyde content was lower. Therefore, the L40 treatment effectively delayed the decrease in the soil plant analysis development (SPAD) value and chlorophyll fluorescence characteristics, promoted grain filling, and achieved the highest thousand-grain weight. Compared with the L40 treatment, the grain yields of the L20 and L30 treatment were significantly reduced, while the water productivity of the L50 treatment was significantly reduced. These findings suggest that 40m was the optimal border length for both high yield and water saving in this experiment. This study provides a simple and low-cost water-saving irrigation method for winter wheat in the HPC under traditional irrigation, which can help alleviate the pressure of agricultural water use.