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Droughts are increasing in frequency and intensity as the global climate changes. Risk assessment for agricultural drought disasters is an important approach for disaster prevention and mitigation. Based on the formation mechanism of natural disaster risk, the index system model of agricultural drought risk assessment in North China was constructed, and the robustness of the established risk assessment model was tested by using the internal test method. Then based on the characteristics of agricultural drought risk formation in North China, the paper proposes corresponding risk prevention recommendations. The conclusions were as follows: when adjusting the indices and methods in the risk assessment model, the range of changes in the agricultural drought risk ranking for each city was mostly 1-2.5 places, and the model was relatively robust. With the exception of Beijing and Tianjin, which had the highest disaster prevention and mitigation capacity, central and northern China had the highest agricultural drought risk, which was previously linked to the high risk and vulnerability of these regions. The agricultural drought risk in northern Henan and southern Shandong is low, mainly due to the low risk. The 34 cities in North China can be divided into 6 agricultural drought risk clusters, which are not dispersed in space and cross-city distribution, and have good aggregation. Cluster 4, located in the northernmost mountainous areas, has the highest risk of drought, which is associated with high environmental vulnerability and low capacity for disaster prevention and mitigation, so agricultural areas should be reduced and agricultural input should be increased. Clusters 2, 5 and 6, located in the central and southern regions, have higher grain acreage and yields due to drought, so agricultural drought risk can be further reduced by increasing agricultural input and improving irrigation guarantee rate. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Henan Agricultural Sciences is the property of Editorial Board of Journal of Henan Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Acta Prataculturae Sinica is the property of Acta Prataculturae Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Advances in Earth Science (1001-8166) is the property of Advances in Earth Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Mycosystema is the property of Mycosystema Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Agricultural Archaeology is the property of Agricultural Archaeology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Science & Technology of Cereals, Oils & Foods is the property of Science & Technology of Cereals, Oils & Foods Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Agricultural Science & Technology (1008-0864) is the property of Journal of Agricultural Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective Global warming has been resulting in more extreme weather events such as drought and flooding, and understanding their severity and frequency is important for improving management to mitigate their detrimental impact. Taking Shandong province as an example, this paper analyzes the spatiotemporal variation of droughts over the past 40 years in the province. Method Monthly temperature and precipitation measured from 1981 to 2020 at 25 meteorological stations across the province were collected. Standardized precipitation evapotranspiration index (SPEI) at each station was calculated at both seasonal and annual scales, from which we calculated the spatiotemporal variation of droughts in the province using linear regression, Tyson polygon, spatial interpolation and wavelet analysis. Result Summer precipitation had been in decline while annual precipitation had been in increase, though neither was at significant level. Meanwhile, seasonal and annual temperature had both been in increase at significant level. At seasonal and annual scales, dry and wet weather occurred alternately, and the summer alternation annual alternation remained almost unchanged over the 40 years. The areas suffering spring and summer droughts had been in increase while areas hit by autumn and winter throughs had been in decline, though neither was at significant level. The frequency of spring drought increased gradually from the southwest-southeast to the north, though spatial difference in summer and annual droughts across the province was small. The frequency of autumn drought increased gradually from the north to the south, while the frequency of winter drought increased gradually from the southwest to the northwest-southeast. Seasonally, the identified drought periods are 10, 29, 4 and 17 a in spring, 20, 4,7 and 10 a in summer, 14, 6, 25, 8 and 3 a in autumn, 5, 24, 16 and 10 a in winter. Annually, the periods were 23, 14, 4, 10 and 7 a. Conclusion Temperature rise in Shandong province was significant, but the change in precipitation was not significant, with dry and wet occurring alternately. [ABSTRACT FROM AUTHOR]

Climate change would increase the frequency of extreme weather events threatening sustainable agricultural production as a warmed atmosphere has significant effects on functions of soil-crop systems. Although moderate drought is known to improve plant water use efficiency (WUE), how warming combined with drought affects terrestrial ecosystems remains largely unknown. Evolutionally, different plants have developed different strategies to facilitate water acquisition, and their physiological and morphological traits respond to drought in different ways. In this paper, we reviewed the combined effects of warming and drought on water and carbon dynamics in cropped lands in three aspects: global climate change and its underlying drivers; effects of warming, drought and other climate change factors on water/carbon dynamics; unknown/known problems and future research directions. Global warming induced by the increased population, carbon emissions from fossil fuel and increase in drought frequency will all pose a significant impact on water and carbon in farmland. Warming will change the amount of biomass thereby affecting crop growth and water use efficiency, in addition to the accelerated soil organic carbon (SOC) loss. In the above-ground, drought will reduce photosynthetic rate and transpiration, while in the below-ground, it will reduce microbial activity and slow down SOC decomposition, thereby inhibiting soil CO2 emissions. Climate change is likely to change the precipitation pattern, which in turn will alter soil respiration. Apparently, there is a lack of studies on water and carbon cycles under combined influence of drought and increasing temperature. This should be strengthened as water and carbon cycles in soil-crop systems are likely to be affected by multiple biotic and abiotic factors including soil water, temperature, carbon and nutrient concentration, in order to provide a mechanistic understanding of their combined effects on functions of farmland ecosystems as well as their feedback interaction with global warming. [ABSTRACT FROM AUTHOR]

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Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Geomatics & Information Science of Wuhan University is the property of Geomatics & Information Science of Wuhan University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Agricultural Science & Technology (1008-0864) is the property of Journal of Agricultural Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

【Objective】The present paper aimed to analyze the expression differences of ZmGly1 gene in different tissues in responsive to drought and high temperature stress, so as to find out its possible role in heat and drought tolerance, and finally to provide useful genetic resources for the upcoming breeding of maize varieties with higher stress tolerance.【Method】The structure, physicochemical properties and genetic relationship of ZmGly1 protein were explored using bioinformatics software such as DNAMAN 8.0, ProtParam tool, MEGA 7.0. The transcript levels of ZmGly1 was performed using qRT-PCR method.【Result】ZmGly1 was composed of 222 amino acids with a theoretical molecular weight of 24.98 kD and an isoelectric point of 6.6. The total number of amino acid residues with negative charges（Asp + Glu） and residues with positive charges（Arg + Lys） was 30 and 29, respectively. The hydrophobic coefficient was 0.448, suggesting that it was a hydrophilic protein. ZmGly1 was not a transmembrane protein and contained a Zn2+ metal binding site on the A chain and B chain, located at Gln68,Glu134 and His162,Glu208, respectively. The phylogenetic tree analysis demonstrated that ZmGly1 and SbGly1 had the highest sequence identity（92.51%）, indicating that they were closely related to each other. The qRT-PCR analysis exhibited that the transcript levels of ZmGly1 was the highest in leaves, but relatively low in roots and stems. Compared with the control, the expression pattern of ZmGly1 in the leaves under drought treatment showed a tendency of first increasing and then decreasing, while under high temperature treatment a tendency of first decreasing, then increasing and finally decreasing with the extension of time. 【Conclusion】ZmGly1 is a Zn2+ enzyme, which is closely related to SbGly1. ZmGly1 participates in the stress response of plant to drought and high temperature. The study lays the foundation for the in-depth analysis of its biological functions in the near future. [ABSTRACT FROM AUTHOR]

Quantitatively evaluation of satellite precipitation and potential evapotranspiration products with the high resolution, wide coverage and dynamic continuity is an important foundation for drought monitoring over mainland China. This paper examined the accuracy of products and the utility of drought monitoring using the newly released long-term (more than 30 years) satellite precipitation products (climate hazards group infrared precipitation with station, CHIRPS) data version 2.0 and potential evapotranspiration products (global land-surface evaporation: the Amsterdam methodology, GLEAM) dataset. We selected standardized precipitation evapotranspiration index (SPEI) and six statistical and classification measures indexes to evaluate accuracy and the utility of CHIRPS and GLEAM-Ep (potential evapotranspiration derived from GLEAM), with China Gauge-based Precipitation Daily Analysis dataset (CGDPA) and potential evapotranspiration calculated by Penman-Monteith (PM-Ep) as evaluation reference data sets. The results showed that CHIRPS and GLEAM-Ep performed well in eastern and southwest of China. However, their performance in western China was uncertain due to the sparsity of meteorological stations. SPEIs (SPEI value calculated by the CHIRPS and GLEAM-Ep) had a good performance on drought monitoring in eastern and southwestern China. Values of correlation coefficient (CC) between SPEIs and SPEIm (SPEI value calculated by the CGDPA and PM-Ep) were more than 0.6 in southeastern China, southwestern China, the middle and lower reaches of the Yangtze River region and northern China, especially in relatively humid areas, which the correlation coefficient values were more than 0.7 and the root mean-squared error (RMSE) values were less than 0.8. In order to further evaluate the performance of SPEIs in drought monitoring at spatial and temporal scales, the SPEIs3 (SPEIs at three-month scale) and SPEIm3 (SPEIm at three-month scale) in southeastern China, southwestern China, the middle and lower reaches of the Yangtze River region and northern China were compared. SPEIs3 had a better simulation effect on the evolution process of the ratio of drought area in those regions during1981-2016. And the success ratio of simulating drought duration was about 0.93, 0.57, 0.71 and 0.81, respectively. Moreover, SPEIs3 displayed a high accuracy over the four regions in capturing drought, which was the spatial distribution of typical drought events on specific month. In conclusion, SPEI based on long-term CHIRPS and GLEAM-Ep could be applied to monitor and evaluate drought in eastern and southwestern China. This paper can provide reliable reference for monitoring and warning of drought events and water resources management in those regions. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Shenyang Agricultural University is the property of Journal of Shenyang Agricultural University Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Yellow River is the property of Editorial Board of Yellow River and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Remote sensing technology is a promising means for agricultural drought monitoring in large area, and can continuously obtain long-term time series of crop drought information. Currently, quite a few agricultural drought monitoring indices based on remote sensing technology have been developed from different perspectives. However, different agricultural drought monitoring indices derived from remote sensing have obviously different temporal and spatial adaptability. Selecting the appropriate drought monitoring indices based on different regions and crop growth stages is vital for timely and accurate evaluation of drought impact on crops. It is also important for effective water resource management and drought mitigation. This paper focused on adaptability of the agricultural drought monitoring based on remote sensing, and systematically summarized agricultural drought monitoring indices and their adaptability evaluation methods. Firstly, the satellite data sources and the corresponding sensors that are commonly used for agricultural drought monitoring were summarized. Secondly, the relevant sensitive spectral bands of agricultural drought monitoring parameters were reviewed from 4 aspects, including the atmospheric rainfall, the soil moisture, the change of crop physiology and morphology (such as crop canopy temperature, vegetation water content, and crop morphology and green degree) due to water stress, and the comprehensive parameter information. Thirdly, the adaptations and limitations of various agricultural drought monitoring indices derived from remote sensing were fully discussed which involved 4 aspects: the precipitation monitoring indices based on active and passive radar satellite, such as TRMM (tropical rainfall measuring mission satellite) and SAR (synthetic aperture radar); the soil moisture monitoring indices based on the inversion method of thermal inertia, spectral feature space and microwave remote sensing; the crop water requirement monitoring indices based on the physiological and morphological characteristics of crop mutation; and the comprehensive drought monitoring indices based on integrated reflection of crop drought multiple characteristics. Lastly, the current literature revealed much valuable information about the sensitivity and adaptability evaluation methods for diverse agricultural drought indices derived from remote sensing, which included the spectral feature matching evaluation methods and the multivariate statistical analysis methods considering environmental impact factors of crop growth. Domestic and foreign scholars have achieved great progress on the adaptability of agricultural drought monitoring indices, including the application of multi-source remote sensing data, the sensitive spectral band, the applicability of the indices' own mechanism, and the adaptability evaluation methods. Nevertheless, how to select the most suitable agricultural drought remote sensing monitoring index, according to different regions and crops growth stage, is still a problem. Finally, this paper discussed the highlights, the existing difficulties and the future research trends. 1) The relationship between crop and its growth environment should be considered according to different regions and different crop growth stages; 2) The spectral bands information ought to be increased in order to reduce the ratio of signal to noise in the process of remote sensing data acquisition; 3) The appropriate drought monitoring indices derived from remote sensing should be confirmed, especially in the areas with part of vegetation coverage, because most of the crop growth period is under the condition of partial vegetation fraction; 4) The appropriate spatial and temporal scale for these agricultural drought monitoring indices should be determined according to the research purpose; 5) The study of hyperspectral data and technology in the inversion of precision agriculture drought monitoring indices need to be strengthened; 6) The sensitivity and adaptability of the agricultural drought monitoring indices derived from remote sensing in accordance with its own mechanism is supposed to be further explored. [ABSTRACT FROM AUTHOR]

Copyright of Acta Agronomica Sinica is the property of Crop Science Society of China and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Objective] The present paper aimed to provide a scientific reference for drought prevention and disaster avoidance of sugarcane production, the temporal and spatial characteristics of sugarcane drought in different growth period in Guangxi were analyzed in recent 60 years. [Method] Firstly the development period of sugarcane, soil data and meteorological data from 1961 to 2020 in Guangxi were collected for the study. Under major concentration for effectiveness of precipitation and dynamic change characteristics of crop coeffi cient, the temporal and spatial variation characteristics of sugarcane drought in growth period were analyzed by linear and periodic analysis method and spatial station technology basing on crop water deficit index. [Result] The interannual drought incidence was the highest in maturity stage, followed by stem elongation stage, and the least in seedling stage and in tillering stage. Light and medium drought are mainly in seedling stage, tillering stage and stem elongation stage. Heavy and extreme drought are mainly in maturity stage. During the study period, there was no obvious linear change trend in the interannual drought incidence at all levels and with a periodic change on the scale of 2 - 5 years. The years of occurrence were mainly in 1970s and 1980s. In terms of spatial distribution, in the seedling stage light drought and medium drought were mainly distributed in the west and south of Guangxi. The occurrence frequency of light drought was less than 40%. The occurrence frequency of medium drought was less than 30 % . The occurrence frequency of heavy drought was less than 10 % and its distribution range was small. In the tillering stage, light drought occurred in all over the region. The occurrence frequency in the southwest of Guangxi was the highest, generally between 21 % and 40%. Medium drought was mainly distributed in the southwest of Guangxi and the occurrence frequency was less than 10% . The occurrence frequency of severe drought was less than 10 % and its distribution range was small. In the stem elongation stage, mild drought was distributed in the whole region with the occurrence frequency between 11 % and 70%. Medium drought was mainly distributed in the northeast of Guangxi with the occurrence frequency between 21 % and 60%. Heavy drought was mainly distributed in the northeast of Guangxi with the occurrence frequency less than 20%. There was no extreme drought in the seedling stage, tillering stage and stem elongation stage during the study period. In the maturity stage, light drought, medium drought, heavy drought and extreme drought were distributed in whole study region. The occurrence frequency of light drought was less than 30%. The occurrence frequency of medium drought and severe drought were less than 40%. The occurrence frequency of extreme drought was the most and its distribution was wide. The regions with high extreme drought occurrence frequency were mainly distributed in the center, south and east of Guangxi with the occurrence frequency between 31 % and 50%. [Conclusion] The light and medium drought are the main drought in the seedling stage, tillering stage and stem elongation stage of sugarcane in Guangxi during the sugarcane development. The heavy and extreme drought is the main drought in the maturity stage. In the maturity stage of sugarcane, the heavy and extreme drought occur once every 2 - 3 years in the center, south and east of Guangxi. The regions above should be get more attention for drought prevention and disaster avoidance. [ABSTRACT FROM AUTHOR]

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Drought is the main agrometeorological disaster of summer maize production in the Huang-Huai-Hai area in China. Establishing the drought grade indexes for more effective monitoring and evaluation is of great significance to the prevention and mitigation of agricultural disasters. There have been lots of published research results about the effects of different soil water conditions on growth, development, yield components and yield of summer maize. However, there are large differences about stage division and grade classification among different researches, and it is difficult to apply and compare in different regions. In this paper, soil relative moisture and crop water deficit index were selected to establish the drought grade indexes according to the growth process of summer maize. The whole growth duration of summer maize was divided into five stages, namely sowing to emergence, emergence to jointing, jointing to tasselling, tasselling to milking and milking to maturity. Drought was classified into five grades, including no drought, light drought, moderate drought, strong drought and severe drought. The drought grade indexes were determined for each stage and grade. The used data included crop phenology, soil water and daily weather record. By analysis and summary of the published results, a set of drought grade indexes based on soil relative moisture were determined. And this set of index included each stage of summer maize from sowing to maturity. The established index was convenient for application because its consistency among stages and grades. After the determination of grade indexes of soil relative moisture, the relationship models between soil relative moisture and crop water deficit index were set up using the observing data at 16 agrometeorological stations in Henan Province. Then, the grade indexes of crop water deficit index were calculated using the relationship models on the basis of the determined soil relative moisture indexes. According to the index of soil relative moisture, the critical index value at five stages of summer maize was 65%, 60%, 70%, 75% and 70% for light drought, respectively; it was 45%, 40%, 50%, 55% and 50% for strong drought and 40%, 35%, 45%,50% and 45% for severe drought, respectively. According to the index of crop water deficit index, the critical index value at five stages of summer maize was 35%, 40%, 20%, 10% and 35% for light drought, respectively; it was 50%, 65%, 55%, 45% and 65% for strong drought and 55%, 75%, 65%, 55% and 75% for severe drought, respectively. The two established drought grade indexes were validated in the Huang-Huai-Hai area by selecting typical stations. Validated results showed that the two indexes are well consistent with the consistency of 71%-91% for the identification of drought grades. Meanwhile, the identification results by the two indexes were basically consistent with the historical occurrences of drought disasters. Therefore, the drought grade indexes established in this paper could be used in the future monitoring and evaluation of drought in summer maize production in the Huang-Huai-Hai area. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Affected by global warming in southwest karst area and monsoon climate, the annual precipitation in southwest karst area and its distribution between seasons have changed obviously, and the frequency and duration of non-rain period are increasing. In addition, karst woody plants face more serious seasonal and geological droughts due to the strong weathering of bedrock and poor water storage capacity. This paper discusses how karst plants adapt to geological and seasonal drought by analyzing their structural characters and physiological regulation by referring to relevant literatures. The results indicate that like plants in arid and semi-arid areas, karst woody plants have two strategies to cope with drought: drought resistance and drought avoidance. Drought-resistant plants generally have some drought-resistant characteristics, such as small specific leaf area, succulent mesophyll, well-developed water storage tissue and high cell fluid concentration and so on, and can adapt to drought by increasing wood density, enhancing vessel anti-embolism and improving water use efficiency. Drought-avoidant plants can reduce water loss by small and dense stomata and leaf veins, developed superficial fur, palisade tissue and vascular sheath, and adapt to drought by defoliation, deep root absorption of deep water and early stomatal closure mediated by Abscisic acid(ABA). Although some progress has been made in the research on karst plants adapting to drought through morphological structure and physiological regulation, there are still some problems to be solved urgently, such as the study of bedrock water condition in karst area and its contribution to plants, the root structure and biomass allocation of karst woody plants, the relationship between tree configuration and drought adaptation and synergistic relationship between rhizosphere microorganisms and woody plants. At the same time explore how to apply the results of physiological and ecological adaptation of karst woody plants to drought in production practice, and scientifically guide the control and ecological restoration of rocky desertification. [ABSTRACT FROM AUTHOR]

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Copyright of Journal of Natural Resources / Ziran Ziyuan Xuebao is the property of Journal of Natural Resources and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Agricultural Science & Technology (1008-0864) is the property of Journal of Agricultural Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Natural Resources / Ziran Ziyuan Xuebao is the property of Journal of Natural Resources and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Drainage & Irrigation Machinery Engineering / Paiguan Jixie Gongcheng Xuebao is the property of Editorial Department of Drainage & Irrigation Machinery Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Drought is a period of deficit in precipitation with impact on agriculture, water resources and natural ecosystems. It has always an impact on agricultural and ecological fields and causes serious environmental consequences worldwide. Drought has been a prevalent concern for local government in Ningxia Hui Autonomous Region over the last decades. Therefore, monitoring drought characteristics and exploring its change trend in Ningxia are crucial for local agricultural production and ecological construction. Based on the difference of the temperature of day and night (ΔLST), which was calculated from day and night land surface temperature (LST) of the moderate resolution imaging spectroradiometer (MODIS) and normalized differential vegetation index (NDVI) data, the monthly temperature vegetation dryness index (TVDI) in Ningxia from 2000 to 2010 was produced. The time series TVDI data were used to monitor the drought characteristics in Ningxia during the past 10 years, and the relationships of TVDI with meteorological factors, meteorological drought index and agricultural disaster-affected area were also analyzed in this paper. The results showed that there was a typical triangular shape between the ΔLST and NDVI which is suitable for building the TVDI model. The dry edges were obtained by a least squares regression that had significant negative slopes (P<0.05), and the wet edges almost were constant isoline which was an optimal theoretical condition. The time series TVDI showed that the drought spatial characteristics were different in 3 typical ecosystem regions. Severe drought with the most frequency and high intensity usually occurred in the arid zone of middle Ningxia. The mountains area of southern Ningxia was moderate affected by drought, for drought occurred with lower frequency and intensity. By contrast, the Yellow River irrigation area of northern Ningxia was slightly affected by drought during the past 10 years, for there was a typical inland oasis and convenient irrigation condition from the Yellow River. By the way, the forest regions of Liupan Mountain in the south and Helan Mountain in the north were also less affected by drought because this ecosystem could adjust moisture by itself. From the perspective of whole Ningxia, there were 3 extreme drought events in 2000, 2005 and 2009 respectively that were detected by time series TVDI data, and this result was consistent with the previous studies. Based on the methods of the linear regression of TVDI and the ensemble empirical mode decomposition (EEMD), the change trends of drought during the past 10 years were detected respectively in annual and quarterly scales. The annual mean drought intensity was weakening from 2000 to 2010, but the monthly extreme drought event of each year was enhancing. The mean drought intensity in spring and summer was significantly enhancing, but in autumn and winter was significantly weakening. The correlation analysis results showed that the variation of TVDI mainly depended on the annual precipitation rather than annual average air temperature, and this phenomenon was related to the land use pattern and vegetation type in Ningxia. The disaster-affected area had a significant correlation with the annual mean drought intensity rather than monthly extreme drought event of each year. This phenomenon indicated that the long-time drought process, prolonged for more than one month, would impact the agricultural production in Ningxia. The seasonal results showed that summer drought was most likely to lead to the reduction of agricultural production, and then were the spring and autumn drought, while the winter drought had no effect on the agricultural production in Ningxia. This work can provide theoretical basis for the local government to make a proper strategy when combating drought, scheduling irrigation and providing disaster relief. [ABSTRACT FROM AUTHOR]

Maize planting in northern region of China plays a vital role in the crop production in China, and it occupies a large proportion in total grain production and planting area in China. Meanwhile, northern region of China is prone to drought and the drought normalization happens in this area seriously, which restricts the steady development of maize. The data used in this paper included daily weather data of 217 meteorological stations in the 14 provinces (municipalities, or autonomous regions) in northern region of China from 1961 to 2010 and crop, soil, field management data of spring maize. Based on the total precipitation during the growing season of spring maize we divided the study area into 6 precipitation zones (I -VI) with the interval of 100 mm, and then analyzed the effects of drought of different grades occurring in main growing stage on grain yield of spring maize in northern region of China by using the crop water deficit index as the agricultural drought index and the agriculture production systems simulator (APSIM) as the research method. The results showed that the yield reduction of spring maize caused by drought in northern region of China had a decreasing trend from west to east, and the precipitation distribution led to the differences of damage degree in each area directly. The precipitation during growing season of spring maize in Zone I located in western region (including Xinjiang, western Inner Mongolia and northern Gansu) was below 100 mm, and the natural precipitation couldn't meet the need of growth and development of spring maize, so the drought risk of planting spring maize under rainfed conditions in western oasis irrigated agricultural area was great, and it needed to energetically develop water-efficient irrigation in this area. While the precipitation during growing season of spring maize in Zone VI located in southeastern region (including Southern Jilin, eastern Liaoning, southern Henan and southern Shaanxi) was above 500 mm, and the natural precipitation could meet the requirements of spring maize growth and development basically, so production in eastern rainfed agricultural area would be less affected by drought, and it was difficult to reflect the influence of drought grade difference on production accurately. In addition, the ratio of the station with yield reduction had a decreasing trend with the increasing of yield loss degree; from jointing to tasselling stage, the yield reduction in northern region of China was between 0 and 50%, and there were 37.3% of stations with the yield reduction of between 0 and 10%, and only 4.1% of stations with the yield reduction of between 40% and 50%. Drought happening from jointing to tasselling stage of spring maize will cause serious influence on grain yield, and the yield reduction in this stage is higher than that from tasselling to maturity stage. Besides, the discrete degree of yield reduction in this stage is also higher than that from tasselling to maturity stage. The influence degree of drought of each grade on crop production is different; from jointing to tasselling stage, the interquartile ranges of yield reduction caused by drought are extreme drought (20.1%-33.6%), severe drought (12.0%- 20.3%), moderate drought (6.3%-15.2%) and light drought (4.7%-11.6%), respectively. [ABSTRACT FROM AUTHOR]

Grain yields of rainfed winter wheat in the Huang-Huai-Hai Plain are often low and vary substantially from season to season. In the past several decades, amount of precipitation in the Huang-Huai-Hai Plain has fallen dramatically. By contrast, agricultural water consumption is so great that water resource is insufficient, leading to excessive exploitation of underground water, in which case irrigation water is far from enough. Under the backdrop of great climate changes, lack of irrigation water and severe drought will have potential impact on winter wheat yield. Simulating the effect of drought on winter wheat has been identified as an important contributor to agricultural production in such environments. In this paper, based on meteorological data and field observations of 6 typical meteorological stations from six agricultural sub-regions of the Huang-Huai-Hai Plain from 1981 to 2010, the yield reduction rate of potential drought in critical growth stages of winter wheat was determined in the Huang-Huai-Hai Plain. Then the probability distribution of yield reduction of 6 typical sites and the relationship between variation of soil moisture and yield in typical wet and dry years were analyzed. The results showed that the regional simulation capability was acceptable and the 3H could be the representative variety of winter wheat in Huang-Huai-Hai Plain for simulation. Regional distribution of yield reduction rate was gradually growing serious from south to north in jointing-heading stage, and the yield reduction rates in agricultural region I, II and III were more than 40%, and in Region IV, V and VI were 38%, 27% and 13% respectively. The regional distribution of yield reduction rate of each agricultural region was mainly caused by the climatic factors. In addition, the probability of the same level of yield reduction rate in jointing-heading stage was much larger than that in filling stage. The probability of the same level of yield reduction rate in northern region was much larger than that in partial southern area. In the drought years, irrigation was needed to provide water for the soil surface layer to meet the demand of winter wheat. If drought happened in the jointing-heading stage and the deep-layer soil water was insufficient, the wheat had to rely on irrigation to provide sufficient water for its later growth stage. If drought happened in the filling stage, the wheat root systems had to grow down deeper to get more water, which would cause the reduction in the wheat yield. China has insufficient water resource, which is especially true in North China. The limited water resource should be applied in critical regions and stages. Water saving and drought prevention are a long-term task. Prediction shall be made on water stress in key growth stages and simulation analysis shall be performed on crop models to determine potential yield reduction due to drought, thereby to make reasonable and scientific irrigation measures. This will have referential value for evading drought risks and developing water-saving agriculture under climate changes. The results are expected to provide basic information for drought management and rational irrigation of winter wheat in the Huang-Huai-Hai Plain by focusing on the potential drought in critical growth stages of winter wheat. [ABSTRACT FROM AUTHOR]

Southwest China is an important region for maize production, accounting for about 15% of the total maize area and output in China. There were abundant rainfall and humid climate in Southwest China. But in recent years, severe drought events often occurred there, which caused huge damage to local social economy and attracted widespread interest. Agro-drought risk analysis is helpful for improving the ability of regional disaster management and reducing potential drought risk. In this paper, the daily meteorological observations from 60 stations and the data related to maize agricultural production in Southwest China during the period of 1961-2012 were used. Based on natural disaster risk theory, maize drought risk assessment model was established from four factors: hazard, exposure, vulnerability, drought prevention and mitigation, and maize drought risk was zoned and analyzed in Southwest China. It showed that maize spring drought mainly occurred in most of District I, DistrictII and District III, maize summer drought appeared in north of District I, most of District III and District IV, District V and District VI. High and sub high drought hazard zones of maize in whole growth period were mainly located in District III, parts of District I and District II. High and sub high exposure zones were mainly located in District II and District III; high and sub high vulnerable zones mainly were distributed in east of District II, parts of District IV and District V; low and sub low drought prevention and mitigation zones were located in parts of District II and District IV. The results showed that maize drought high risk and sub high zones in Southwest China were mainly located in District III, small parts of District I, District II, District IV and District V, in the majority of which maize drought hazards in whole growth period were high or sub high, maize area ratios were higher than maize average area ratio in Southwest, and maize yield per unit was higher than maize average yield per unit in Southwest. Moderate risk zones were mainly located in District I and District II, in the majority of which maize drought hazards in whole growth period were moderate, maize area ratios, yield fluctuations and yield levels were comparable to maize average productivity level in Southwest. Low and sub low risk zones were mainly distributed in central of District I, southwest of District II, south and east of District IV, where maize drought hazards in whole growth period were low, and maize productivity levels were different. The study provides a theoretical basis for the maize production risk management and sustainable development in Southwest China. [ABSTRACT FROM AUTHOR]

This article intended to achieve drought risk assessment in complex topography area, such as Sichuan Province, in the support of natural disaster risk theory and multi-source data, especially satellite data which was widely used to reflect the properties of study area from different angles including meteorology, hydrology, topography. In detail, TRMM satellite precipitation data was used to make up for the shortage of data from meteorological stations. And the latitude, longitude and digital elevation model were introduced to improve the accuracy of temperature interpolation; furthermore, drought frequency instead of drought degree was calculated using Normalized Vegetation Index data to more accurately quantify drought risks. Meanwhile, an index of water acquisition cost was constructed to quantify the affections of terrain on water distribution and acquisition. In addition, raster data were used as far as possible, such as raster populations and economies. Thus, an index system which revealed variable properties of study area in different angles was constructed. And then, weights of the index system were calculated using entropy method. Finally, the drought risk in Sichuan Province was assessed. The accuracy of this assessment was tested by agricultural drought risk loss. It showed a high correlation between the agricultural loss and the drought risk achieved from this paper (R2=0.8347, P<0.001). Thus, the reliability of this research in aspect of drought risk assessment in complex topography areas was proved. Through the analysis of drought risk assessment result, it showed that: 1) Most of Sichuan Basin, part of Panzhihua and Liangshan showed high drought risks; 2) Northern Guangyuan, Bazhong, Dazhou, most of Liangshan and Panzhihua, southern Yibin and Luzhou reached average risk degrees, as well as some valleys in the Western Sichuan Plateau; 3) However, there was quite low risk in most of the Western Sichuan Plateau. Through this study, it proved that the index system and method in drought risk assessment had some reference significance especially in complex topography areas. At the same time, there were some shortages which needed to be improved. 1) Using Entropy method, statistical characteristics of data was fully taken into consideration, and weights of the indexes were determined according to the variation of each index. However, it failed to distinguish the importance of each index. To improve the accuracy of weight determination in further study, it was best to combine the objective method and subjective method. 2) The spatial resolution was greatly improved by introducing a large number of spatial data into study, which was a great breakthrough in drought risk assessment, for most studies just took administrative region as the basic unit. However, uncertainty was actually inevitably increased because of the accuracy problem of spatial data itself. 3) According to the requirements of natural disaster risk theory, 4 factors and 11 indexes were selected to construct the assessment system, which basically met the need of drought risk assessment in the study area. But the assessment system may need a further refinement and improvement in order to be able to reflect the complex background information of the complex topography area in all aspects more accurately and comprehensively. [ABSTRACT FROM AUTHOR]