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BACKGROUND: Drought affects the characteristics of water use during crop production and so quantitatively evaluating the impacts is important. However, it remains unclear how crop water use responds to drought. To address this gap, water footprint (WF) and standardized precipitation evapotranspiration index (SPEI) were calculated by remote sensing approaches to assess the effects of drought on crop water use. Rainfed maize is the most important crop in Jilin Province, and its growth and water use are more susceptible to drought. The present study explored not only the impact of growing season drought on the maize WF values in Jilin Province, but also the response of WF values to drought at different time scales. RESULTS: Spatially, 72.94% of the WFblue pixels showed a non‐significant increase, and the WFgreen in 68% pixels decreased significantly, being mainly concentrated in the middle region. Furthermore, the pixels affected by monthly time scale drought were mainly in the middle region, whereas the pixels affected by annual time scale drought were mainly in the western region. CONCLUSION: Drought not only affected on the source and structure of agricultural water consumption, but also had different effects on WF values at different time scale. These effects had obvious spatial differences. The present study systematically explored the effects of drought on the WF values for rainfed maize in different climate regions and a consideration of these effects could provide valuable information on rainfed maize growth and the agricultural water use response to a changing climate. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND Water footprint ( WF) methodology is essential for quantifying total water consumption of crop production and making efficient water management policies. This study calculated the green, blue, grey and total WFs of maize production in Northeast China from 1998 to 2012 and compared the values of the provinces. This study also analyzed the spatial variation and structure characteristics of the WFs at the prefecture level. RESULTS The annual average WF of maize production was 1029 m3 per ton, which was 51% green, 21% blue and 28% grey. The WF of maize production was highest in Liaoning Province, moderate in Heilongjiang Province and lowest in Jilin Province. The spatial differences of the WFs calculated for the 36 major maize production prefectures were significant in Northeast China. There was a moderate positive spatial autocorrelation among prefectures that had similar WFs. Local indicator of spatial autocorrelation index ( LISA) analysis identified prefectures with higher WFs in the southeast region of Liaoning Province and the southwest region of Heilongjiang Province and prefectures with lower WFs in the middle of Jilin Province. CONCLUSION Spatial differences in the WF of maize production were caused mainly by variations in climate conditions, soil quality, irrigation facilities and maize yield. The spatial distribution of WFs can help provide a scientific basis for optimizing maize production distribution and then formulate strategies to reduce the WF of maize production. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Rain-fed crops are a major crop type, and their water use is extremely vulnerable to climate change. Studying the water requirement characteristics of rain-fed crops in different growth stages and associated climatic driving factors is of great significance for sustainable crop production. The water footprint (WF) of crops can comprehensively reflect the type and quantity of water consumption during the crop growth period. Previous studies have focused on quantifying the crop WF throughout the growth period, and less attention has been given to quantifying the crop WF in different growth stages. This study quantified the WFs of rain-fed maize and associated climatic driving factors in five growth stages from 1996 to 2018 in Northeast China. The results show that (1) the WF of rain-fed maize in each growth stage showed distinct differences. The highest WF occurred in the tasseling-milky growth stage, whereas the lowest WF occurred in the sowing-emergence growth stage. (2) The variation trends of maize WF in different growth stages were heterogeneous across Northeast China. The declining trends were mainly distributed in the southwest, while increasing trends were mainly distributed in the east in most growth stages. (3) Sunshine hours and temperature had a greater impact on the maize WF in most growth stages. The impacts of other climatic factors on the WF of rain-fed maize differed among different growth stages. Precipitation contributed much more to the variation in maize WF in early growth stages, relative humidity had the greatest impact on the WF of maize in the jointing-tasseling growth stage, and wind speed played a major role in the variation in the maize WF at the milky-mature growth stage. Management measures should be adjusted to alleviate the impact of climatic conditions on crop water consumption in different growth stages according to the results. • Water footprint (WF) of rain-fed maize in different growth stages was analyzed. • The highest WF was in tasseling-milky stage and the lowest in sowing-seeding stage. • Sunshine hours and temperatures had a greater impact on WF in most growth stages. • Feasible measures to reduce the impact of climatic factors on WF were discussed. [ABSTRACT FROM AUTHOR]

Grey water footprints (GWFs) can be used as an indicator to describe the influence of diffuse pollution on water environments and identify major contaminants. To improve the calculation of GWF, we conducted a field experiment with combinations of different slopes and fertilizer types on maize production in the black soil region of China. The goals of this study were to determine the actual amount of water used to dilute the pollutants; to explore the changes in the GWF under different slopes and fertilization types; and to identify the most critical pollutants and determine if they are consistent with those identified in previous studies. The results showed that the average GWFs of maize production were much different in 2016 and 2017. The GWFs of the 5° plots were much larger than those of the 1° plots and 3° plots, and the GWFs of the mineral fertilizer plots were larger than those of the organic manure plots in most cases. The loss rates of total nitrogen (TN) in the mineral fertilizer plots and the organic manure plots were all 0.2% in 2016 and 2.7% and 3.1% in 2017, respectively, which was much lower than 10% as reported in most articles. The most frequent critical pollutant was total nitrogen (TN), while total phosphorus (TP) and chemical oxygen demand (COD) were also critical pollutants in some cases, which differed somewhat from the results of previous studies. The uneven annual distribution of rainfall led to large interannual differences in the size of the GWFs. Therefore, using field observations, pollutant loss from agricultural ecosystems could be determined in line with local conditions, which should provide a reference for relevant measures to control diffuse pollution. [ABSTRACT FROM AUTHOR]