Current issue

• 2024 Vol.14 No.12 Published:20 December 2024

  A Study on Local Varieties and Germplasm of Food Crops in Fujian Province-- Based on Investigations of Pucheng and Pingnan Counties GUO Yangjie, WANG Songliang, HE Zibin 2024, 14 (12):  1-7.  DOI: 10.11923/j.issn.2095-4050.cjas2024-0033 Abstract + ( 13 )   HTML ( 2 )   PDF ( 1335KB )   ( 2 ) Crop germplasm resources are the basic materials for modern crop breeding and the material basis for developing the agricultural seed industry, playing a significant role in ensuring China's grain food and sideline food security. This study aims to promote effective strategies to conserve the diversity of local germplasm resources of food crops in Fujian Province in the context of the transformation in modern crop breeding technology and changes in the socioeconomic system. Through in-depth field research in Pucheng County, Nanping City, Pingnan County, and Ningde City, combined with key interviews and questionnaire surveys with key interest groups, we systematically analyzed the preservation status and utilization of local varieties of cereals, yams, and pulses, as well as their germplasm resources. In view of the serious problem of loss of local germplasm resources of the grain and starch crop varieties under the dominance of high-yielding hybrid crop combinations, this study combines the opinions of breeding experts and other stakeholders, and further puts forward countermeasures and recommendations to promote the effective preservation and rational utilization of local varieties of grain crops and their germplasm resources in Fujian Province.

  Effects of Plant Immune Elicitor VDAL on Disease Resistance and Yield of Rice MIU Kang, SHU Zhaolin, ZHANG Fuqiang, ZHANG Guo, YU Julong, XIANG Lirui, XU Chao, ZHAO Laicheng 2024, 14 (12):  8-13.  DOI: 10.11923/j.issn.2095-4050.cjas2023-0166 Abstract + ( 9 )   HTML ( 1 )   PDF ( 1239KB )   ( 1 ) In order to further verify the efficacy of VDAL on rice yield and disease resistance, and provide scientific basis for its popularization and application in rice production, different application time (before sowing stage, rice seedling stage, rice burst stage, rice full heading stage) and different application methods (seed dressing, stem and leaf spray) were set. The results indicated that the disease index of rice sheath blight treated with different treatments were significantly lower than that of clean water control. The best control effect of rice blast was seed dressing + spraying at rice burst stage + spraying at full heading stage, and the control effect of diseased fingers reached 76.53%. At the same time, this treatment combination also showed the most significant improvement in rice yield, with an increase of 13.27%. The effects of different treatments on characters of rice plants were significantly different. Therefore, in rice production, it is recommended to use VDAL for seed dressing, and spray 150 g / hm2 of stems and leaves at rice burst stage and full heading stage.

  Effects of Reducing Chemical Fertilizers and Applying Mineral Biochar on Corn Yields and Soil Properties in Yellow River Beach BAI Xueyuan, SU He, ZONG Li, YAN Dong, WANG Xiaofeng, NA Na 2024, 14 (12):  14-18.  DOI: 10.11923/j.issn.2095-4050.cjas2023-0250 Abstract + ( 12 )   HTML ( 1 )   PDF ( 1217KB )   ( 2 ) Concerning the issue of soil quality decline caused by excessive use of chemical fertilizers, and to provide scientific fertilization reference for corn cultivation and soil improvement in this region, this study explored the effects of reducing chemical fertilizers with applying mineral biochar on soil properties and corn yields in the Yellow River floodplain area. In order to study their effects on corn yield and soil properties, different chemical fertilizer reduction combined with mineral biochar treatments were set in this study, including conventional fertilization (F1, applying diammonium phosphate 300 kg/hm2), reducing 12.5% fertilizer with 75 kg/hm2 mineral biochar (F2), reducing 25% fertilizer with 150 kg/hm2 mineral biochar (F3), reducing 37.5% fertilizer with 300 kg/hm2 mineral biochar (F4), and reducing 50% fertilizer with 600 kg/hm2 mineral biochar (F5). The results indicated that the application of mineral biochar in the 0-20 cm soil layer enhanced nitrogen uptake by crops, effectively stabilized soil potassium levels, and increased soil phosphorus content. Compared to F1, the combined application of fertilizer and mineral biochar could significantly improve the corn yields by 1.48%-12.61%. Especially, when the application rates were 262.5 kg/hm2 of diammonium phosphate and 75.0 kg/hm2 of mineral biochar, corn yields and economic benefits reached their maximum. These findings demonstrated that replacing chemical fertilizer with mineral biochar could improve soil properties and ensure corn yields.

  Effects of Biochar and Nitrogen Fertilizer on CO2 and N2O Emissions from Cotton Fields at Different Temperatures WANG Jia, LIU Weiyang, HAO Xingming, ZHANG Sheng, HE Duo, ZHANG Xiaogong, ZHOU Limin 2024, 14 (12):  19-27.  DOI: 10.11923/j.issn.2095-4050.cjas2023-0253 Abstract + ( 7 )   HTML ( 0 )   PDF ( 1734KB )   ( 0 ) The greenhouse gas emission rules under different farmland management methods were revealed, and the influencing factors and action mechanisms were expounded, so as to deal with greenhouse gas emissions from saline-alkali land in extremely vulnerable areas, mitigate climate change, and provided theoretical basis for greenhouse gas emission reduction in China. An extremely saline soil with electrical conductivity of 9.35 mS/cm and pH of 8.38 was used for indoor culture experiments. Three temperature gradients were set as 15, 25 and 35℃; three nitrogen application levels were set as 0, 120 and 240 kg N/hm2 and three biochar application levels were set as 0, 5 and 10 t/hm2. All treatments were carried out under 60% field water holding capacity and cultured for 45 days. The results showed that temperature and nitrogen application significantly increased CO2 and N2O emissions, and short-term application of biochar could reduce N2O emissions. (1) Under the same temperature and biochar conditions, the application of nitrogen fertilizer significantly increased greenhouse gas emissions. The cumulative emissions of CO2 and N2O at 120 kg N/hm2 were 2.02 times and 1.28 times of the control, respectively. The cumulative emissions of CO2 and N2O were the highest when nitrogen fertilizer rate was 240 kg N/hm2, which were 2.22 times and 1.64 times of the control, respectively. (2) Under the same temperature and nitrogen fertilizer conditions, the application of biochar significantly reduced the emission of N2O. Compared with the control, when the application rate of biochar was 5 t/hm2, the emission of N2O was reduced by 7%. The amount of biochar applied was 10 t/hm2, and the N2O emission was reduced by 13%. (3) Compared with 15℃, cumulative CO2 and N2O emissions at 25℃ increased by 11.34 g C/kg and 39.69 mg N/kg, respectively; the cumulative emissions of CO2 and N2O at 35℃ were the largest, increasing by 48.17 g C/kg and 69.69 mg N/kg, respectively. In summary, this study demonstrates that in the management of extreme saline-alkali soils in agricultural fields, reasonable control of temperature, nitrogen fertilization strategies, and the use of biochar are of significant importance for regulating greenhouse gas emissions.

  Evolution of Soil Quality of Sandy Marine Soils in Hangzhou Bay with Reclamation Time WEN Xiujuan, GU Guoping, LI Fangzhen, XIE Lu, ZHANG Mingkui 2024, 14 (12):  28-32.  DOI: 10.11923/j.issn.2095-4050.cjas2024-0079 Abstract + ( 8 )   HTML ( 1 )   PDF ( 1114KB )   ( 9 ) To understand the evolution pattern of soil quality of the marine soils with land use process, the fertility characteristics of the soils with different periods of reclamation from Xiasha Bridge to Jiashao Bridge in Hangzhou Bay were sampled and analyzed. The changes in quality indicators of the soils with reclamation time were explored subsequently. The results showed that the desalination and decalcification of sandy soil were relatively rapid. After 15 to 30 years of reclamation, the soil salt content decreased to less than 1 g/kg, reaching the safe range for crops. After 100 years of cultivation, the surface soil had been decalcified, and the decalcification rate of the subsoil was higher than 50%. After the reclamation of sand marine, soil organic matter, nitrogen and phosphorus gradually accumulated, while potassium gradually decreased. After 15 to 30 years of reclamation, the organic matter, total nitrogen and total phosphorus in the topsoil were 111%, 39% and 33% higher than that before reclamation, respectively. After 100 years of reclamation, the total potassium in the topsoil decreased by 12% as compared with before reclamation. With the increase of reclamation and utilization time, the content of available calcium, available magnesium, available boron and available molybdenum in the topsoil gradually decreased, while the content of heavy metals showed a slight increase trend. The content of water-stable aggregates in the soils was very low, but it could also increase with reclamation time. Overall, the soil quality of reclaimed sandy marine soils develops in a clear trend that is conducive to crop growth with the increase of utilization time.

  Effect of Continuous Organic Materials Application on Soil Bacterial Community JIN Zhili, LI Xiaohui, WANG Yan, GUO Wenlong, JING Liheng, LI Hu 2024, 14 (12):  33-39.  DOI: 10.11923/j.issn.2095-4050.cjas2023-0275 Abstract + ( 5 )   HTML ( 1 )   PDF ( 2015KB )   ( 0 ) A long-term fertilizer experiment was performed to investigate the effect of organic fertilizer application (oilcake manure and rice straw) on soil bacterial community diversity and structure. The results showed that soil bacterial diversity increased by the combined application of organic (oilcake manure or rice straw) and chemical fertilizers compared to only chemical fertilizers application, with rice straw returning exhibiting the highest efficacy. Meanwhile, the combined application of organic and chemical fertilizers significantly altered soil bacterial community structures. Specifically, the treatment of combining rice straw returning and chemical fertilizers exhibited twice as much unique operational taxonomic units (OTUs) compared to other treatments. At the taxonomic level of bacterial community family, there was an increase in relative abundance of Hydrogenophilaceae and Intrasporangiaceae in response to the combined use of rice straw and chemical fertilizers. In conclusion, employing a combination of organic and chemical fertilizers can effectively maintain soil bacterial diversity while modifying bacterial community structure. The combined application of rice straw returning and chemical fertilizers is a feasible management strategy for preserving soil bacterial diversity in tobacco fields, thereby improving both soil structure and fertilizer conservation capacity.

  Comprehensive Evaluation of Chrysanthemum morifolium Varieties Based on Principal Component Analysis and Grey Correlation Degree LIANG Guan, ZUO Hongjuan, LA Guixiao, LIU Yongkang, CAO Hui, LU Cuihong, ZHAO Zhengwei, ZHANG Xiaoshen 2024, 14 (12):  40-44.  DOI: 10.11923/j.issn.2095-4050.cjas2024-0100 Abstract + ( 13 )   HTML ( 4 )   PDF ( 1146KB )   ( 1 ) In order to explore a simple and feasible comprehensive evaluation method of Chrysanthemum morifolium, and select suitable C. morifolium varieties for cultivation in Zhengzhou, C. morifolium varieties were used as test materials, the comprehensive evaluation of 9 agronomic traits was carried out using grey correlation degree, correlation analysis and principal component analysis. The results showed that 9 agronomic traits of C. morifolium varieties were different, and the coefficient of variation was 6.07%-34.42%. According to the analysis of the gray correlation, the correlation between each agronomic trait and C. morifolium yield was as follows: branch number> flower number> crown width> plant height> fresh weight of single flower> leaf length> flower diameter> leaf width. The results indicated that the number of branches, the number of flowers and the width of crown should be paid attention to in the breeding and introduction of C. morifolium. The results of principal component analysis showed that the first highest score of C. morifolium ‘Wuyuanhuangju’ was consistent with the first highest yield of fresh C. morifolium, and the top four highest scores of principal component analysis were consistent with the top four highest yield of fresh C. morifolium. Therefore, the comprehensive evaluation method based on principal component analysis and grey correlation degree can be effectively evaluated, the selected varieties of C. morifolium ‘Wuyuanhuangju’, C. morifolium ‘Jinsihuangju’, C. morifolium ‘Huaihuang’ and C. morifolium ‘Huaibai’ can be popularized and applied in Zhengzhou and its surrounding areas.

  Effects of Different Fertilization Treatments on Growth, Yield and Quality of Guava FAN Xiaoyue, CHEN Bin, YAO Liping, ZHAO Yijie 2024, 14 (12):  45-49.  DOI: 10.11923/j.issn.2095-4050.cjas2024-0089 Abstract + ( 9 )   HTML ( 1 )   PDF ( 1322KB )   ( 0 ) In order to explore the effects of different fertilization treatments on the growth, yield and fruit quality of guava, no fertilization (CK), single application of organic fertilizer 15 kg/plant (T1), conventional application of compound fertilizer 2 kg/plant (T2), organic fertilizer 15 kg/plant+ compound fertilizer 1.6 kg/plant (T3), organic fertilizer 15 kg/plant+ compound fertilizer 1.2 kg/plant (T4) and organic fertilizer 15 kg/plant+ compound fertilizer 0.8 kg/plant (T5) were set up. The results showed that the branch length of T3 increased by 15.75% compared with T2, the longitudinal diameter of the two batches of fruits increased by 7.73% and 7.49% compared to T2, and the transverse diameter increased by 9.57% and 9.97%. The average single fruit mass of two batches of fruits treated with T3 increased by 18.80% and 21.36% compared to T2. The T3 and T4 had a better effect on improving fruit quality. Among them, the vitamin C content of the two batches of fruits treated with T3 increased by 19.98% and 10.80% compared to T2 treatment, and the soluble solids content increased by 19.61% and 11.30%. The total sugar content of two batches of fruits treated with T4 increased by 25.97% and 27.18% compared to T2, the reducing sugar content increased by 27.24% and 36.27%, and the crude fiber content decreased by 24.19% and 24.43%. To sum up, compared with the treatment of no fertilization or single fertilization, increasing the application of organic fertilizer by 15 kg and adding 1.2-1.6 kg of compound fertilizer per plant have a more significant promotion effect on improving the yield and quality of guava.

  Fruit Maturity Regulation Techniques for Grape Cultivation in Zhangzhou ZHENG Yuanqing 2024, 14 (12):  50-54.  DOI: 10.11923/j.issn.2095-4050.cjas2024-0126 Abstract + ( 9 )   HTML ( 7 )   PDF ( 1111KB )   ( 6 ) This paper aims to investigate the cultivation methods and key technical measures for regulating the grape production period in the Zhangzhou region, and to evaluate their effectiveness in improving grape quality and extending the harvest period. Leveraging the climatic advantages of the Zhangzhou area, the study employs techniques such as early cultivation, delayed cultivation, and dual-harvest cultivation mode, and applies technical measures, including cultivating strong buds to increase the flowering rate of secondary crops and precise pruning to enhance bud break, to different grape varieties. The results indicated that the grape production period regulation techniques improved both the growth quality and yield of the grapes while effectively extending the harvest period from the traditional 1month to 8 months. This not only increased the economic benefits of grape cultivation but also promoted the development of leisure agriculture. The production experiences summarized in this study, such as precise pruning, secondary crop management, irrigation, and fertilization, provide practical reference value for enhancing the economic benefits of grape cultivation in Zhangzhou and other southern regions through production period regulation.

  Effects of Different Salinity Stresses on Physiological Characteristics of Juvenile Sea Intestine (Urechis unicinctus) WANG Haoyu, KANG Zujia, YU Wensong, LIU Feng 2024, 14 (12):  55-61.  DOI: 10.11923/j.issn.2095-4050.cjas2024-0112 Abstract + ( 5 )   HTML ( 1 )   PDF ( 1314KB )   ( 1 ) To investigate the effects of different salinity conditions on physiological indices and analyze the physiological regulation mechanism of Urechis unicinctus Juvenile in the face of salinity stress, the salinity of aquaculture water were maintained at 15‰, 20‰, 25‰, 30‰ and 35‰ in five experimental groups. Serum, intestinal homogenate and body wall samples were collected at 0h, 6h, 12h, 18h, 24h, 48h and 72h and the activities of SOD, CAT, ACP, intestinal lipase and glycogen content were measured. In conclusion, salinity stress has a significant effect on antioxidant capacity and nonspecific immunity of Urechis unicinctus. A certain degree of salinity stimulation can activate the activities of digestive enzymes and accelerate metabolism; the increase rate of digestive enzyme activity under low-salt stimulation is slower than that under high-salt stimulation; the time of digestive enzymes and muscle glycogen reaching the highest value in the medium-high salinity group was earlier than that in the low-salinity group. However, when the salinity of water exceeds the limit tolerance range of Urechis unicinctus or the stress time is too long, the regulatory load of osmotic pressure will increase, which will inhibit the activities of the immune system and digestive enzymes, and even cause severe damage to the body. In contrast, the changes of each index in salinity 25‰ group are relatively stable, which are suitable for Urechis unicinctus cultivation.

  Quality Evaluation and Influence Analysis of Meteorological Conditions of Crayfish (Procambarus clarkii) at Different Cultivation Stages HUANG Yongping, FANG Mingdan, LIU Kaiwen, LIU Zhixiong, YANG Qingqing 2024, 14 (12):  62-69.  DOI: 10.11923/j.issn.2095-4050.cjas2023-0247 Abstract + ( 9 )   HTML ( 0 )   PDF ( 1342KB )   ( 2 ) Through comparative experiments in different breeding periods of crayfish from April to October, 34 quality factors such as conventional nutritional components, texture properties, amino acid composition and content of 25-30 g crayfish meat were analyzed and compared. The results showed that 32 quality factors of crayfish in different breeding periods were significantly different (P<0.05, the same below). The conventional nutritional components and texture properties of crayfish increased first and then decreased, and those of shrimp from June to August were significantly higher than those in other months. The total amino acid (TAA) was 16.57%-19.72%, the highest was in April, followed by July, and the lowest was in October, showing an overall downward trend. The ratio of essential amino acids (EAA) to TAA was 32.63%-36.58%, and the ratio of EAA to non-essential amino acids (NEAA) was 59.67%-73.51%, which was the highest in shrimp from September to October, showing an upward trend. The essential amino acid index (EAAI) was 68.34-90.14, with the highest in April and the lowest in August, showing a downward trend. The correlation analysis between 32 quality factors and meteorological factors in breeding period showed that 23 quality factors were significantly correlated with meteorological factors in breeding period, among which the most quality factors were significantly correlated with the number of cloudy days, sunshine hours and temperature suitability index. They were mostly positively correlated with the number of cloudy days, mostly negatively correlated with the number of sunshine hours, and positively correlated with the temperature suitability index. The optimum temperature of the temperature suitability index related to the conventional nutrients were 22℃, the texture properties were 24-26℃, and the amino acids were 20℃. Therefore, under the appropriate temperature, the appropriate shade was conducive to improving the quality of crayfish. Analyzing the correlation between meteorological factors and quality factors in different periods, the results showed that the early stage of breeding was the critical impact period of meteorological factors on conventional nutrients and amino acids, and the middle and late stages of breeding was the critical impact period of meteorological factors on texture properties.

  Study on Optimization of Cellulose Degradation Process of Distiller’s Grains FENG Yikai, SHAO Qingling, LUO Aiguo, ZHU Min, YANG Yanjun 2024, 14 (12):  70-77.  DOI: 10.11923/j.issn.2095-4050.cjas2023-0257 Abstract + ( 5 )   HTML ( 1 )   PDF ( 1599KB )   ( 1 ) The primary aim of this study is to optimize the process of cellulose degradation of distiller's grains. Utilizing discarded distiller's grains from liquor and rice wine factories for NaOH pretreatment, this research conducted a univariate experiment to investigate the impacts of NaOH concentration, distiller's grain particle size and NaOH treatment duration on the cellulose content in the grains. The distiller's grains and the optimal pretreatment conditions were selected based on the experimental results. Subsequently, cellulase was used for enzymatic hydrolysis, and the effects of enzyme dosage, hydrolysis temperature, and hydrolysis time and pH value on the enzymatic hydrolysis of distiller's grains cellulose were studied. A response surface analysis of three-level, four-factor was performed with reducing sugar absorbance as the response variable to determine the optimal conditions for enzymatic hydrolysis. The results showed that: (1) in the pretreatment test, different NaOH concentration and NaOH action time had significant effects on cellulose content of the same distillers, but mesh number had no significant effects on cellulose content of distillers. Under the same treatment conditions, the cellulose content of liquor distiller's grains was significantly higher than that of rice wine distiller's grains. Considering these factors, liquor distiller's grains were selected for subsequent enzymatic hydrolysis experiments. (2) The single-factor of the enzymatic hydrolysis process showed that the optimal effects of enzyme dosage, hydrolysis temperature, hydrolysis time, and pH were 800 U/g, 50℃, 4.5 h, and pH 5.5, respectively. Based on the single-factor results, a four-factor and three-level response surface analysis was conducted, which showed that enzyme dosage, temperature, and time had significant effects on the absorbance of reducing sugar, while pH had no significant effect. Among the pairwise interactions, enzyme dosage with time and temperature with time had significant effects on the absorbance of reducing sugar. The regression relationship between these four factors and the absorbance was significant and well-fitted, which could be used for prediction in actual production. The optimal hydrolysis conditions were as follows: cellulase dosage of 950 U/g, reaction temperature of 48℃, reaction time of 5.1 hours, and pH 5.5. Under these conditions, the maximum absorbance reached 0.47. This study indicates that through proper pretreatment and enzymatic hydrolysis, the cellulose in distillers' grains can be effectively converted into reducing sugars, offering a viable approach for the high-value utilization of distillers' grains.

  Analysis of Drought Characteristics During Growing Season of Alpine Grasslands in High-altitude Areas of Ili River Valley Based on SPEI WUMITI·Jumatai, SHEN Wei, GUO Yanyun, YILIYAER·Yekemujiang, MEILIKAN·Kermaimaiti, YEERBULAN·Nuerdawulieti, MA Yuping 2024, 14 (12):  78-84.  DOI: 10.11923/j.issn.2095-4050.cjas2023-0258 Abstract + ( 6 )   HTML ( 1 )   PDF ( 1899KB )   ( 2 ) Using monthly temperature and precipitation data from Zhaosu County meteorological station in the Ili River Valley from 1956 to 2022, as well as data on the growth period of grasslands, the standardized precipitation evapotranspiration index (SPEI), regression analysis, Mann-Kendall test, and other methods were adopted to analyze the drought variation characteristics during the growing season (April to August) of alpine grasslands in the high-altitude areas of the Ili River Valley. The results showed that the annual average temperature in Zhaosu County from 1956 to 2022 was 3.5°C, with a significant upward trend of 0.3°C/10 years. The annual precipitation was 509.3 mm, showing significant interannual variability but no significant increasing trend. The drought frequency during the entire growth period of grasslands in Zhaosu County was 16.4%, with a probability of severe drought occurrence at 7.5%. The drought frequencies during the greening, tillering, heading, and flowering stages were 13.4%, 16.4%, 22.3%, and 22.4% respectively. The greening stage showed no significant drought trend, while the tillering, heading, and flowering stages exhibited significant drought trends. The results are expected to provide a scientific theoretical basis for monitoring, early warning, and defense against grassland drought disasters in Zhaosu County.

  Classification of Low Temperature Disaster Types of Greenhouse Cucumber in Central and Southern Hebei ZHAO Yubing, SUN Dian, ZHANG Jie, YANG Lina, ZHANG Ziyao, SUN Donglei 2024, 14 (12):  85-91.  DOI: 10.11923/j.issn.2095-4050.cjas2023-0266 Abstract + ( 8 )   HTML ( 0 )   PDF ( 1338KB )   ( 0 ) The aim of this paper is to establish a meteorological service index system for the disaster caused by low temperature in greenhouse vegetable production in central and southern Hebei Province, in order to further improve the accuracy of agricultural meteorological service for the risk level prediction of greenhouse freezing damage. From December 2017 to February 2022, a typical energy-saving solar greenhouse was selected with ‘Jinyou No. 6’ cucumber as the test material. The low-temperature oligolighting environment was established by hanging sunshade net, and the effect of low-temperature oligolighting on the growth of cucumber seedlings in the solar greenhouse was studied by pot experiment. (1) The lowest indoor meteorological index of disaster caused by low temperature in solar greenhouse in south Hebei Province was 10℃. (2) The daily minimum temperature in the greenhouse had no significant correlation with the sunshine of the day, the minimum humidity of the day before and the sunshine of the day before, but had extremely significant or significant positive correlation with other meteorological factors; when the average temperature of the previous day, the maximum temperature, the average temperature of the previous day, the minimum temperature and the minimum temperature of the previous day were lower, the daily minimum temperature in the greenhouse dropped obviously, which was easy to cause disaster to cucumbers and other fruits and vegetables in the greenhouse. (3) Frost damage was divided into three types according to weather conditions outside the greenhouse: From December 2017 to February 2022, the number of freezing damage days of different types was 12 d, 22 d and 36 d, accounting for 17.14%, 31.43% and 51.43% of the total number of days, respectively. A regression model was established for the indoor minimum temperature of the three groups and the significant correlation between outdoor meteorological elements. The indoor meteorological index of low-temperature disaster caused by solar greenhouse in central and southern Hebei Province was defined and the types of low-temperature disaster were divided, which provided support for the prediction of the risk level of greenhouse freezing damage.

  Research Hotspots and Trend Analysis of Urban Agriculture in China Based on CiteSpace Approach CHANG Pengyan, WEI Anni, XU Haobin, WANG Songliang 2024, 14 (12):  92-100.  DOI: 10.11923/j.issn.2095-4050.cjas2024-0049 Abstract + ( 7 )   HTML ( 1 )   PDF ( 3025KB )   ( 3 ) With people's enhancing awareness of the importance of urban-rural integration and food safety, urban agriculture (UA) has become an important part of sustainable urban development planning and design. The development of UA serves as an effective supplement to rural agriculture and provides multiple ecosystem services to urban residents. To address the research hot topics and trends of UA in China, this article is based on the literature related to UA collected by China National Knowledge Infrastructure (CNKI) in the past 20 years, the CiteSpace graph method is applied to draw and analyze a visual graph of its publication volume, institutions, authors and keywords, analyzing the research hotspots, frontiers, and overall evolutionary paths of UA research in China from 2003 to 2012 and 2013 to 2022, respectively. The results indicated that: (1) from 2003 to 2012, the overall number of publications showed an upward trend, and reached its peak in 2011(122 ); from 2013 to 2022, there was a trend of first decreasing and then gradually stabilizing, with the lowest number of publications in 2018, only 34. (2) From 2003 to 2012, the author with the most publications on urban agriculture in China was Zhou Pei, with 9 publications. The Institute of Geographical Sciences and Resources of the Chinese Academy of Sciences had issued the most papers, reaching 18. The author with the most publications from 2013-2022 is Zhou Zhongxue, with 19. The institution with the highest number of publications was the School of Tourism and Environment of Shaanxi Normal University, with a total of 19 articles. (3) From 2003 to 2012, the six keywords “UA”, “development of UA”, “countermeasures for UA”, “new rural construction”, “green Beijing” and “Beijing City” constituted the research hotspots and frontiers of UA in China's academic community. From 2013 to 2022, the three keywords of “metropolitan area”, “urbanization” and “UA” had become research hotspots. The three keywords of “landscape architecture”, “rural revitalization” and “rural population transfer” had become core issues of this field in the future. The institutions and authors that contributed the most to UA research in the past 20 years from 2003 to 2022 had changed, indicating that new scholars and institutions had joined the research team on UA study. However, relevant scholars and institutions lacked sustainability in their research on UA. Based on the characteristics presented by the UA researches, future research areas should continue to focus on rural revitalization and expanding the research scope and depth of the agricultural transfer population. The authors suggest that local governments should carry out the development of UA based on local characteristics.