Current issue

• 2021 Vol.11 No.7 Published:20 July 2021

  Effects of Planting Density on Agronomic Traits, Yield and Lodging Resistance of Maize with Different Plant Types Men Hongwen, Guo Shoupeng, Huang Changjian, Yu Jinyou, Kang Zhenqiang, Wang Baoguo 2021, 11 (7):  1-6.  DOI: 10.11923/j.issn.2095-4050.cjas20191200306 Abstract + ( 466 )   HTML ( 17 )   PDF ( 1335KB )   ( 338 ) Two maize varieties of different plant types were used to explore the effects of planting density on yield, plant agronomic traits, lodging rate and stalk puncture intensity, by setting up seven planting densities. The results showed that ‘Quanyu 217’ had the highest yield under the condition of 60000 plants/hm 2 (9325.5 kg/hm2), and ‘Yuyu 30’ had the highest yield under the condition of 75000 plants/hm 2 (9640.5 kg/hm2). With the increase of planting density, the number of ear rows and thousand-grain weight decreased; the plant height, ear height, and the 3rd internode length at the base first increased and then decreased, and the 3rd internode diameter at the base decreased. The yield of ‘Quanyu 217’ was extremely and significantly positively correlated with internode diameter, the number of ear rows, and number of grains per row, and significantly positively correlated with thousand-grain weight; the lodging rate was extremely and significantly positively correlated with the internode length, and extremely and significantly negatively correlated with internode diameter, number of ear rows, number of grains per row, thousand-grain weight and yield. The yield of ‘Yuyu 30’ was significantly positively correlated with thousand-grain weight; the lodging rate was extremely and significantly negatively correlated with internode diameter, number of ear rows, number of grains per row, and thousand-grain weight. The lodging rate increase was closely related to corn stalk puncture intensity. With the increase of planting density, the puncture intensity of the rachisinternode and the 3 rd internode gradually decreased, and the puncture intensity of the 3rd internode was significantly higher than that of the rachisinternode. At the same planting density, the puncture intensity of the rachisinternode of ‘Quanyu 217’ was significantly lower than that of ‘Yuyu 30’. Therefore, the optimum planting density of the flat corn variety ‘Quanyu 217’ in this region was 60000 plants/hm 2, and the optimum planting density of the compact corn variety ‘Yuyu 30’ was 75000 plants/hm 2. In corn production, the appropriate planting density should be selected according to the plant type of the variety, the flat corn variety should be properly sparsely planted, and the compact corn variety can be properly densely planted.

  Effects of 5-Aminolevulinic Acid on Seed Germination and Seedling Growth of Maize Under Salt Stress Zhang Jiaxiang, Guo Yifan, Zhang Mei 2021, 11 (7):  7-12.  DOI: 10.11923/j.issn.2095-4050.cjas20191000231 Abstract + ( 397 )   HTML ( 9 )   PDF ( 1416KB )   ( 314 ) The purpose is to explore the effects of ALA on maize seed germination and seedling growth under salt stress. ‘Jinhai 5’ was selected as the experimental material, NaCl concentration was set at 100 mmol/L, and ALA concentration gradient was set at 0, 25, 50, 100 and 200 mg/L. The seeds and seedlings were treated to determine the germination rate and seed vigor, and the content of MDA, soluble sugar, proline and chlorophyll, and to analyze the physiological and biochemical indexes. The results showed that maize seed germination and seedling growth were inhibited to varying degrees under salt stress, while the application of ALA significantly reduced the level of plant salt damage, enhanced seed vigor, and increased the content of stress-resistant substances in seedlings. Among them, when the concentration of ALA was 25 mg/L, seed germination, seedling growth and development could be promoted, and the effect was significantly better than that of other treatments

  Rice Sheath Blight: Control Effect and Safety Evaluation Under Different Thifluzamide Seed Treatments Yao Kebing, Yu Julong, Zhang Guo, Zhao Laicheng, Miao Kang, Shu Zhaolin, Yang Hongfu, Xu Chao, Zhu Feng 2021, 11 (7):  13-17.  DOI: 10.11923/j.issn.2095-4050.cjas20200300047 Abstract + ( 513 )   HTML ( 8 )   PDF ( 1276KB )   ( 326 ) To clarify the control effect of thiofuramide seed treatment on rice sheath blight and its impact on rice growth, and provide a basis for its popularization and application, 24% thiofuramide SC was used as the experimental material, and three seed treatment methods, including seed soaking, wet mixing and dry mixing were conducted, and each method was set with five treatments of 150, 300, 450, 600 ai.g/hm2 and CK, to determine the control effect on rice sheath blight and safety on rice seed. The results showed that the control effect on sheath blight by wet mixing was 90.46%-98.10% when seeds were treated with 24% thifluzamide 150-600 ai.g/hm2 after 91 days. The control effect on sheath blight by dry mix treatment was 91.16%-99.28%. The control effect on sheath blight was poor when seeds were treated by soaking. The effect of each treatment on rice sheath blight slightly decreased after 108 days, but the trend was basically the same as 91 days after sowing. At the same time, all treatments had no adverse effect on rice germination, emergence and growth. Therefore, rice seed treatment with 24% thifluzamide SC should be used by wet mixing or dry mixing. In addition, from the perspective of control effect and economic cost, the recommended concentration should be 300-450 ai.g/hm2, which has a good control effect on rice sheath blight and a long efficacy, and is safe for rice growth.

  Effects of Lime Nitrogen on Stem Base Rot Disease of Sweet Potato Lin Feirong, Yu Jihua 2021, 11 (7):  18-22.  DOI: 10.11923/j.issn.2095-4050.cjas2021-0013 Abstract + ( 396 )   HTML ( 4 )   PDF ( 1359KB )   ( 248 ) To effectively prevent and control the rot disease at the base of sweet potato stem, thus promote the sustainable and healthy production of sweet potato in mountainous areas, the effects of treating soil with lime nitrogen before cutting and spraying base stem with tebuconazole after cutting on the disease were studied. The results showed that the effect of soil treated with lime nitrogen + soaking and spraying tebuconazole after cutting (GSS2) was 75.34% higher than that of the control (GSS5); the soil treated with lime nitrogen + soaking tebuconazole after cutting (GSS3) had only 30.43% increase in disease control effect; the disease rate of sweet potato spraying with tebuconazole after cutting (GSS2) was 6.85% lower than those spraying with tebuconazole at the initial occurrence of the disease (GSS1). Soaking base stem with tebuconazole alone (GSS5) had no effect on disease control. The effect of GSS4 was 52.16% higher than that of the control (GSS5). This research indicates that the application of lime nitrogen to soil could reduce the incidence of the rot disease at the base of sweet potato stem, thereby increasing the yield of sweet potato. Moreover, the soil treated with lime nitrogen also has significant effect on disease control and yield increase in the next year. Applying lime nitrogen as soil disinfection could prevent diseases and increase the yield of fresh sweet potato, and has great significance to promote the sustainable production of sweet potato in mountainous areas.

  Effects of Soil and Foliar Zinc Application on Agronomic Traits, Grain Yield and Grain Zinc, Iron and Selenium Concentration of Wheat Wang Lan, Xia Haiyong, Kong Weilin, Xian Weihua, Ma Guoxing, Wang Zihao, Zhang Rongting, Li Haosheng, Gong Kuijie, Liu Kaichang 2021, 11 (7):  23-27.  DOI: 10.11923/j.issn.2095-4050.casb2020-0206 Abstract + ( 587 )   HTML ( 18 )   PDF ( 1215KB )   ( 395 ) Zinc (Zn) is an essential micronutrient element for the growth and development of animals, plants and the human body, which can prevent pneumonia and other diseases and improve human immune function. Wheat (Triticum aestivum L.) is a major food crop in China, to meet the nutritional demand of human body for Zn, it is necessary to increase the Zn concentration in wheat grains. To provide a theoretical basis and technical support for the production of high quality wheat grains enriched with Zn, effects of soil and foliar Zn application on agronomic traits, grain yield, and the concentration of Zn (in particular) and also other two beneficial micronutrients including iron (Fe) and selenium (Se) in wheat grains were investigated under field condition. The results showed that the number of wheat ears of per hectare increased from 4470 thousand to 5115 thousand by soil Zn application, with an increase of 14.4%. Soil and foliar Zn application increased the grain yields of wheat from 5419.5-6250.5 kg/hm2 to 6372.0-6811.5 kg/hm2 with an increase rate of 5.2%-17.6%. Simultaneously, it had non-significant effect on the concentration of Fe and Se in grains, but effectively increased the Zn concentration from 34.0-39.6 mg/kg to 44.6-46.6 mg/kg with an increase rate of 17.7%-32.9%, achieving the target value of biofortification recommended by the World Health Organization and other institutions and scientists (40-50 mg/kg). Therefore, the application of Zn via soil and foliar spraying could improve the nutritional quality of grain Zn while increasing wheat yield, which is an effective way to improve the quality and efficiency of wheat production and is worth popularizing in large scale.

  Effects of Fertilization on the Composition of δ15N in Soil, Vegetables and Runoff of Vegetable Field Zhang Lijun, Hu Yanfang, Wang Jingwen, Zhang Mingkui 2021, 11 (7):  28-31.  DOI: 10.11923/j.issn.2095-4050.cjas20190900203 Abstract + ( 369 )   HTML ( 4 )   PDF ( 1190KB )   ( 226 ) To understand the effect of fertilization on the abundance of δ15N in soil, vegetables and surface water, 28 plots of vegetable field applied with different fertilizers during 2012 to 2018, including 13 plots with chemical fertilizer, 8 plots with livestock manure and 7 plots with commercial organic fertilizer and chemical fertilizer, were selected. The surface soil, both aboveground and groundwater parts of vegetables, and surface runoff samples in the fields were collected and their abundance of δ15N was measured. The results showed that fertilizer types had significant effects on the abundance of δ15N in soil, vegetables and surface runoff, and the abundance decreased in the order of livestock and poultry fertilizer > commercial organic fertilizer + chemical fertilizer > chemical fertilizer. There was a positive correlation between the abundance of δ15N in vegetables and surface water and soil. It is concluded that the nitrogen isotope composition of vegetable products could be used as an auxiliary basis for the identification of organic vegetables, and the abundance of δ15N in surface water could be used as an indicator of nitrogen pollution sources in water body.

  Soil Fertility of Red Soil Reclamation Land in Low Hilly Area: Evolution and Maturity Criteria Jiang Mingbei, Zhang Mingkui, Yan Jianli, Wang Daoze 2021, 11 (7):  32-36.  DOI: 10.11923/j.issn.2095-4050.cjas20190600075 Abstract + ( 344 )   HTML ( 9 )   PDF ( 1152KB )   ( 233 ) To understand the evolution law of soil fertility of red soil reclamation land in low hilly area, we studied the soil quality evolution in the process of reclamation, fertilization and maturation from red soil farmland by the method of replacing time with space. The results showed that: the contents of soil organic matter, total nitrogen, water-stable aggregates, available phosphorus and available potassium decreased significantly at the initial stage of reclamation of wasteland red soil because of the mixing of topsoil and subsoil, but with the increase of fertilization and maturation time, the soil acidity decreased gradually, the base saturation, the organic matter and the ratio of humus to organic matter increased; meanwhile, the contents of water-stable aggregates, total phosphorus, available phosphorus and microbial biomass carbon gradually increased, the soil texture gradually became lighter, and the C/N ratio gradually tended to be stable. Based on the comparative study of the soil fertility and productivity of reclamation cultivated land in different places and at different reclamation times, the following indicators are put forward for soil maturation of reclamation cultivated land in red soil hilly area: the thickness of tillage layer is >15 cm; the structure mainly dominated by small block and cluster; the percentage of >0.25 mm water stable aggregates is >30%; the soil pH value is >5.5 the base saturation is >60%; the soil organic matter content ranges from 15 to 20 g/kg with C/N ratio of 12-17, H/F is >0.40, and the ratio of humic acid and organic matter is >0.30; the soil available phosphorus, available potassium, and microbial biomass carbon are 7.5-30 mg/kg, >75 mg/kg, >75 mg/kg, respectively.

  Long-term Straw Mulching: Effects on Soil Physical and Chemical Properties and Organic Carbon Accumulation in Orchards Hu Yanfang, Zhang Mingkui 2021, 11 (7):  37-43.  DOI: 10.11923/j.issn.2095-4050.cjas20190400005 Abstract + ( 349 )   HTML ( 5 )   PDF ( 1360KB )   ( 271 ) To understand the effects of long-term straw mulching on soil quality in low hilly orchards in southern China, 2 adjacent orchards with the same site condition and planting time were selected in central Zhejiang (orchard with straw mulching for 6 years and orchard with conventional planting, respectively). We collected soil samples of 0-10 cm, 10-20 cm and 20-30 cm from the two orchards, and comprehensively analyzed the physical and chemical properties of soil samples, and discussed the effects of long-term straw mulching on the soil quality. The results showed that: long-term straw mulching could significantly reduce the soil bulk density of 0-10 cm and 10-20 cm, and increase the soil water-holding capacity and the water-stable aggregates’ content; could significantly increase the accumulation of organic matter, the amount of active organic matter, available potassium and medium and trace elements, as well as the number of soil microorganisms and enzyme activities; meanwhile, long-term straw mulching could reduce the soil acidity and prevent the sanding of topsoil; compared with the control, the contribution of light, coarse and fine particulate organic carbon to total organic carbon in soil with straw mulching increased significantly; the straw mulching had little influence on 20-30 cm soil layer. In conclusion, the straw mulching has obvious ecological effects on citrus orchards, which can effectively prevent soil erosion, improve the physical and chemical properties of soil, and enhance the nutrient supply capacity of soil. It can be used as a water conservation measure to improve the soil fertility in low hilly citrus orchards.

  Stagnic Anthrosols in Guizhou: Formation, Taxonomic Classification and Geographical Distribution Zhang Mingkui, Qiu Zhiteng 2021, 11 (7):  44-50.  DOI: 10.11923/j.issn.2095-4050.cjas19030010 Abstract + ( 493 )   HTML ( 7 )   PDF ( 1216KB )   ( 371 ) To understand the distribution characteristics of the stagnic anthrosols in mountainous areas of southwest China and promote the quantitative soil classification, based on the analysis data of representative soil profiles obtained from soil investigation in Guizhou from 2015 to 2017, and combined with previous soil survey data in Guizhou, we studied the formation, taxonomic classification and geographical distribution of stagnic anthrosols in Guizhou and their relationship with the soil formation environments by applying the diagnostic classification method of Chinese soil taxonomy. The results show that: there are 4 groups of stagnic anthrosols in Guizhou (i.e, gleyi-, Fe-leachi-, Fe-accumuli-, and Hapli-stagnic anthrosols), and 11 subgroups of them are identified; the diagnostic horizons of Guizhou include “anthrostagnic epipedon”, “Fe-leachi-hydragric horizon”, “Fe-accumuli-hydragric horizon”, and “albic horizon”; the identified diagnostic characteristics include “gleyic fertures” and “secondary calcic accumulation”; the stagnic anthrosols in Guizhou has obvious characteristics of organic matter accumulation and clay vertical migration, and the soil pH value varies greatly. The topographic condition is the main factor that affects the differentiation in groups and subgroups of the stagnic anthrosols in Guizhou, the main soil groups are Fe-accumuli-stagnic anthrosols and Hapli-stagnic anthrosols.

  The Suitability and Problems of Quinoa in Yongchang Zhang Tao, Jiang Jufang, Dong Jide 2021, 11 (7):  51-55.  DOI: 10.11923/j.issn.2095-4050.cjas20200300053 Abstract + ( 369 )   HTML ( 9 )   PDF ( 1244KB )   ( 323 ) To grasp the suitability of quinoa in Yongchang and the existing problems in the cultivation process, we collected the growth period data of Yongchang quinoa from 2017 to 2019, combined with meteorological data and soil nutrients’ data, to analyze the relationship between the growth period of quinoa and meteorological factors and the reasons for the yield reduction of Yongchang quinoa. The results show that the whole growth period of Yongchang quinoa is 139 days, and the average accumulated temperature required during the whole growth period is 2363.9℃. Late April is the best seeding time for quinoa, and after the cultivation of quinoa, the reduction of soil phosphorus and potassium is obvious, which has a negative impact on the quality of cultivated land. Delayed sowing, rainy weather, and no crop rotation after quinoa cultivation are all reasons for quinoa yield reduction, so the cultivation of quinoa should be based on local conditions.

  Application of Gaofen No.6 Satellite in Vegetation Ecological Remote Sensing Monitoring Zhang Qing, Chen Peng 2021, 11 (7):  56-59.  DOI: 10.11923/j.issn.2095-4050.cjas20191200315 Abstract + ( 336 )   HTML ( 8 )   PDF ( 1712KB )   ( 364 ) With the establishment and improvement of domestic Gaofen satellite ground observation system, the need for refined ecological remote sensing monitoring and analysis has been put on the agenda. The authors took Xinjiang Uygur Autonomous Region Bayinguoleng Mongolian Autonomous Prefecture Hejing County as an example, used GIS and remote sensing technology to perform normalized vegetation index (NDVI) inversion on the satellite data of Gaofen No.6, to generate vegetation index coverage levels and combined land use types, analyzed the current situation of vegetation ecological landscape in the study area; and used DEM data to extract the two main topographic factors of elevation and slope to conduct correlation analysis of the spatial distribution of NDVI values. The results show that: (1) the spatial distribution of vegetation coverage in Hejing County has obvious spatial heterogeneity, in general, it is mainly moderate and low coverage vegetation; (2) the vegetation index of Hejing County at low altitude and high altitude area is relatively low, and the vegetation index reaches the maximum in the middle altitude area (2500-3200 m), the maximum value was 0.48; (3) the slope has greater impact on vegetation. At about 10°, the vegetation growth is good and the vegetation index reaches the maximum.

  Characteristics of Main Chemical Components of Flue-cured Tobacco Leaves in Fujian Tobacco-growing Area Zhang Zhiling, Fang Quanxiang, Lin Zubin, Lin Haibin, Chen Qingwen, Lin Long, Chen Xingfeng 2021, 11 (7):  60-64.  DOI: 10.11923/j.issn.2095-4050.cjas2020-0012 Abstract + ( 469 )   HTML ( 8 )   PDF ( 1154KB )   ( 422 ) The paper analyzed the characteristics of main chemical components of flue-cured tobacco leaves in Fujian tobacco-growing area, so as to provide references for production technology plan design, distribution optimization, and raw material purchase by cigarette corporations. The contents of total sugar, reducing sugar, total nitrogen, nicotine, starch, potassium, chlorine in tobacco leaf samples collected from 3 main tobacco-growing areas in Fujian from 2013 to 2019 were determined, the derivative values of the nitrogen/alkali ratio, sugar/alkali ratio, potassium/chlorine ratio, the difference of total sugar and reducing sugar were calculated, and finally a comparative analysis on annual change rules, cultivars, parts and regional characteristics of main chemical components of flue-cured tobacco leaves was conducted. The results showed that the contents of total sugar (32.9%), reducing sugar (23.1%), potassium (3.37%), starch (7.09%) were relatively high, while the content of chloride (0.20%) was relatively low. On annual changing characteristics, the variation coefficients of total nitrogen and sugar were less than 20%, and the variation coefficient of chlorine was 71.5%. There were significant differences in chlorine in tobacco leaves, but there was no significant difference in potassium and starch among different cultivars. ‘K326’ had least total sugar and reducing sugar, ‘Yunyan 87’ had the highest reducing sugar content. ‘CB-1’ had significantly less nicotine than both ‘K326’ and ‘Yunyan 87’. On producing area characteristics, tobacco leaves from Longyan showed the highest reducing sugar and the least starch contents, and tobacco leaves from Nanping showed the highest chlorine and the least potassium contents. There was no significant difference in total sugar, nicotine, nitrogen/alkali ratio and sugar/alkali ratio among the three producing areas. In summary, flue-cured tobacco leaves in Fujian showed relatively high contents of total sugar, reducing sugar, potassium, starch, appropriate contents of total nitrogen and nicotine, and relatively low content of chloride. The content of total nitrogen and sugar in the flue-cured tobacco leaves showed great stability and the content of chlorine had more volatility; main chemical components in tobacco leaves were quite different among the cultivars and producing areas, and significant differences were observed in different parts of tobacco leaves.

  The Adaptability of Different Flue-cured Tobacco Varieties in the Western Tobacco Area of Xuanwei Xia Rongshuai, Xia Xianren, Zhang Xiaolong, Zhang Jungang, Zhou Yusi, Yang Sen, Liu Guangwei, Yang Meili, Qian Jin, Pan Yihong, Wang Quanzhen 2021, 11 (7):  65-71.  DOI: 10.11923/j.issn.2095-4050.cjas2021-0009 Abstract + ( 545 )   HTML ( 8 )   PDF ( 1346KB )   ( 324 ) To screen out high-quality varieties of flue-cured tobacco suitable for planting in the western tobacco area of Xuanwei City, a field comparative experiment was conducted to study the differences of agronomic characters, incidence of major diseases, economic benefit, stem percentage, chemical composition and sensory quality of ten flue-cured tobacco varieties in 2019. The results showed that the field growth performance of flue-cured tobacco varieties such as ‘Yunyan 105’ and ‘Zhongchuan 208’ was relatively good, and the incidence of four main diseases were all lower than 2.34% for the two varieties, among which the incidence rate of black shin was lower than 0.93%, lower than that of other varieties. ‘Yunyan 105’, ‘Zhongchuan 208’ and ‘Yunyan 97’ had good economic characters based on unit output value, with the output value of more than 71711.70 yuan per hectare, and the ecological adaptability was relatively good. At the same time, ‘Yunyan 105’ had a relatively low average stem percentage (35.98%) and a relatively high average comprehensive score of chemical composition and sensory quality (0.63 and 0.58, respectively), indicating its good market adaptability. While the overall performance of flue-cured tobacco varieties including ‘Yunyan 121’, ‘Yunyan 123’ and ‘Yunyan 116’ was poor, which were not suitable for planting and promotion in the western tobacco area of Xuanwei City.

  Species and Distribution of Key Medicinal Plants in Bazhou, Sichuan Hu Ping, Zhang Mei, Li Changshi, Qi Yuanpei, Zeng Jian, Fang Qingmao 2021, 11 (7):  72-76.  DOI: 10.11923/j.issn.2095-4050.cjas20190900200 Abstract + ( 365 )   HTML ( 4 )   PDF ( 1227KB )   ( 374 ) The species and distribution of key medicinal plants in Bazhou of Sichuan were investigated through the combination of interview, sample-plot survey and route survey. The results showed that there were 526 kinds of medicinal plants in Bazhou, belonging to 135 families and 396 genera, in which there were 127 kinds of key medicinal plant, 37 kinds of key cultivated medicinal plants. There were more species of key medicinal plants in Baimiao, Pingliang and Siling and more species of key cultivated medicinal plants in Pingliang, Qingjiang and Baimiao. The information about the species and distribution of key medicinal plants is obtained comprehensively by the survey, which can be used as a reference for the research and development planning of traditional Chinese medicine resources in Bazhou.

  The Potential of China-Vietnam Fishery Cooperation and the Development Strategy from the Perspective of the Belt and Road Initiative Miao Miao, Liu Huang, Zhang Chenglin, Chen Jun 2021, 11 (7):  77-83.  DOI: 10.11923/j.issn.2095-4050.cjas2021-0041 Abstract + ( 401 )   HTML ( 9 )   PDF ( 1349KB )   ( 355 ) Vietnam is the only country along the Belt and Road that has land and sea connections to China. The article firstly introduced the current development of Vietnam’s fishery industry including its fisheries resources, production scale, cultivation and fishing pattern, trade, fishery administration, main policy as well as scientific research institutes based on on-the-spot investigation as well as database. Then the article analyzed the constraints of fishery development in Vietnam and the potential of bilateral fishery cooperation between China and Vietnam under the background of “the Belt and Road Initiative”. Lastly the article put forward future development strategies like promoting the recovery of the aquaculture industry through strengthening the leading role of digital government, accelerating the intelligentization and informationization of the whole aquatic industry, integrating the production and marketing through e-commerce platform, facilitating on-line negotiations and exchanges, carrying out multi-field, multi-level and multi-channel cooperation, and strengthening the training of international talents.

  An Autotoxicity p-Hydroxybenzoic Acid-degrading Strain ZH2: Isolation and Application Xiao Rong, Deng Shu, Zhao Jing, Zhang Chunfen, Nie Yuanjun, Cao Qiufen 2021, 11 (7):  84-91.  DOI: 10.11923/j.issn.2095-4050.cjas2020-0115 Abstract + ( 420 )   HTML ( 8 )   PDF ( 2393KB )   ( 433 ) Autotoxicity is the main factor causing obstacles to continuous cropping plants. The aim of the study is to screen bacteria from soil which can degrade autotoxicity. A selective screening method was used to screen p-Hydroxybenzoic acid (PHBA) degradation bacterium. Bacterial species were identified by combining the morphological characteristics, physiological and biochemical characteristics and 16S rRNA sequencing results. The ability of the strain to degrade PHBA was determined by ultraviolet spectrophotometry. The effect of detoxification was verified by a pot experiment of cucumber. The results showed that one degradation strain (No. ZH2) was isolated and identified as Pseudomonas chlororaphis. On the condition of pure culture, ZH2 could degrade 97% at 72 h under 5 mg/mL PHBA concentration. In potted conditions, when the concentration of PHBA in the substrate was 10 mg/g, ZH2 could effectively alleviate the growth inhibition of PHBA on cucumber. We report a Pseudomonas chlororaphis strain screened from soil can degrade PHBA, it has the potential value of controlling continuous cropping obstacles.

  Design of Formula Fertilization System Based on Nutrient Balance Fertilization Method Wang Nannan, Zhang Chunfeng, Meng Qingying, Zhu Baoguo, Li Yu, Zhang Hongquan, Song Yingbo, Fan Weimin, Li Candong, Jin Xiaochun 2021, 11 (7):  92-94.  DOI: 10.11923/j.issn.2095-4050.cjas2020-0100 Abstract + ( 311 )   HTML ( 4 )   PDF ( 1497KB )   ( 450 ) To solve the excessive use of chemical fertilizer and reduce environmental pollution, we promote precise fertilization. In this study, a formula fertilization system was developed by using Visual Basic language and nutrient balance fertilization method, fertilizer application was calculated by five parameters: fertilizer demand, soil fertilizer supply, fertilizer utilization, target yield and available nutrient content in fertilizer. Under the premise of constant yield, it provided the most scientific and minimum fertilizer application. This system could accurately, efficiently and scientifically complete the work of formula fertilization.

  The Introduction History, Spreading Routes and Influence of Potato in Yunnan Zhu Juli, Li Canhui, Zhou Run, Geng Yan, Lu Chaoyan, Tang Wei, Zhu Shouqing 2021, 11 (7):  95-103.  DOI: 10.11923/j.issn.2095-4050.cjas20191100271 Abstract + ( 532 )   HTML ( 8 )   PDF ( 2123KB )   ( 950 ) Potato is a foreign crop, and its introduction and spread in Yunnan played an important role in solving social, economic, cultural and religious problems since the Ming and Qing Dynasty. After textual criticism, this paper discussed the time and main routes of potato introduction to China and Yunnan Province and the spreading routes in Yunnan. The main routes of introduction and spread were verified as below: (1) after 1615, potato was introduced into western Yunnan from northeastern India via the India-Myanmar-Yunnan Corridor and widely planted in Diqing, Lijiang, Dali and Nujiang, the cytoplasmic type was W/α; (2) after 1788, potato was introduced into Yongren, Chuxiong from Liangshan, Sichuan, and then widely spread in western and central Yunnan, these varieties representing W/α cytoplasmic type; (3) around the year of 1843, potato entered Zhaotong through southeastern Guizhou, widely planted in northeastern Yunnan and southwestern Guizhou with T/β cytoplasmic type. The introduction and spread of potato had a profound impact on the agricultural structure, population migration, mineral development, minority customs and religious beliefs in Yunnan for hundreds of years. Its localization had also accelerated the process of staple food grain production and provided new methods for scientific breeding.

  The Competitiveness of E-commerce Platform of Agricultural Products Based on Diamond Model in Haiyang City Kong Fanming, Guo Caixia, Liu Na, Sui Haolin, Chen Xiaofeng 2021, 11 (7):  104-111.  DOI: 10.11923/j.issn.2095-4050.cjas2020-0014 Abstract + ( 359 )   HTML ( 7 )   PDF ( 1381KB )   ( 405 ) E-commerce platform of agricultural products is one of the innovative ways of new agricultural development in China. Compared with the traditional sales model of agricultural products, e-commerce platform of agricultural products has more prominent advantages, and the industrial development will become more competitive. By the first half of 2019, more than 30,000 e-commerce platforms of agricultural products with multiple developmental patterns were established in China, which greatly promoted the revitalization of agriculture and rural industries. Based on the framework of diamond model, elements such as the factor conditions, demand conditions, relevant supporting industries and competitiveness status of the development of e-commerce platform of agricultural products in Haiyang City were analyzed though field research. According to the survey results, the current advantages and disadvantages of the e-commerce platform were explored, and suggestions were put forward on expanding the scale and enhancing the competitiveness of the e-commerce industry in the future.

  The Construction of Agro-technical Extension Team Under the Background of the Overall Promotion of Rural Revitalization Mo Guanggang, Zhou Xuesong 2021, 11 (7):  112-118.  DOI: 10.11923/j.issn.2095-4050.cjas2021-0037 Abstract + ( 432 )   HTML ( 14 )   PDF ( 1320KB )   ( 395 ) The implementation of the Rural Revitalization Strategy is a major decision deployed at the 19th National Congress of the CPC, and a key step in serving the Sannong goals, namely agriculture, rural community and farmers, in the new era. To revitalize the countryside, industrial revitalization is the foundation and the key, which can not be separated from the efforts of agricultural extension technicians at the grass roots. Agricultural extension technicians play an irreplaceable role in promoting agricultural progress, rural development and increasing farmers’ income, but the status quo of China’s agro-technical extension team still needs to be more adaptable to the tasks of the Rural Revitalization Strategy. Facing the new situation and new requirements, this article puts forward targeted initiatives from strengthening top-level design, foster a favorable social atmosphere, expanding the development space, improving the talent evaluation mechanism, and effectively raising the income level, etc., aiming to stimulate the vitality of agricultural technicians and give a full play to their role in scientific and technological innovation in agricultural production and countryside building, and provide strong talent support for the rural revitalization and the modernization of agriculture and rural areas.

  Current Status and Development Trend of Leisure Agricultural Industry in Xi'an Under the Strategy of Rural Revitalization Li Tong, Li Dongmei, Zhang Xiaofei, He Yu, Liu Zhe, He Gouni, Xi Xiaoxiang, Wang Yagang, Zhang Xuanhou 2021, 11 (7):  119-124.  DOI: 10.11923/j.issn.2095-4050.cjas20200300084 Abstract + ( 539 )   HTML ( 13 )   PDF ( 1341KB )   ( 633 ) As a new industrial form and consumption form, leisure agriculture plays an irreplaceable role in developing agriculture, prospering rural areas, making farmers rich, protecting ecology, inheriting culture and other aspects. It has become one of the highlights of agricultural and rural economic development. In order to promote the healthy and orderly development of leisure agriculture industry in Xi'an, the current situation of the industry was investigated through literature review, focus discussion and field research. The results show that Xi'an’s leisure agricultural industrial pattern of "two belts and three areas" has been basically formed, including the leisure agricultural industrial belt in the north foot of Qinling Mountains, the leisure agricultural industrial belt along the Weihe River and the leisure agricultural demonstration areas in Bailuyuan, Dulingyuan and Jingshanyuan. The main industrial modes are agritainment, leisure farm and leisure agricultural park. The rural complex and the characteristic leisure agricultural town are vigorously developed, and various models coexist and develop. It shows a good development trend with the industrial scale expanding year by year, with continuously enriched modes and expanded functions. In view of the existing problems, the study points out factors constraining the industrial development such as outdated industrial environmental infrastructure, imbalanced industrial development and imperfect management system, and proposes several integrated measures such as compliance management, orderly development, strengthening organization and coordination, and making the leisure agricultural industry stronger and with high quality.