Rising agricultural water scarcity in China is driven by expansion of irrigated cropland in water scarce regions

Improving agricultural water productivity to ensure food security in China under changing environment: From research to practice

Exploring China's water scarcity incorporating surface water quality and multiple existing solutions

Irrigation water use and efficiency assessment coupling crop cultivation, commutation and consumption processes

Efficient irrigation water allocation and its impact on agricultural sustainability and water scarcity under uncertainty

Book Reviews

With the growing irrigation water scarcity, the researchers and policymakers are more concerned to improve the irrigation water use efficiency at farmers’ field level. The water-saving technologies provide greater control over water delivery to the crop root zone and reduce the non-beneficial evaporation from the crop field. Water productivity is an important concept for measuring and comparing water use efficiency. The present study tried to estimate the irrigation water use and physical water productivity of cotton under alternate furrow and drip irrigation methods in the Bhavnagar district of Gujarat. Results suggest that crop yield and physical water productivity were higher for cotton irrigated by drip method than alternate furrow method during normal rainfall and drought year. The irrigation water use under the drip method of irrigation was lower as compared to the alternate furrow method. In the case of total water (effective rainfall + irrigation water) use, per hectare crop yield and physical water productivity were higher for the drip method of irrigation than the alternate furrow method of irrigating cotton crop during normal rainfall and drought year. In the case of total water use (effective rainfall + irrigation water), it was lower for drip irrigation than the alternate furrow method of irrigating cotton crop during normal rainfall year and drought year. While estimating total water (effective rainfall + irrigation water) use, it was assumed that there is no return flow of water from the cotton field in the study area under both irrigation methods.

The paper characterizes the phenomena of droughts and water scarcity in Polish agriculture and their impacts on crop yield. Various preventive measures should be undertaken to mitigate the harmful effects of droughts and water scarcity. The most important is the development of water resources. To accomplish this aim, small scale water retention projects and irrigation development programs should be further implemented in many provinces of Poland. Effective use of irrigation water, optimization of water distribution, crop rotation, rehabilitation and modernization of the existing irrigation systems, soil reclamation are the examples of other measures. The pressure for increased water supplies is intensifying in Poland. That is why there is an urgent need to improve the uniform national plans of drought and water scarcity mitigation including guidelines on how to prevent and counteract the effects of water scarcity in agriculture and to release recommendations stating the most adequate measures to be undertaken.

Virtual water flows in the international trade of agricultural products of China

Water footprints can reflect the sources and utilities of water resources. Introducing the water footprint theory to evaluate irrigation water use efficiency can reflect agricultural water consumption more scientifically and accurately. This study analyzes the variation trends of the blue, green and gray water footprints of grains in different regions of Heilongjiang Province and selects the grain-sowing area, total agricultural machinery power, grain blue water footprint and green water footprints and absolute fertilizer amount as input indexes and the agricultural gross product and gray water footprint of grain as output indexes. A slacks-based measure–data envelopment analysis (SBM-DEA) model is used to estimate the irrigation water use efficiencies of 11 cities in Heilongjiang Province, analyze the corresponding spatiotemporal distribution and further decompose and calculate the irrigation water use efficiencies of the five economically underdeveloped second-level cities. The results suggest that the spatial distribution of the grain water footprint in Heilongjiang Province reflects coexisting areas of excess and scarcity. The irrigation water use efficiency showed a steady and slow downward trend from 2008 to 2018. The irrigation water use efficiency reflected significant spatial differences in Heilongjiang Province, with a pattern of high values in the southwest and low values in the northeast; these differences have gradually narrowed. The average irrigation water use efficiency in Heilongjiang Province was 0.821 and the irrigation water efficiencies of Harbin, Qiqihar and Jixi were at the forefront of the province. Jiamusi, Hegang, Shuangyashan, Yichun, and Mudanjiang are the five cities with below-provincial-average irrigation water use efficiencies. The irrigation water use efficiency of Heilongjiang Province mainly depends on the pure technical efficiency. In the future, technical inputs should be improved on the basis of optimizing the agricultural production layout, focusing on improving the pure technical efficiency. The research results obtained herein can provide a theoretical basis for agricultural water management in Heilongjiang Province.

Water scarcity has emerged as a critical constraint on agricultural development and food security worldwide, particularly in arid and semi-arid regions such as Central Asia, Western Asia, and North Africa, which are part of the “Belt and Road” Initiative. This study, based on a global multi-regional input–output model, quantitatively analyzes the virtual water flows between China and countries along the “Belt and Road”. It focuses on water-scarce regions, examining the impact of virtual water trade on agricultural resource pressures and food security, as well as the transfer of water resources in trade patterns. The findings indicate that virtual water trade, as an innovative water resource management strategy, can redistribute water resources through international trade, thereby alleviating water stress and enhancing food security in water-scarce areas. Despite China’s status as a net importer in virtual water trade with “Belt and Road” countries, the majority of virtual water flows toward nations with relatively abundant water resources, rather than to the most water-deficient areas. This discovery reveals imbalances in virtual water trade patterns, suggesting that current trade models do not effectively alleviate water and food security pressures in water-scarce regions. The “Belt and Road” mechanism should provide new ideas for solving the huge gap between virtual water theory and reality. In response, this paper proposes optimizing trade structures, strengthening agricultural water resource management, promoting green virtual water trade, fostering regional cooperation, improving data quality and transparency, encouraging agricultural diversification, and increasing investment in water-saving agricultural technologies.

Water management and crop production for food security in China: A review

High resolution annual irrigation water use maps in China based-on input variables selection and convolutional neural networks

مهمترین هدف برنامه‌ریزی و مدیریت آبیاری افزایش بهره‌وری و راندمان مصرف آب و در عین حال دارا بودن یک سامانه پایدار تولید است. به منظور بررسی تاثیر انواع خاک‌پوش بر کارایی مصرف آب، شاخص‌های رشدو عملکرد ذرت، پژوهشی به صورت طرح بلوک‌های کامل تصادفی با 6 تیمار و 3 تکرار در سال زراعی 93-94 در مزرعه پژوهشی دانشگاه شهرکرد انجام شد. تیمارها شامل شاهد (بدون پوشش)، پوشش پلاستیک شفاف، پلاستیک سیاه، گونی نخی کناف، گونی سفید و آبی بود. در طول فصل کشت، رطوبت خاک تا عمق توسعه موثر ریشه اندازه‌گیری و آبیاری‌ها بر اساس کمبود رطوبت خاک با تأمین نیاز آبی کامل تعیین و اعمال گردید. در طول فصل رشد نمونه‌برداری برای تعیین میزان ماده خشک برگ، ساقه و میزان آماس نسبی برگ انجام گرفت و در پایان فصل رشد نیز میزان حجم آب مصرفی، میزان دانه تولیدی، اندازه‏گیری و ثبت گردید. نتایج نشان دادکه خاک-پوش‌ها در تمام مراحل اندازه‏گیری تأثیر افزاینده بر محتوای نسبی آب برگ داشته‌اند که این می‌تواند ناشی از تأثیر آن‌ها بر حفظ رطوبت خاک باشد. خاک‌پوش پلاستیک شفاف بیشترین تأثیر را بر شاخص برداشت با مقدار 97/53 درصد داشت که این مقدار متناظر افزایش 32 درصد نسبت به تیمار شاهد بود. بیشترین و کمترین میزان کارایی مصرف آب به ترتیب مربوط به تیمار گونی‌سفید و شاهد با مقادیر 7/2 و 4/1 کیلوگرم وزن خشک دانه بر مترمکعب بدست آمدکه این معادل افزایش 93 درصد میزان کارایی مصرف آب می‌باشد. بنابراین خاک‌پوش گونی‌های سفید وآبی بیشترین تأثیر را بر حفظ رطوبت خاک و عملکرد محصول دارا بودند.

Water scarcity is becoming a critical problem in arid and semi-arid areas of the world, where part of the production of the main horticultural crops is located, as is the case of the Mediterranean area. Drought is one of the main limiting factors in agriculture and it is seriously affecting the production of horticultural crops. The improvement of water productivity in agriculture in general, and in horticulture in particular, can be achieved through the use of certain strategies. Deficit irrigation consists of the supply of water below the irrigation water requirements (IWR), so that there is a reduction in evapotranspiration. It can be done continuously (CDI) or regulated (RDI). With deficit irrigation, the irrigation water use efficiency can be improved, maintaining yield, and it could even lead to an improvement in the quality of the harvest. This study, carried out at the Cajamar in Paiporta Experimental Center (Valencia, Spain), analyzes the effect of deficit irrigation on four of the main cultivated horticultural crops, open field cultivated in the Mediterranean area: two of autumnal-winter crops (cauliflower and onion) and two spring-summer crops (pepper and watermelon). In the evaluation, the following parameters have been analyzed: plant growth and water status, yield, irrigation water use efficiency, quality of production and crop profitability. In the first season the CDI was tested, which allowed to establish the different growth stages for each crop, which were used in the following season for the RDI. In the four crops, the control plants (100% IWR) have shown an adequate water status, in terms of both relative water content and membrane stability index, while those subjected to a severe CDI, have shown the lowest values of both indexes. The negative effect of deficit irrigation on yield has been less important in autumn-winter crops than in spring-summer crops, especially in cauliflower. The CDI at 50% IWR has drastically reduced the marketable yield and, consequently, the gross revenue, although it has supposed an improvement in the irrigation water use efficiency for the autumn-winter crops. From the individual analysis of the crops, it can be stated that cauliflower yield obtained with CDI at 75% IWR or RDI at 50% IWR during the juvenile phase, has remained at levels similar to the control, improving the irrigation water use efficiency. In relation to onion, in case of severe water restriction, it would be advisable to apply CDI with 75% IWR or RDI at 50% IWR during bulb ripening, since these strategies have slightly decreased yield, improving the irrigation water use efficiency. In less restrictive conditions, RDI at 75% IWR during the bulb maturation has led to a satisfactory yield, with an increase in the irrigation water use efficiency. In Italian sweet pepper, the application of RDI to 75% IWR during the harvesting has resulted in a considerable reduction of the yield, and therefore, of the gross income, although with important water savings and increasing the fruit soluble solids and phenolic compounds content. By shortening the cultivation cycle until the beginning of September, when most of the marketable yield has already been harvested, significant water savings would be achieved, and the land could be used in other crops. CDI at 75% IWR and 50% IWR, or RDI at 50% IWR at harvesting have resulted in a high incidence of fruit affected by blossom-end rot. In watermelon the RDI application can be recommended, both 75% and 50% IWR, during the fruit ripening, since it has led to acceptable marketable yields. In general terms, it can be affirmed that the application of CDI and RDI in the four crops has not significantly affected the product quality, in terms of the analyzed parameters.

Virtual scarce water flows and economic benefits of the Belt and Road Initiative