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Climate is one of the main factors affecting agricultural water use. The variation of different climate factors will have a great impact on the balance of water supply, which will significantly aggravate the water-related threats to the sustainability of agricultural production. As a typical agricultural area of China, the Huang-Huai-Hai region is one of the major grain-producing areas. In order to evaluate the response of future agricultural water use to future uncertain changeable factors, this study assessed future agricultural water use with the coupling effect of climate change, irrigation efficiency and plantation structure change. The results showed that the temperature and precipitation both increased to different degrees under the two greenhouse gas emission and radiation forcing scenarios, which have great impacts on the crop water requirement (ETc) of main crops. Under RCP (Representative Concentration Pathways) 8.5, a 10% increase in the irrigation water utilization coefficient will reduce the regional irrigation water requirement by about 13 Gm3, and the adjustment of plantation structure will reduce the irrigation water consumption by about 11 Gm3. The quantitative analysis suggests that the improvement of the irrigation efficiency and the expansion of water-saving crop plantation areas in the future will moderate the adverse impact of climate change on agricultural water use. This study provides a reference for the management of agricultural water and the rational distribution of water resources under the future climate change. HIGHLIGHTS Various climatic factors will change with global warming trend in the study area.; Climate change will increase the total irrigation water requirements in the area.; Improving plantation structure and irrigation efficiency will alleviate the issue.;

Simple Summary: Quantitatively exploring the impact of climate change on crop production and water consumption (i.e., crop evapotranspiration during crop growth period, ET) is very important to achieve sustainable regional agricultural development. In this study, based on daily downscaled climate data from 22 Global Climate Models (GCMs), we applied the Agricultural Production Systems sIMulator (APSIM) to investigate the possible impact of climate change (e.g., temperature (Temp), solar radiation (Rad), precipitation (Prec) and CO2) on crop phenology, yield and water consumption for the rice (Oryza sativa L.) -wheat (Triticum aestivum L.) rotation. Due to the increase in Temp, the key phenological periods (flowering and maturity) of wheat in the future mainly tend to advance, while the phenological changes of rice show different trends at different sites. Both rice and wheat yields were negatively correlated with Temp, but positively correlated with Rad, Prec, and CO2 concentration ([CO2]). However, crop ET was positively correlated with Rad, but negatively correlated with [CO2], as elevated [CO2] decreased stomatal conductance. Moreover, the water use efficiency (WUE) of rice and wheat was negatively correlated with Temp, but positively correlated with [CO2]. Overall, climate change will have a significant impact on the crop growth process, yield and water consumption. Global climate change has had a significant impact on crop production and agricultural water use. Investigating different future climate scenarios and their possible impacts on crop production and water consumption is critical for proposing effective responses to climate change. In this study, based on daily downscaled climate data from 22 Global Climate Models (GCMs) provided by Coupled Model Intercomparison Project Phase 6 (CMIP6), we applied the well-validated Agricultural Production Systems sIMulator (APSIM) to simulate crop phenology, yield, and water use of the rice–wheat rotation at four representative stations (including Hefei and Shouxian stations in Anhui province and Kunshan and Xuzhou stations in Jiangsu province) across the Huang-Huai-Hai Plain, China during the 2041–2070 period (2050s) under four Shared Socioeconomic Pathways (i.e., SSP126, SSP245, SSP370, and SSP585). The results showed a significant increase in annual mean temperature (Temp) and solar radiation (Rad), and annual total precipitation (Prec) at four investigated stations, except Rad under SSP370. Climate change mainly leads to a consistent advance in wheat phenology, but inconsistent trends in rice phenology across four stations. Moreover, the reproductive growth period (RGP) of wheat was prolonged while that of rice was shorted at three of four stations. Both rice and wheat yields were negatively correlated with Temp, but positively correlated with Rad, Prec, and CO2 concentration ([CO2]). However, crop ET was positively correlated with Rad, but negatively correlated with [CO2], as elevated [CO2] decreased stomatal conductance. Moreover, the water use efficiency (WUE) of rice and wheat was negatively correlated with Temp, but positively correlated with [CO2]. Overall, our study indicated that the change in Temp, Rad, Prec, and [CO2] have different impacts on different crops and at different stations. Therefore, in the impact assessment for climate change, it is necessary to explore and analyze different crops in different regions. Additionally, our study helps to improve understanding of the impacts of climate change on crop production and water consumption and provides data support for the sustainable development of agriculture. [ABSTRACT FROM AUTHOR]

Simulation of land and water management for the irrigated farmlands has become an interest to answer how agricultural productivity is related to the water use in a river basin. This research was undertaken in the Brantas River Basin in Indonesia, involving a modelling process with the virtual water concept as a tool to analyze water productivity. The research simulated the agricultural water demand and provided the results of the virtual water content of paddy and maize, based on the available farming land, water availability, cropping pattern and climatological conditions of the respective hydrological years of 1997 and 2011 as a benchmark. After which projections were made based on the low rainfall scenario for the years 2021 to 2025. The research concluded that the presence of excess irrigation in the tropical climates hinders the increase in agricultural productivity, and therefore, the irrigation in the Brantas River Basin needs to be improved by, among others, selecting plants with higher water productivity, developing water-sensitive cropping patterns, and water conveyance savings.

Global climate change has had a significant impact on crop production and agricultural water use. Investigating different future climate scenarios and their possible impacts on crop production and water consumption is critical for proposing effective responses to climate change. In this study, based on daily downscaled climate data from 22 Global Climate Models (GCMs) provided by Coupled Model Intercomparison Project Phase 6 (CMIP6), we applied the well-validated Agricultural Production Systems sIMulator (APSIM) to simulate crop phenology, yield, and water use of the rice–wheat rotation at four representative stations (including Hefei and Shouxian stations in Anhui province and Kunshan and Xuzhou stations in Jiangsu province) across the Huang-Huai-Hai Plain, China during the 2041–2070 period (2050s) under four Shared Socioeconomic Pathways (i.e., SSP126, SSP245, SSP370, and SSP585). The results showed a significant increase in annual mean temperature (Temp) and solar radiation (Rad), and annual total precipitation (Prec) at four investigated stations, except Rad under SSP370. Climate change mainly leads to a consistent advance in wheat phenology, but inconsistent trends in rice phenology across four stations. Moreover, the reproductive growth period (RGP) of wheat was prolonged while that of rice was shorted at three of four stations. Both rice and wheat yields were negatively correlated with Temp, but positively correlated with Rad, Prec, and CO2 concentration ([CO2]). However, crop ET was positively correlated with Rad, but negatively correlated with [CO2], as elevated [CO2] decreased stomatal conductance. Moreover, the water use efficiency (WUE) of rice and wheat was negatively correlated with Temp, but positively correlated with [CO2]. Overall, our study indicated that the change in Temp, Rad, Prec, and [CO2] have different impacts on different crops and at different stations. Therefore, in the impact assessment for climate change, it is necessary to explore and analyze different crops in different regions. Additionally, our study helps to improve understanding of the impacts of climate change on crop production and water consumption and provides data support for the sustainable development of agriculture.

China has witnessed accelerated urbanization since the reforms and open policies which began in 1978. This eventually resulted in increased residential water requirements and worsening water shortages, particularly in the current century. In the context of resource and environmental constraints, improving agricultural water use efficiency (AWUE) is a crucial issue to ensure food security, improve the ecological environment, and meet the needs of sustainable agricultural development. Based on the panel data of 30 provinces in China from 1999 to 2018, the article uses the Super-SBM model to measure the AWUE. Moreover, the study uses the entropy method to establish the urbanization evaluation index system from the dimensions of population, land, economy, measures the comprehensive level of urbanization development, and further constructs a dynamic spatial econometric model. We use the unconditional maximum likelihood estimation method to evaluate the impact of urbanization development on AWUE and its heterogeneity. The findings reveal that the AWUE considering undesired outcomes has generally shown a steady improvement, but there is ample space for resource conservation and environmental protection, and there are noticeable differences among regions. The decomposition of spatial effects shows that urbanization development in each region has a short-term positive effect on AWUE in the region and neighboring regions, and a long-term effect exists only in the western region. The impact of urbanization in different dimensions has been found that both land urbanization and economic urbanization contribute to the improvement of AWUE, while population urbanization helps to improve AWUE by improving the awareness level of the farmers.

Groundwater resources carrying capacity (GRCC) is defined as the capacity of groundwater resources for supporting social-economic development, which has been incredibly reduced in groundwater-depended agricultural regions due to unreasonable use of groundwater resources. Identifying the key factors influencing GRCC and providing the optimal strategy is critical for sustainable use of groundwater resources. The present study used the improved GRCC index, regression functions, and random forest to identify the key factors influencing the GRCC in a groundwater over-exploited area [Zhangjiakou, Hebei province, China (ZJK)]. And the particle swarm optimization and optimal water allocation model were used to select the best crop distribution scenarios for improving the GRCC. The results showed that IncMSE index (random forest) for each influencing factors ranging from − 3.4–8.9, indicating that crop distribution is the most important factor affecting the GRCC. Therefore, changing the crop distribution is the key factor to improve the GRCC in ZJK. The results of optimizing crop distribution scenarios showed the total water use for optimized crop distribution O26 (potato and cabbage planting area were 36,885 and 362,936 ha) was 713,701,500 m3, which was reduced by 14% compared to base scenarios in 2016. Furthermore, the GRCC index (D) has decreased by 53%～83%, which means the groundwater resources would be sustainable by using this crop distribution with irrigation quotas are 900 and 1875 m3/ha respectively. The results can provide decision-making references for sustainable use of groundwater resources in groundwater over-exploitation regions. • Groundwater resources carrying capacity (GRCC) consists of hydrological and economic parameters. • GRCC was examined in a groundwater over-exploited area in Zhangjiakou, Hebei province, China (ZJK). • Changing the crop distribution was the kay factor to improving GRCC in ZJK. • An optimal crop distribution was indentified. [ABSTRACT FROM AUTHOR]

China has witnessed accelerated urbanization since the reforms and open policies which began in 1978. This eventually resulted in increased residential water requirements and worsening water shortages, particularly in the current century. In the context of resource and environmental constraints, improving agricultural water use efficiency (AWUE) is a crucial issue to ensure food security, improve the ecological environment, and meet the needs of sustainable agricultural development. Based on the panel data of 30 provinces in China from 1999 to 2018, the article uses the Super-SBM model to measure the AWUE. Moreover, the study uses the entropy method to establish the urbanization evaluation index system from the dimensions of population, land, economy, measures the comprehensive level of urbanization development, and further constructs a dynamic spatial econometric model. We use the unconditional maximum likelihood estimation method to evaluate the impact of urbanization development on AWUE and its heterogeneity. The findings reveal that the AWUE considering undesired outcomes has generally shown a steady improvement, but there is ample space for resource conservation and environmental protection, and there are noticeable differences among regions. The decomposition of spatial effects shows that urbanization development in each region has a short-term positive effect on AWUE in the region and neighboring regions, and a long-term effect exists only in the western region. The impact of urbanization in different dimensions has been found that both land urbanization and economic urbanization contribute to the improvement of AWUE, while population urbanization helps to improve AWUE by improving the awareness level of the farmers. [ABSTRACT FROM AUTHOR]

Abstract: Tradable water rights systems are becoming an important way to achieve distributive efficiency for water resources. However, it is not easy for countries or regions to establish water markets due to the existence of various barriers. In early 2002, the Ministry of Water Resources (MWR) of China initiated an experimental project—Building Water-saving Society in Zhangye City. This project was the first of its kind in China. The aim of the project was to establish a new water use rights (WUR) system with tradable water quotas and to reallocate water resources reasonably and efficiently through market-based instruments. This paper presents the research done on the system and water markets. It has been found that that the system is hard to implement well and that WUR trading is not popular. The barriers to implementing a WUR system are social and administrative in nature. WUR trading faces management, legal, administrative, and fiscal barriers. We discuss why these barriers exist and we provide policy recommendations to overcome them. [Copyright &y& Elsevier]