Current issue

• 2022 Vol.38 No.1 Published:05 January 2022

  Comprehensive Optimal Cultivation Technique of Edible-type Sweet Potato ‘Chuan M1422’ QU Huijuan, LI Ming, SHEN Xueshan, ZHU Ling, PU Zhigang, FENG Junyan, ZHANG Cong 2022, 38 (1):  1-6.  DOI: 10.11924/j.issn.1000-6850.casb2021-0156 Abstract + ( 334 )   HTML ( 4 )   PDF ( 1278KB )   ( 180 ) This paper aims to select suitable comprehensive cultivation techniques of edible-type sweet potato ‘Chuan M1422’ in the hilly region of middle Sichuan Province. The effects of transplant density, compound fertilizer and water retaining agent amount on the tuber yield and quality indexes were studied with orthogonal experiment by a ternary quadratic general combinatorial orthogonal design. The results showed that the influence of the three factors on the fresh tuber yield, commodity rate, dry matter rate, protein content, starch content and vitamin C content was in an order of transplant density > water retaining agent amount > compound fertilizer amount. The influence of the three factors on β-carotene content was in an order of water retaining agent amount > transplant density > compound fertilizer amount. The comprehensive optimal cultivation technique that satisfied β-carotene content above 0.47%, vitamin C content above 29.00 mg/100 g and the commodity rate above 93.00% was: transplant density of 4.82×10 4-5.76×104 plant/hm2, compound fertilizer amount of 709.72-785.21 kg/hm2, and water retaining agent amount of 32.67-41.03 kg/hm2.

  Effects of Different Hosts on Propagation of Arbuscular Mycorrhizal Fungi MA Junqing, HOU Ning, SUN Chenyu, YANG Yisen, QIN Shengfeng, WANG Yong, LIU Lu, LIAO Honglin, HUANG Jinghua 2022, 38 (1):  7-14.  DOI: 10.11924/j.issn.1000-6850.casb2021-0050 Abstract + ( 299 )   HTML ( 5 )   PDF ( 1550KB )   ( 203 ) Arbuscular mycorrhizal fungi (AMF) play an important role in soil ecosystem, but currently AMF cannot be purely cultured, and can only be propagated by symbiosis with host plants. In order to research the effect of different host plants on the propagation of AMF, maize (Zea mays L.), sorghum (Sorghum bicolor (L.) Moench), ryegrass (Lolium perenne L.) and clover (Trifolium pratense L.) were selected as hosts to propagate Rhizophagus aggregatus and Claroideoglomus etunicatum, respectively. The colonization rate, spore density, and inoculum potential of AMF were measured on the 30th, 60th, 90th and 120th day after AMF inoculation. The results showed that the effects of different hosts on the propagation of AMF were different. The colonization rates of R. aggregatus and C. etunicatum from high to low were maize > sorghum > clover > ryegrass, and the order of spore density of R. aggregatus was maize> sorghum > ryegrass > clover, the order of spore density of C. etunicatum was sorghum > maize> clover > ryegrass. The propagation effect of the same host on different AMF was also different. The effect of maize and ryegrass on R. aggregatus was higher than that of C. etunicatum, but the effect of clover and sorghum on the propagation of C. etunicatum was higher than that of R. aggregatus. It was also found that the spore density of AMF was related to the colonization rate of AMF, and there was a significantly positive correlation. The results show that maize is the best host plant for R. aggregatus propagation and sorghum is the best host plant for C. etunicatum propagation.

  Water Inorganic Anions Profiles in Stemflow of Cinnamomum camphora: Variation Characteristics OUYANG Zeyi, OUYANG Shuolong, LIAO Juyang, LI Qiaoyun, LIU Yan, OUYANG Cuilan, WU Linshi, YI Haoyu 2022, 38 (1):  15-22.  DOI: 10.11924/j.issn.1000-6850.casb2021-0169 Abstract + ( 224 )   HTML ( 2 )   PDF ( 1318KB )   ( 37 ) To explore the change rule of acid rain in urban forest ecosystem, this research investigates SO42-, NO3-, Cl-, NO2-, F- in both the rainwater and the stemflow of Cinnamomum camphora forest ecosystem in Changsha. The results showed that SO4 2- and NO3- were the major inorganic anions in rainwater and stemflow, which accounted for 84.36% and 90.49%-91.42% of total anion contents in the rainwater and stemflow, respectively. The ratio of SO42-/NO3- was 1.14 and 2.32-2.61 in rainwater and stemflow, respectively. The pH value of rainwater averaged 4.87 in the study area, which indicated that the rainwater was a sulfuric-nitric mixed acid rain. The leaching coefficient of each inorganic anion in stemflow of different diameter at breast height(DBH) class ranged from 1.04 to 11.41, indicating different enrichment effects. The monthly variations of each inorganic anion showed that NO2- was the most unstable one and its variable coefficient was 0.49, while F- was the most stable inorganic anion, with the variation coefficient of F- at all DBH classes was 0.24. Except NO2 -, the variation coefficient of the other 4 anions decreased with the DBH class increase, i.e. The larger the diameter, the more stable the anion content was. The contents of SO4 2-, NO3, Cl- and F- of different DBH class were all in the order of d1(8-10 cm)> d2(16-18 cm)> d3(24-26 cm)> d4(32-34 cm),while for NO2 -, the order was: d1>d4>d2>d3. The contents of SO42-, NO3-, Cl-, NO2-, F- at all DBH class showed significantly negative correlation with the precipitation, indicating that the greater the rainfall amount, the greater the decrease trend of the inorganic anion was. However, there was no significant correlation between the inorganic anion content in the stem flow and the inorganic anion content in atmospheric precipitation, showing that the inorganic anions in stemflow mainly came from dry disposition of acidoids. Therefore, the bark of Cinnamomum camphora can adsorb acid materials in air, and has positive effects on air cleaning and acid rain mitigation.

  Genetic Relationship Analysis and Agronomic Traits Evaluation of 18 Agrocybe aegerita Strains WANG Hongxiu, SUN Peng, AN Ying, HU Jia, CHEN Xutao, LI Jing, WEI Yunhui 2022, 38 (1):  23-31.  DOI: 10.11924/j.issn.1000-6850.casb2021-0440 Abstract + ( 279 )   HTML ( 3 )   PDF ( 3901KB )   ( 38 ) In this study, 18 strains of Agrocybe aegerita (4 wild strains, 7 commercially cultivated strains, 5 strains mutated by cobalt-60 irradiation and 2 mutagenesis strains from Shenzhou 10 spacecraft) were used as experimental materials, to study the genetic relationship of Agrocybe aegerita and screen out strains with better agronomic traits for industrial production. Molecular markers ISSR, antagonistic test and isozyme techniques were used to analyze the genotyping and genetic relationship of the strains. By analyzing the cap thickness and diameter, stalk length and diameter, growth period and yield, the agronomic traits of the 18 strains of Agrocybe aegerita were compared. The 18 strains of Agrocybe aegerita were divided into 7 groups by antagonistic test. The 20 ISSR primers screened out could amplify 164 clear bands, and the average ratio of polymorphic bands was 81.1%. Clustering analysis of ISSR markers showed that the 18 strains could be divided into 6 groups when the genetic similarity coefficient was 0.828. The 18 strains were also divided into 6 groups by esterase isozyme test. The agronomic traits analysis showed that ‘Cha 5’, ‘AS-1’, ‘Cha 3’, ‘Baicha’, ‘Chayuan 1’ and ‘Yangshudong 1’ had better comprehensive traits. The results of ISSR molecular marker test, antagonistic test and esterase isozyme test were basically consistent. The optimal strains ‘Chayuan 1’, ‘Yangshudong 1’, ‘AS-1’, ‘Cha 3’, ‘Baicha’ and ‘Cha 5’ were selected as the industrial production strains of Agrocybe aegerita.

  Effects of Bio-organic Fertilizer on Growth, Physiological Characteristics of Apple Seedlings and Soil Microbial Functional Diversity YU Huili, XU Bianbian, XU Guoyi, SHAO Wei, GAO Dengtao, SI Peng 2022, 38 (1):  32-38.  DOI: 10.11924/j.issn.1000-6850.casb2020-0704 Abstract + ( 318 )   HTML ( 3 )   PDF ( 1360KB )   ( 58 ) To understand the effect of bio-organic fertilizer on growth and soil microbial functional diversity, one-year-old ‘Yanfu No.8’ apple seedlings were used as materials in pot experiment, and four treatments were set up, namely: chicken manure CK [35 g/(kg·soil)], bio-organic fertilizer T1 [23.3 g/(kg·soil)], T2 [35 g/(kg·soil)] and T3 [70 g/(kg·soil)]. The results showed that bio-organic fertilizer could promote the growth of apple seedlings. Among the treatments, the plant height and root length under 23.3 g/(kg·soil) treatment significantly increased by 14.24% and 24.02% compared with those under CK, while the difference between 23.3 g/(kg·soil) treatment and other treatments was significant. Bio-organic fertilizer could enhance the resistance of apple seedlings and promote nutrient absorption. Leaf proline content, chlorophyll SPAD value and potassium content significantly increased by 38.46%, 15.45% and 27.33%, while the MDA content was decreased significantly under 23.3 g/(kg·soil) treatment. The soil microbial Shannon's index H', richness index S, McIntosh index U, and soil microbial utilization of carbohydrates and amines in the treatment of 70 g/(kg·soil) were the highest, increased by 0.91%, 7.60%, 4.14%, 6.33%, and 18.92% compared with those of CK. respectively, while the difference between 70 g/(kg·soil) and 23.3 g/(kg·soil) treatments was not significant. In the principal component analysis, the 23.3 g/(kg·soil) bio-organic fertilizer treatment had the highest score. Therefore, bio-organic fertilizer can improve the growth, stress resistance and nutrient absorption of apple seedlings, and soil microbial functional diversity and utilization intensity of carbon source, and 23.3 g/(kg·soil) treatment is the best.

  Effect of Harvest Period on the Quality of ‘Huangguan’ Pear ZHANG Zishen, KE Zehua, ZHAO Shuliang, CHENG Fuhou, LI Xiangxi 2022, 38 (1):  39-43.  DOI: 10.11924/j.issn.1000-6850.casb2021-0623 Abstract + ( 284 )   HTML ( 5 )   PDF ( 1150KB )   ( 89 ) This experiment was conducted to study the effect of harvest period on fruit quality of ‘Huangguan’ pear and to reveal the growth regulation of the fruit quality factors during late fruit development, thus determining the best harvest period of ‘Huangguan’ pear in production. ‘Huangguan’ pear was used as test material, the fruit weight, soluble solid, Vc and pulp hardness at different harvest periods were measured. The composition and content of sugar and acid in fruits at different harvest periods were measured by liquid chromatography. These data were used to analyze the relationship between fruit quality factors at the later stage of fruit development and different harvest periods of ‘Huangguan’ pear. The results showed that the pulp hardness decreased significantly and the soluble solid content increased with the delay of harvest period from 106 days of fruit development, and the soluble solid content reached the peak at 137 days of fruit development. The change of Vc content was insignificant, and it was only significantly high at 120 days. Fructose was the main sugar in the fruits harvested at the near maturity stage, accounting for 70.09%-84.00%, which was the highest at 137 days of fruit development. Malic acid was the main acid in the fruit, accounting for 93.05%-97.28% of the total acid, and malic acid D accounted for 82.92%-91.84% of malic acid. With the delay of harvest time and the extension of fruit development days, the content of fruit acid decreased. The later the harvest period, the higher the sugar acid ratio was. During 130-137 days of fruit development of ‘Huangguan’ pear, the contents of soluble solids, fructose, glucose, sucrose and Vc in the fruit are relatively high, the sugar acid ratio and pulp hardness are appropriate. The suitable harvest period to obtain the best quality of ‘Huangguan’ pear is August 8-15.

  Microbial Community Structure Analysis on Different Phenophases of Late-maturing Peach ‘Snow Giant’ JIANG Lili, GUO Tengda, GONG Qingtao, WU Haibin, SUN Ruihong 2022, 38 (1):  44-52.  DOI: 10.11924/j.issn.1000-6850.casb2020-0745 Abstract + ( 241 )   HTML ( 3 )   PDF ( 4406KB )   ( 27 ) To explore the microbial community structure during the whole annual growth cycle of late-maturing peach ‘Snow Giant’, high-throughput sequencing technology was used to analyze the composition and abundance of bacterial and fungal communities in different phenophases and parts, so as to provide a theoretical basis for the scientific management. The diversity index analysis showed that, the Shannon and Simpson indexes of the bacteria in the germination stage and the young fruit stage were lower than those in the hardcore stage, the fruit growth stage and the mature stage, indicating higher bacterial diversity in later stage. The Shannon and Simpson indexes of the fungi in the flower stage and the young fruit stage were higher than those in the hardcore stage, indicating higher fungi diversity in early stage. For fungal abundance comparison among different phenophases of the same part, the abundance of Cladosporium (scab pathogen) was higher in leaf at the fruit growth stage and branch at the germination stage. The abundance of Alternaria (black spot pathogen) was higher in branch and fruit at the hardcore stage. Under current management mode, the risk that ‘Snow Giant’ is infected by scab at the fruit growth stage and the germination stage is relatively high, and the risk of hardcore stage infected by black spot is relatively high.

  Effects of AM Fungi on Mineral Element Uptake in Tissue Culture Seedlings of Paeonia suffruticosa ZENG Duanxiang, WANG Lianying 2022, 38 (1):  53-58.  DOI: 10.11924/j.issn.1000-6850.casb2021-0836 Abstract + ( 238 )   HTML ( 1 )   PDF ( 1332KB )   ( 74 ) The study aims to explore the inoculation effect and mechanism of arbuscular mycorrhizal fungi(AMF) on tissue culture seedlings of Paeonia suffruticosa, conserve and multiply germplasm resources of hybrid strain of P. suffruticosa, and provide means to solve bottleneck problems such as difficult rooting of in vitro plants and low transplantation survival rate, etc. We took embryo-culture and got the sterile systems with seeds of the new optimal hybrid strain of P. suffruticosa, then obtained mycorrhizal tissue culture seedlings by inoculating different AMF plantlets in vitro, and studied the effects of AM fungi on the growth and absorption of mineral elements in mycorrhizal seedlings. The results showed that, the mixture spore of Gg+Gm had the highest colonization frequency (93.12%) and colonization intensity (31.23), which were significantly higher than those of Gg, Gm and CK (P=0.01). AMF could improve the mycorrhization and absorption of mineral elements in P. suffruticosa tissue culture seedlings, and significantly promote the absorption of N, P, K, Fe and Ca of tissue culture seedlings of ‘Z1-10-3’, but decrease the content of Mg and Mn. Gg+Gm had the most significant improvement effect on absorption of P, which was increased by 63.4% compared with that of CK, and N, K and Fe contents were increased by 47.2%, 47.3% and 31.2%, respectively. The effects of inoculation of Gm and Gg consisted with that of Gg+Gm with a smaller change range. However, Gg+Gm had the most significant synergistic effect. The study can provide an effective way for rapid propagation of seedlings of P. suffruticosa.

  Cold Tolerance of Different Phalaenopsis Cultivars: An Evaluation FENG Xiaolu, KONG Yan’e, SUN Yin, JIANG Nannan, FANG Yifu, LI Yueling, NIU Xiaohua 2022, 38 (1):  59-67.  DOI: 10.11924/j.issn.1000-6850.casb2021-0164 Abstract + ( 779 )   HTML ( 3 )   PDF ( 1715KB )   ( 50 ) By studying the physiological differences of various species of Phalaenopsis under low temperature stress, and comprehensively evaluating their cold tolerance, the paper aims to provide a theoretical basis for Phalaenopsis cold-tolerant cultivation, cold-tolerant cultivar breeding and the research on its physiological mechanism of cold tolerance. The gradual cooling method was adopted to observe and determine the leaf morphological characteristics and various physiological indexes of 16 Phalaenopsis cultivars under different low temperature stress. The cold tolerance of the 16 Phalaenopsis cultivars was comprehensively evaluated by the subordinate function method and the cluster analysis method. The correlation between various physiological indicators and the cold tolerance of Phalaenopsis was analyzed using the grey relational analysis method. The results show that ‘Alishan’, ‘In the Mood for Love’, ‘Wedding Promenade’, ‘Love at First Sight’, ‘Fule Star’ and ‘1372’ are strong low-temperature tolerant cultivars; ‘Big Chili’, ‘Wax Red Flower’, ‘Black Lightning’, ‘Red Sky’ and ‘5064’ are medium low-temperature tolerant cultivars; ‘Golden Armor’, ‘Red Butterfly’, ‘Red Crown Sky’, ‘wk1753’ and ‘Bingshan Beauty’ are weak low-temperature tolerant cultivars. Fo, Fm, Fv/Fm, chlorophyll content, relative conductivity, SOD and CAT activity, and MDA content are all closely related to the cold tolerance of Phalaenopsis, and could be used as identification indicators.

  Mechanism Underlying the Light-induced Leaf Chlorosis of Pseudostellaria heterophylla LIU Xiaofeng, ZHA Daoxi, ZHU Qifa, XU Fangzheng, CHEN Yang, ZHANG Guangyu, WANG Xueying, XUE Lin, XU Lifeng, ZHANG Zhongfeng, XU Haiqing, ZHANG Hongbo 2022, 38 (1):  68-74.  DOI: 10.11924/j.issn.1000-6850.casb2021-0717 Abstract + ( 248 )   HTML ( 3 )   PDF ( 2646KB )   ( 91 ) This study aims to explore the correlation between light intensity and the leaf chlorosis of Pseudostellaria heterophylla, and further investigate the role of light intensity in mediating the leaf chlorosis and plant decay. The effects of light intensity and nitrogen level on the leaf chlorosis and carbohydrate accumulation in P. heterophylla were analyzed by biochemical analysis and microscopic observation to reveal the physiological mechanism underlying the leaf chlorosis of P. heterophylla. The differences of P. heterophylla leaf chlorosis characteristics and climatic factors between Xuancheng in Anhui and Zunyi in Guizhou were analyzed, which indicated that light intensity was an important factor affecting the leaf chlorosis of P. heterophylla. Field and greenhouse experiments showed that the extent of leaf chlorosis and the carbohydrate accumulation in P. heterophylla increased along with the increase of light intensity. Electron microscopic observation further suggested that the increase in light intensity could promote the enlargement of starch granules in chloroplasts, destroy the chloroplast structure, thus leading to leaf chlorosis in P. heterophylla. Increasing the nitrogen level could reduce the carbohydrate accumulation in P. heterophylla leaves and inhibit the light-induced leaf chlorosis. This study investigated the role of light and nitrogen in regulating leaf chlorosis of P. heterophylla, and could provide support to the agricultural practices in P. heterophylla cultivation.

  Isolation of Endophytic Fungi from Medicinal Plants and Screening and Identification of Antagonism WANG Zhanbin, ZHOU Xuan, MA Xinbo, WANG Jinglin 2022, 38 (1):  75-81.  DOI: 10.11924/j.issn.1000-6850.casb2021-0117 Abstract + ( 286 )   HTML ( 3 )   PDF ( 1536KB )   ( 518 ) To study the endophytic antagonistic strains, six medicinal plants, including Glechoma longituba, Conyza canadensis, Ranunculus japonicus, Gynura segetum, Thalictrum aquilegifolium and Chelidonium majus, were used as plant materials to extract and isolate the strains, and the antibacterial activities were tested. Three strains with high antibacterial activity were selected for molecular identification through 18S rDNA sequencing and phylogenetic tree construction. The results showed that all the six medicinal plants contained endophytic fungi, and 5 endophytic fungi were isolated from Glechoma longituba, 2 from Conyza canadensis, 4 from Ranunculus japonicus, 2 from Gynura segetum, 1 from Thalictrum aquilegifolium, and 2 from Chelidonium majus. Seven strains of antagonistic bacteria were obtained, which were LJ3, MJ2, MY1, TJ1, TJ2, J1 and BY1. MJ2 had the highest inhibitory rate of 56.47% against Alternaria alternata. MY1 and BY1 were identified as Clonostachys rosea, and TJ2 as a strain of Fusarium. It is proved that the endophytic bacteria have obvious antagonistic effect on Alternaria alternata and could be used for biological control of plant diseases.

  Sources and Influencing Factors of Soil Heavy Metals in the High Mountain and Hilly Area of Central Yunnan: Taking Wuding County as an Example XU Lei, HUANG Jiazhong, ZHANG Ya, XIANG Jingwei, YE Lei, YANG Minglong, DUAN Xingwu, GUAN Jiyun 2022, 38 (1):  82-92.  DOI: 10.11924/j.issn.1000-6850.casb2021-0128 Abstract + ( 316 )   HTML ( 3 )   PDF ( 4115KB )   ( 266 ) Taking Wuding County as an example, the source and influencing factors of heavy metals in soil were explored to provide a theoretical basis for the prevention and control of soil heavy metal pollution in the mountain and hilly area. This paper studied the content and the spatial distribution characteristics of heavy metals in Wuding County of Yunnan Province, used multivariate statistical analysis methods combined with geological characteristics to comprehensively analyze the sources and influencing factors of soil heavy metals. The research results show that: the spatial distribution characteristics of heavy metals in the surface soil are consistent with those in the deep layers. Except Cd, Pb and Zn, there was no significant difference in the content of heavy metals in the surface and deep layers. Controlled by the fault zone in the region, heavy metals are mainly concentrated in the iron-copper and lead-zinc polymetallic metallogenic belts. In the vertical distribution, Cd is greatly affected by human factors, Cr and Ni are controlled by their own physical and chemical properties. As, Cu, Hg, Pb, and Zn may be controlled by geological background. 8 kinds of heavy metals are all derived from soil parent material, Cd, Pb and Zn are greatly affected by mining, Cr and Ni are derived from soil-forming parent materials. As, Cd, Cu, Hg, Pb and Zn are derived from the combined effects of high background value soil-forming parent material and mineral mining in the polymetallic metallogenic belt. The contents of heavy metals in different soil types and land use types are different. Soil heavy metal content also has a significant correlation with organic carbon, iron and manganese oxides, clay minerals, nutrient elements, and pH.

  Effect of Different Passivators on Cadmium Contaminated Soil in Enshi MING Jiajia, XIANG Jiqian, KANG Yu, HUANG Lin, CHEN Yongbo, QU Yong, HU Baishun, YIN Hongqing 2022, 38 (1):  93-99.  DOI: 10.11924/j.issn.1000-6850.casb2021-0108 Abstract + ( 241 )   HTML ( 2 )   PDF ( 1229KB )   ( 52 ) To solve the problem of heavy metal cadmium pollution in vegetable soil in mountainous areas of Enshi by applying different passivators, the passivation effects of different passivators on cadmium in soil and on the yield, quality and cadmium content of pakchoi were investigated by pot experiments. Five treatments were set up, including biochar, hydroxyapatite, lime powder, fly ash and mixed organic passivator. The results showed that the fresh weight and plant height of pakchoi were promoted by the treatments except lime powder, and the fresh weight of pakchoi increased by 109.72% in the fly ash treatment. Meanwhile, soil pH increased by 25.18%, 36.61% and 28.21% in the hydroxyapatite, lime powder and mixed organic passivator treatments, respectively. All treatments had no significant effect on the activities of urease, cellulase and sucrase in the soil. The biochar and mixed organic passivator treatments significantly increased phosphatase activity by 52.85% and 69.82%, while the lime powder treatment significantly inhibited the activity. Five treatments all reduced the cadmium content of pakchoi. Among them, biochar, hydroxyapatite, lime powder and mixed organic passivator all achieved significant inhibition effects on cadmium absorption, and the effect of lime powder was the best, reducing the cadmium content by 73.80%. All treatments had no significant effect on the quality of pakchoi. In addition, the biochar and mixed organic passivator treatments reduced the total cadmium content in soil by 27.21% and 46.98%, respectively, and the lime powder and mixed organic passivator treatments reduced the ion-exchange cadmium content by 43.67% and 47.35%, respectively. In conclusion, the application of the five passivators can reduce the cadmium content of pakchoi. Among them, the mixed organic passivator treatment can not only enhance enzyme activity, but also reduce the proportion of total cadmium and available cadmium (ionic and water-soluble) in soil without affecting the yield and quality of pakchoi.

  Fertilizer Reduction and Efficiency Improvement and Farmland Nitrogen and Phosphorus Loss Control Technology in Wuhu City LI Chen, GUO Long, MA Zhongwen, WU Sheng, WU ZhiHang, MA Youhua 2022, 38 (1):  100-105.  DOI: 10.11924/j.issn.1000-6850.casb2021-0138 Abstract + ( 266 )   HTML ( 2 )   PDF ( 1188KB )   ( 73 ) Wuhu City is located in the Yangtze River Economic Zone, where the agricultural non-point source pollution control is vitally important to the ecological conservation of the Yangtze River. This study analyzed the amount of chemical fertilizer use in Wuhu City in 2017, calculated the nitrogen and phosphorus loss of farmland, and analyzed the present situation of chemical fertilizer application. It is found that the main problems of traditional chemical fertilizer use in Wuhu City are unreasonable fertilizing method and structure, single fertilizer type with large application rate, and low popularization rate of high-efficiency fertilizing technology. The research put forward the side deep fertilizing technology of mechanized rice transplantation, the accurate quantitative cultivation technology of rice, the light and simple cultivation technology of rape, the interception technology of ecological ditches and the utilization technology of farmland tail water, aiming to establish the technical system of fertilizer reduction and efficiency improvement. The results can provide technical reference for improving the ecological environment of the Yangtze River Basin and promoting the green development of agriculture in Wuhu City.

  Effects of Decomposing Microbial Inoculum on Decomposition and Nutrient Release Dynamics of Chamaecrista rotundifolia in Red Soil of Orange Orchards DONG Chunhua, ZHOU Xuan, SUN Jimin, LUO Zhiyong, XIE Yi, HU Kexin 2022, 38 (1):  106-113.  DOI: 10.11924/j.issn.1000-6850.casb2021-0204 Abstract + ( 231 )   HTML ( 2 )   PDF ( 1319KB )   ( 81 ) To clarify the decomposition and nutrient release of green manure combined with microbial inoculum in arid red soil, and to make better use of the nutrients, under field conditions, four treatments were conducted including control (CK), decomposing microbial inoculum (DM), decomposing microbial inoculum + biochar organic fertilizer (BM), and decomposing microbial inoculum + nitrogen-fixing bacteria (NM). The dynamic characteristics of decomposing and nutrient release of Chamaecrista rotundifolia in arid red soil of orange orchard were simulated by nylon-bag method, and the nutrient residual rate was also determined. The results showed that the rate of organic matter decomposition and nutrient release were the fastest in the first two weeks after turnover, and then decreased gradually. Ten days after turnover, the average daily decomposition rate of green manure straw was 3.319 g/d, and the average daily release rate of C, N, P and K was 1.765, 0.124, 0.009 and 0.090 g/d, respectively. The average daily decomposition rate of green manure straw from the 10 th to 70th day after turnover was 0.531 g/d, and the average daily release rate of C, N, P and K was 0.230, 0.014, 0.002 and 0.007 g/d, respectively. On the 70th day of the decomposition of green manure, the cumulative reduction rate of straw mass treated by CK, DM, BM and NM treatment was 67.96%, 73.72%, 79.73% and 76.68%, respectively; and the cumulative release rate of C under the four treatments was 70.07%, 76.84%, 85.07% and 77.70%, respectively; the cumulative release rate of N was 78.00%, 82.20%, 85.34% and 83.81%, respectively; the cumulative release rate of P was 81.27%, 84.85%, 91.74% and 85.08%, respectively; the cumulative release rate of K was 97.58%, 98.39%, 98.45% and 98.36%, respectively. The nutrient release rate of straw of Chamaecrista rotundifolia under different treatments was in the range of K > P > N > C, and BM treatment had the fastest rate of decomposition and nutrient release. Considering the decomposition of green manure and nutrient release comprehensively, the application of decomposing microbial inoculum in combination with Chamaecrista rotundifolia and turnover could effectively improve the soil microbial structure, increase the rate of decomposition and the efficiency of nutrient release in arid red soil.

  Temporal Characteristics and Driving Factors of Sown Area Variation for Main Economic Crops in Southern China WANG Jing, FANG Feng, WANG Ying 2022, 38 (1):  114-124.  DOI: 10.11924/j.issn.1000-6850.casb2021-0084 Abstract + ( 368 )   HTML ( 4 )   PDF ( 2071KB )   ( 68 ) The crop sown area is the basis of the adjustment and optimization of agricultural planting structure, so it is of significance to understand its temporal variation characteristics and driving factors in time. Based on historical statistical data, this paper selected five provinces in southern China (Guangdong, Guangxi, Sichuan, Yunnan and Guizhou) as representative areas to explore the temporal characteristics and driving factors of the changes in the sown areas of major economic crops in this region. The results are as follows. (1) In Guangdong, the sown area of oil, peanuts, sugar-yielding crops and sugarcane in Guangdong all displayed a trend of increase-decrease-flat; that of rapeseed, sesame and fibre showed a trend of increase-decrease-increase-decrease, increase-flat-decrease-flat and continuous decline, respectively; and that of jute, tobacco leaves and flue-cured tobacco presented a trend of first increase and then decrease. In Guangxi, the sown area of oil and peanuts displayed a trend of increase, while that of sesame, sugar-yielding crops and sugarcane showed a trend of first increase and then decrease, that of cotton and fibre showed a trend of increase-decreased-flat and continuous decline, respectively, and that of flue-cured tobacco and tobacco leaves fluctuated greatly. In Sichuan, the sown area of oil, peanut and rapeseed constantly increased, that of sesame decreased, that of cotton, fibre and jute showed a trend of first increase and then decrease, and that of sugar-yielding crops, sugarcane, tobacco leaves and flue-cured tobacco presented a trend of increase-decrease-increase-decrease. In Guizhou, the sown area of oil, peanut and rapeseed displayed an increasing trend, that of sesame and cotton showed an increase-decrease-increase-decrease trend and increase-decrease-flat trend, respectively, that of fibre and jute presented a trend of first increase and then decrease, that of tobacco leaves and flue-cured tobacco showed an increase-flat-decrease trend, and that of sugar-yielding crops and sugarcane changed heavily. In Yunnan, the sown area of oil, rapeseed and peanut displayed a trend of increase-decrease-flat-increase, that of sesame, cotton, sugar-yielding crops and sugarcane showed a trend of first increase and then decrease, and that of tobacco leaves and flue-cured tobacco presented a trend of increase. (2) The main driving factors of sown area variation were different in different provinces and for different economic crops, population, agricultural technical indicators, and wind, hail and flood disasters could have a great impact.

  Colonization of GFP-labelled Bacillus amyloliquefaciens Bam22 in Brassica napus YANG Xiaoxiang, HUANG Xiaoqin, ZHANG Lei, ZHANG Zhongmei, XIAN Yunxi, ZHOU Xiquan, LIU Yong 2022, 38 (1):  125-130.  DOI: 10.11924/j.issn.1000-6850.casb2021-0830 Abstract + ( 257 )   HTML ( 2 )   PDF ( 1900KB )   ( 57 ) The paper aims to investigate the colonization of GFP-labelled Bacillus amyloliquefaciens Bam22 in Brassica napus and lay a solid foundation for the application of this biocontrol agent. In this study, plasmid pGFP4412 containing green fluorescent protein gene was introduced into Bam22 cells by natural transformation method to construct GFP fluorescent labelled strain. The growth curve and inhibition activity to pathogenic microorganism of wild type strain Bam22 and Bam22-GFP were compared. The number of colonized strains in different tissue parts of B. napus was observed, and the colonization rule and ability were analyzed. The results showed that the labelled strain Bam22-GFP emitted strong green fluorescence under the excitation light wavelength of 488 nm, and the GFP fluorescent protein labelling and its gene expression did not affect the growth curve and inhibition activity to pathogenic microorganism of Bam22. The labelled strain could colonize in the B. napus plant through the root irrigation, and was transmitted from the root to the stem and leaf of B. napus. The colonization rules of Bam22-GFP in the root, stem and leaf all showed a trend of first increase and then decrease. On the 45 th day after inoculation, the labelled strains could still be detected in the roots, stems and leaves of B. napus. The results show that Bam22 could colonize and transfer in B. napus by root irrigation and display good colonization ability, and it has a good application prospect in agricultural production.

  Molecular Identification of a New Pathogen of Watermelon Anthracnose and Preliminary Study on Its Biological Characteristics HUANG Wei, CUI Lihong, XIE Wangchao, XIAO Guoqiang 2022, 38 (1):  131-136.  DOI: 10.11924/j.issn.1000-6850.casb2021-0077 Abstract + ( 233 )   HTML ( 3 )   PDF ( 2493KB )   ( 121 ) To explore the pathogenic species of watermelon anthracnose in western Hunan, and provide a theoretical basis for watermelon anthracnose prevention and control, we took the diseased leaves of watermelon grown in the Science and Technology Park of Xiangxi Vocational and Technical College for Nationalities as the research objects, isolated and purified the pathogen of the disease, and conducted morphological observation, Koch's rule verification, 18S rDNA-ITS sequence analysis and the biological characteristics analysis. The colony of strain C913 was round, hyphae of villiform and neatly arranged. It was white at first and then grayish white. The conidia discs were arranged in a ring shape, and there were orange-red conidia clusters. The conidia are cylindrical, blunt at both ends, single cell, with a septum in the middle, and the size was (9.8~17.5) µm× (4.5~5.9) µm. The 18S rDNA sequence was 100% similar to the four Colletotrichum gloeosporioides included in GenBank. The hyphae could grow normally when the temperature was 10-37℃, but the growth rate of the hyphae was the fastest at 25℃, and the colony diameter was 78.28 mm. The growth slowed down when the temperature was less than 10℃ or greater than 37℃. The hyphae spores could grow under the condition of pH 5-11. The hyphae grew fastest when the pH was 6 and the colony diameter was the largest, 84.62 mm. The colony diameter with glucose and sucrose as the carbon source medium was significantly higher than that of other treatments, 63.4 mm and 62.2 mm, respectively; while lactose was not conducive to the growth of mycelium (P<0.01), which was 33.1 mm, and 19.06% less than that of the control. (NH4)2SO4 obviously inhibited the growth of C913 hyphae. According to the morphological characteristics of the strain and the results of 18S rDNA-ITS sequence analysis, the strain C913 was identified as Colletotrichum gloeosporioides of the genus Colletotrichum of the subphylum Coelospora. The pathogen is found on diseased leaves of watermelon for the first time. When the temperature is 20-31℃ and pH is 6, it is the most suitable condition for mycelial growth, and when the temperature is 25-31℃ and pH is 9, it is the most suitable condition for sporulation. The colony diameter is the largest in the medium with glucose and sucrose as carbon sources, and the colony diameter is in the order of peptone>NaNO3>glycine>glutamic acid>agar>(NH4)2SO4.

  Study on Agricultural Machinery Safety Accidents in China Based on System Safety Theory MA Chao, XU Zisheng 2022, 38 (1):  137-141.  DOI: 10.11924/j.issn.1000-6850.casb2021-0089 Abstract + ( 281 )   HTML ( 7 )   PDF ( 1415KB )   ( 53 ) The popularization of agricultural machinery improves the efficiency of agricultural production and alleviates the problems of abandoned rural land and insufficient seasonal labor force. But restrained by technology development, operators’ quality and other factors, agricultural machinery safety accidents occur from time to time. In view of the safety situation of agricultural machinery, it is of great significance to analyze the causes of the accidents and to construct the mechanism of accident prevention to ensure the safety of workers and property. By analyzing the causes of agricultural machinery accidents and using system safety theory to investigate agricultural machinery accidents, this paper aims to establish safety thinking, put forward preventive measures, and reduce the occurrence of agricultural machinery accidents, thus providing theoretical and technical support for ensuring the sustainable development of agricultural machinery safety in production.

  Effect of Mechanization on Quinoa Industry in Gansu Province YANG Zhao, HUANG Jie, WEI Yuming, LIU Wenyu, JIN Qian, YANG Farong 2022, 38 (1):  142-144.  DOI: 10.11924/j.issn.1000-6850.casb2021-0090 Abstract + ( 242 )   HTML ( 1 )   PDF ( 1012KB )   ( 82 ) Quinoa has drawn wide attention from researchers and consumers because of its comprehensive nutrition, drought resistance, cold tolerance, barren tolerance, salt tolerance and other characteristics. Gansu Province has made considerable achievements in quinoa planting and processing since 2018. In this paper, the development status and problems of mechanization in quinoa cultivation, harvest, utilization as feed and products’ processing were summarized, and a complete set of suitable cultivation techniques was put forward according to the condition of different planting areas. Suggestions on quinoa industry of Gansu Province were proposed including establishing cultivation techniques for high and stable yield, increasing field purity and quality, strengthening the straw feed utilization, improving the comprehensive quality, expanding the depth and breadth of products’ processing, and building local brands. The study aims to explore new approaches for the development of quinoa industry in Gansu Province, and to provide a basis for its further development.

  Analysis of Nutritional Components of Glutinous Dioscorea from Zhejiang YE Wen, SUN Caixia, YE Jueyu, XU Mingfei 2022, 38 (1):  145-148.  DOI: 10.11924/j.issn.1000-6850.casb2020-0682 Abstract + ( 364 )   HTML ( 2 )   PDF ( 1166KB )   ( 90 ) The nutritional components of three different varieties of Dioscorea were analyzed, aiming to explore the advantages of glutinous Dioscorea and provide data support for the research on the nutritional value of glutinous Dioscorea. The contents of protein, starch, amino acids and mineral elements in Dioscorea were determined using corresponding scientific methods (Kjeldahl determination of nitrogen, acid hydrolysis, anthrone-sulfuric acid colorimetry, flame atomic absorption spectrometry). The results show that there are remarkable differences in the nutritional components of different Dioscorea varieties. Wencheng glutinous Dioscorea is rich in starch, reducing sugar, dietary fiber, β-carotene and available carbohydrates, with the content of 16.13%, 0.75%, 0.85%, 251.67 mg/100 g and 16.91%, respectively. Additionally, Wencheng glutinous Dioscorea is also rich in mineral elements and amino acids, especially for histidine and arginine. The content of total amino acids, essential amino acids and flavorful amino acids in Wencheng glutinous Dioscorea is 1.57%, 0.46%, and 0.57%, respectively. In summary, the starch content of Wencheng glutinous Dioscorea is significantly higher than that of the other two varieties of Dioscorea (Huaishan and Iron Stick Yam), resulting in better flavor with abundant amino acid, and it could be recommended as a high-quality variety as both vegetable and grain.

  Development of an Expert Diagnosis System for Jujube Diseases and Pests Based on WeChat Public Platform ZHAI Yingyan, ZHANG Feng, REN Bowen, JING Yangping, XIE Yufen, HAO Zhe, HONG Bo 2022, 38 (1):  149-154.  DOI: 10.11924/j.issn.1000-6850.casb2021-0058 Abstract + ( 242 )   HTML ( 3 )   PDF ( 2690KB )   ( 57 ) To quickly popularize the knowledge of jujube diseases and insect pests, this study used an agricultural expert system to improve the diagnosis and management efficiency of jujube diseases and insect pests. Based on the WeChat platform, the jujube expert diagnosis system ‘JujubaExpert2020’ was developed using php script language and mysql database. The system includes three functional modules: disease and pest diagnosis, cultivation history, and news on jujube planting. The core function is the database query and expert diagnosis forums of jujube pests and diseases. Users can query in two ways of keywords or the list of diseases and insect pests, to obtain information about the occurrence rules, hazard characteristics and prevention methods of related diseases and pests quickly and easily; the expert diagnosis forum provides a communication platform for users and experts, and experts can diagnose jujube diseases and pests online and answer the questions raised by users. In addition, the system also integrates the jujube industry distribution and agro-meteorological information of related producing areas nationwide, so that users can understand the development status of the national jujube industry better. The development of this system is beneficial to improving the early identification, diagnosis and scientific management ability of farmers on jujube diseases and pests, and could promote the IT application in jujube industry.

  Bibliometric Analysis of Rhizobia Research at Home and Abroad WU Man, MENG Cuiping, LIANG Haiyan, YANG Liyu, WU Qi, CI Dunwei, ZHENG Yongmei, LI Xinguo 2022, 38 (1):  155-164.  DOI: 10.11924/j.issn.1000-6850.casb2021-0071 Abstract + ( 472 )   HTML ( 4 )   PDF ( 2127KB )   ( 61 ) Based on bibliometrics and CiteSpace V analysis, the number of literatures, publications, research contents and hot spots of nitrogen fixation by rhizobia in Web of Science and CNKI database were analyzed in depth. The key points and weak points of current research on crop nitrogen fixation in rhizobia were summarized to provide reference for researchers and decision makers in the field. The results indicate that research papers on nitrogen fixation by rhizobia have showed a wavy rising trend since 1980. The United States of America, France and the United Kingdom are the top three countries with the largest number of publications and citation frequency in this field at present. In China, publishing organizations are mainly from the provinces (municipalities) with strong agricultural and academic strength, such as Beijing, Jiangsu, Heilongjiang, etc. The Chinese Academy of Agricultural Sciences has largest number of papers published in this field, and the research literature on rhizobia is mainly published in agricultural professional academic journals. CiteSpace V analysis shows that in recent 40 years, the high-frequency keywords in the field of nitrogen fixation by rhizobiua at home and abroad are soybean, symbiotic nitrogen fixation, alfalfa, etc. The emerging hot spots include molecular dialogue, chemical simulation, functional genomics, etc. Based on the above analysis, it is an effective way to improve the output level of scientific research results by strengthening the cooperation and exchange between high-level scientific research institutes at home and abroad in the future. In addition, current and future research in this field should focus on studying the molecular mechanism of nitrogen fixation by rhizobia, breeding high-efficiency varieties, strengthening the efficient application of rhizobia, optimizing fertilization technology, building the best system of nitrogen fixation by rhizobia and increasing its efficiency. The study will provide a basis for researchers to grasp the frontier issues and determine the direction of topic selection in this field.