Vol.32, NO.4, 2021

column
  Previous Issue | Next Issue 
Display Method:
Articles
Distributions of High and Stable Yield Zones for Potato in the Single-cropping Region in Northern China
Sun Shuang, Wang Chunyi, Song Yanling, Yang Xiaoguang
2021, 32(4): 385-396. DOI: 10.11898/1001-7313.20210401
[FullText HTML] (408) [PDF 7186KB](143)
Abstract:
The planting area and production of potato in the single-cropping region in northern China (SCRN) are in the first place in China, which plays a prominent role for maintaining national food security. It's essential to understand the potato yield potential in SCRN for regional optimized distribution and improvement of potato production. Two indices, i.e., the average and the coefficient of variation of potato yield potential under different production levels, are employed to investigate the potato yield level and yield stability. Based on the meteorological data from 234 weather stations from 1981 to 2019, the soil data and the crop data in the study region, the yield potentials under different production levels (i.e., potential production level, rainfed potential production level, and the climate-soil potential production level, respectively) are simulated using the well-calibrated and validated Agricultural Production Systems sIMulater of Potato (APSIM-Potato). The study area is classified into four types of zones with different yield patterns: High yield level and high yield stability zones, high yield level and low yield stability zones, low yield level and high yield stability zones, and low yield level and low yield stability zones. Based on the zoning indices and the standards, the distributions of four types of yield zones under different production levels are clarified and the effect of precipitation and soil on yield level and yield stability are analyzed. An increasing trend of the station percentage for high yield zones is defined during the period from 1981 to 2019. The proportion of high yield level and high yield stability zones in the study area decreases gradually with the constraints increasing from the potential production level with the radiation and temperature constrained to the climate-soil potential production level with the radiation, temperature, precipitation and soil constrained. Only 13% of the study area over the study period (1981-2019) shows the yield pattern of high yield level and high yield stability zones under the climate-soil potential production level. The high yield level and low yield stability zones are the potential high yield level and high yield stability zones in the future, which need further attention and effective measures to improve the yield stability of potato. Precipitation shows a greater effect on the potato yield level and yield stability than soil in the study region. To ensure the high and stable yield of potato in the study region, more attentions should be paid on the regions with negative effect of precipitation and soil on the yield level and yield stability. Actions should be taken into considering both on the local irrigation levels and the tillage measures.
Climatic Suitability Zoning of Tea Planting in Mainland China
Tang Junxian, Wang Peijuan, E Youhao, Youhao Ma, Yuping Wu, Dingrong Huo
2021, 32(4): 397-407. DOI: 10.11898/1001-7313.20210402
[FullText HTML] (598) [PDF 5430KB](227)
Abstract:
Starting from the national scale and annual level, the potential climate factors are interpolated into 10 km×10 km grid data based on the daily data set of 1903 weather stations from 1961 to 2019 across the country, and a tea plant distribution dataset consisting 1115 records is established. Using the maximum entropy model and GIS technology, the dominant climatic factors affecting tea plant in mainland China are screened according to the contribution percentage and Jackknife method, and the climatic suitability zoning of tea plant is divided into 4 grades: Unsuitable, sub-suitable, suitable and optimum, using the natural break point classification method. The threshold values of dominant climate factors for different division levels are determined and the climate characteristics of tea suitable zones are analyzed. The result shows that the maximum entropy model constructed based on the dominant affecting climatic factors is suitable for climatic suitability zoning of tea plant. The dominant climatic factors affecting the distribution of tea plant are averaged extreme minimum temperature, the frequency of spring frost, annual mean temperature, annual precipitation, and averaged relative humidity from March to September. The zoning results by the model are in good agreement with the distribution of famous tea towns and the location of geographical symbol tea. The changes of areas suitable for tea plant in different periods are also studied, and it shows that the north boundary of the tea plant suitable area for the six decadal periods from 1961 to 2019 is roughly the same, and all regions show a decreasing distribution trend from high latitudes in the east to low latitudes in the west. The areas where the northern boundary moves obviously are mainly in the high-latitude provinces in the east. The decadal variation of the centroid of the overall tea plant suitable area is relatively slight: The suitable areas expand northwards gradually except for the 1960s-1970s and the 1980s-1990s. These results provide a scientific basis for rational planning of tea planting layout and scientific development of tea industry. The zoning method adequately considers climatic conditions of the study area under natural conditions. However, other factors such as land use types, soil conditions, and tea varieties are not fully considered, and the interpolation method does not consider the influence of altitude on meteorological elements, which makes the result of area optimum for tea planting larger than reality.
Refined Climatic Zoning of Spring Soybean in Northeast China
Li Kaiwei, Zhang Jiquan, Wei Sicheng, Liu Cong, Wang Chunyi
2021, 32(4): 408-420. DOI: 10.11898/1001-7313.20210403
[FullText HTML] (409) [PDF 22381KB](135)
Abstract:
The spring soybean in Northeast China is studied, and its climatic zoning index is determined by multi-year relative meteorological yield and meteorological data considering three maturity types of soybeans: Early, medium and late. Considering the influence of temperature, light and water on soybean growth, two suitability evaluation methods, zoning indicator affiliation function and crop response function, are selected to evaluate the climatic suitability of soybean in Northeast China using meteorological data from 1990-2019 after refined interpolation (Anusplin interpolation). The evaluation results are verified using yield indicators. Climatic zoning class thresholds are determined based on the quantitative relationship between yield reduction rate and suitability of soybeans, and refined climatic zoning is conducted for two time periods, 1990-2004 and 2005-2019. The results show that the average temperature in August, cumulative rainfall from May to September and cumulative sunshine hours in July are the main meteorological factors affecting the relative meteorological yield of soybeans. The climatic zoning indexes for soybean in early, medium and late maturity zones are different. Compared with the results of climate suitability evaluation without maturity type, the evaluation results based on different maturity type indicators are more detailed in spatial distribution and better in expressing the distribution of soybean yields and yield stability. When yield data are lacking, the climate zoning results based on crop response functions is a good complement, which can indicate the distribution of soybean yields, but has shortcomings in the description of yield stability. According to the quantitative relationship between climate suitability and yield reduction rate, the evaluation results are classified as four levels: Most suitable (0.76 ≤ S ≤ 1), suitable (0.65 ≤ S < 0.76), sub-suitable (0.49 ≤ S < 0.65) and unsuitable (0 ≤ S < 0.49). The most suitable areas for soybean cultivation in Northeast China are concentrated in the northern part of the Songnen Plain and the south-central part of the Sanjiang Plain. As the climate warms, areas suitable for soybean cultivation expand to higher latitudes and higher altitudes. Refined climatic zoning of soybean in Northeast China is carried out at three levels: Temporal, spatial (1 km by 1 km farmland), and maturity type. The results of the refined climatic zoning can provide scientific basis for the full and rational use of climate resources and optimization of soybean planting structure in Northeast China.
Refined Climatic Zoning for Citrus Cultivation in Southern China Based on Climate Suitability
Liu Cong, Li Kaiwei, Zhang Jiquan, Yang Yueting, Wei Sicheng, Wang Chunyi
2021, 32(4): 421-431. DOI: 10.11898/1001-7313.20210404
[FullText HTML] (449) [PDF 5188KB](159)
Abstract:
In recent years, global warming leads to the increase of heat resources, the shift of agricultural climatic zones, and the lengthening of crop growing season. These phenomena make citrus often suffer the effects of high temperature heat damage and low temperature freezing damage. At present, the refined climatic zoning of cash crops mainly focuses on tomato, cotton and other crops, but there are few studies involving citrus. Therefore, suitability evaluation model is used to accurately and quantitatively regionalize citrus planting, and to provide a basis for scientific planting and rational distribution of citrus.Using the climate suitability function, the temperature, precipitation, sunshine and comprehensive suitability models of citrus growth period are established. With Anusplin software, the observations of 361 meteorological stations in southern citrus growing region in recent 60 years (1960-2019) are interpolated and the climate suitability is calculated. Then the natural breakpoint method is used to divide the citrus growing area into four levels. The spatial variation characteristics of climate resources and suitability in target area are compared and analyzed in three decades. The results show that most of the regions in target area meet the climatic resources required for the normal growth and development of citrus, and the suitability of temperature, precipitation and sunshine show obvious spatial heterogeneity. The temperature suitability increases from west to east, the precipitation suitability decreases from north to south, the spatial distribution of sunshine suitability is high in the east and low in the west. The suitability of citrus planting is divided into 4 grades: Unsuitability (0 < Fc ≤ 0.17), sub-suitability (0.17 < Fc ≤ 0.36), suitability (0.36 < Fc ≤ 0.48), and most suitability (0.48 < Fc ≤ 0.74). The most suitable areas are mainly in the eastern part of Sichuan, the southern part of Yunnan, the northwestern part of Chongqing, Guangxi and Hubei, and the northwestern part of Sichuan is the unsuitable area. Since 1990, the area of the most suitable planting area has decreased by about 29%, and the area of the unsuitable planting area has increased by 34%. The spatial distribution of high temperature and heat damage and low temperature freezing damage probability verify the accuracy of the zoning results, which can be used to guide and optimize citrus planting and production practice.Different varieties of citrus and site conditions lead to different climate suitability responses. Besides, climate change has obvious impacts on crop planting structure, physiological traits and yield. Therefore, climatic regionalization research on different varieties should be paid more attention especially considering the future climate change scenarios, so as to support the planting and production of citrus.
Refined Risk Zoning of High Temperature and Heat Damage to Greenhouse Tomato in Southern China
Zheng Yanjiao, Yang Zaiqiang, Wang Lin, Yang Shiqiong
2021, 32(4): 432-442. DOI: 10.11898/1001-7313.20210405
[FullText HTML] (471) [PDF 2234KB](95)
Abstract:
With the intensification of global warming, high temperature and heat damage of spring-summer occurs frequently in recent years, which seriously affects the growth of greenhouse tomato and reduces agricultural economic efficiency. The high temperature and heat damage risk zoning of tomato is especially important, but the research is not sufficient. Based on meteorological data of 359 stations from 1990 to 2019 and greenhouse microclimate measured data, the highest daily temperature in the southern greenhouse is simulated by the BP neural network. Combining high temperature control test data using correlation analysis and principal component analysis methods, the main indicators are screened out, and a high temperature stress index model is constructed. The mean-standard deviation method is used to divide three levels of high temperature stress, and then the temperature with duration corresponding to the critical value of different levels of high temperature stress index are determined respectively, and the risk index system is established. Using geographic information system (GIS) software and other mathematical statistical methods, the characteristics of the year-over-year changes in the frequency of high temperature and thermal damage of tomatoes in the research area are analyzed, and a comprehensive risk index is established to assess the trend of risk development of high temperature and heat damage to greenhouse tomato in the past 30 years. The results show that the frequency of mild and severe high temperature and heat damage is increasing from 1990 to 2019, while the frequency of moderate high temperature and heat damage shows a different pattern (insignificant decrease trend). Among them, the frequency of mild high temperature and heat damage is the highest, followed by moderate high temperature and heat damage. The frequency of heat damage of various grades varies greatly from year to year. There are obvious differences in the distribution of the risk of high temperature and heat damage in space. High-risk areas of heat damage in southern greenhouse tomato are mainly distributed in the western and eastern parts of Guangdong, the eastern and western parts of Guangxi, and the northern, central, and southern parts of Yunnan. The second high-risk areas are mainly distributed in southern Hunan, most areas of Guangxi, central and northern Guangdong, southern Jiangxi, and most areas of Fujian. Areas with moderate heat damage are mainly distributed in north-central Hunan, northwestern Jiangxi, Zhejiang, Anhui, Hubei, and Chongqing. And the risk in western region is low.
Construction and Application of Climate Quality Evaluation Model for Indian Jujube
Chen Hui, Lin Jing, Yang Kai, Wang Peijuan, Yang Feiyue, Chen Huiling, Chen Tao, Li Lichun, Li Lirong, Chen Fuzi
2021, 32(4): 443-455. DOI: 10.11898/1001-7313.20210406
[FullText HTML] (285) [PDF 4880KB](118)
Abstract:
In order to adapt and fully utilize climate resources, improve the quality of Indian jujube, and increase the income and economic benefits of fruit farmers, 62 samples of fresh fruit weight, soluble sugar, soluble solids, vitamin C, hardness and other main quality factors are obtained from the field experiments in main production areas of Indian jujube in Fujian and Guangdong from 2015 to 2016. Combining literature review, expert investigation and quantitative grade evaluation standard of conventional agrometeorological conditions, the key climatic factors affecting the quality of Indian jujube are selected, and the grade evaluation model of climatic quality of Indian jujube is established. The temporal and spatial distribution of climate quality of Indian jujube in Fujian is analyzed based on 36 independent samples of main quality and meteorological data in major Indian jujube producing areas of Fujian and Guangdong, Guangxi from 2014 to 2019. The results show that three key climatic factors affecting the quality of Indian jujube are the 90-day average temperature 90 days before harvest, daily temperature range and sunshine hours 30 days before harvest. The accuracy of this evaluation model is 86.3%. The evaluation model can objectively reflect the influence of climate conditions on the quality of Indian jujube. Based on the model analysis, the results show that the climate quality of Indian jujube in Fujian picked in the early and middle stages is better than those picked in the later stages, and the proportion of high-quality jujube in the whole production period can be improved by adjusting the production period. Based on the spatial distribution map of climate quality of Indian jujube in the main picking period obtained from Fujian by the model, the climate quality of Indian jujube in southern region is better than that in central and northern regions. Therefore, the proportion of high-quality Indian jujube in the whole region can be improved by increasing the planting area in the south and reducing the planting area in the north. The results have been applied in the evaluation of climate quality grade of Indian jujube in Fujian for three years.
Effects of Water Stress/Rewatering on Leaf Photosynthetic Characteristics and Grain Yield of Foxtail Millet
Ren Chuanyou, Jiang Zhuoqun, Su Xiaoxuan, Mi Qianchuan, Wang Jing, Li Yue, Gao Xining
2021, 32(4): 456-467. DOI: 10.11898/1001-7313.20210407
[FullText HTML] (280) [PDF 2183KB](61)
Abstract:
Foxtail millet behaves strong drought resistance, but its photosynthesis process and grain yield are restricted by drought. The effects of water stress/rewatering on photosynthetic characteristics and yield of foxtail millet are studied through field water control experiment at booting and flowering stage and grain filling stage. The restraint factor on photosynthesis rate and the follow-up impact on grain yield are expounded, which may provide guidance for foxtail millet grain yield assessment and field water management under drought condition. The results are as follows: Water stress can lead to the decrease of photosynthetic rate and grain yield of characterized by larger decrease amplitude with the increase of stress intensity and duration, and increasing water use efficiency is the main survival strategy. The effect of water stress/rewatering on foxtail millet yield at grain filling stage is more obvious than that at booting and flowering stage, characterized by 22.1% production loss under 14-day mild water stress and 47.1% for FH-21 treatment group. After rewatering, photosynthesis performs compensation effect, and the photosynthetic capacity is recovered to some extent. The recovery of photosynthesis ability is lower when the the water stress intensity is stronger and the water stress duration is longer, and the recovery of photosynthetic capacity at grain filling stage is weaker than that at booting and flowering stage. Under mild and short duration water stress, the decrease of photosynthetic rate is mainly determined by stomatal factors, and the non-stomatal restriction gradually becomes the main cause for the decrease of photosynthetic rate with the increase of water stress intensity and the extension of duration. Mild negative effects of water stress on grain yield for 7 and 14 days, and severe effects for 7 days can be partially offset by the compensating effect after rewatering to some extent at booting and flowering stage, so the final effect on grain yield is not significant. In comparison, the effect of water stress on photosynthetic rate is larger, and the recovery of photosynthetic is not as good after rewatering at the grain filling stage. The formation of grain yield is more sensitive to water stress at the grain filling stage, for the closer synergistic relationship between photosynthetic rate and ultimate grain yield. The results reveal that a mild or short-term water deficit can be made up by rewatering, when the water use efficiency and photosynthesis rate will rise, and stable foxtail millet grain yield can be obtained. This can improve sustainable development by allowing deficit irrigation and water-saving agricultural practices. These critical information for optimizing water management practices is beneficial for foxtail millet sustainable development, particularly under warmer and drier climate in the future in the northern China.
Effects of High Temperature Stress on Leaf Chlorophyll Fluorescence Characteristics of Kiwifruit
Li Hualong, Wang Jinghong, Zhang Weimin, Bai Qinfeng, Zhang Tao, Pan Yuying, Quan Wenting
2021, 32(4): 468-478. DOI: 10.11898/1001-7313.20210408
[FullText HTML] (399) [PDF 1672KB](66)
Abstract:
Kiwifruit is a vine with poor resistance to high temperature. The original habitat is mostly semi shade environment under mountain forest, with humid air, mild temperature change and weak light. The main problem in production is that the temperature of tree is often too high when the tree is introduced from the original forest environment in mountainous areas to cultivated under the direct sunlight in farmland. The leaves, fruits and trunks often get damaged.With the background of climate warming, in Shaanxi, the main kiwifruit producing area, extreme high temperature weather with daily maximum temperature over 40 ℃ often occurs. The high temperature damage of kiwifruit is particularly prominent, such as leaf wilting, shedding, fruit sunburn, fruit drop, and even tree death.In order to explore the effects of high temperature stress on photosynthetic apparatus of kiwifruit leaves and establish a heat injury identification index based on chlorophyll fluorescence response, the variation characteristics of the FO(minimal recorded fluorescence intensity), Fm(maximal recorded fluorescence intensity), Fa(maximal photochemistry efficiency), ΔWK(relative variable fluorescence difference at 300 μs), Tr(trapped energy flux per area at t=0), Et(electron transport flux per area at t=0), Dd(dissipated energy flux per area at t=0), Rm (density of QA-reducing PSⅡ reaction centers) in kiwifruit leaves under 30 ℃, 33 ℃, 36 ℃, 39 ℃, 42 ℃, 45 ℃, 48 ℃, 50 ℃, 52 ℃, 54 ℃ condition are studied by using the technique of fast chlorophyll fluorescence induction dynamics analysis(JIP-test). The results show that Tr, Rm and ΔWK are all affected by temperature stress in the range of 30-54 ℃, which belongs to PSⅡ sensitive site parameters, in which Tr, Rm show a linear downward trend with the increase of stress temperature, while ΔWK shows an exponential upward trend with the increase of stress temperature. FO, Fm, Fa, Dd, Et show stable or less variable under lower temperature stress, and intensified under higher temperature stress, which belongs to the secondary sensitive site parameters of PSⅡ. Most chlorophyll fluorescence parameters have two mutation critical points at 39 ℃ and 45 ℃. The results show that kiwifruit leaves have mild temperature stress at 30 ℃ ≤ T < 39 ℃, moderate temperature stress at 39 ℃ ≤ T < 45 ℃, and severe temperature stress at T ≥ 45 ℃.
Effects of Waterlogging on Photosynthetic Characteristics and Yield of Summer Peanut
Ma Qingrong, Zuo Xuan, Hu Chengda, Cheng Lin, Li Tongxiao
2021, 32(4): 479-490. DOI: 10.11898/1001-7313.20210409
[FullText HTML] (509) [PDF 769KB](70)
Abstract:
Yield of summer peanut is often reduced due to waterlogging caused by excessive rainfall in flood season. Exploring the effects of waterlogging duration under different cultivation pattern on photosynthetic characteristics and yield of peanut can provide scientific and technological support for dynamic monitoring, evaluation of waterlogging process, disaster prevention and mitigation. Field experiment is carried out in main peanut production area with clay soil. Peanut variety Yuhua 22 is used in field experiment under flat and ridge cultivation patterns. The yield formation process of peanut is divided into three stages: Early, middle and late, and four irrigation treatments (3 days, 5 days, 7 days and 9 days) are designed in these stages. In flat pattern, the depth of water in field is no less than 2 cm during irrigation, and the daily irrigation amount of ridged plots is consistent with that of flat plots. The results show that under the same irrigation amount, the waterlogging lasting days of ridge pattern are reduced by 1 to 5 days, and the flooding days are reduced by 3 to 5 days. The waterlogging duration is 4 to 5 days in 3 days irrigation treatment. Chlorophyll content and net photosynthetic rate show positive effects, resulting in the increase of dry matter accumulation in stems and leaves. The effects of waterlogging in all stages increase with waterlogging duration, but it has little effect in late stage because of the slow growth of peanut itself. For the 100-seed weight, the effects of heavy waterlogging are most significant in the middle period, followed by the early period, and then the late period. While for other factors, the effects are most significant in the early period. The waterlogging duration in all treatments is between 4 days and 16 days. The effects range from 1.3% to 64.2% on photosynthetic parameters and from 0.9% to -44.9% on biomass and yield. Compared with flat pattern, ridge pattern has less effects due to the decrease of waterlogging duration. The peanut yield loss of each treatment ranges from 3.4% to 11.6% in early stage, and from 1.2% to 6.9% in middle stage. The experiments take possible waterlogging lasting days in peanut production and two different cultivation patterns (flat and ridge) into consideration reasonably. The results are of great significance to enhance the capacity of disaster prevention and mitigation in peanut production.
Construction of Soybean Chilling Damage Indicator and Its Evolution Characteristics in Northeast China
Li Hainan, Zhu Lijie, Li Mingqian, Jiang Lixia, Ren Chuanyou, Gao Xining
2021, 32(4): 491-503. DOI: 10.11898/1001-7313.20210410
[FullText HTML] (319) [PDF 3757KB](113)
Abstract:
Chilling damage is the major cause of soybean yield reduction in Northeast China. Chilling damage indicator is an important basis for the monitoring and early warning. Taking soybean in Northeast China as the research object, based on daily average temperature data of 98 meteorological stations from 1971 to 2020, the soybean growth period data and historical disaster data of 42 agro-meteorological stations from 1992 to 2020, using heat index as the indicator, the disaster sample sequences of soybean under 5 growth stages and 3 chilling damage levels are constructed by disaster data. Probability distribution fitting and Kolmogorov-Smirnov test methods are used to obtain the probability distribution of chilling damage indicator, and then the t-distribution interval estimation method is used to determine the damage level threshold, and finally the indicator is verified. In addition, the temporal and spatial characteristics of chilling disaster are studied by applying trend analysis, Mann-Kendallt test method and other methods. The results show that the perfect match rate of disaster level and chilling damage indicator is 84.4%. Therefore, this level threshold of the indicator can well reflect the occurrence of soybean chilling damage in Northeast China. Under the same chilling damage level, the threshold value of chilling damage level in the three-leaf-flowering-podding stage is higher, and that in the sowing-emergence-three-leaf stage is relatively lower. Soybean has higher heat demand in the middle and late stage of growth and development, and lower heat demand in the early stage of growth and development. The frequency of chilling damage is the highest in the 1970s, and the mutation occurred around 1993 and then showed a downward trend until 2004. The spatial distribution of chilling injury frequency in each development stage shows the same change characteristics, and the highest value area is the widest in podding-mature stage. The areas with high incidence of cold damage is the Greater Khingan Range in the northernmost of Heilongjiang Province and the Changbai Mountain in the southeast of Jilin Province. And the frequency of chilling damage shows a decreasing trend around this center. With the inter-decadal change, the high-value area gradually shrinks and the low-value area gradually expands northward.
Freezing Injury Indicator of Tasty Kiwifruit During Overwintering Period
Bai Qinfeng, Wang Jinghong, Li Hualong, Zhang Weimin, Guo Jianping, Zhang Tao, He Chenxin
2021, 32(4): 504-512. DOI: 10.11898/1001-7313.20210411
[FullText HTML] (273) [PDF 438KB](61)
Abstract:
China has the largest artificial planting area of kiwifruit, of which 67% is tasty kiwifruit. Tasty kiwifruit is mainly distributed in the north foot of Qinling Mountains in Shaanxi Province (about 40% of the national kiwifruit industry scale), and Funiu Mountain and Tongbai Mountain in Henan Province (about 20% of the national kiwifruit industry scale). These two producing areas locate in the northern edge of China's kiwifruit planting area, where the risk of overwintering freezing injury is high to cause great economic losses to fruit farmers. Therefore, it is especially important to study the freezing injury indicator of tasty kiwifruit for the introduction and expansion of tasty kiwifruit, disaster prevention and mitigation, and stable development of the industry.Through disaster investigation, expert interview, data research and other methods, 7 large-scale freezing injury cases of tasty kiwifruit in 1991, 2002, 2007, 2009, 2011, 2015 and 2020 are selected. The disaster cases of four counties, namely Huyi, Zhouzhi, Meixian and Tongbai are used as samples. The critical occurrence indicator of the overwintering freezing injury of tasty kiwifruit is determined as -8.0 ℃. The low temperature indicator (TD) of mild, moderate and severe freezing injury of tasty kiwifruit are determined as follows: -12.0 ℃ < TD ≤ -8.0 ℃, -15.0 ℃ < TD ≤ -12.0 ℃, and TD ≤ -15.0 ℃. Four factors are defined as: Winter minimum temperature (X1), days of low temperature below -8.0 ℃ (X2), absolute value of negative accumulated temperature below -8 ℃ (X3), and process harmful accumulated cold below -8 ℃ (X4). Using principal component analysis and K-means clustering analysis, the comprehensive indicator (Ih) of tasty kiwifruit overwintering freezing injury is constructed, and the ranges of Ih for different levels of freezing injury are as follows: -2.08 < Ih ≤ 0.82 for mild freezing injury, 0.82 < Ih ≤ 2.15 for moderate freezing injury, and Ih>2.15 for severe freezing injury. The indicators mentioned above are verified by the freezing injury cases of tasty kiwifruit in Changan, Wugong and Xixia counties. The results show that low temperature indicators and comprehensive indicators of overwintering freezing injury of tasty kiwifruit are basically consistent with the actual situation. The results can support the prevention and evaluation of the freezing injury of tasty kiwifruit during overwintering period, and also can provide reference for industrial layout optimization and introduction of tasty kiwifruit in China.
Journal Online
Contact

© 2020 Journal of Applied Meteorological Science   京ICP备15006967号-1

Supported by Beijing Renhe Information Technology Co. Ltd