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Highlights • Northeast China is the center of maize production in the country. • Assess varying impacts of drought across different maize growth stages in Northeast China. • Probability of extreme events in irrigation water shortage will increase in the future. • Irrigation infrastructure and efficient irrigation scheme and technologies are of great importance. Abstract Northeast Farming Region of China (NFR) produces about one-third of the national maize output. Shortage of crop irrigation water is one of the main threat to the stable level of maize production in the NFR. Previous studies on the sensitivity of maize production to drought are typically based on field experiments and treat the maize growing season as a whole, with rare attention to the varying impacts of drought across different maize growth stages. Given the importance of NFR on China's food security, it is crucial to optimize the irrigation schedule to mitigate the adverse effects of drought. In this study, we employ Agro-ecological Zone (AEZ) model to investigate how climate change affects irrigation water requirement (IWR) of maize during different growth stages and under different climate change scenarios. Results indicate that the NFR would experience a substantial increase in the probability of extremely shortage of crop irrigation water under future climate change. The ensemble simulation under future climate projections indicates more frequent demands for irrigation with substantially increased amount in the mid-season stage (G3) when maize is more sensitive to water deficit compared with other stages. These findings indicate that earlier planning of irrigation infrastructure and development of more efficient irrigation scheme and technologies is of great importance to secure maize production in the region. [ABSTRACT FROM AUTHOR]

This study establishes a procedure to couple Decision Support System for Agrotechnology Transfer (DSSAT) and China Agroecological Zone model (AEZ-China). This procedure enables us to quantify the effects of two natural adaptation measures on soybean production in China, concern on which has been growing owing to the rapidly rising demand for soybean and the foreseen global climate change. The parameters calibration and mode verification are based on the observation records of soybean growth at 13 agro-meteorological observation stations in Northeast China and Huang-Huai-Hai Plain over 1981–2011. The calibration of eco-physiological parameters is based on the algorithms of DSSAT that simulate the dynamic bio-physiological processes of crop growth in daily time-step. The effects of shifts in planting day and changes in the length of growth cycle (LGC) are evaluated by the speedy algorithms of AEZ. Results indicate that without adaptation, climate change from the baseline 1961–1990 to the climate of 2050s as specified in the Providing Regional Climate for Impacts Studies-A1B would decrease the potential yield of soybean. By contrast, simulations of DSSAT using AEZ-recommended cultivars with adaptive LGC and also the corresponding adaptive planting dates show that the risk of yield loss could be fully or partially mitigated across majority of grid cells in the major soybean-growing areas. [ABSTRACT FROM AUTHOR]

There have been increasing concerns on risks and uncertainty posed by climate change to China's future crop production. The existing assessments using popular process-based and site-specific crop growing models highlight the significant extent of climate-induced yield reduction, and thus suggest a scary downward risk for China's future food production. Surprisingly, much less attention has been paid to exploring the potential gains that may also be brought by climate change. To address this imbalance, we develop an integrated agro-climatic and ecological assessment tool that is capable of detecting the shifts of multicropping opportunities under different climate change scenarios. The application of this tool to the context of China reveals significant extension of multicropping opportunities brought in by climate change. We argue for an active adaptation to such emerging opportunities through both market and policy incentives, because the aggregate gain of such adaptation is sufficient to outweigh the loss as revealed by the existing assessments. [ABSTRACT FROM PUBLISHER]

• Precise winter fallow periods in the Yangtze River basin are identified at the grid level using remote sensing and a unique dataset of rapeseeds growing records at 84 observation stations over 1981-2011. • Considering adaptations on sowing dates and cultivars, the total potential of rapeseed production on winter fallow land could reach 15.17 million tons, on average 1,950 kg/ha. • By coupling the AEZ and CHINAGRO-II models, we estimate economic benefit of rapeseed production and its impact on edible oil security of China. • A 60% realization of the production potential would reduce China's rapeseed import to zero and further reduce soybean import by 8.1 million tons in 2020. To solve the energy crisis and protect the ecological environment has been the central concern of the sustainable development debate. The reproducibility and lower environmental impacts of bioenergy have attracted increasing attention in the debate. This research investigates the potentials of growing rapeseed in winter fallow fields across the Yangtze River Basin (YRB) to serve the goal of boosting bioenergy production and improving edible oil security in China. It first quantifies the extent of winter fallow fields in the Basin and identifies the accurate starting and ending dates of the fallowing at the grid-cell level. It then matches the fallowing periods with the growing period grid-by-grid and assesses the current and future potentials of rapeseed production across the matched grid-cells in the region. The assessments take into consideration of climate change adaptations on sowing dates and on the choice of varieties with suitable growth cycle length. Finally, by coupling the Agro-Ecological Zones (AEZ) model and CHINAGRO-II economic model, this research simulates economically meaningful levels of rapeseeds production and trade for 2020 and 2030. A 60% realization of the production potential would increase total rapeseed supply by 9.1 million tons, reduce China's rapeseed import to zero and further reduce soybean import by 8.1 million tons in 2020. In 2030, the import of rapeseed would be reduced from 15 million tons under baseline to 7.3 million tons. [ABSTRACT FROM AUTHOR]

Unsustainable overexploitation of groundwater for agricultural irrigation has led to rapid groundwater depletion and severe environmental damage in the semi-arid Hebei Plain of China. Field experiments have recommended annual winter fallowing (i.e., forgoing winter wheat production) as the most effective way to replenish groundwater. However, adopting the recommendation across the Hebei Plain would lead to a significant reduction in total wheat production. This research aims to find the most favorable water-sustainable cropping systems for different localities in the Hebei Plain, which at the regional aggregation level maintains the uppermost overall levels of wheat and grain production respectively. Our simulations indicate that in the Hebei Plain, an optimal allocation of a wheat-early maize relay intercropping system and an early maize-winter fallow cropping system across the Hebei Plain could lead to significant water savings while minimizing grain production losses to around 11%. Compared to the prevailing wheat and summer maize cropping system , to prevent a drop in the water table, 39% of the current wheat cropping land would need to be fallowed in winter, reducing irrigation water use by 2639 × 106 m3. Replacing the prevailing wheat and summer maize cropping system with our optimized allocation system could lead to a 36% increase in total maize production and 39% decrease in total wheat production, resulting in total agricultural irrigation water savings of 2322 × 106 m3 and a total grain production reduction by 11%. The findings indicate the potential benefits of our cropping system adaptation method to meet the challenge of recovering local groundwater level with the least possible reduction of wheat and total grain production in the Hebei Plain. • The current practice of overexploiting groundwater in the Hebei Plan is unsustainable • We search for the desired water-sustainable cropping systems across localities in the Plain • Minimizing the reduction of wheat production and recovering water table • The crop allocation procedure and findings enrich the literature and inform policy makers [ABSTRACT FROM AUTHOR]

Background and aims Consecutive climatic extremes have more intense impacts on natural ecosystems and human activities than occasional events. There were many studies about the frequency or intensity of extreme weather events, but few focused on the consecutiveness or continuousness of climatic extremes. We analyzed the temporal and spatial distributions and tendencies in the consecutive temperature and precipitation extremes in China during 1961–2015. Methods Daily temperature and precipitation data at 1867 meteorological stations over China was used and four consecutive indices of climate extremes, i.e. cold spell duration indicator (CSDI), warm spell duration indicator (WSDI), consecutive dry days (CDD) and consecutive wet days (CWD), were calculated by RClimDex 1.0. Linear trends in the time series of consecutive days of temperature and precipitation extremes were examined and their statistical significance was evaluated using Mann–Kendall test. Results and discussion There were obvious differences in the spatial distributions of consecutive days of climate extremes in China. During 1961–2015, CSDI and CWD decreased significantly at rates of 0.9 and 0.1 days per decade respectively, while WSDI increased significantly at rate of 0.8 days per decade in China. Spatially, CSDI decreased at rates of 0–3.0 days per decade in almost all parts of China, and WSDI increased at rates of 0–2.0 days per decade in most parts of China. The spatial trends of CDD and CWD were significant only in several regions of China. CSDI and WSDI had higher percent changes than those of CDD and CWD. Changes in the CSDI and WSDI were associated with large-scale oceanic and atmospheric circulation oscillations, such as Atlantic Multidecadal Oscillation (AMO), El Niño/Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO). With global warming, there will be fewer cold extremes, more frequent hot extremes and precipitation extremes. Conclusions Given the increases in the frequency and intensity of some consecutive climatic extremes and an increasing physical exposure and socio-economic vulnerability to such extremes in China, more strategies and capacities of mitigation and adaptation to consecutive climatic extremes are essential for the local government and climate-sensitive sectors. [ABSTRACT FROM AUTHOR]