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Background The influence of foliar nitrogen fertilizer during veraison (FNFV) on anthocyanin accumulation and chromatic characteristics of 'Cabernet Sauvignon' grapes over two seasons was investigated. Results Urea and phenylalanine fertilizers (TU and TP, respectively) and a control were sprayed three times at veraison. In 2018, TU displayed a significant enhancement in total individual anthocyanin content and a* and Cab * profiles. In 2019, FNAV significantly improved the content of total non-acylated, acylated anthocyanin and total individual anthocyanin, and the profiles of L*, a* and Cab *, except a* in TU. The whole process from phenylalanine variation to anthocyanin accumulation in grape skins was analyzed. On the whole, after the first FNFV to harvest, the increase in phenylalanine metabolism, abscisic acid content, effects of PAL (Phenylalanine ammonia lyase), UFGT (UDP glucose-flavonoid 3-O-glucosyltransferase) and transcript concentrations of VvPAL and VvUFGT involved in anthocyanin biosynthesis were also strong evidence explaining the increased anthocyanin and chromatic profiles in 2019. Conclusion Overall, FNFV for nitrogen-deficient grapevines could significantly improve grape color, especially in the 2019 veraison with a proper climate. © 2021 Society of Chemical Industry.

As one of the most principal meteorological factors to affect global climate change and human sustainable development, temperature plays an important role in biogeochemical and hydrosphere cycle. To date, there are a wide range of temperature data sources and only a detailed understanding of the reliability of these datasets can help us carry out related research. In this study, the hourly and daily near-surface air temperature observations collected at national automatic weather stations (NAWS) in China were used to compare with the China Meteorological Administration (CMA) Land Data Assimilation System (CLDAS) and the Global Land Data Assimilation System (GLDAS), both of which were developed by using the advanced multi-source data fusion technology. Results are as follows. (1) The spatial and temporal variations of the near-surface air temperature agree well between CLDAS and GLDAS over major land of China, except that spatial details in high mountainous areas were not sufficiently displayed in GLDAS, (2) The near-surface air temperature of CLDAS were more significantly correlated with observations than that of GLDAS, but more caution is necessary when using the data in mountain areas as the accuracy of the datasets gradually decreases with increasing altitude, (3) CLDAS can better illustrate the distribution of areas of daily maximum above 35 &deg, C and help to monitor high temperature weather. The main conclusion of this study is that CLDAS near-surface air temperature has a higher reliability in China, which is very important for the study of climate change and sustainable development in East Asia.

Climate change impacts crop productivity as atmospheric conditions and water supply change, particularly in intensive cropping areas. This study used the validated AquaCrop Model, which was run with downscaled daily climate data produced by SDSM and CanESM2. The changes in the potential grain yield of winter wheat and summer maize and water budget during the cropping seasons were estimated for the Huang-Huai-Hai Plain (3H Plain) under RCP4.5 and RCP8.5 scenarios. The results show that the potential yield of winter wheat is increasing with similar spatial patterns in the 2030s, 2050s, and 2080s, with much of the increase is distributed in Shandong and northeastern parts of Henan. During the winter wheat growth period, the water budget deficit will likely improve from −210 mm in the 2030s to −202 mm in 2080s under RCP4.5 and from −206 mm in the 2030s to −191 mm in 2080s under RCP8.5 across the 3H Plain. The water budget during the winter wheat period will continue to be in deficit in the north 3H Plain and improvements are estimated mostly in the lower southern areas of the Plain. The summer maize potential yield is estimated to increase from the baseline period, but yields will decrease by 0.81%, 1.19%, and 2.10% in the 2030s, 2050s, and 2080s, respectively, under RCP8.5 compared to RCP4.5. During the summer maize growth period, the water budget is also estimated to improve from 109 mm in 2030s to 126 mm in 2080s under RCP4.5 and 107 mm in the 2030s to 163 mm in 2080s under RCP8.5. This increase is mainly estimated in the central and south of the 3H Plain. The estimated ETc of winter wheat shows no significant decrease, while the reduction of 6 mm and 13 mm for summer maize is observed under RCP4.5 and RCP8.5, respectively. The study provides scientific evidence to devise adaptation and mitigation climate change strategies for agricultural productivity and water resource management.

Crop simulation models play an essential role in evaluating irrigation management strategies for improving agricultural water use in crop production. In this study, the AquaCrop model was used to calibrate and validate the grain yield and biomass of 11 cultivars (9 winter wheat and 2 summer maize) under full and water-saving irrigation practices. The model results were verified with the available data from the published literature. Under the full irrigation practice, widely used by farmers in the region for winter wheat, the Normalized Root Mean Square Error (NRMSE) was found to be between 2.00–9.90% for grain yield, 2.40–10.85% for biomass, and 0.42–19.61% for water productivity. Under water-saving irrigation for winter wheat, the NRMSE range was found to be between 5.80–16.00% for grain yield, 3.70–17.30% for biomass, and 3.80–13.79% for water productivity. For summer maize, the NRMSE was 5.95%, 6.08%, and 16.41% under full irrigation, and 9.51%, 8.41%, and 3.60% under water-saving irrigation for grain yield, biomass, and water productivity, respectively. For winter wheat and summer maize, the simulation accuracy of grain yield was high under full irrigation, with percent deviations under ± 11.00%. In this study, the simulation accuracy for winter wheat was low under water-saving irrigation, while the model simulated the yield and biomass for summer maize to acceptable accuracy. The model can be reliably used as a tool to simulate grain yield and biomass across the NCP region for winter wheat and summer maize. However, the limitations of the model must be considered when simulating winter wheat under water-stressed conditions.

Drought is a typical disaster in the main soybean production area of northeast China. The spatiotemporal variations of drought related to soybean production based on a crop water deficit index (CWDI) and sensitivity to meteorological variables were investigated in northeast China using daily meteorological data from 87 weather stations from 1981 to 2010. Statistical analysis revealed that precipitation could not meet the water demands of soybeans during the seedling–branching, filling, and maturing stages, and excessive drought occurred more often in northeast China. The Mann–Kendall test indicated that the soybean CWDI significantly increased during the filling stage. Kriging spatial analysis showed that the most drought-prone area was located in the west of northeast China. Explanations for the spatiotemporal variations of the drought for soybean production were explored in terms of meteorological variables. Statistical analysis showed that the crop evapotranspiration, air temperature, wind speed, and number of sunshine hours were significantly higher and the precipitation and relative humidity were significantly lower in the drought-prone area than in the dry area less prone to droughts. An explored method of sensitive analysis quantitatively revealed that precipitation and humidity negatively affected the CWDI, whereas temperature, wind speed, and number of sunshine hours positively affected the CWDI. The CWDI was most sensitive to precipitation. These results not only provide valuable information for soybean planning and management but also produce important background and physical evidence for the influence of climate on the drought related to soybean production in northeast China.

Regulated deficit irrigation (RDI) is a new type of water-saving irrigation technology developed in recent years which was well suited to arid and semi-arid grape plant areas. The anthocyanin synthesis of grapes under RDI was revealed through omics in this study. RDI slightly decreased the hundred-grain weight and increased the soluble solid content, juice pH, reducing sugar content, and total anthocyanin content. Meanwhile, the total acid content decreased before ripening. Transcriptomics and metabolomics analyses revealed that large numbers of differentially expressed genes (DEGs) and significantly changed metabolites (SCMs) were filtered in the RDI groups. RDI1 with 30% ETc upregulated 7 related gene expression levels in the anthocyanin biosynthetic pathway and also increased some metabolites contents. Eventually, the contents of most monomeric anthocyanins in the RDI groups were increased, and the proportion of Mv increased in the ripe grapes of the RDI groups. In all, RDI is a useful water-saving irrigation method which could also increase anthocyanin content in grapes.

High-resolution meteorological data products are crucial for agrometeorological studies. Here, we study the accuracy of an important gridded dataset, the near-surface temperature dataset from the 5 km &times, 5 km resolution China dataset of meteorological forcing for land surface modeling (published by the Beijing Normal University). Using both the gridded dataset and the observed temperature data from 590 meteorological stations, we calculate nine universal meteorological indices (mean, maximum, and minimum temperatures of daily, monthly, and annual data) and five agricultural thermal indices (first frost day, last frost day, frost-free period, and &ge, 0 &deg, C and &ge, 10 &deg, C active accumulated temperature, i.e., AAT0 and AAT10) of the 11 temperature zones over mainland China. Then, for each meteorological index, we calculate the root mean square errors (RMSEs), correlation coefficient and climate trend rates of the two datasets. The results show that the RMSEs of these indices are usually lower in the north subtropical, mid-subtropical, south subtropical, marginal tropical and mid-tropical zones than in the plateau subfrigid, plateau temperate, and plateau subtropical mountains zones. Over mainland China, the AAT0, AAT10, and mean and maximum temperatures calculated from the gridded data show the same climate trends with those derived from the observed data, while the minimum temperature and its derivations (first frost day, last frost day, and frost-free period) show the opposite trends in many areas. Thus, the mean and maximum temperature data derived from the gridded dataset are applicable for studies in most parts of China, but caution should be taken when using the minimum temperature data.

Evapotranspiration integrates atmospheric demand and surface conditions. The Penman-Monteith equation was used to calculate annual and seasonal reference evapotranspiration (ET0) and thermodynamic and aerodynamic components (ETrad and ETaero) at 77 stations across northeast China, 1961–2010. The results were: (1) annual ETrad and ETaero had different regional distribution, annual ETrad values decreased from south to north, whereas the highest ETaero values were recorded in the eastern and western regions, the lowest in the central region; (2) seasonal ETaero distributions were similar to seasonal ET0, with a south–north longitudinal pattern, while seasonal ETrad distributions had a latitudinal east-west pattern; and (3) in the group for ET0 containing 69 sampling stations, effects of climatic variables on ET0 followed sunshine hours > relative humidity > maximum temperature > wind speed. Changes in sunshine hours had the greatest effect on ETrad, but wind speed and relative humidity were the most important variables to ETaero. The decline in sunshine duration, wind speed, or both over the study period appeared to be the major cause of reduced potential evapotranspiration in most of NEC. Wind speed had opposite effects on ETrad and ETaero, and therefore the effect of wind speed on ET0 was not significant.

Studying the causes of drought is important because the formation of large regional droughts is linked to global atmospheric system abnormalities in China. Information about the effects of drought on crop production is needed in order to improve understanding of a region’s drought vulnerability and to improve food production safety in the North China Plain. This paper uses agricultural statistics and monthly Southern Oscillation Index data between 1961 and 2007 to quantitatively evaluate regional agricultural meteorological disasters and to assess the regressive models used to predict the grain yield and climatic yield losses caused by drought disasters. The data showed that the drought-covered area ratios declined, but the drought-affected area ratios rose. During the La Nina stage, the probability of a drought disaster was higher than during the El Nino stage, especially in Hebei. In the El Nino years, there were negative trends for the drought-covered, -affected and -destroyed area ratios in winter and positive trends in the other three seasons. In the La Nina years, the drought disaster area ratios were positive for all seasons. In Neutral years, there was more likely to be a drought event in autumn. The regression analyses for the three provinces showed that the grain climatic yield loss was significantly associated with the grain yield loss caused by drought disasters. This showed that regional grain yield simulations and evaluations of agro-meteorological disasters reliably predicted the field measured statistical data for drought disasters. Therefore, our results showed that there is a mixed seasonal trend in the drought disaster areas in the El Nino years, but a consistent upward trend for all seasons in the La Nina years. We also showed that the damage caused by drought disasters can be quantified by estimating the yield loss.

Crop insurance is one of the most useful risk management tools for natural disasters. Jilin as the main soybean production province in China suffers the natural disaster frequently by the global warming. The purpose of this study was to promote the crop insurance management of soybean risk of natural disaster in Jilin by identifying the factors affecting farmers’ decisions about participating in soybean crop insurance and estimating the willingness to pay (WTP) for soybean insurance. The analysis of data from a farmer survey in Jilin showed that droughts and pests were the main soybean disasters, most respondents recognized the importance of crop insurance, and government subsidies can significantly increase farmers’ enthusiasm about purchasing insurance; diversity of income sources was significantly negatively correlated with willingness to participate in soybean insurance, and diversity of soybean production disasters, level of awareness of the importance of soybean insurance and whether crop insurance had been used were all significantly positively correlated with farmer willingness to participate in insurance; on average, farmers were willing to pay a soybean crop insurance premium of 48.75 ¥/hm2 (equals 7.73 $/hm2, referring to the exchange rate of 2011 and 2012), and the WTP-to-premium ratio was 21.69 %. Starting the soybean crop insurance in the frequent natural disaster areas, improving farmers’ understanding of crop insurance by advertisement and training, launching some crop insurance test products to increase farmer’s experience, and implementing subsidies for crop insurance insistently were suggested to promote the development of soybean crop insurance in Jilin.

A field experiment was carried out to research the effect of soil temperature distribution on root water uptake in soil water simulation. Soil temperature distribution patterns under border irrigation and surface drip irrigation were researched. The root water uptake model was modified based on the effect of soil temperature on root water uptake. Results showed soil temperature profile distribution was greatly influenced by irrigation method. The range of temperature was larger under border irrigation, with the temperature being 3-6°C higher in 0-20 cm depth than in 20-100 cm depth. Except for the top layer under surface drip irrigation, mean soil temperature showed the trend of exponential decay throughout the soil profile. The relationship between temperature and water uptake rate was expressed in exponential function. With the modification of the root water uptake model as affected by temperature profile distribution, the value of the root mean square error between the simulated and observed soil water decreased from approximately 0.04 to 0.02 in the top layer under border irrigation, but showed no obvious difference under surface drip irrigation. When soil temperature differed greatly in the top layer from the deep layer, the root water uptake model considering soil temperature could improve the precision of soil water simulation. The results indicated that the modified root water uptake model could be used to simulate soil water dynamics. DOI: 10.1061/(ASCE)HE.1943-5584.0000642. © 2013 American Society of Civil Engineers. CE Database subject headings: Irrigation; Soils; Temperature effects; Soil water; Simulation. Author keywords: Irrigation method; Root water uptake; Soil temperature; Soil water simulation.

Agricultural water resource security is faced with serious challenges in the background of climate change. It is important to study the trend of evapotranspiration (ET) for future planning and management of agricultural water resources. On the basis of the 1961–2004 weather data, the trends of six meteorological variables were analysed. Also, the potential ET (PET) of maize (Zea mays L.) in the growing season was simulated by the World Food Study (WOFOST) model. Results indicated that the maximum and minimum temperatures increased significantly, and the daily minimum temperature increased much faster than the daily maximum temperature, which resulted in the decrease in the diurnal temperature range (DTR). The precipitation showed an increasing trend, whereas the sunshine duration and wind speed (WS) showed a declining trend. No remarkable linear tendency was found on vapour pressure. As a result, the simulated maize PET showed a significant decrease by 1 mm year−1, and it was mainly as a result of decreased sunshine duration and WS. This may provide valuable information on the aspect of water resource management in the Yellow River basin. Copyright © 2011 John Wiley & Sons, Ltd.

As an innovative tool, weather index agricultural insurance (WIAI) was introduced into China in 2008. Before product designing and selling to farmers, it is necessary to understand farmers’ real desire so that the product can be tailored to fit their needs. This paper focuses on the demand analysis for WIAI on household level. With this goal, 660 households located in 22 administrative villages in Changfeng and Huaiyuan county, Anhui province, China were surveyed. Survey questions covered risks faced by households, their coping mechanisms and willingness to pay for WIAI. Survey data were assessed and findings are shown as below: drought and flood were major weather risks for crops; the key coping strategies to crop loss were seeking employment elsewhere, or borrowing money from relatives or friends; most of investigated farmers showed interest in WIAI; those who were more familiar with insurance, or whose losses were higher due to deficient or excessive rainfall, or who had more trust in the accuracy of local weather forecasts, expressed more interest in WIAI with the quite low correlation coefficient, while statistically significant. It hints that there are potential demands for WIAI among farmers. However, methodologies deserve further development so as to provide more reliable assessment of the relationships between the willingness to pay and the abovementioned three factors.