Current issue

• 2021 Vol.37 No.20 Published:15 July 2021

  Mixed Application of Superphosphate and Organic Fertilizer: Effects on Photosynthetic Characteristics and Yield of Wheat in Saline Alkali Soil Xue Yuansai, Shi Changhai, Wang Yuanxi, Wu Zhen, Zhang Shoufu, Liu Yiguo 2021, 37 (20):  1-6.  DOI: 10.11924/j.issn.1000-6850.casb2020-0508 Abstract + ( 313 )   HTML ( 8 )   PDF ( 1264KB )   ( 184 ) Different fertilization measures were studied in order to provide a theoretical basis for wheat production in saline alkali soil. ‘Qingmai 6’ was used as experimental material, and four processing methods were set up: compound fertilizer (CK), organic fertilizer (T1), superphosphate (T2), organic fertilizer and superphosphate (T3). The effects of different measures on the photosynthetic characteristics of wheat flag leaves and yield of wheat were studied. The results showed that, compared with other treatments, T3 treatment increased chlorophyll content (SPAD), leaf area index (LAI), photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) of wheat in saline alkali soil, while it reduced the intercellular carbon dioxide concentration (Ci) of flag leaves. At the late flowering stage, the increase range of T3 was more obvious, which effectively guarantee the photosynthesis at the late flowering stage. Compared with other treatments, T3 could significantly increase the ear number, kernel number per spike, and 1000-grain weight, and promote the increase of yield. The yield of T3 reached 8523.32 kg/hm2. Therefore, the results indicate that the mixed application of organic fertilizer and superphosphate fertilizers (T3) can be used as proper fertilization practice of wheat in saline alkali soil.

  The Hyperspectral Inversion for Estimating Maize Chlorophyll Contents Based on Regression Analysis Zhao Zhanhui, Zhang Congzhi, Zhang Jiabao, Wu Yunjin, Zhang Hongmin, Lu Chunyang 2021, 37 (20):  7-16.  DOI: 10.11924/j.issn.1000-6850.casb2020-0534 Abstract + ( 343 )   HTML ( 6 )   PDF ( 1909KB )   ( 55 ) The long-term gradient experiment of nitrogen fertilizer was selected as the study area, and the collected 42 samples of chlorophyll contents from maize leaf were treated as training samples. Unmanned Aerial Vehicle (UAV) hyperspectral remote sensing system was used to obtain maize hyperspectral images, and seventeen spectral parameters were extracted from these hyperspectral images. Using correlation analysis result, four spectral parameters, which closely related to the SPAD values or the values of after mathematical transformation (R, lgR, 1/lgR,1/R,\sqrt[]{R} and\sqrt[]{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$R$}\right.}) were selected and used to build unary or multiple regression equation. The results showed that λr, Rg, SDb, NDVI were the most closely related to SPAD values. The coefficients of determination between SPAD values and these four parameters were relatively high, which were 0.19, 0.83, 0.71 and 0.80, respectively. What’s more, the determination coefficient of multivariate regression equation between the four parameters and SPAD values was 0.93. The test results for the unitary or multivariate diagnostic model by using 21 independent samples from the training samples showed that the multivariate diagnostic model of SPAD values based on λr, Rg, SDb and NDVI had higher prediction accuracy. Compared with previous research results, the diagnostic model established in this study has the advantages of simple parameters and higher determination coefficient, which could be used as the data support for related field research.

  Effects of Combined Application of Potassium and Silicon Fertilizer on Dry Matter Accumulation and Grain Filling of Oil Flax Gou Zhenyu, Guo Lizhuo, Gao Yuhong, Xia Zhangxiang, Wang Yueping, Liu Yahui 2021, 37 (20):  17-25.  DOI: 10.11924/j.issn.1000-6850.casb2021-0263 Abstract + ( 347 )   HTML ( 6 )   PDF ( 1404KB )   ( 56 ) To explore the regulation effect of potassium (K) and silicon (Si) coupling on yield, two oil flax varieties were used to study the effects of K (0, 52.5 and 105 kg K2O/hm2) and Si (0 and 90 kg SiO2/hm2) amount on dry matter accumulation (DMA) and grain filling (GF) characteristics by split plot design. The results showed that there were significant differences in DMA and GF characteristics between the varieties. K application significantly increased the DMA after emergence stage, which was increased by 11.85%-20.49% on average under the two dosage levels than that under no K treatment. K amount increase enhanced the growth promoting effect during the period from branching to green fruit; K increased the average grain filling rate, prolonged the duration of rapid growth period, slow growth period and active grouting period, and increased grain yield by 10.79%-19.52%. Si had no significant main effect on DMA and GF, however, low K supply accompanied by Si increased DMA by 27.96%, and the interaction between K and Si affected GF rate of rapid growth period. Under the same soil fertility condition as the test area, K fertilizer dosage of 52.5 kg K2O/hm2 has a significant growth-promoting and yield-increasing effect, and low K supply combined with Si fertilizer has a certain growth-promoting effect.

  CRISPR/Cas9 System and Its Research Progress in Grain and Oil Crop Genetic Improvement Gao Zhongkui, Jiang Jing, Han Zhuqiang, Huang Zhipeng, Xiong Faqian, Tang Xiumei, Wu Haining, Zhong Ruichun, Liu Jing, Tang Ronghua, He Liangqiong 2021, 37 (20):  26-34.  DOI: 10.11924/j.issn.1000-6850.casb2020-0728 Abstract + ( 334 )   HTML ( 6 )   PDF ( 1448KB )   ( 63 ) CRISPR is a kind of natural immune system, which is produced by bacteria or archaea through nucleic acid specific recognition and cas9 protease cleavage, when viruses invade the bacteria or archaea. The genome editing technology based on CRISPR/cas9 system could realize the targeted editing of target genes through sgRNA mediation and cas9 protein cutting. Because of its simple operation, high editing efficiency and wide application range, the technology has rapidly become an important means to study the gene functions of plants, animals and microorganisms. At the same time, with the wide establishment of the large number of genomic information and corresponding databases, CRISPR/Cas9 technology has become a new and very effective way to promote genetic improvement and create special germplasm by using reverse genetics and bio-information technology. In this paper, the basic principle of CRISPR/Cas system, the mechanism of CRISPR/cas9 gene editing technology, the genetic improvement and variety breeding progress of grain and oil crops by using the technology were reviewed. The study could provide effective references for genetic improvement and variety optimization.

  Comparative Study on Tetraploid Induction of Taraxacum kok-saghyz Rodin with Oryzalin and Colchicine Yang Yushuang, Qin Bi, Zhang Jichuan, Zhang Liqun, Nie Qiuhai, Liu Shizhong 2021, 37 (20):  35-41.  DOI: 10.11924/j.issn.1000-6850.casb2020-0581 Abstract + ( 392 )   HTML ( 8 )   PDF ( 2616KB )   ( 41 ) To explore the induction effect of different mutagens on Taraxacum kok-saghyz Rodin (TKS), the seedlings of TKS were used as materials, the polyploid induction effects of different concentrations and treatment time of oryzalin and colchicine on TKS were analyzed, and the changes of morphological characteristics of polyploid TKS were studied using the buds soaking method. The results showed that, the seedling rate (60%-75%) and the highest mutation rate (14.08%) of the TKS treated with oryzalin were both higher than those of colchicine (0-59% and 5.56%), respectively. The chimera rate (27.27%) treated with oryzalin was lower than that of colchicine (75.00%). The treatment with 0.04 mmol/L oryzalin for 30 min was the optimal condition for TKS tetraploid induction, the seedling rate was 71.00% and the induction rate was 14.08%. Therefore, colchicine was more suitable for TKS polyploid induction than colchicine. The leaf thickness, stomata size in the lower epidermis, flower size and seed size of tetraploid TKS plants were significantly larger than those of wild-type diploid plants, and stomatal density was significantly less than that of wild-type plants. These morphological characteristics could assist the rapid screening and identification of polyploid TKS. The induction effect of two mutagens on TKS was preliminarily explored in this study, which could provide a theoretical basis and technical support for TKS polyploid breeding in the future.

  Landscape Suitability Evaluation of Bryophytes in Mountain Parks:A Case Study of Guanshanhu Park in Guiyang Li Yuqi, Wang Xiurong 2021, 37 (20):  42-48.  DOI: 10.11924/j.issn.1000-6850.casb2021-0256 Abstract + ( 372 )   HTML ( 4 )   PDF ( 1503KB )   ( 305 ) The purpose of this study is to improve the evaluation method of bryophyte landscape suitability and to provide theoretical support for improving the spatial layout quality of bryophyte landscape in the park. The contribution rate and comprehensive score of all indexes were obtained by principal component analysis, and the suitability of bryophyte community types from high to low was tree community> stone community> soil community. The influence of each index on the suitability of bryophyte landscape was from strong to weak as follows: landscape suitability> social suitability> ecological suitability. The combination of turf+weft+mat, mat+weft, turf+weft, pendant+mat+weft bryophyte communities had good suitability. The combination of weft, turf+weft, pendant+weft bryophyte communities had bad suitability. The key to the protection and construction of the bryophyte landscape is to reasonably grasp the balance and unity among landscape suitability, ecological suitability and social suitability. The suitable bryophyte community collocation form should be adopted in the design.

  Spatiotemporal Variations of Soil Water and Saline-alkali in Compound Ecosystem of Sand and Meadow in the Songnen Plain Zhang Qilin, Hu Juan, Gao Yingzhi, Zhou Daowei 2021, 37 (20):  49-58.  DOI: 10.11924/j.issn.1000-6850.casb2020-0518 Abstract + ( 355 )   HTML ( 5 )   PDF ( 1611KB )   ( 185 ) To explore the spatiotemporal variations of soil water and saline-alkali in compound ecosystem of sand and meadow in the Songnen Plain, the soil water content (SWC), electrical conductivity (EC), and pH in 0-300 cm soil profile in sand, meadow and middle area (between sand and meadow) regions from May to September were analyzed. The results showed that the mean SWC in meadow region was 20.5% and 52.7% higher (P<0.01) than that of middle area region and sand region, respectively. In middle area region, higher SWC in 0-20 cm soil and lower SWC in 30-150 cm soil were observed in September. In meadow region, SWC was lower in 0-10 cm soil in July and it gradually declined with the increase of soil depth from 10 to 150 cm. The mean EC and mean pH in meadow and middle area regions were higher (P<0.01) than that of sand region. The mean EC in meadow region was 39.8% higher (P<0.01) than that of middle area region. In meadow region, higher EC and pH were observed in 0-10 cm soil in July and in 30-70 cm soil in September. In middle area region, higher EC and pH were observed in 0-10 cm soil in September. The surface soil saline-alkali mainly occurred in meadow region and middle area region in July and September, respectively, and the different saline-alkali degree of the two kinds of regions was determined by species, soil texture and soil water table level.

  Effects of Different Mulch on Soil Temperature and Soil Water Potential in Key Growth Stages of Summer Black Grape Yang Xiang, Su Xuede, Li Pengcheng, Guo Shaojie, Li Ming 2021, 37 (20):  59-65.  DOI: 10.11924/j.issn.1000-6850.casb2020-0520 Abstract + ( 268 )   HTML ( 5 )   PDF ( 1290KB )   ( 40 ) Mulching is an effective way to regulate soil temperature and reduce ineffective evaporation of soil moisture. To investigate the effects of different mulching materials on soil temperature and soil water potential from flowering stage to ripening stage of summer black grape, we set 4 treatments including mulching geotextile cloth (T1), black cotton felt (T2), black plastic membrane (T3) and no mulch (control, CK). The results showed that, compared with CK, T1, T2 and T3 could increase the minimum soil temperature at florescence stage by 0.55, 0.87 and 3.25℃, respectively. T1 treatment reduced the soil maximum temperature of fruit rapid expansion period and veraison period by 0.83℃ and 1.11℃, respectively, made the soil temperature closer to the temperature environment suitable for root growth. T2 and T3 treatments increased the soil maximum temperature in fruit rapid expansion period and veraison period, by 0.71, 0.01℃ and 3.18, 2.40℃, respectively. Different mulching treatments could reduce the daily variation of soil water potential under the same irrigation condition, the soil water potential of T1 was between 0-1 kPa, which was basically saturated. The maximum daily range of soil water potential of T2, T3 and CK was 1.69-11.08, 0.24-1.09 and 12.63-18.08 kPa, respectively. Different mulching treatments increased the maximum and minimum soil water potential, in which, mulching geotextile cloth and black plastic membrane had more significant effect. Comprehensive comparison of the effects of different mulching materials on soil temperature and soil water potential showed that mulching geotextile cloth was the best.

  Analysis of Soil Bacterial Composition, Abundance and Diversity Based on High-throughput Sequencing Fan Na, Peng Zhidong, Bai Wenbin 2021, 37 (20):  66-70.  DOI: 10.11924/j.issn.1000-6850.casb2020-0528 Abstract + ( 469 )   HTML ( 8 )   PDF ( 1418KB )   ( 399 ) To study the changes in soil microbial community structure in saline-alkali soils, and the number of bacteria can be used as one of the criteria for screening sorghum salt-tolerant materials. This study will provide a theoretical basis for the selection of sorghum salt-tolerant materials and the study of sorghum salt tolerance. In the experiment, the Illumina Miseq high-throughput sequencing method was used to analyze the structure of the rhizosphere flora of sorghum in saline-alkali land. Ten different sorghum parent materials were selected to collect rhizospheric soil samples of sorghum in saline-alkali land. The increase in the number of microorganisms and their growth rate can effectively promote the activity of soil enzymes, thereby increasing the growth rate of the material; the Chao1, ACE and Shannon indexes of samples 342 and 473 are the highest, and the Simpson index is the smallest. The species diversity is the highest; on the contrary, the Chao1, ACE and Shannon indexes of the salt-sensitive materials 68 and 622 are the lowest, the Simpson index is the largest, and the diversity is the lowest. The research results show that the rhizosphere soil bacteria of salt-tolerant materials have high species diversity, and this index can be used as an evaluation index for screening salt-tolerant materials.

  Effects of Heat Modified Kaoline on Soil Cadmium Form and Cadmium Uptake by Pepper Yang Jiaojiao, Chai Guanqun, Liu Guihua, Wang Ying, Qin Song, Fan Chengwu 2021, 37 (20):  71-76.  DOI: 10.11924/j.issn.1000-6850.casb2021-0288 Abstract + ( 315 )   HTML ( 4 )   PDF ( 1360KB )   ( 180 ) To investigate the effect of heat modified kaoline on Cd migration in soil-pepper system, heat modified kaoline at 2 temperatures (300 and 500℃) was studied, the effects of kaoline and heat modified kaoline on the morphological distribution of Cd in Cd contaminated soil and the accumulation of heavy metals in pepper were investigated by pot culture. The results showed that in Cd contaminated soil, the application of kaoline and heat modified kaoline improved soil pH, but the difference between the treatments was not significant; compared with that of CK, the reducible Cd content in 300℃ and 500℃ treatment was reduced by 1.82%-33.94% and 11.76%-26.67%, respectively, the residue Cd content was increased by 46.63%~64.58% and 45.96%-1.14%, respectively; dry weight of the roots, stems, leaves and fruits of pepper in each treatment were higher than those of CK, capsicum fruit dry weight was increased by 31.00%-49.28%, the enrichment of Cd in pepper plants was roots > leaves > stems > fruits. In conclusion, the application of kaoline and heat modified kaoline could improve soil pH, decrease the content of soil weak acid extraction state and reducible Cd, ease Cd pressure on chili pepper, and the remediation effect is TK>FK>K.

  Change Characteristics of Growth Period of Spring Rape in Central and Southern Tibet During 2010-2019 Du Jun, Gao Jiajia, Li Aili, Tsewang Thondup, Tse Wang 2021, 37 (20):  77-84.  DOI: 10.11924/j.issn.1000-6850.casb2020-0527 Abstract + ( 278 )   HTML ( 7 )   PDF ( 1441KB )   ( 500 ) To study the response characteristics of the growth period of highland spring rape to climate change under global warming, we used linear regression method to analyze the change of spring rape growth period in central and southern Tibet based on the rape development stage data in the Zedang agro-meteorological observation station of 2010-2019 and the corresponding daily meteorological data of 1981-2019. The results showed that: (1) both sunshine duration and mean wind speed exhibited a decreasing trend during 1981-2019, with the rate of -22.37 h/10 a and -0.32 (m/s)/10 a, respectively, the other meteorological factors presented an increasing trend simultaneously, with an obvious characteristic of warm and wet climate; however, both heat (Tm, Tmax, Tmin and ∑T0) and sunshine hours (S) during vegetative growth period (VGP), reproductive growth period (RGP) and whole growth period (WGP) exhibited a deceasing trend from 1981 to 2019, and water resources (precipitation and relative humidity) and mean wind speed increased; (2) the main growth stages, including squaring, peduncle, flowering and green ripening stage, did not have significant change during 2010-2019, but the sowing and emergence stage were delayed, while the five-leave and mature stage exhibited earlier trend; all growth periods of VGP, RGP and WGP were shortened, which was particularly significant for the WGP with a rate of -2.23 days per year; (3) most of the spring rape growth periods had a significantly positive correlation with S &∑T0, but no significant correlation could be identified between the spring rape growth periods and the other meteorological factors, the WGP days had a significantly positive correlation with S and ∑T0, but negative correlation with RH. With the increasing RH and decreasing S & ∑T0, the WGP days of spring rape exhibits a decreasing trend during 2010-2019.

  Variation Characteristics and Influencing Factors of Crop Potential Evapotranspiration During Growing Season in Changji Erkejan Hoyhazi, Apar Ruzi, Huang Jian 2021, 37 (20):  85-92.  DOI: 10.11924/j.issn.1000-6850.casb2021-0253 Abstract + ( 348 )   HTML ( 6 )   PDF ( 1741KB )   ( 36 ) This paper explored the variation characteristics of evapotranspiration during the growing season in Changji from 1963 to 2020, aiming to provide a basis for the optimal management of water resources, rational crop planting distribution, agricultural irrigation planning and the development and utilization of water resources. Based on the meteorological data of eight meteorological stations in Changji from 1963 to 2020, the spatial and temporal variation characteristics of potential evapotranspiration were analyzed by Thornthwaite method, climate trend method, M-K test method and wavelet analysis method, and the influence of climate factors on the potential evapotranspiration was discussed by correlation analysis. The results showed that: (1) on the time scale, the potential evapotranspiration in the growing season increased significantly with a change rate of 2.3 mm/10 a and an average annual value of 876 mm; the potential evapotranspiration of 8 meteorological stations showed increasing trends; (2) on the spatial scale, the potential evapotranspiration decreased from west to east in the growing season of crops, as a whole, it showed a trend of decreasing first and then increasing; (3) the mutation occurred in 2009 in the western region, in 1994 in the central region, and in 2013 in the eastern region; the mutation occurred in 1997 in Changji, and the mutation in the central-eastern region was earlier than that in the western-eastern region; the periodic variation showed that the potential evapotranspiration in the growing season of crops had a period of 3.7-4.2 year; (4) temperature was the main factor affecting the potential evapotranspiration in the growing season, and the minimum temperature contributed the most to the increase of the potential evapotranspiration year by year, while the change of other climate factors weakened the potential evapotranspiration.

  Main Technical Models and Their Implementation Effects in Fallow Pilot Areas of Gansu Province Gao Fei, Cui Zengtuan, Jia Ruihong, Guo Shiqian 2021, 37 (20):  93-97.  DOI: 10.11924/j.issn.1000-6850.casb2020-0585 Abstract + ( 301 )   HTML ( 4 )   PDF ( 1205KB )   ( 31 ) Gansu Province is one of the pilot provinces for fallow projects in China. After three years of promotion and application of the fallow technical models, the implementation area continues to expand, and the technology models for different fallow areas have basically taken shape. This paper summarized and analyzed the monitoring data of the fallow area and the control area for three consecutive years, and grasped the basic characteristics of the changes in the physical and chemical properties of the fallow land in Gansu. After three years of fallow, the monitoring results show that the soil water storage capacity and fertilizer have been improved. The thickness of the soil plow layer increases and the bulk density decreases, and the nutrient content of organic matter, total nitrogen, available phosphorus, available potassium, available sulfur and available silicon all show an increasing trend. Among them, the soil bulk density in the fallow pilot area is slightly lower than that before the pilot, decreasing by 0.01 g/cm3; the soil organic matter content in the fallow pilot area is significantly higher than before, increasing by 4.6 g/kg with an increase range of 55.7%. The soil fertility is initially restored through the fallow technology model. Fallow measures have positive impact on increasing the potential of cultivated soil for increasing and stabilizing yield. The quality of fallow is improved by 0.09. The total water-soluble salt content and most of the water-soluble ions in the soil are reduced, the soil is showing a trend of desalinization to benign development, and the obstacle factors to degraded farmland are gradually alleviated.

  Characteristics and Driving Force of Land Use Change in Southwest China from 2000 to 2015:A Case Study of Fengjie County in Chongqing Xu Chenglong, Ji Peiyao, Gong Wenfeng, Liu Yueyang, Du Chong 2021, 37 (20):  98-107.  DOI: 10.11924/j.issn.1000-6850.casb2020-0632 Abstract + ( 407 )   HTML ( 6 )   PDF ( 2145KB )   ( 116 ) This thesis studied the space-time evolution of land use pattern and its driving force of Fengjie County, Chongqing City, aiming to provide a theoretical basis and technical references on land use optimization, ecological protection and sustainable development at county scale southwest China. Based on RS and GIS technology and the 4 phases of basic data (2000, 2005, 2010 and 2015), this thesis revealed the dynamic changing feature and regular pattern of spatial-temporal evolution of local land use from 2000 to 2015 from aspects like land use dynamic model and geographic information map. By means of principal component analysis and linear regression analysis model, and taking the socioeconomic statistics of Fengjie County as the basic factor, the driving mechanism of land use was explored. The results showed that in the study years, the studied area presented a land use spatial pattern with forestland and cultivated land as the main types and other lands interspersing. According to the analyzed data, the cultivated land, grassland and unused land respectively had a reduction of 78.84, 3.734 and 2.54 km2, while the forestland, water area and residential and industrial and mining area increased by 23.364, 46.67 and 9.034 km2 respectively. Affected by the migrants from the Three Gorges area, the distribution of regional land use developed from overall disorder to locally in order. From 2000 to 2010, the land use type transfer was mainly found among the forest land, grassland and cultivated land. The total transfer area from forest land to cultivated land and grassland were 849.38 and 425.17 km2, respectively. From 2010 to 2015, the forest land and the residential and industrial and mining area increased by 9.93 and 7.09 km2, respectively. The thesis found that it was effective to explore the driving mechanism of regional urbanization from the perspectives of industrial structure adjustment, policy influence and social development, and concluded that the land use pattern change in Fengjie County were mainly driven by urbanization factors, policy factors, economic factors, social development factors and agricultural factors.

  The Sublethal Effects of Avermectin and Avermectin·imidacloprid on Myzus persicae (Sulzer) in Potato Zhang Yanlei, Song Weihu, Lin Chunyan, Liu Changzhong 2021, 37 (20):  108-112.  DOI: 10.11924/j.issn.1000-6850.casb2020-0541 Abstract + ( 442 )   HTML ( 5 )   PDF ( 1318KB )   ( 33 ) To clarify the interference effects of abamectin and avermectin·imidacloprid at different sublethal doses on the F0 adult and F1 generation of Myzus persicae (Sulzer) in potato, the life tables of their populations at the LC10, LC25, LC40 doses were constructed in the laboratory, and the effects of different sublethal doses on the fecundity, growth, development and population parameter of M. persicae were analyzed. The results showed that after treated with abamectin and avermectin·imidacloprid LC10, LC25 and LC40, the mean fecundity of aphids was significantly less than the control, and the mean longevity was also significantly shorter than the control. The mean fecundity of aphids and the mean longevity with avermectin·imidacloprid LC40 group were the lowest (9.52) and the shortest (8.07 days). Compared with the control, the nymph period of F1 generation was significantly prolonged and the adult aphid stage was significantly shortened. The effects on population parameters of F1 generation were as follows: the net reproductive rate (Ro), intrinsic rate of increase (rm) and finite rate of increase (λ) were all significantly reduced, and the doubling time (Dt) was significantly prolonged. These results suggests that avermectin and avermectin·imidacloprid at different sublethal doses could significantly inhibit the mean longevity and mean fecundity per female of parental generation adult aphid and effectively control F1 generation pest resurgence simultaneously.

  The Research and Application Progress of Agricultural Information Processing Technology Ou Feifan, Zhang Chaoqun 2021, 37 (20):  113-118.  DOI: 10.11924/j.issn.1000-6850.casb2021-0135 Abstract + ( 616 )   HTML ( 8 )   PDF ( 1117KB )   ( 801 ) Agricultural information processing technology refers to the specific application of information technology to the service of agricultural internet of things. It is a rational choice for modern agriculture, and it is also the main indicator of the future trend of agricultural and its level of development. This article is based on the literature search data of China National Knowledge Infrastructure (CNKI). It makes a brief analysis of the research and application of China's agricultural information processing technology in recent years from four aspects: agricultural data mining technology, agricultural data processing technology, agricultural forecasting and early warning technology, and agricultural artificial intelligence technology. The future of agricultural information processing technology will show the development trend of integration, specialization and intelligence.

  Bibliometric Analysis of Soil Acidification of Tea Garden Based on CNKI Database Jia Kuankuan, Shu Yingge, Zhang Zhongliang, Wang Yuan, Ren Minghui 2021, 37 (20):  119-125.  DOI: 10.11924/j.issn.1000-6850.casb2020-0603 Abstract + ( 341 )   HTML ( 6 )   PDF ( 1439KB )   ( 653 ) Since 2006, the issue of soil acidification in tea plantations has received widespread attention in the academic community, with a large number of related research results emerging and gradually developing into a new field of knowledge. To analyze the existing literature in the field of soil acidification in tea plantations, identify knowledge clusters and research networks, grasp the research trends and developments as a whole and provide new ideas and references for future research, the article used CiteSpace software to visually analyze the research status, research hotspots and research frontiers of tea garden soil acidification. The results showed that the research on tea garden soil acidification roughly experienced three stages: budding stage (1976 to 1990), slow development stage (1991 to 2005) and rapid growth stage (2006 to 2019); the research group was mainly composed of universities and scientific research institutes in Zhejiang, but the scientific research institutes published a small amount of paper. Among the keywords, “tea tree” had the highest attention, “pH value” was the earliest and long-lasting keyword, and the research of tea garden soil acidification has become a continuous frontier research field. Based on the existing research on tea garden soil acidification, it is necessary to break through the framework of “soil acidity” in the future, expand the research scope, build a research network, innovate research methods and conduct diversified research from a broader perspective.

  Effects of Digestible Crude Protein and Lipid Levels on Growth Performance, Metabolism of Energy Substances and Antioxidant Capacity of Juvenile GIFI Tilapia, Oreochromis niloticus Li Guangbin, Li Ying, Wang Qiumei, Zhang Xindang, Lin Beibei, Chen Lusi, Deng Junming 2021, 37 (20):  126-135.  DOI: 10.11924/j.issn.1000-6850.casb2020-0335 Abstract + ( 305 )   HTML ( 4 )   PDF ( 1414KB )   ( 490 ) This experiment was conducted to evaluate the effects of digestible crude protein (DCP) and lipid (DL) levels on growth performance, metabolism of energy substances and antioxidant capacity of juvenile GIFI Tilapia (Oreochromis niloticus), and thereby to determine the optimal rate of digestible crude protein to digestible energy (DCP/DE). Juvenile fish with an initial average body weight of 2 g were fed 12 experimental diets with different nitrogen to energy ratios prepared with different DCP levels (22%, 24%, 26%, 28%) and DL levels (3%, 5%, 7%) for 10 weeks. The results showed as follows: with the increasing level of DCP and DL, the body weight gain (WG) and specific growth rate (SGR) of fish were significantly increased, but there was no significant difference between the 5%DL and the 7%DL group, and the protein efficiency showed a gradually decreasing trend. The WG and SGR of fish in the DCP26DL5 group were not significantly different from those in the highest DCP26DL7 group. The pepsin activity in DCP26DL5 group was significantly higher than that in DCP28DL3 group. The serum AST activity in DCP26DL5 group was the lowest. The TC and LDL-C content in DCP26DL5 group were significantly lower than those in DCP22DL7 group, and there was no significant change in blood glucose level among all groups. The antioxidant function of fish body was significantly increased. The SOD activity in liver of DCP26DL5 group was significantly higher than that in DCP22DL3 group. Findings reveal that high dietary DCP level will reduce protein efficiency, and high DL level will cause plateauing period of growth performance. The suitable level of DCP for juvenile tilapia is 26%, and the level of lipid is 5%. The optimal DCP/DE is 19.18 mg/KJ.

  Effects of Dietary Methionine and Cystine on Growth Performance, Methionine Metabolism and Protein Metabolism of Asian Red-tailed Catfish (Hemibagrus Wyckioides) Zhang Xindang, Li Guangbin, Wang Qiumei, Sun Yan, Huang Han, Su Linhai, Li Biwei, Deng Junming 2021, 37 (20):  136-143.  DOI: 10.11924/j.issn.1000-6850.casb2020-0244 Abstract + ( 364 )   HTML ( 6 )   PDF ( 1312KB )   ( 31 ) Previous experimental results showed that adding 0~1.5% methionine in the basic diet (0.5% methionine) had no significant effect on growth and biochemical indexes of Asian red-tailed catfish (Hemibagrus wyckioides), which is contrary to the traditional animal nutrition theory. Four experimental diets were formulated by adding crystal amino acid in the basic diet, including control diet (Con), methionine deficiency diet (-Met), cysteine deficiency diet (-Cys) and methionine and cysteine deficiency diet (-(Met+Cys)), and thereby to determine whether methionine is the essential amino acid for Hemibagrus wyckioides. The results showed that: The weight gain, feed intake and protein efficiency ratio of fish fed Con and -Cys diets were significantly higher than those of fish fed -Met and -(Met+Cys) diets. Conversely, the feed conversion rate was lower in fish fed Con and -Cys diets compared to fish fed -Met and -(Met+Cys) diets. The hepatic lipase activity of fish fed -Met and -(Met+Cys) diets was significantly lower than that of fish fed the Con diet. The disaccharidase activity was significantly higher in fish fed -Cys diet compared to that in fish fed Con diet. The hepatic AMPD activity of fish fed Con diet was significantly lower than that of fish fed -(Met+Cys) diet. Conversely, the alanine aminotransferase activity of fish fed -(Met+Cys) diet was significantly higher than that of other fish fed diets. The MAT and CBS activities of fish fed -Met diet were significantly higher than those of other fish fed diets. The BHMT activity of fish fed -(Met+Cys) diet was significantly higher than that of fish fed Con and -Cys diets. These results indicate that the lack of methionine could decrease the growth, protein metabolism and antioxidant capacity of Hemibagrus wyckioides. Therefore, methionine is the essential amino acid for Hemibagrus wyckioides.

  Genetic Diversity and Genetic Structure of Coilia nasustaihuensis Population Based on Cyt b Gene in Jiangsu Province Li Daming, Tang Shengkai, Liu Yanshan, Gu Xiankun, Yin Jiawen, Jiang Qichen, Zhang Tongqing, Pan Jianlin 2021, 37 (20):  144-151.  DOI: 10.11924/j.issn.1000-6850.casb2020-0336 Abstract + ( 338 )   HTML ( 7 )   PDF ( 1511KB )   ( 400 ) To scientifically manage and rationally use the germplam resources of Coilia nasustaihuensis, it is necessary to understand its background. In the present study, the mitochondrial DNA cytochrome b (Cyt b) genes were amplified and sequenced from 224 C. nasustaihuensis specimens that were collected from six freshwater lakes (Lake Tai, Lake Ge, Lake Gaoyou, Lake Baima, Lake Hongze, Lake Luoma). The results showed that 62 polymorphic nucleotide sites and 57 haplotypes were detected among the Cyt b sequences of 224 individuals. The haplotype diversity (h) and nucleotide diversity (π) were 0.783±0.028 and 0.00260±0.00019, respectively. AMOVA analysis indicated that genetic variations between the populations from different lakes were mainly within the populations. Genetic differentiation index (Fst) suggested high genetic differentiation between Lake Ge population and the other five populations. The results of neutrality test showed that the values of Tajima’s D and Fu’s Fs were significant negative, and the mismatch distribution analysis map showed a peak type (except Lake Ge population), indicating that the other lake populations had undergone population expansion in evolutionary history, and the population expansion appeared in 0.12 Mya. The research indicates that the genetic diversity of C. nasustaihuensis of six lakes’ populations is abundant in Jiangsu province. The lake Ge population owns multiple specific haplotypes, and there are high genetic differences between Lake Ge population and the other populations. Therefore, the Lake Ge population and the populations of other five lakes should be managed and utilized as distinct evolutionarily significant units.

  Isolation, Identification and Virulence Gene Analysis of an Aeromonas hydrophila from Diseased Pelodiscus sinensis Xue Mingyang, Zhou Yong, Liang Hongwei, Li Xiang, Fan Yuding, Zeng Lingbing, Qu Chunjuan, Meng Yan 2021, 37 (20):  152-159.  DOI: 10.11924/j.issn.1000-6850.casb2020-0484 Abstract + ( 338 )   HTML ( 6 )   PDF ( 1447KB )   ( 56 ) The study aims to determine the pathogen causing disease in a Chinese soft-shelled turtle farm in Anhui Province, and provide reference for effective prevention and control of the disease in future production. The pathogenic bacteria were isolated from the moribund turtle with typical symptoms under aseptic condition, and then were identified by the morphological examination, biochemical analysis, and sequence analysis of bacterial 16S rDNA. The drug susceptibility test was conducted by Kirby-Bauer agar diffusion method, and the virulence genes of the pathogen were analyzed. The results showed that the pathogen was identified as Aeromonas hydrophila, called AM-1. Artificial infection showed that the typical symptoms of the disease could be replicated as the ones naturally occurred and this bacterium was of high pathogenicity to Chinese soft-shelled turtle. The drug resistance tests showed that the isolated pathogen was highly sensitive to enrofloxacin and levofloxacin, while extremely resistant to cotrimoxazole, ampicillin and tetracycline. The amplification results of 6 virulence genes showed that the isolated pathogen carried 5 virulence genes including aerolysin, heat-labile enterotoxin, heat-stable enterotoxin, hemolysin and elastase. This study indicates that Aeromonas hydrophila AM-1 is the pathogenic bacteria which could cause the deadly disease outbreak of the Chinese turtle. Enrofloxacin and levofloxacin can be used for treatment.

  Integrated Farming Mode of Rice-crayfish: Benefit Analysis and Technical Discussion Li Jie, Li Yan, Ji Meidi, Zhang Na 2021, 37 (20):  160-164.  DOI: 10.11924/j.issn.1000-6850.casb2020-0615 Abstract + ( 314 )   HTML ( 4 )   PDF ( 1119KB )   ( 103 ) The rice-crayfish farming mode is a typical kind of integrated rice-aquatic animal farming mode, which has played an important role in promoting the adjustment of agricultural structure and increasing the compound income of paddy field. On the basis of production and literature research, this paper analyzed the economic, social and ecological benefits of integrated rice-crayfish farming mode, and expounded its main technical problems. Based on the experimental demonstration and production practice, the green and efficient technical specifications for integrated rice-crayfish farming mode were put forward, including rice field selection, field works, preparations, juvenile crayfish releasing, raising management, adult crayfish catching, rice cultivation and field management after rice harvest, for the co-cultured of rice-crayfish during the whole course and catching crayfish only one season from May to June. The purpose of this paper is to provide technical references for the development of integrated rice-crayfish farming mode.