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Analysis of Annual Compound Events of Heat and Drought in North China Based on Copula Function YU Xin, ZHANG Qi, YANG Zai-qiang Chinese Journal of Agrometeorology    2023, 44 (08): 695-706.   DOI: 10.3969/j.issn.1000-6362.2023.08.005 Abstract （261）      PDF（pc） （2053KB）（353）       Knowledge map    Save The Copula function was used to analyze the annual compound events of heat and drought in North China, which can provide reference for agricultural water management and disaster prevention and mitigation in North China. Based on the daily maximum temperature and precipitation data of 36 meteorological stations in North China from 1960 to 2019, the year-by-year heat intensity and drought intensity were identified, the Copula function was introduced to construct a two-dimensional joint cumulative probability distribution function of heat intensity and drought intensity, and the return period of compound events of heat and drought in different grades were analyzed to assess the occurrence characteristics of the compound events. The results showed that when fitting the marginal distributions of annual number of heat days and drought intensity, the GEV function worked best at more stations; the most applied Copula function was the Symmetrised Joe-Clayton function when combining annual number of heat days and drought intensity in two dimensions; compared with high temperature intensity, drought intensity had a greater effect on the magnitude of the joint return period of compound events. North China is more prone to compound events with high heat intensity in the southwest and drought intensity in the south-central part of the country. The leading factors of compound events in North China vary from region to region, and different measures need to be taken to mitigate the damage caused by compound events in different regions. Related Articles | Metrics | Comments（0）

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Application of Deep Learning Technology in Monitoring, Forecasting and Risk Assessment of Agricultural Drought HUANG Rui-xi, ZHAO Jun-fang, HUO Zhi-guo, PENG Hui-wen, XIE Hong-fei Chinese Journal of Agrometeorology    2023, 44 (10): 943-952.   DOI: 10.3969/j.issn.1000-6362.2023.10.007 Abstract （274）      PDF（pc） （343KB）（340）       Knowledge map    Save The development of artificial intelligence technology, especially the emergence of deep learning, has promoted new developments of agriculture, and is regarded as a new direction of modern agricultural production. Deep learning has the advantages of strong learning ability, wide coverage, strong adaptability, and great portability. Considering that its development of simulated datasets can solve real-world problems, it is more and more widely used in monitoring, forecasting and risk assessment of agricultural drought. This paper used the method of literature review to summarize the development and application of monitoring, forecasting and risk assessment of agricultural drought, and summarized the principles, advantages and disadvantages of the deep learning model. The practical applications of depth learning model in monitoring, prediction and risk assessment of agricultural drought were systematically summarized. The existing problems of large dataset requirements, long data preprocessing time, narrow predefined category range, and complex remote sensing images were discussed, and the future research directions were prospected. The results showed that in recent years, the technologies of monitoring, prediction and risk assessment of agricultural drought had made important progress. However, due to the nonlinearity of agricultural system and the complexity of disasters, existing technologies were still difficult to meet the needs of actual agricultural production in the new situation in terms of applicable regions, objects and accuracies. The deep learning technology provided a new means for agricultural drought research. However, the deep learning model could not accurately express the specific process and mechanism of crop growth, so coupling of crop growth model with deep learning model could ensure the interpretability of deep learning model. For correcting the prediction sequence, coupling models based on general circulation model and depth learning model could be established to further improve the prediction ability of deep learning model for medium and long-term agricultural drought. Aiming at the problem of limited disaster sample size, strengthening the research on agricultural drought monitoring and evaluation based on migration learning could further improve the precisions in fine monitoring and evaluation of agricultural drought. In view of the fact that the factors affecting agricultural drought formation was characterized by large amount of data, diverse types and nonlinearity, the method of combining deep learning and information fusion was adopted to further improve the accuracies in regional monitoring, prediction and risk assessment of agricultural drought. Therefore, the coupling of deep learning models and crop growth models, agricultural drought prediction by integrating deep learning models and general circulation models, fine monitoring and evaluation of agricultural drought based on deep learning and migration learning, regional monitoring, prediction and risk assessment of agricultural drought based on deep learning and information fusion were considered as the development trends of applicating deep learning technologies in monitoring, prediction and risk assessment of agricultural drought in the future. Related Articles | Metrics | Comments（0）

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Application Effectiveness and Problems of Biodegradable Mulch GUO Bo, YANG Zhen-xing, HE Wen-qing, LIU Jia-lei Chinese Journal of Agrometeorology    2023, 44 (11): 977-994.   DOI: 10.3969/j.issn.1000-6362.2023.11.001 Abstract （288）      PDF（pc） （625KB）（309）       Knowledge map    Save Mulch film mulching cultivation technology not only increases agricultural production and income, but also causes serious pollution problems because of the long-term use of polyolefin mulch film and low recovery rates. In areas with serious mulch film residue, the soil structure is seriously damaged, the quality of cultivated land is reduced, agricultural operations are blocked, and crop emergence, nutrient absorption and root growth and development are restricted. Biodegradable mulch film can be degraded by microorganisms such as bacteria, fungi and actinomycetes in the natural environment, and finally decomposed into CO2 and H2O, which not only has no pollution to soil but also promotes the growth and development of crops, and has become one of the effective ways to solve the problem of white pollution. With the deepening of the research on biodegradable mulch film, people found that biodegradable mulch film has different effects on soil environment and crop yield, and these effects are quite different in different regions and crops. It is not possible to directly draw the conclusion that biodegradable mulch film is better than PE mulch film through one or several experiments. In this paper, the effects of biodegradable mulch film on soil environment, crop growth and yield in recent years were summarized, and the experimental effects of biodegradable mulch film (BM) and mulch mulch film (PE) were compared, and their advantages and disadvantages were analyzed, and suggestions were put forward to improve the performance of biodegradable mulch film, so as to continuously improve the performance of biodegradable mulch film and realize the sustainable development of agricultural science and technology. Summary and analysis show that: (1) Biodegradable mulch film can increase soil temperature and humidity, meet the needs of crops in the early stage of growth, accelerate the emergence of seedlings, shorten the growth cycle, and have beneficial effects on soil organic matter, available nitrogen and soil enzyme activity, and improve soil nutrient content. In terms of microorganisms, biodegradable mulch film can promote the growth of soil microbial content and soil respiration rate. At the same time, biodegradable mulch film has better weed control ability than PE mulch film, among which black biodegradable mulch film has the best effect, which can effectively reduce the number of weeds in the field and ensure the supply of nutrients needed by crops. (2) In terms of crops, biodegradable mulch film can promote corn growth, shorten the growth period and increase the yield in the early and middle stages of corn growth. There was no significant difference between the yield of cotton seed cotton covered with biodegradable mulch film and PE mulch film, and the yield of cotton seed cotton covered with mulch film is significantly higher than that of bare land. The potato treated with biodegradable mulch film germinated faster in the early growth stage because of the increase of soil temperature, which significantly shortened the growth cycle and brought it to market earlier, and significantly increased the yield compared with PE mulch film and bare land, among which the black biodegradable mulch film had the most obvious effect. For millet crops, there was no significant difference in yield between the treatment with biodegradable mulch film and the treatment with PE mulch film, and the yield of the treatment with mulch film was significantly improved compared with the treatment with bare land. For vegetable crops such as tomato, eggplant and beet with short growth cycle, biodegradable mulch film can play the role of heat preservation and moisture increase for a long time, and promote the rapid growth of crops. The final yield is not significantly different from that of PE mulch film mulching treatment, even slightly improved, and significantly improved compared with bare land treatment. (3) Put forward the influence of different components of biodegradable mulch film on soil and crops, controllable degradation and cost problems, such as the difficult control of degradation speed, environmental problems caused by incomplete degradation of biodegradable mulch film, low technical maturity and high price, and put forward suggestions for future research and development, so as to modify and innovate biodegradable raw materials, reduce costs and regulate the degradation mechanism of biodegradable mulch film. Strengthen the research on raw materials, formula and production technology of biodegradable mulch film, and develop new biodegradable mulch film with high performance and multifunction, which can meet the regional applicability and crop applicability at the same time, and lay a theoretical foundation for the popularization and application of biodegradable mulch film to more regions and more crop varieties. Related Articles | Metrics | Comments（0）

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A Review of the Response Characteristics of Soil Respiration to Temperature and Moisture Changes under Global Climate Change RAN Man-xue, DING Jun-jun, SUN Dong-bao, GU Feng-xue Chinese Journal of Agrometeorology    2024, 45 (01): 1-11.   DOI: 10.3969/j.issn.1000-6362.2024.01.001 Abstract （263）      PDF（pc） （724KB）（287）       Knowledge map    Save Warming of the climate and changes in precipitation patterns are major manifestations of climate change and abiotic factors affecting soil respiration. Authors presents a systematic analysis of recent research advances on the effects and mechanisms of temperature and moisture on soil respiration. The results show that:（1）there is positive feedback between soil respiration and climate warming, but the temperature adaptation weakens this positive feedback. The effect of temperature on soil respiration varies spatially and temporally due to the different duration of warming and soil carbon storage. The main mechanisms of soil respiration adaptation to temperature include soil microbial adaptation, substrate depletion and soil mineral activation.（2）The effect of precipitation on soil respiration depends on the initial soil water content. When soil water content is lower than the wilting factor, precipitation not only increases soil water content but also promotes soil respiration, reaching a maximum when soil water content is close to the field holding capacity, while soil respiration is inhibited when soil water content reaches saturation value. The main mechanisms by which water affects soil respiration are substitution and blocking effects, substrate supply, microbial stress and root response. （3）The coupling of soil respiration with soil temperature and moisture depends on the ratio of soil water and heat factors. When soil temperature becomes a stress factor, the stimulating effect of increasing soil water content induced by precipitation on soil respiration is suppressed by the negative effect of low temperature. When soil moisture becomes a stress factor, the promoting effect of increased soil temperature due to climate warming on soil respiration is counteracted by the negative impact of drought. The interaction between soil temperature and moisture should be fully considered when studying soil respiration. In order to understand the disturbance factors of soil carbon emissions in terrestrial ecosystems, this paper proposes that future research on the relationship between soil respiration and the environment under climate change. Firstly, strengthen the research on the effects of multi-factor interaction on soil respiration and quantify the soil respiration components. Secondly, continue to pay attention to the characteristics of soil respiration in response to initial soil temperature and temperature fluctuations, and to explore the effects of biodiversity or community structure composition on soil respiration. Related Articles | Metrics | Comments（0）

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Hyperspectral Remote Sensing of Crop Information Based on Machine Learning Algorithm: State of the Art and Beyond ZHAO Jin-long, ZHANG Xue-yi, LI Yang Chinese Journal of Agrometeorology    2023, 44 (11): 1057-1071.   DOI: 10.3969/j.issn.1000-6362.2023.11.007 Abstract （223）      PDF（pc） （403KB）（254）       Knowledge map    Save Machine learning, as a new technique combining statistics and computer science, has been widely used in crop information acquisition tasks in recent years. Traditional methods for obtaining crop information mainly rely on chemical detection methods, which is time-consuming and labor-intensive. Based on machine learning algorithms and hyperspectral remote sensing techniques, crop appearance and internal physical and chemical parameters can be quickly sensed in a non-destructive way, which has obvious application advantages and development prospects. First, the researches related to the hyperspectral remote sensing of crop information were systematically reviewed in this paper. Second, the application, advantages and disadvantages and uncertainties of different machine learning algorithms in hyperspectral sensing crop information were summarized. Finally, it was pointed out that the future development trends of hyperspectral sensing crop information were as follows: (1) complementary crop information acquisition methods could be realized through multi-source remote sensing collaborative observations. (2) The assimilation technologies of hyperspectral remote sensing and crop model as well as the deep integration technologies of hyperspectral remote sensing and artificial intelligence could be developed. (3) The intelligent acquisition of key information oriented to the whole growth period of crops and decision-making could be realized. Related Articles | Metrics | Comments（0）

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Spatiotemporal Variation and Risk Zoning of Spring Frost Disaster for Tea Plant in Dabie Mountains CAO Qiang, YANG Xian-gui, DONG Shi-jie, LUO Xiao-dan, LI Hong-fei, CHEN Xi, YUE Wei Chinese Journal of Agrometeorology    2024, 45 (01): 67-78.   DOI: 10.3969/j.issn.1000-6362.2024.01.007 Abstract （165）      PDF（pc） （3420KB）（227）       Knowledge map    Save Based on the daily meteorological data of 35 national meteorological observation stations in Dabie Mountains from 1971 to 2020, the spatiotemporal distribution characteristics of spring frost disaster for tea plant were analyzed with trend surface interpolation and ArcGIS technology. According to the theory of natural disasters risk, the risk of hazard-formation factors, the exposure of hazard-formation environments, the vulnerability of hazard-affected bodies and the capability of hazard prevention and mitigation were taken as the evaluation factors, the weighted comprehensive evaluation method was used to construct the comprehensive risk assessment model of spring frost disaster. The risk zoning had been carried out based by the means of ArcGIS technology. The results showed that: (1) the number of occurrence days of spring frost in different grades decreased significantly from 1971 to 2020, with the average number of occurrence days of total, slight, moderate and severe spring frost being 9.6, 5.2, 3.0 and 1.4d respectively, and the climatic tendency rates being -1.45, −0.61, −0.54 and −0.30d·10y−1. The number of occurrence days was positively correlated with altitude and latitude, and the downward trend of the number of occurrence days in the northern region was much more obvious than that in the southern region. (2) The high risk, medium risk and low risk areas of tea spring frost disaster accounted for 16.67%, 41.88% and 41.45% of the total area in the study region respectively. The high-risk areas were mainly located in the high mountainous regions with an altitude of more than 600m in Jinzhai, Yuexi, Huoshan, Yingshan and Xinyang, as well as scattered shady slopes (northern slopes); the medium-risk areas were mainly located in the mountainous region with an altitude of less than 600m and most of the low-altitude region at the northern foot of Dabie Mountains, and scattered shady slope (north slope) in the low-altitude region at the southern foot of Dabie Mountains; the low-risk region were mainly located in the low-altitude region at the southern foot of Dabie Mountains, and scattered sunny slope (south slope) in the low-altitude areas at the northern foot of Dabie Mountains. The refined assessment of the risk of tea spring frost could provide reference for optimizing the layout of the tea industry and enhancing disaster prevention and mitigation capabilities in Dabie Mountains. Related Articles | Metrics | Comments（0）

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Climatic Suitability and Potential Analysis of Apple Planting in Northern Expansion Area of Shaanxi Province LIANG Yi, QU Zhen-jiang, LU Cheng, ZHANG Li, LIU Lu, WANG Jing-hong Chinese Journal of Agrometeorology    2023, 44 (05): 347-360.   DOI: 10.3969/j.issn.1000-6362.2023.05.001 Abstract （300）      PDF（pc） （5232KB）（224）       Knowledge map    Save The purpose of this study is to clarify the fine distribution of climatic suitable area for apple planting in the northern extension area of Shaanxi province in the new climate period (1991−2020), and reveal the development potential of apple planting in this region. Based on the meteorological observation data, the digital elevation model data and the arable land confirmation data，the requirements for the climatic suitability and mountainous site conditions of apple planting in the northern expansion area of Shaanxi province were comprehensively analyzed. Seven factors, including annual average temperature, annual precipitation, average relative humidity from June to August, average minimum temperature from June to August, average temperature in January, aspect and slope, were selected as zoning indexes to divide the climatic suitability of apple planting in the research area. The multiple regression method was used to simulate and calculate the spatialization of every climatic factor. Then the suitability quantitative evaluation model of each single factor was constructed by fuzzy set linear membership function method. The climatic suitability regionalization of apple planting in the northern extension area of Shaanxi was developed by weighted comprehensive evaluation and set optimization methods. Finally, the distribution of dry land and irrigation area in the suitable planting area for apple of each district was extracted by using the arable land confirmation data. The results showed：(1) the northern boundary of the suitable area for apple planting in Shaanxi was from Wuqi county, the middle and south of Jingbian county to the northeast through the south of Hengshan county, Mizhi county to the middle and southern of Jiaxian county, whose terrain were mainly hilly and gully area along the sunny gentle slope, with a general altitude of 730-1660m. (2) The field investigation showed that the zoning result was about 80% consistent with the field planting distribution of apple orchard. (3) The refined spatial distribution of climatic appropriate areas for apple by county (district) based on the arable land confirmation data showed that the area of climatic suitable level above for apple could be developed in the northern expansion zone was about 276.9kha, accounting for 24.6% of the available arable land, among which the dry land area accounted for 96.3%, with rain-fed agriculture as mainstay. Compared with the statistical data of apple planting status in each county (district), it could be seen that there was still 4.9−28.5kha development space in most counties (districts) except Shenmu county and Fugu county in Yulin city, and Wuqi county in Yan’an city. The potential planting area of climatic suitable for apple in Zhidan county in Yan’an city had tended to be saturated. The results can provide reference for optimizing regional layout of apple industry under the background of climate change. Related Articles | Metrics | Comments（0）

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Study on Frost Risk during Apple Blossom in Northern China under Different Climate Change Scenarios QIU Xing-lin, LIN Ze-quan, LI Can, YU Hai-yang, WANG Ying Chinese Journal of Agrometeorology    2024, 45 (01): 33-44.   DOI: 10.3969/j.issn.1000-6362.2024.01.004 Abstract （163）      PDF（pc） （11528KB）（212）       Knowledge map    Save The main apple-producing areas in northern China are located in the North China plain and the loess Plateau, and the apple blossom frost hazard events have had a severe impact on the income of fruit growers and the economy of the production areas. Future climate change will exacerbate the frequency and intensity of extreme weather and climate events. In this study, based on the climate model data shared by NEX-GDDP, the seven models with the best fitting ability for the minimum temperature during apple blossom were selected using Taylor diagrams, and the annual encounter values of the minimum temperature during apple blossom were calculated and revised using the transfer function correction method of the extreme value distribution, so as to predict the risk of frost disaster and yield reduction of apples in northern China under climate change. Taking the intensity of the apple blossom frost disaster with a 30-year occurring period event across the study area as an example, in the near and distant future under the RCP4.5 scenario, the regions of Henan, Shanxi, northern Shaanxi and, northern Ningxia were the main affected areas, dominated by the minimum temperature of −3 to −2°C, and the highest yield reduction rates were in the northern regions of Henan, Ningxia, Shanxi, and northern Shaanxi provinces, with the yield reduction rate of apples in northern China ranging from 2.47% to 5.22%. Under the RCP8.5 scenario, the frost disaster area with a minimum temperature of −3°C or less expands to the whole of Henan, central Shandong and other places, and the yield reduction rate of apples in northern China is 4.57%−12.39%. In the future, apple cultivation in these areas needs to strengthen the prevention of frost disaster risk. Related Articles | Metrics | Comments（0）

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Review on the Impacts of Climate Change on Highland Barley Production in Tibet Plateau HAO Shuai, SONG Yan-ling, SUN Shuang, WANG Chun-yi Chinese Journal of Agrometeorology    2023, 44 (05): 398-409.   DOI: 10.3969/j.issn.1000-6362.2023.05.005 Abstract （215）      PDF（pc） （444KB）（209）       Knowledge map    Save The Tibet plateau is strongly sensitive to global climate change and the ecosystem is very fragile. Highland barley is a major crop on Tibetan plateau and sensitive to climate change. Authors reviewed the studies on the impact of current and future climate change on barley production over the Tibetan plateau and summarized the changes of agro-meteorological resources and agro-meteorological disasters, as well as the impact of climate change on barley cropping systems, fertility and yield. The results of studies have shown that a significantly warmer trend was observed on the Tibet plateau compared to the trend in other regions, together with increasing precipitation, reduced sunshine hours, and more frequent agro-meteorological disasters such as drought and floods under climate change. The potential planting boundary of highland barely moved to higher latitudes and altitudes under climate change, which led to the potential cultivated region increasing. The climate change shortened the growth period and showed a potentially positive impact on highland barley growth. Cultivar renewal combined with technological advances boosted highland barley yields and the ability to climate change adaption. The future climate change would shorten the growth period of highland barley, which posed a big threat to highland barley production and food security on the Tibet plateau. Existing reports are limited in terms of the study area and there are few studies on climate compounding impacts and integrated risk assessment. Therefore, it is necessary to gain a deeper understanding of the mechanism of climate change impact on barley production, the technology of dynamic assessment of meteorological disaster impact and comprehensive risk, and to develop effective measures to promote the adaptation of highland barley to climate change, which can ensure food security for Tibetans over Tibet plateau. Related Articles | Metrics | Comments（0）

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Assessment and Re-examination the Disaster-yield Model Based on Regional Grain Yield Loss for Five Provinces across North of China LIU Yuan, LIU Bu-chun, MEI Xu-rong, HE Jin-na, CHEN Di, HAN Rui, ZHU Yong-chang Chinese Journal of Agrometeorology    2023, 44 (11): 1009-1021.   DOI: 10.3969/j.issn.1000-6362.2023.11.003 Abstract （184）      PDF（pc） （1564KB）（206）       Knowledge map    Save Based on statistical data on grain acreage, yields and agricultural disasters from 1961 to 2020, the variability characteristics of grain yields and disasters in China and five northern provinces were compared and analyzed. Disaster yield assessment models for Hebei, Shandong and Henan provinces were used to estimate the loss of grain production due to disasters and grain yields by inputting data on disasters from 2008 to 2020. The sensitivity and stability of the disaster-yield assessment model were examined. Based on the statistical modeling method, the model of grain crop disaster-yield evaluation in Shanxi and Shaanxi was constructed, and the universality of the model construction method was evaluated. The results showed that: (1) the grain planting area and total output of the five northern provinces accounted for 28% and 25% of the national total from 1961 to 2020, respectively. In the five northern provinces, the planting area of summer harvest grain and autumn harvest grain decreased significantly at rates of 3.39ha·a−1 and 106.3ha·y−1(P<0.01) respectively, while the total output increased significantly at rates of 137.3×104t·y−1 and 119.9×104t·y−1(P<0.01), respectively. From 2008 to 2020, the grain planting area and grain yield in the five northern provinces increased significantly at the rates of 209.42ha·y−1 and 258.06×104t·y−1(P<0.01), respectively. (2) From 1961 to 2020, the areas of covered, affected and destroyed disaster in the five northern provinces accounted for 28%, 28% and 23% of the national average, respectively, while the disaster situations in the five northern provinces and the whole country showed a significant trend of first increasing and then decreasing. After reaching historically high values in 2008, 2000 and 2000, the covered disaster, affected disaster and destroyed disaster area had declined year on year. The corresponding disaster situations in the five northern provinces showed a downward turning point in 1990, 1989 and 2004, respectively. Drought and flooding are the main causes of crop disasters in China, with 76 percent of the total area affected by drought and flooding. The disaster in the five northern provinces was mainly caused by drought. The areas affected by drought accounted for 66%, 61% and 58% of the disaster statistics, respectively. From 2008 to 2020, the area affected by drought in Shandong was the largest. The area of drought disaster in Hebei and Shanxi was relatively high. Hebei province has the highest area of flooding and hail. (3) When the data series is extended to 2020, the simulated value of grain yield is significantly correlated with the actual value(R2=0.95, P < 0.01), the simulation accuracy of the model was high. In the past 60 years, the grain loss rates of Hebei, Shandong, Henan, Shanxi and Shaanxi provinces were 8.99%, 18.02%, 9.79%, 12.84% and 20.04%, respectively. In the last 12 years, the grain loss rates of Hebei, Henan, Shanxi and Shaanxi provinces had recorded by 4.4%, 17.4%, 9.65%, 8.14% and 17.9%, respectively, influenced by the reduction of disaster zones and advantage in agricultural science and technology. They all went down. With the verification and construction of the model, the modeling statistical method performs well in evaluating the loss of grain yield due to meteorological disasters, had a promising performance in predicting grain yield, and is feasible for commercial applications. As the five northern provinces account for a high proportion of the country's grain output, it is important to prevent the risk of regional hydrometeorological disasters to ensure the country's food security in the new period. Related Articles | Metrics | Comments（0）

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Spatialization of Spring Maize Yield Area in Northeast China Based on Multiple Linear Regression ZHAO Xue-qing, JIN Tao, DONG Wen-yi, LIU Mei-xia, LIU Qin, LIU En-ke Chinese Journal of Agrometeorology    2023, 44 (11): 1022-1031.   DOI: 10.3969/j.issn.1000-6362.2023.11.004 Abstract （180）      PDF（pc） （6492KB）（201）       Knowledge map    Save Spring maize is the primary food crop in Northeast China. Researching and analyzing the spatial difference in yield under diverse climate and soil models holds immense significance in guiding agricultural production and ensuring food security. In this study, a total of 13 key influencing factors were selected from the three aspects of soil, topography and climate, and a multivariate stepwise linear regression model was constructed for spring maize per unit yield and 13 influencing factors by using multivariate stepwise regression analysis. Then the spatial distribution of spring maize per unit area yield in Northeast China was analyzed by using ArcGIS software to rasterize the spring maize yield per unit area. The results showed that: (1) the spatialized data (with a spatial resolution of 1km) calculated by the multiple linear regression model are basically consistent with the statistical data of spring maize yield per unit area. The spring maize yield in Northeast China is between 2482.49-10147.10kg·ha−1. (2) The spatial distribution map of spring maize yield objectively reflects that the spatial distribution trend of spring maize yield, which generally shows a pattern of decreasing from the central to the surrounding areas. This study accurately obtained the grid-scale simulation results of spring maize yield per unit area spatialization in Northeast China (the average relative error is 1.45%), which provides a method reference for the optimization of agricultural production layout and decision-making in Northeast China. Related Articles | Metrics | Comments（0）

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Characteristics Analysis on Carbon Reduction of Crop Production in Henan Province Based on the Statistical Yearbook Data LI Jie, NIE Hong-min , XU Guo-zhen Chinese Journal of Agrometeorology    2023, 44 (09): 759-768.   DOI: 10.3969/j.issn.1000-6362.2023.09.001 Abstract （195）      PDF（pc） （535KB）（201）       Knowledge map    Save Based on the statistical yearbook data of Henan province from 2000 to 2020, such as production input, cultivated land area, crop sown area and crop yield, the carbon emission at input end of crop production in Henan province was calculated to analyze the characteristics of carbon reduction in crop production, using the emission factor method that relied on five indexes of fertilizer, pesticide, agricultural film, diesel fuel and irrigation, which provide the theoretical basis for achieving green and low-carbon transformation of agricultural production in Henan province. The results show that, except for the irrigation area, the usage of various inputs in crop production in Henan province showed a trend of first increasing and then decreasing from 2000 to 2020. The total carbon emissions from various crop production inputs also showed a trend of first increasing and then decreasing. The highest point was reached in 2015, reaching 8.6732 million tons, and by 2020, the total carbon emissions had decreased by 10.27% compared to that of 2015. In the average carbon emissions over 21 years, fertilizer had the highest emissions, followed by agricultural plastic film, agricultural diesel, pesticides, and agricultural irrigation, accounting for 73.35%, 9.41%, 8.08%, 7.77% and 1.39% respectively. Therefore, fertilizer is the main source of carbon emissions. The carbon emission intensity of crop production inputs in Henan province showed a trend of first increasing and then decreasing from 2009 to 2020. In 2015, it reached the highest value of 1.0670t·ha−1, but by 2020, the carbon emission intensity had decreased by 2.87% compared to that of 2015. The study found that carbon emissions from crop production inputs are significantly affected by policies. As the main source of carbon emissions in crop production, reducing emissions and increasing efficiency is still an important measure, followed by the rational use of agricultural plastic film. Strengthening policy guidance, controlling the use of fertilizers and pesticides, implementing actions to reduce fertilizer and pesticide use while increasing efficiency, promoting the demonstration and popularization of high-quality and efficient green pest control technologies, and regulating the use and recycling of agricultural plastic film are all effective ways to reduce carbon emissions from crop production in Henan province. Related Articles | Metrics | Comments（0）

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Analysis on Characteristics of Spring Tea Frost Damage in Different Risk Areas in Jiangsu Province REN Yi-fang, WANG Pei-juan, QIAN Ban-dun, MA Yun-bo, SUN Qin-fei Chinese Journal of Agrometeorology    2023, 44 (09): 820-833.   DOI: 10.3969/j.issn.1000-6362.2023.09.006 Abstract （154）      PDF（pc） （3344KB）（191）       Knowledge map    Save Using global atmospheric reanalysis data ERA5 from 1981 to 2020, based on the meteorological indicators representing the degree of tea frost damage, the risk index (RI) during the spring frost monitoring period in Jiangsu province was constructed. The k-means clustering algorithm was selected to realize the spring tea frost risk zoning. Based on that, the Mann-Kendall method was applied to identify the climatic abrupt change points in each frost risk region, the impacts of climate change on the occurrence characteristics of spring tea frost in different risk areas were assessed by the daily and hourly scales, separately. The result showed that the frost risk of spring tea in Jiangsu province was characterized by "low in the southwest and high in the northeast". Light to moderate frost and extremely severe frost mainly occurred in low-risk area and high-risk area, with an average frequency of 11.91% and 15.4%, respectively. In the low-risk and high-risk areas, the average appearance times of the frost ending date showed an advance trend of 2.7d10y−1 and 1.5d10y−1, while RI value showed a decreasing trend of 0.024 and 0.015 per 10 years, respectively. Influenced by climate change, in terms of daily time scale, the occurrence frequency and volatility of spring tea frost at all levels during the monitoring period in low-risk and high-risk areas were significantly reduced, especially in the case of severe frost. The distribution patterns of occurrence frequency of spring tea frost at all levels changed from the type of multi peak to the type of single peak with descending trend, while still having different peak times, but mainly concentrated in the first ten days of February to the last ten days of March. From the hourly time scale, the occurrence frequency of spring tea frost at all levels basically presented a "sinusoidal" distribution pattern. After climate change, the high incidence period of mild frost was delayed for two to four hours, and that of moderate to severe frost was basically unchanged or delayed for one hour, and the high incidence period of moderate to severe frost and extra severe frost were concentrated at 5：00−7：00 and 6：00−8：00 respectively in the morning for each risk region. With the climate change, the spring tea frost in Jiangsu was characterized by "later, weaker, shorter and fewer", which still needed to be actively addressed. Related Articles | Metrics | Comments（0）

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Impact of Climate Warming on the Threshold Temperature in Tibet under Global Climate Change DU Jun, HUANG Zhi-cheng, Tsewangthondup, Dechendolkar, ZHOU Kan-she Chinese Journal of Agrometeorology    2024, 45 (02): 111-123.   DOI: 10.3969/j.issn.1000-6362.2024.02.001 Abstract （157）      PDF（pc） （16222KB）（181）       Knowledge map    Save Under the influence of global climate change, agricultural and livestock production is facing greater risks. It is important to study the spatio-temporal changes of the threshold temperature, in order to provide the informative scientific foundation for adjusting the agricultural cultivation structure to achieve sustainable agricultural development. Based on the daily average temperature observed at 38 meteorological stations over Tibet from 1981 to 2020, the spatial and temporal variation characteristics of ≥0℃,≥5℃ & ≥10℃ threshold temperatures[initial date(ID), final date(FD), duration days(DD) and active accumulated temperature(ATT)] over Tibet in the recent 40 years in the context of global warming were analyzed by various statistic methods, including linear tendency estimation, Person coefficient, Mann-Kendall, and dominance analysis. The results showed that: (1) the distribution of ≥0℃,≥5℃ & ≥10℃ threshold temperatures in Tibet generally presented the characteristics of delayed ID, earlier FD, shortened DD and reduced ATT from southeast to northwest, without significant vertical zonal characteristics of altitude. Generally, the accumulated temperature of ≥0℃, ≥5℃ & ≥10℃ decreased by 143.0, 136.1, 141.5℃·d, respectively, with an increase of 100m in altitude. The average values for all three types of ATT in Tibetan stations have increased respectively in the period of 1991−2020, compared with those in the period of 1981−2020, especially ≥10℃. The majority of stations were featured by an earlier ID, a later FD, and a more DD. (2)In the past 40 years, the amplitude of the ID, FD and DD of the threshold temperature in Tibet was the largest at ≥0℃, with an average prolonging rate of 5.4d·10y−1, caused by an advancing rate of 3.2d·10y−1 and a postponing rate of 3.5d·10y−1, respectively. The maximum increase of ATT for ≥10℃ was 86.1℃·d·10y−1. The increase of DD for ≥0℃ and ≥5℃ was caused by the significantly advanced ID, while the increase of DD for ≥10℃ can be attributed to the significantly postponed FD. (3)The linear trend(LTR) of ≥0℃ threshold temperature were significantly greater in lower elevation area than in higher elevation. The maximum LTR of the ID and ATT for ≥5℃ were in lower altitude area, and the maximum LTR of FD and DD were in middle and high altitude area(3500−4000m). The LTR of ID for ≥10℃ was the largest in middle and high elevation area, and the maximum LTR of FD, DD and ATT for ≥10℃ appeared in the altitude range of 4000−4500m. (4) In the 1980s, ≥0℃, ≥5℃ & ≥10℃ exhibited later ID, earlier FD, shorter DD and lower ATT. In the 1990s, the ID, FD and DD did not change much, which was normal, and ATT was still lower. After entering the 21st century, the threshold temperature presented the characteristics of earlier ID, later FD, longer DD and higher ATT, especially in the 2010s. (5)The mutation of FD for ≥5℃ occurred earliest in the early 1990s, while the mutation of FD at ≥10℃ was the latest in the middle of the 21st century. The abrupt changes of ID and ATT happened in the mid-late 1990s and the early 21st century, respectively. In contrast, the abrupt change of DD occurred during the late 1990s and the mid-early 21st century. Related Articles | Metrics | Comments（0）

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Variation Trend and Attribution Analysis of Potential Evapotranspiration in Different Climate Regions LIU Wen-hui, ZHANG Bao-zhong, WEI Zheng, HAN Song-jun, HAN Cong-ying, WANG Ya-qi, HAN Xin Chinese Journal of Agrometeorology    2023, 44 (07): 545-559.   DOI: 10.3969/j.issn.1000-6362.2023.07.001 Abstract （205）      PDF（pc） （3706KB）（175）       Knowledge map    Save Based on the daily meteorological data of 710 stations from 1970 to 2017, authors apply the Mann-Kendall test method and contribution analysis method, analyze the variation characteristics of annual ETo (potential evapotranspiration) and its sensitive factors, further quantify the contribution of meteorological factors to ETo variation in different climate regions. The results showed that, (1) among 710 meteorological stations, 177 stations showed a significant increase trend (0.51 to 5.55mm·y−1, P<0.05), 147 stations showed a significant decrease trend (−0.65 to −5.00mm·y−1, P<0.05), and 386 stations showed no-significant change trend. T and U showed an increasing trend, while RH and RN showed a decreasing trend in different climate regions. (2) The sensitivity factors of ETo to meteorological variables were differ in climate regions, in extreme arid region, arid region and semi-arid region ETo was most sensitive to net radiation(RN), and most sensitive factor change to relative humidity(RH) in the semi-humid region and humid region, also the sensitivity of ETo to RH and RN increased with the increase of humidity. (3) The change trend of ETo was influenced by the sensitivity of climate factors and the relative rate of change. The rise of ETo in extreme arid region, arid region, semi-arid region and semi-humid region were mainly caused by the increase of T, while the decrease of ETo was mainly caused by the decrease of U, the change of ETo in humid region was caused by its high sensitivity to RH and RN. In summary, compared with the sensitivity coefficient, the contribution index considering the relative rate of change is more indicative of the influence of climate factors on ETo change. This study is conducive to for scientific understanding of regional climate change and hydrological cycle response mechanism. Related Articles | Metrics | Comments（0）

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Effects of High Temperature on Photosynthetic Characteristics and Antioxidant Enzyme Activities of Maize Leaves during Filling Stage YU Meng-qi, LU Meng-li, ZHANG Ya-ting, CHEN Zhi-ying, LI Wen-yang Chinese Journal of Agrometeorology    2023, 44 (07): 599-610.   DOI: 10.3969/j.issn.1000-6362.2023.07.005 Abstract （241）      PDF（pc） （513KB）（170）       Knowledge map    Save The present study was carried out to investigate the effects of high temperature on photosynthetic fluorescence characteristics and antioxidant enzyme activities in maize ear leaves. The pot experiments were carried out at Fengyang Experimental Station of Anhui Science and Technology University June to October 2021. Two maize cultivars, "Anke 985" and "Longping 206", were chosen in this study. The average temperature of high temperature treatment was (37±2)°C during the daytime, and the high temperature duration was 30 days. The indices including contents of yield, chlorophyll relative content (SPAD), photosynthetic parameters, chlorophyll fluorescence parameters, antioxidant enzyme (CAT, SOD, POD) activity and malondialdehyde (MDA) content of maize were measured under different treatments. The results showed that compared with the control, high temperature treatment reduced significantly grain number per row, 100-grain weight, thereby reducing maize yield per plant. The chlorophyll relative content (SPAD), net photosynthetic rate (Pn) and stomatal conductance (Gs) of maize leaves significantly decreased under high temperature treatment, while intercellular carbon dioxide concentration (Ci) increased significantly, indicating that the decreased of net photosynthetic rate (Pn) was mainly affected by non-stomatal factors. High temperature treatment had significant effect on fluorescence parameters of maize. The maximum photochemical efficiency Fv/Fm, actual photochemical efficiency (ΦPSII) and photochemical quenching (qP) of maize ear leaves decreased significantly, but the non-photochemical quenching (qN) increased significantly under high temperature treatment. After high temperature treatment, the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in maize significantly decreased, but the malondialdehyde (MDA) content increased significantly. In conclusion, high temperature treatment damaged the photosynthetic apparatus of maize leaves, the activity of antioxidant enzymes decreased, the degree of membrane peroxidation increased, the relative content of chlorophyll decreased, and inhibited the photosynthetic performance, which led to the accumulation of photosynthetic assimilates blocked, resulting the maize yield decreased significant. Related Articles | Metrics | Comments（0）

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Change in Forage Grass Climate Productivity and Response to Meteorological Drought in Sanjiangyuan SANG Chun-yun, WANG Qian, GUO Jian-mao, LI Jian-hua, LI Wen-feng, WANG Yong Chinese Journal of Agrometeorology    2024, 45 (01): 12-22.   DOI: 10.3969/j.issn.1000-6362.2024.01.002 Abstract （163）      PDF（pc） （10091KB）（162）       Knowledge map    Save Based on monthly ground observation data from 18 meteorological stations in Sanjiangyuan region from 1970 to 2020, the SPEI at different time scales was used as the meteorological drought monitoring index. The climate productivity of forage grass was calculated by stepwise correction method. The temporal and spatial characteristics of meteorological drought and climate productivity in the forage grass growing season in the Sanjiangyuan region were analyzed, and the response of climate productivity to meteorological drought was initially revealed. The results show that: in recent 50 years, meteorological drought of forage grass growing season in the Sanjiangyuan region showed an aggravating trend (P<0.01). The climate gradually changed from humid to arid around 1995, drought occurs mainly in the west, south central and northeast regions; The aridification in the northwest of Sanjiangyuan region is more obvious. The climate productivity of forage grass in the growing season was decreased by 7.38kg·ha−1·y−1(P<0.01). The spatial distribution decreases from northwest to southeast, rising in the west and falling in the east. There is a strong positive correlation between climate productivity of forage grass growth season and SPEI in different time periods in the Sanjiangyuan region. Moreover, with the increase of SPEI forward time, the correlation coefficient increases slightly. The response of forage grass climate productivity to meteorological drought in central and western regions was higher than that in other regions. Related Articles | Metrics | Comments（0）

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Development Status, Problems and Prospects of Agrometeorological Observation Operation in China ZHANG Quan-jun, HONG Guan, WU Dong-li, HOU Ying-yu, ZHUANG Li-wei, ZHU Yong-chao, YANG Da-sheng, LIU Cong, SHI Yao-hui, HOU Biao, ZHANG Jing, LING Cong-jing, LI Yan Chinese Journal of Agrometeorology    2023, 44 (08): 735-749.   DOI: 10.3969/j.issn.1000-6362.2023.08.008 Abstract （182）      PDF（pc） （5482KB）（160）       Knowledge map    Save Agrometeorological observation is an important cornerstone of agricultural modernization development. This study comprehensively sorted out the development process, business status and existing problems of agricultural meteorological observation in China, and discussed the development prospects of agrometeorological observation in the future, in order to provide a reference for escorting the sustainable development of modern agriculture and national food security. The development of China's agrometeorological observation operation has roughly experienced six stages: theoretical exploration, organization establishment, pilots construction, scale formation, optimization and adjustment, and stable and rapid development. At present, China has established a network of observation stations based on 653 agrometeorological observation stations (including 70 agrometeorological experimental stations) to carry out observation and research on crops, soil moisture, natural phenology, animal husbandry, fruit trees, trees, vegetables and agricultural microclimate. Based on the development of observation business, a national, provincial, municipal and county agrometeorological operational service system with scientific structure and advanced functions has been established. The national agrometeorological monitoring and evaluation, crop yield forecast, agrometeorological disaster monitoring and evaluation and impact forecast, agricultural weather forecast, meteorological grade forecast of occurrence and development of agricultural and forestry diseases and insect pests, agricultural soil moisture, drought relief, and ecological meteorological monitoring and prediction have been relatively mature and service results remarkable. In the past ten years, China's agricultural industry layout, planting structure and planting methods have undergone tremendous changes, and automatic observation technique such as automatic crop meteorological observation and automatic phenology observation have also developed rapidly. The agrometeorological observation operation also gradually shows a series of questions, such as the layout of the network of observation station and the observation tasks needs to be adjusted and optimized, the observation specifications need to be revised and supplemented, the modern technology and automatic observation equipment need to speed up the application and the operational service capacity needs to be improved and strengthened. From the perspective of the strategic deployment of the Party Central Committee of the CPC, the State Council and the China Meteorological Administration for the development of agrometeorological observation operation, the goal of high-quality development of agrometeorological observation, and the demand of modern agricultural development for agrometeorological operation, the future agrometeorological observation operation in China will gradually form a network of observation stations with reasonable layout, perfect specifications, advanced technical equipment, diversified and sophisticated service products, a modern agrometeorological observation and operational service system that can be in line with international standards. Related Articles | Metrics | Comments（0）

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Characteristics of Cold Wave Events Changes in Northeast China from 1981 to 2015 WANG Xiao-wei, LI Xiao-yu, SHI Wen-qi, GU Jia-tong, ZHAO Hai-gen, SUN Chen, YOU Song-cai Chinese Journal of Agrometeorology    2023, 44 (05): 423-432.   DOI: 10.3969/j.issn.1000-6362.2023.05.007 Abstract （169）      PDF（pc） （7330KB）（159）       Knowledge map    Save The Northeast China is one of the regions with a high frequency of cold wave events. It is crucial to clarify the pattern of cold wave events to develop disaster prevention and mitigation strategies. Authors used the Chinese national standard "Cold Wave Levels" (GB/T 21987-2017) and daily minimum temperature data from 226 meteorological stations in Northeast China from 1981 to 2015 to calculate the times and days of different levels of cold wave events occurring annually and monthly at the stations during 35 years. Linear regression and climate trend analysis were used to derive the spatial and temporal characteristics of cold wave events in Northeastern China. The results showed that the three levels of cold wave events occur more frequently at high latitudes and altitudes than at low latitudes and altitudes. High-occurrence areas are located in high-altitude areas, such as Daxinganling, Xiaoxinganling, and the Changbai mountains. The times of cold wave, strong cold wave, and extreme cold wave events at the stations during the last 35 years ranged from 37 to 447, 2 to 213, and 0 to 190, and their days ranged from 81 to 894, 5 to 464, and 0 to 475, respectively. In January, February, March, November, and December, the average times of cold wave events were 1.41, 1.46, 1.09, 1.36, and 1.39, and the average days was 3.04, 3.15, 2.23, 3.13, and 3.20, respectively. There were fewer cold wave events in April, May, September, and October, with an average times of 0.18, 0.01, 0.02, and 0.36 and an average days of 0.30, 0.02, 0.03, and 0.74 respectively (average of all stations). A trend of decreasing cold wave events is observed in the Northeast. The times of cold wave and strong cold wave events decreased at low latitudes and increased at middle and high latitudes, and the times of extreme cold wave events decreased. Climate trend analysis shows that the monthly average times and days of cold wave events for all three levels was in the range of [-1, 1]. The cold wave events in January and May showed an increasing trend, and those in February and October showed a decreasing trend. The cold wave events in March occurred primarily in the central region. Those in April showed a decreasing trend in times and an increasing trend in days. The trend in September was opposite to that in April and in November in the middle and high latitudes. The trend of cold wave events in April and September is unfavorable for agricultural production. Thus, measures should be implemented to adjust to this trend. However, since the temperature affects different crops and agricultural activities to various degrees, the cold wave events have different effects. Subsequent studies should determine appropriate temperature indicators, evaluate the level of cold wave events, investigate the changing patterns of cold wave events, and provide practical and reliable information to formulate disaster prevention and mitigation strategies. Related Articles | Metrics | Comments（0）

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Ecological Suitability and Potential Distribution of Chuanminshen violaceum Sheh et Shan in Sichuan ZHAO Jin-peng, WANG Ming-tian, LUO Wei, LI Yu-rui, LI Chao, WANG Ru-lin Chinese Journal of Agrometeorology    2023, 44 (08): 664-674.   DOI: 10.3969/j.issn.1000-6362.2023.08.002 Abstract （110）      PDF（pc） （3353KB）（157）       Knowledge map    Save Based on the distribution of Chuanminshen violaceum Sheh et Shan (C. violaceum) obtained from field investigation and literature, and the data of three future climate scenarios presented by CMIP6, a relationship model between potential distribution and environmental factors was established to analyze the key environmental factors affecting the distribution of C. violaceum in Sichuan, and to simulate and verify the distribution law and suitable range of C. violaceum in the background of climate change. The result showed that: the key environmental factors affecting the potential distribution of C. violaceum were annual precipitation, precipitation of the coldest quarter, the minimum temperature of the coldest month and temperature annual range. The thresholds for the moderately suitable and above regions were 874.0−1231.2mm, 22.1−83.9mm, −4.4−3.5℃ and 25.0−31.2℃. In the historical period (2000−2020) under the current climate scenario, the suitable regions of C. violaceum mainly concentrated in the bottom of Sichuan basin, the mountainous regions along the basin and the eastern of Panxi plateau, with a total area of 21.49×104km2. Compared with the historical period, the highly suitable areas of C. violaceum would decrease by 14.07% and 10.04% under SSP1−2.6 and SSP2−4.5 scenarios，while it would increase by 3.46% under SSP5−8.5 scenarios in the 2050s. The moderately suitable area of C. violaceum would increase by 27.36%, 10.94% and 30.66%. The highly suitable areas would decrease by 40.89%, 33.53% and 36.71% in the 2090s, while the moderately suitable area would increase by 4.85%, 20.05% and 8.9%. In order to cope with the adverse effects of climate change on the growth and development of C. violaceum in the future, the protection of wild germplasm resources of C. violaceum should be carried out based on the existing major producing areas, such as Chengdu, Bazhong, Guangyuan and Nanchong. At the same time, work such as seed selection, seedling breeding and good gene storage, should be carried out, also artificial cultivation should be vigorously promoted to develop characteristic industries and indirectly protect wild resources. Related Articles | Metrics | Comments（0）

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Agricultural Drought Monitoring in Yunnan Based on CLDAS Soil Relative Moisture JIN Yan, XU Ling, ZHOU Qun, LU Wei-kun, SUN Shuai Chinese Journal of Agrometeorology    2024, 45 (01): 79-90.   DOI: 10.3969/j.issn.1000-6362.2024.01.008 Abstract （152）      PDF（pc） （5887KB）（157）       Knowledge map    Save Based on the observation quality analyzing of daily soil relative humidity data in Yunnan from 2016 to 2020, 0−10cm CLDAS soil relative humidity data was introduced and its applicability was analyzed. The results showed that the observation efficiency of relative humidity data in Yunnan soil water observation station was not high, so it was necessary to use land surface fusion data to monitor agricultural drought. The absolute error between the relative humidity of nearly 80% of CLDAS soil in Yunnan region and the observed values of soil moisture observation stations is less than 30%, indicating high data reliability. In the central region of Yunnan, where drought occurs frequently, the correlation coefficient between the soil relative humidity of CLDAS and the observed values of soil moisture observation stations is above 0.8, and the average deviation is less than 10%. From the perspective of agricultural drought monitoring effectiveness, the drought monitoring index based on CLDAS soil relative humidity can well describe the changes in soil moisture caused by abnormal temperature and precipitation. When the daily rainfall is close to or exceeds 5.0mm, it can quickly respond to the decrease in the number of light drought stations; When continuous effective precipitation occurs, the monitoring index can reflect the relief of agricultural drought of medium and above grade. In summary, CLDAS soil relative humidity is suitable for agricultural drought monitoring in Yunnan province. Related Articles | Metrics | Comments（0）

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Assessing the Sustainability of Cotton Production under Climate Change Based on the AquaCrop Model WANG Hong-bo, LI Guo-hui, XU Xue-wen, HUANG Wei-xiong, ZHAO Ze-yi, GAO Yang, WANG Xing-peng Chinese Journal of Agrometeorology    2023, 44 (07): 588-598.   DOI: 10.3969/j.issn.1000-6362.2023.07.004 Abstract （155）      PDF（pc） （2491KB）（154）       Knowledge map    Save Under the condition of limited available water resources, it is increasingly important to optimize irrigation strategies and adjust sowing dates to improve sustainability and profitable production. Authors calibrated and verified the crop parameters in AquaCrop model by using soil moisture, cotton growth, biomass and yield 2017−2018, and inputting the data into the meteorological, crop, irrigation, and field management modules. The biomass and yield of cotton under mulch drip irrigation in the oasis area of southern Xinjiang from 1988 to 2017 were simulated under 30 scenarios of different irrigation (TS1: 18mm, TS2: 24mm, TS3: 30mm, TS4: 36mm, TS5: 45mm, and TS6: 54mm) and sowing dates (D1: March 23, D2: April 3, D3: April 13, D4: April 23, and D5: May 3). The stability and sustainability of cotton production for 30 consecutive years were also analyzed. The results showed that the AquaCrop model could well simulate the cotton canopy coverage, aboveground biomass, and soil moisture under different irrigation and sowing dates. The normalized root mean square error (NRMSE) was less than 20%, and the synergistic index (d) and correlation coefficient (R2) were close to 1. The AquaCrop model underestimated cotton evapotranspiration (ET) and yield (Y) with relative error (RE) of −4.5% to 1.2% and −8.6% to −6.8%, respectively. However, it proves that AquaCrop model can be used for scenario simulation. The model prediction showed that the stability and sustainability of cotton production were less affected by sowing date, but increased with the increase of irrigation quota. With the same sowing date, the cotton biomass and yield increased with the irrigation quota. Under the 495mm irrigation quota, higher irrigation water efficiency was obtained, and the cotton yield was not significantly reduced. At the same time, under the 495mm irrigation quota, if the sowing date was postponed to April 13, it could save 36.78mm of water. If early maturing cotton seeds were used for sowing on April 23, it could save 65.34mm of water. Therefore, for regions with rich water resources, early sowing can be considered to obtain high yield, while for regions with poor water resources, late sowing is an economic and effective strategy to adapt to the current and future climate change and the shortage of water resources under the combination of varieties and cultivation models. Related Articles | Metrics | Comments（0）

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Characteristics of Water Footprint for Crop Production in Shaanxi Province HE Yu-tong, XIE Li-yong, JIN Ze-qun, LI Kuo, LIU Ying, GUO Li-ping Chinese Journal of Agrometeorology    2023, 44 (07): 560-574.   DOI: 10.3969/j.issn.1000-6362.2023.07.002 Abstract （157）      PDF（pc） （1112KB）（152）       Knowledge map    Save The demand of crop production to water resources is huge. In order to guide the strategies on water and nitrogen management study in sustainable agriculture, it is crucial to calculate the water footprint (WF) and analyze its characteristics. Taking Shaanxi province as the research area, WFs of three types crops including cereal, vegetable and fruit crops were calculated at the prefecture city level during 2011−2020 at the per unit area and total province level. The specific WFs and compositional structure, including green water footprint (GWF), blue water footprint (BWF) and grey water footprint (RWF) of major crop production at the prefecture city level and associated characteristics, were calculated and analyzed. Based on the calculation and analysis, suggestions on reducing WF and promoting for the sustainable agriculture were proposed. In the calculation, WF theory was used based on other data including meteorological data, statistical yearbook etc. Results showed that: (1) at the provincial level, the average WF per unit production area of major crops in Shaanxi province was ranked by: apples (10498.6m3ha−1), open-field vegetable (10233.6m3ha−1), soybean (5451.7m3ha−1), summer maize (4771.9m3ha−1) and winter wheat (3357.4m3ha−1), the WF at per unit area for either apples or open-field vegetable were more than twice that of food crops, and non-natural precipitation water consumption (BWF and RWF) of open-field vegetable and apple production accounts for 75.7% and 55.3% in the total three fraction WFs, respectively. (2) The WF of crop production averaged in ten-years at the province level was ranked by apple (6.91 billion m3), open field vegetable (3.77 billion m3), winter wheat (3.37 billion m3), summer maize (2.68 billion m3) and soybeans (890 million m3) in order. The irrigation water consumed by open-field vegetables was higher than that for other crops, and the water consumption from either apples or open-field vegetables production due to nitrogen fertilizer application were higher than that from other crops. The water footprint of fruits and of vegetable crops, which consumed 47% of the total WF with only 31% of the total crop harvest area in the province. It is effective to optimize the water and fertilizer management in vegetable and fruit production processes to help release the potential of agricultural water conservation in Shaanxi province. (3) At the prefecture city level, the crop planting types in different regions in Shaanxi province were different. The WF for apple production was concentrated in the region of Yan'an, Xianyang and Weinan (77.0%), open-field vegetables was mainly planted in Guanzhong and Southern Shaanxi (90.4%), summer maize and winter wheat were mainly produced in Guanzhong (84.9% and 87.1%), and soybean planting was mainly concentrated in Northern and Southern of Shaanxi (81.1%). In order to reduce the WF of crop production aims to improve the efficiency of regional water resource use in different crop concentrated production areas, specific measures appropriated to local conditions and crop characteristics should be applied, such as techniques for rainwater collection and water-saving irrigation, high-efficiency water-saving irrigation technology and water-nitrogen coupled practices, so as to achieve the goal of sustainable agricultural development for ensuring saving water saving in crop production. Related Articles | Metrics | Comments（0）

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Climate Suitability Refined Zoning of Seed Production of Two-line Hybrid Rice for the Safety and High Yield in Fujian Province SU Rong-rui, LIN Rui-kun, SUN Chao-feng, CHEN Jia-jin, WU Zhi-yuan, YANG Kai Chinese Journal of Agrometeorology    2024, 45 (01): 45-57.   DOI: 10.3969/j.issn.1000-6362.2024.01.005 Abstract （131）      PDF（pc） （21603KB）（152）       Knowledge map    Save The meteorological data of 67 national meteorological observation stations in Fujian Province from 1971 to 2020, geographic information data and investigation data of two-line hybrid rice seed production base were used. The climate risk model and grade index in the sensitive period of fertility conversion, and the weather comprehensive hazard index model and grade index in the flowering and pollination period were constructed. The starting temperature index of fertility transformation of sterile line as 23℃ was selected for research. Based on the climate suitability grade standard of two-line hybrid rice seed production, the multi-layer composite method was used to carry out the climate suitability refined zoning of two-line hybrid rice seed production for the safety and high yield in Fujian Province based on GIS. The results show that critical temperature index of fertility transformation of two-line sterile line was 23℃, the fertility transformation were arranged from early July to late July, and from mid-July to early August, the flowering pollination period was arranged in early August and mid-August, the most suitable zone and suitable zone were distributed in northern Fujian, southwestern Fujian below altitude of 300m, the less suitable zone was distributed in northern Fujian, southwestern Fujian at the altitude of 300 to 500m. Fertility transformation was arranged from late July to mid-August, early August to late August, flowering pollination period was arranged in late August and early September, the most suitable zone and suitable zone were distributed in northern Fujian, southwestern Fujian below altitude of 400m, less suitable zone was distributed in northern Fujian, southwestern Fujian at the altitude of 400 to 500m. The low suitable zone was distributed at the altitude of 500 to 1000m. The unsuitable zone was distributed above altitude of 1000m. Related Articles | Metrics | Comments（0）

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Product Design and Pricing of Kiwifruit High Temperature and Drought Composite Weather Index Insurance WANG Wen, CHEN Yan, WANG Hong-mei Chinese Journal of Agrometeorology    2023, 44 (06): 513-522.   DOI: 10.3969/j.issn.1000-6362.2023.06.006 Abstract （173）      PDF（pc） （490KB）（147）       Knowledge map    Save Weather index insurance with the advantages of transparent information, convenient claim and settlement strong secondary market liquidity is an effective method to diversify agricultural risks, compared with traditional agricultural insurance products. However, the disaster mechanism of crops that are often affected by multiple hazards together during their growth process is very complex. Accurately constructing the correlation relationship model among multiple weather indices and between weather index and yield per unit area of agricultural products, expanding the underwriting liability of weather index insurance are important to reduce the basis risk, reasonably design weather index insurance and transfer the risk of agricultural weather disasters. In this study, based on the precipitation and temperature data of 24 years of day-by-day from 1995 to 2018 from the national meteorological network, a three-dimensional nested Copula model and a conditional mixed three-dimensional Copula model among precipitation, temperature and yield per unit area had been constructed for kiwifruit in Meixian county, Shaanxi province. The relationship between the three variables was simulated using the conditional mixed three-dimensional Copula model with higher simulation accuracy by comparing the error and the pure rate of composite weather index insurance was determined. The results showed that the pure insurance rate was 10.07% at 70% coverage level for a payout under the conditions of cumulative precipitation below 423.2mm and average daily maximum temperature above 26.40℃ from May to September. This study explored the cross-influence of high temperature and drought weather on the unit yield loss of kiwifruit and better clarified the correlation among high temperature, drought and kiwifruit yields, which could reduce the basis risk to a certain extent, improve the agricultural weather index insurance system, provide a new idea and method for the design of composite weather index insurance products, and contribute to the promotion and application of weather index insurance. Related Articles | Metrics | Comments（0）

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Impacts Report of Spring Weather Condition on Agricultural Production in 2023 LIU Tao, LI Yi-jun, ZHAO Xiao-feng, HAN Li-juan Chinese Journal of Agrometeorology    2023, 44 (08): 750-752.   DOI: 10.3969/j.issn.1000-6362.2023.08.009 Abstract （142）      PDF（pc） （287KB）（146）       Knowledge map    Save Based on the daily national meteorological data in spring of 2023, relationships between meteorological factors and agricultural production in China were analyzed using statistical methods. The results showed that the national average air temperature in spring of 2023 was 11.3℃, which was 0.6℃ higher than the same period from 1991 to 2020, but with significant fluctuations. The national average precipitation was 127.2mm, which was 7.4% lower than the same period from 1991 to 2020 and the lowest since 2012. The spatial distribution of precipitation was uneven, with an overall distribution characteristic of more in the middle and less in the north and south of China. The national average sunshine duration was 634.6h, which was close to the same period from 1991 to 2020. The most summer-harvesting areas had sufficient light and heat during the yield formation stage, which was conducive for increasing the number of grains per ear and forming large ears. However, strong temperature drops and snowfall in mid-March and late-April caused varying degrees of freezing damage to winter wheat and rapeseed in Shaanxi, Shanxi, Henan and other regions. Wheat of Shaanxi and Henan experienced severe continuous rain in late-May, with the rainy period highly overlapping the wheat maturity period, resulting in moldy grains and sprouting of mature wheat. The soil moisture of spring sowing area in the northeast China was generally suitable, and the progress of spring sowing was relatively smooth. During the sowing and seedling raising period, there was no significant low temperature and low light weather in early rice regions, but there was a periodic low temperature in late-April and mid-May, which delayed the turning green and tillering process of early rice. Moderate to severe agricultural drought has occurred in southern of Sichuan and central and northern of Yunnan, affecting the sowing and emergence of maize, as well as the transplanting of one season rice and tobacco. Related Articles | Metrics | Comments（0）

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Establishment of Freezing Injury Index of Camellia oleifera during Flowering Period YUAN Xiao-kang, WU Ding-rong, WANG Pei-juan, WANG Qing-ling, FAN Yu-xian, HE Na Chinese Journal of Agrometeorology    2023, 44 (07): 633-641.   DOI: 10.3969/j.issn.1000-6362.2023.07.008 Abstract （216）      PDF（pc） （462KB）（146）       Knowledge map    Save In order to find out the freezing injury index of Camellia oleifera, a Camellia variety named “Tiecheng No. 1”was used as test material, a artificial control experiment was carried out at the Camellia oleifera base in Changde city, Hunan province in 2020 and 2021, respectively. Taking the natural state as a control, several low-temperature freezers were used to set low-temperature treatments with different intensities at −6℃ to 3℃(or −8℃ to 2℃) for 4 hours, and the Camellia oleifera branches at the flowering stage were placed in the freezers in a non-isolated way. 7 days after treatment, the morphological changes of Camellia oleifera were observed, and the rate of falling flower (fruit) and photosynthetic parameters were determined. The results showed that the morphological indicators of Camellia oleifera, falling flowers (fruit) rate and the light response parameters were clearly changed by low temperature. As the temperature decreased, the symptoms of freezing injury became more obvious, falling flowers (fruit) rate increased, while the maximum net photosynthetic rate, apparent quantum efficiency and saturation irradiation decreased. According to the symptoms of freezing damage and the response of the above physiological indicators to different low temperatures, it was determined that −2℃ was the upper limit of freezing damage of Camellia oleifera during flowering period, −6℃ was the critical temperature for significant aggravation of freezing damage, and −8℃ was the critical temperature for serious freezing damage. It was concluded that the slight freezing injury index of Camellia oleifera during flowering period was: −6℃＜daily minimum temperature≤−2℃, and the moderate freezing injury index was:−8℃＜daily minimum temperature≤−6 ℃, and the severe freezing damage was: daily minimum temperature ≤−8℃. Related Articles | Metrics | Comments（0）

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Analysis on Change Characteristics of Drought Intensity during the Growth Period of Highland Barley in Tibet SHI Ji-qing, DOU Yong-li, ZHANG Xin-ping, XI Feng, LUO Zhen, GAN Chen-long Chinese Journal of Agrometeorology    2023, 44 (09): 834-844.   DOI: 10.3969/j.issn.1000-6362.2023.09.007 Abstract （132）      PDF（pc） （2559KB）（145）       Knowledge map    Save Based on the daily meteorological data of 25 meteorological stations in the main highland barley planting areas in Tibet from 1981 to 2020, the daily meteorological drought comprehensive index (MCI) was calculated. The Mann-Kendall mutation test, Morlet wavelet analysis and R/S analysis were used to analyze the temporal and spatial distribution and trend change of drought intensity in each growth period of the region in the past 40 years, in order to provide a scientific basis for agricultural production safety and local disaster prevention and mitigation in Tibet. The results showed that: (1)the drought characteristics of Tibetan highland barley at different growth stages were different, and the drought intensity at the sow-tillering stage was not significantly increased, while the drought intensity at the whole growth stage was significantly decreased compared with that at the tiller-heading stage and the heading-maturity stage.（2）The drought intensity at the sow-tillering stage reached the lowest level in the 2000s, and the tiller-heading stage, head-maturity stage and the whole growth reached the highest level in the 1980s. The drought intensity of tiller-heading stage, head-maturity stage and the whole growth stage showed significant weakening mutations in 1989, 2001 and 1989, respectively. (3)The drought intensity at the sow-tillering stage was weakened as a whole, and the regional difference between tiller-heading stage was small, while the spatial difference between head-maturity stage was large. The drought intensity in the whole growth period showed a distribution feature of increasing from the central and southern marginal areas of the study area to the east and west. (4) The future drought intensity in the sow-tillering stage, the head-maturity stage and the whole growth stage has a trend of continuous drought on the scale of 15 years, 33 years and 33 years respectively, and the tiller-heading stage has a trend of continuous wet on the scale of 13 years. Related Articles | Metrics | Comments（0）

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Effects of Leaf Removal in Different Directions on the Fruit Quality of Cabernet Sauvignon in the Vineyard at the Helan Mountain East Foothill Wine Region LI Hong-ying, WANG Jing, LI Na, JIANG Lin-lin, YANG Yang, HU Hong-yuan, ZHANG Xiao-yu Chinese Journal of Agrometeorology    2024, 45 (01): 23-32.   DOI: 10.3969/j.issn.1000-6362.2024.01.003 Abstract （133）      PDF（pc） （1208KB）（144）       Knowledge map    Save Leaf removal will change the microclimate around fruits during the stage of color-changing, also the fruit quality accumulation will be affected. To study the effect of leaf removal in different directions on the quality of mature fruits, taking the Cabernet Sauvignon planted in the north-south direction as the experimental materials, the leaf removal experiments in the east side, in the west side and in both sides were carried out at the Helan mountain east foothill wine region. The results showed that: (1) compared with the control, in the eastern leaf removal treatments, the content of soluble solids, glucose, fructose, total acid, ratio of sugar to acid, malic acid, citric acid, tartaric acid and Tannin in the mature fruit of Cabernet Sauvignon grape increased, especially the level of fructose, citric acid and tartaric acid increased significantly; There was no significant decrease in content of reducing sugar, total phenol, anthocyanidin. (2) In the west leaf removal treatments, the content of soluble solids, reducing sugar, total phenols and anthocyanins in fruits also decreased slightly, fructose, malic acid, citric acid and tannin increased significantly, and the glucose content, the ratio of sugar to acid and tartaric acid content increased slightly. (3) The tannin level of grape fruit in both side leaf-removal treatments increased significantly, the content of glucose, fructose, citric acid and tartaric acid increased slightly, and the content of soluble solids, reducing sugar, total acid, the ratio of sugar to acid, malic acid, total phenol and anthocyanin were lower than that in CK treatment. Through comparative analysis, the sugar content of the fruit with leaf removal all increased slightly, while in the eastern leaf removal treatment, the acid content increased, and the tannin content increased, falling of total phenols and anthocyanins was relatively small compared to the other two treatments. Considering the present level situation of high sugar and low acidity in the wine production areas of the Helan Mountain East Foothill Wine Region, the leaf removal in the east is recommended as the main pattern to manage the leaf curtain and to control the quality of fruit in the vineyard with the north-south row direction, which plays a role in balancing the overall flavor substances of grape fruits. Related Articles | Metrics | Comments（0）

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Comparison of Temperature Suitability Differences of Summer Maize Based on Hourly and Daily Average Temperature WEI Rui-jiang, WANG Xin, KANG Xi-yan, LIU Bu-chun Chinese Journal of Agrometeorology    2024, 45 (01): 58-66.   DOI: 10.3969/j.issn.1000-6362.2024.01.006 Abstract （138）      PDF（pc） （905KB）（143）       Knowledge map    Save In order to evaluate the impact of temperature on crops more precisely, taking summer maize growth periods in different years in Hebei province as an example, the temperature suitability-degree of summer maize based on two time scales followed as the stroke of every hour of one single day and daily average temperature has been compared and analyzed by temperature suitability model. The results show that the probability of the difference values between 24h average daily temperature suitability-degree and daily temperature suitability-degree of the three national agricultural meteorological observation stations followed as Feixiang, Luancheng, and Zhuozhou for six years from 2015 to 2020, ≥0.6, ≥0.5, ≥0.4, ≥0.3, ≥0.2, ≥0.1 and ≥0.01 were 0.05%, 0.6%, 2.1%, 6.9%, 23.8%, 62.4% and 96.3% respectively, the proportions of coefficients of variation＞100%, 10%−100%, and＜10% were 0.2%, 50.0%, and 49.8%, respectively. There were moderate or above differences in 50.2% of the difference samples. The difference values between the 24h average daily temperature suitability-degree and daily temperature suitability-degree was quadratic with respect to the daily temperature range of the station on same day. If the daily temperature range was less than 12.5℃, 80.1% of the samples with a difference between the two would be within 0.2. If the daily temperature range was less than 8.4℃, 34.6% of the samples with a difference between the two would be within 0.1. In the case of continuous high temperature weather, the trend was consistent, and both timescales of temperature suitability-degree could reflect the effects of high temperature, with a 91.7% agreement of the test results. On consecutive days of low temperature, the 24h daily average temperature suitability-degree more accurately reflect the effect of low temperature, but the daily temperature suitability-degree does not respond to low temperature, the consistency between the two is only 30.0%. Related Articles | Metrics | Comments（0）