Table of Content

15 May 2022, Volume 24 Issue 5

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AGRICULTURAL INNOVATION FORUM

Research on the Global Innovation Layout and Competition Situation of Food Crop Bio-breeding Technology： Based on the Perspective of Core Patent Data Mining

Zunkang CUI, Danyang LI, Xiaoting XU, Junfeng ZHU, Laping WU, Wenge ZUO

2022, 24(5):  1-14.  DOI: 10.13304/j.nykjdb.2021.0518

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“To carry out the research of the ‘neck stuck’ technologies in the breeding field， and to make a good turn for the seed industry”， it is urgent to ascertain the current patent innovation layout and competitive situation in the field of food crop bio-breeding technology. According to the patent oriented industrial competitive intelligence analysis framework， based on the core patent data （not dincluding Hongkong， Aomen and Taiwan regions of China）， the global innovation layout and competition situation in the field of food crop bio-breeding technology were analyzed from 3 aspects of the overall environment， technology layout and institutional competition in this paper. The results showed that technological innovation in the field was very active， and the number of core patents in China was in the forefront， but there was still a big gap compared with the United States； North America， Europe and China were the main technology locations in the world， especially the United States. The patents of Chinese inventions were mainly located in China， and the global competitiveness was insufficient. Genome re-sequencing technology， molecular marker assisted breeding， resistance technology and hybridization technology were hot technologies in the field； Mutation or genetic engineering， methods of improving genotypes were “dominant-mature” technologies in the field， and all major countries had carried out special patent layouts in this field. China had a comparative advantage in the field of “emerging-growth” technology. The technology and market competition of multinational seed companies had covered major countries and regions in the world， and the technology layout had a wide range of topics. So our country urgently needed to foster local competitive R & D institutions with international competitiveness. Above results provided reference for the government and scientific research departments to formulate guidance policies for technological innovation in this field， to carry out forward-looking R & D layout and optimize competitive decision-making.

Temporal and Spatial Analysis of Total Factor Productivity of Double Cropping Rice in China and Its Countermeasures

Qionghua LI, Lin ZHANG, Xinru HAN, Lili SONG

2022, 24(5):  15-23.  DOI: 10.13304/j.nykjdb.2021.0512

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Double cropping rice plays an important role in ensuring food security in China. Based on estimation method of total quantity total factor productivity （TFP）， the annual data of 9 major double cropping rice producing provinces in China were used to estimate the variation of TFP and its decomposition index of double cropping rice in China from 2004 to 2018. It was found that the TFP of early Indica rice and late Indica rice in China from 2004 to 2018 was 1.081 and 0.931， respectively. The total factor productivity increased slightly from 2004 to 2008 and from 2014 to 2018， but showed a wavelike decrease from 2009 to 2013. The increase of TFP of double cropping rice was mainly attributed to the contribution of technological progress and scale expansion. Among the dominant production areas of double cropping rice， the TFP index of double cropping rice in the Yangtze River basin was higher than that in the southeast coast， among which the expansion of the scale played a decisive role. Therefore， this paper suggested that the regional advantages should be utilized， promote the large-scale production of double-cropping rice， increase the adoption rate of superior varieties and the level of mechanization， ensure the basic income from rice planting， mobilize the enthusiasm of farmers， and further safeguard national food security.

BIOTECHNOLOGY & LIFE SCIENCE

Drought Resistance Regulated by Allelic Variations of ZmSNAC13 in Maize

Ming CHENG, Ying ZHU, Xiaonan WANG, Ping LUO, Yong CHEN, Zhuanfang HAO, Zhangying XI

2022, 24(5):  24-31.  DOI: 10.13304/j.nykjdb.2021.0213

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NAC family is a class of plant specific transcription factors， which has important biological functions in plant growth and development， stress response and hormone regulation. A NAC transcription factor gene， namedas ZmSNAC13， was selected from differentially expressed genes under drought stress by RNA-Seq. In order to clarify the role of ZmSNAC13 in response to drought stress， maize inbred lines B73 （drought sensitive） and Qi319 （drought tolerant） with different drought tolerance were used as materials， qRT-PCR analysis showed that the expression of ZmSNAC13 was down regulated in roots of 2 materials， up regulated in stems and leaves of Qi319 after 12 d of drought treatment， down regulated in leaves of B73 after 8 and 10 d of drought treatment， indicating that ZmSNAC13 responded to drought stress. The promoter activity of ZmSNAC13 under ABA treatment was analyzed by dual-luciferase fusion reporter vector. The results showed that the promoter activity of ZmSNAC13 in Qi319 was significantly higher than that in B73 under ABA treatment， furthermore， 9 highly linked variants in 5’-UTR region of ZmSNAC13 in Qi319 were found to improve the promoter activity. Moreover， the expression of ZmSNAC13 in Qi319 leaves was higher than that in B73 after 12 d of drought treatment. It was speculated that genetic allelic variations in 5’- UTR region of ZmSNAC13 affected promoter activity， and then controlled gene expression level， and ultimately regulated the adaptability of maize to drought. Above results laid foundations for understanding the genetic mechanism of drought resistance in maize.

Physiological Responses of Different Quinoa Varieties to Salt Stress and Evaluation of Salt Tolerance in Yili Valley

Hongliang CUI, Xiaoxiao SONG, Qing YAO, Wangang AN, Bao XING, Peiyou QIN

2022, 24(5):  32-45.  DOI: 10.13304/j.nykjdb.2020.1074

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In order to study the physiological responses of quinoa plants to salt stress and to evaluate salt tolerance among different quinoa varieties in Yili Valley， seeds and seedlings of different quinoa varieties were treated with NaCl solution of 50， 100， 150， 200， 250， 300， 350， 400 mmol·L^-1 respectively. The results showed that as the concentration of NaCl increased， the germination rate， germination energy of seeds， dry and fresh weight of the underground part， chlorophyll content， SOD activity， soluble sugar content of the seedlings， all first increased and then decreased. The relative electrical conductivity， proline， MDA， Na⁺ and soluble sugar content in leaves of seedling were continuously increased， but the content of cellulose， K⁺， dry and fresh weight of the aboveground parts decreased. It indicated that quinoa seedlings could resist salt stress by increasing osmotic substance content and root absorption area， enhancing SOD activity and other self-protective mechanisms under NaCl stress. Quinoa varieties of NXSG85 and NXSG56 were more salt-tolerant than others but QA13-9 more sensitive to NaCl stress.

Evaluation and Screening of Salt and Alkali Tolerance Indices of Upland Cotton Seedlings

Yajie HUANG, Dan REN, Shengmei LI, Jinxin CUI, Tao YANG, Jiaojiao REN, Wenwei GAO

2022, 24(5):  46-55.  DOI: 10.13304/j.nykjdb.2021.0085

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In order to comprehensively evaluate the salt-alkali tolerance of upland cotton and screen out the key identification indexes， 90 cotton varieties from different origins were as materials. The salt tolerances of 90 varieties were evaluated by principal component analysis， cluster analysis and stepwise regression， and the key identification indicators were screened. The results showed that the hypocotyl lengths， plant height， number of leaves， leaf area of the first true leaf of cotton at seedling stage decreased under stress， while the emergence rate and SPAD value increased. Plant height significantly positively correlated with seedling emergence rate， and extremely significantly positively correlated with hypocotyl length， leaf number and first true leaf area. According to the D values， Junmian 1 was the highest with the strongest saline-alkaline tolerance， while Zhongmiansuo 49 was the lowest with the worst saline-alkaline tolerance. And 90 varieties were classified into 4 groups including 3 varieties with strong saline-alkali resistant， 18 varieties with medium saline-alkali resistant， 52 varieties with weak saline-alkali resistant and 17 varieties with salt sensitive. According to the optimal regression equation， emergence rate， SPAD value， leaf area of the first true leaf and plant height were selected for identifying salt tolerance of cotton， which should provide theoretical basis for the preliminary identification of salt and alkali resistance of cotton.

Evaluation of Flax Germplasm Phenotype

Liuxi YI, Rula SA, Xin FAN, Can ZHAO, Ru LI, Bateer SIQIN

2022, 24(5):  56-67.  DOI: 10.13304/j.nykjdb.2021.0666

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In order to deeply understand the genetic variation of main quality and agronomic traits of oil flax， 253 oil flax germplasms were selected as the research materials. 14 traits such as days of sowing to seed maturity， plant height， stem lenght， capsule number per plant， seeds of per capsule， seeds weight per plant， 1 000-seed weight， branch number and contents of palmitic acid， stearic acid， oleic acid， linoleic acid， linolenic acid， oil content were repeatedly detected in three environments including Hohhot （HO）， Jining （JN） and Ximeng Taipusi Banner （XM）. The results showed that the variation coefficients of 8 agronomic characters were from 5.66% to 42.65%， and the variation coefficients of 6 quality traits were from 4.10% to 30.14%. The days of sowing to seed maturity in XM was the longest with 112.51 d； 1 000-seed weight and seeds weight per plant in JN area were the largest with 5.94 and 0.55 g， respectively； the seeds per capsule and the capsule number per plant in HO were the most with 5.65 and 16.90， respectively； the contents of crude fat and linolenic acid in XM were the highest with 39.53% and 53.45%， respectively； the contents of linoleic acid and palmitic acid in JN area were the highest with 16.41% and 5.09%， respectively； the contents of oleic acid and stearic acid in HO were the highest with 24.03% and 8.31%， respectively. 253 oil flax germplasms were divided into 4 groups， and oil flax germplasm from the same geographical source were clustered into the same group， which provided a scientific basis for the collection， preservation and reproduction of oil flax germplasm resources.

Genetic Diversity Analysis of Different Characteristics of Sweetpotato Varieties by ISSR Molecular Marker

Chenke CUI, Tao LIN, Yanbo AN, Peng CUI

2022, 24(5):  68-75.  DOI: 10.13304/j.nykjdb.2021.0078

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To broaden the genetic background and screen the excellent parents of sweetpotato cultivars， the genetic diversity of 37 sweetpotato from China were assessed by ISSR markers in this study. The results indicated that 19 highly efficient amplification primers were selected from 100 primers， and 118 of the total 115 bands amplified showed polymorphisms. The mean frequency of polymorphism was 97.50%. The genetic distance among the 37 varieties floated from 0.04 to 0.36. The genetic distance between Taishu 66 and Hongdong was the smallest （0.04）. Ziluolan （ornamental type） and Xuzishu 8 （anthocyanin process type） were clustered in the same group. Anthocyanin process type had the largest genetic distance to vegetable and fruit type （0.43 and 0.40， respectively）， which was the smallest nearest （0.08） to ornamental type. The fruit type was far from other types （>0.30）， however， the genetic distance between edible type and other types showed the opposite trend. The genetic relationships of different sweetpotato varieties were analyzed in this study. Related to these morphological markers，these 37 germplasm accessions could be clarified by ISSR. The molecular markers showed advantage in analysis of the genetic relationship among sweetpotato germplasm resources of different types. These results could provide reference for parents’ selection of varieties for different purposes.

Effects of Pre­harvest Red and Blue Continuous Light Intensity on Growth， Quality and AsA Metabolism of Hydroponics Lettuce

Jiayuan LIU, Yubin ZHANG, Wenke LIU

2022, 24(5):  76-84.  DOI: 10.13304/j.nykjdb.2020.1008

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In order to explore the effects of continuous light of LED red （R） blue （B） light on the growth and ascorbic acid （AsA） metabolism of lettuce （Lactucasativa L.） before harvesting， a red and blue LED （R∶B=4∶1） was used in a closed plant factory as the light source. Before harvesting， the hydroponic lettuce was subjected to 72 h continuous illumination with light intensity of 100， 150， 200， 300 and 500 μmol·m^-2·s^-1. The effect of front continuous light intensity on the growth， quality， AsA content and key enzyme activities of hydroponic lettuce. The results showed that： from the perspective of yield， with the increase of the continuous light intensity before harvest， the fresh weight and dry weight of the above ground of the lettuce increased， the fresh weight and dry weight of the root increased， and the leaf area and dry matter content of the lettuce both increased significantly， and the yield of lettuce had gradually increased. From quality point， the soluble sugar content in lettuce leaf increased with the continuous light intensity， and the nitrate content gradually decreased with the light intensity. After the LED continuous light treatment before harvest， as the continuous light intensity increased， the AsA content in the lettuce leaf gradually increased， and the DHA content in the lettuce leaves increased first and then decreased.

Effects of Three Bacillus Agents on Seedling Growth of Flue-cured Tobacco

Yuqin XIAO, Xiao LEI, Mingjin ZHANG, Yuangai ZHANG, Shan TANG, Hongfei JI, Chuan WANG, Cuiling MA, Yanqiu JING

2022, 24(5):  85-92.  DOI: 10.13304/j.nykjdb.2021.0559

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In order to further understand the effects of microbial agents on the growth and development of root in tobacco seedling period，3 microbial agents including Brevibacilluslaterosporus， Bacillussubtilis and Bacilluslicheniformis were added into the floating seedling nutrient solution. Agronomic traits， root activity， antioxidant enzymes and chemical composition of tobacco leaves after transplantation were determined. The results showed that application of microbial agents had significant effects on agronomic traits， root activity， antioxidant enzymes and chemical components of flue-cured tobacco. Compared with CK， Brevibacilluslaterosporus increased the root fresh weight， root length， root surface area and volume of tobacco seedling， improved the activities of SOD， POD and CAT， significantly enhanced the root activity， increased the soluble protein content， reduced the MDA content， and made the leaf tobacco chemical composition more harmonious. So， Brevibacilluslaterosporus was recommended as adding microbial agents into the nutrient solution of floating tobacco seedlings， which should promote the root development of tobacco seedlings. The application of Brevibacilluslaterosporus could significantly enhance the activity of protective enzymes in the roots of tobacco seedlings， thus improve the growth and development of tobacco roots， cultivate strong seedlings and improve the quality of tobacco leaves.

INTELLIGENT AGRICULTURE & AGRICULTURAL MACHINERY

CFD-DEM Simulation of Paddy Drying in Lifting Screw Conveyor of Harvester

Pinglu CHEN, Shihua XIAO, Jing XU, Muhua LIU

2022, 24(5):  93-101.  DOI: 10.13304/j.nykjdb.2021.0056

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In order to prevent the newly harvested paddy from mildewing due to the high moisture content， a method of direct drying paddy in lifting screw conveyor of combine harvester was proposed by combining far infrared and hot air. The internal heating scheme of installing the infrared heater in the center of the screw conveyor and the external heating scheme of setting the infrared heater on the outer of the screw conveyor were designed. The paddy movement， heat and mass transfer process and fluid flow in the screw conveyor were simulated by coupling method of discrete element methodologies （DEM） and computational fluid dynamics （CFD）. The simulation results were verified by the paddy drying experiment of external heating scheme. The results showed that： the variation trends of simulated and experimental values were consistent and the maximum relative error between the simulated and experimental value was 8.34%， which meaned that the simulation method was acceptable； under different conditions of screw conveyor rotate speed， hot air temperature， hot air speed and feed rate， the dehydration rate of the external heating scheme was at least 2.91% faster than those of the internal one， which showed that the drying effect of the external heating scheme was better than that of the internal one； the increasing temperature of the paddy decreased with the increase of the screw conveyor rotate speed， hot air speed and feeding amount， while increased with the increase of the hot air temperature； the paddy dehydration rate decreased with the increase of the screw conveyor rotate speed and feed rate， and increased with the increase of the hot air temperature and hot air speed. Above results provided theoretical basis for the design and optimization of drying paddy in lifting screw conveyor of combine harvester.

Research on Compression Mechanical Characteristics of Sorghum Grains

Yu FENG, Shujin QIU, Xiangyang YUAN, Qingliang CUI, Zhiqiang JI

2022, 24(5):  102-110.  DOI: 10.13304/j.nykjdb.2021.0615

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In order to investigate the mechanical damage of sorghum grain during sowing， harvesting， storage， transportation and processing， this paper studied the compression mechanical properties of sorghum grains. The grains of 3 sorghum varieties， Jinza 34， Liaoza 37 and Xingxiangliang 2 were selected. The varieties， moisture content and compression direction were used as the test factors to study the influence on compression deformation， yield load， and damage energy. The results showed that： variety， moisture content and compression direction had significant effects on the compression deformation， yield load， and damage energy of sorghum grains （P<0.000 1）. With the moisture content increased， the yield load showed a downward trend， the compression deformation and the damage energy showed a trend of first decreasing and then increasing. Under the same moisture content， the compression deformation， yield load， and damage energy corresponding to the Z axis direction of 3 varieties of sorghum grains were the largest， followed by the Y axis direction， and the X axis direction was the smallest. Above results provided theoretical references for the development and optimization of equipment for sowing， harvesting， storage and transportation of sorghum.

Research and Application of Intelligent Recognition Method of Peach Tree Diseases Based on AI

Jianwei WU, Jie HUANG, Xiaofei XIONG, Han GAO, Xiangyang QIN

2022, 24(5):  111-118.  DOI: 10.13304/j.nykjdb.2021.0935

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In order to solve the problems of low efficiency， high cost and low accuracy of traditional methods of manually identifying peach tree diseases， an intelligent recognition method of peach tree diseases based on AI deep learning was proposed. Using and fine-tuning the DenseNet-169 classification model pre-trained by ImageNet， data preprocessing and model training were performed on the image of 11 common diseases of peach trees， then the web terminal was built to integrate and develop a software system for intelligent recognition of peach tree diseases. The average recognition rate of these 11 peach tree diseases was over 91% by this method. Using image recognition technology to automatically identify peach tree diseases， combined with modern science and technology such as image processing， deep learning， data mining and analysis， the intelligent diagnosis and prevention suggestions for peach tree diseases were realized. This proposed method could reduce labor costs， simplify operations， and improve recognition efficiency， so it was conducive to timely diagnosis and decision-making for prevention and treatment of diseases. Therefore， this research had important significance and application value for promoting the intelligent management of orchard disease controling， and provided support for the research and practice of image recognition methods based on deep learning with small sample sets.

Parameter Calibration of Radish Seeds with Different Filling Particle Radius by DEM

Jianwei YAN, Song WEI, Dongjun HU, Qihe LIU, Fuigui ZHANG

2022, 24(5):  119-128.  DOI: 10.13304/j.nykjdb.2021.0363

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When using EDEM and FLUENT to simulate the seeding process of radish seed metering device， the parameters and the model of radish seed directly affect the reliability of the simulation results. 2 main contact parameters of white radish seed-organic glass static friction and inter-seed static friction were calibrated according to the actual and simulated packing experiment of white radish seed. In this paper， the discrete element models of radish particles with different filling diameters were established by using the automatic filling method. Plackett-Burman test was used to analyze the influence parameters of material characteristics. The results showed that the static friction of white radish seed-organic glass and the static friction of white radish seed-organic glass had significant effect on the stacking angle. Based on the bench test and the simulation stacking test， the binary regression model of 2 main contact parameters and stacking angle was established， the static friction coefficient between seeds and organic glass and the static friction coefficient between seeds of turnip with different filling radius were obtained. According to the relative error rate of stacking angle and the simulation time， the best filling radius of spherical particles was analyzed. The results showed that when the filling radius of radish seed dem was 0.25 mm， the simulation precision and the simulation time were the best. The best model of filling pellet and the calibrated contact parameters could provide some references for the related research of seed metering device of white radish.

ANIMAL AND PLANT HEALTH

Community Structure of Stem-based Fungi Infected with Adzuki Bean and Mung Bean

Hongyan ZHAO, Junwei TAN, Jie ZHANG, Haonan CHEN, Chunxu WANG, Di ZHAO, Haipeng LI, Lixia ZHU, Yiqiang HAN

2022, 24(5):  129-136.  DOI: 10.13304/j.nykjdb.2021.0324

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To understand the fungal composition of the stem base susceptible parts of adzio bean and mung bean， the fungal community in basal susceptible parts of adzabella and mung bean stems were sequenced by Illumina high-throughput sequencing. The results showed that a total of 231 operational taxonomic units （OTUs） were obtained from 6 samples of adzio bean and mung bean， and the common OTUs were 97. In fungal compositions of the stem base susceptible parts of adzio bean and mung bean， Ascomycota was the common dominant phylum， Sordariomycetes was the common dominant class， Hypocreales was the common dominant order， Nectriaceae was the common dominant family. And Fusarium was the common dominant genus， and the relative abundances in adzio bean and mung bean were 32.94% and 18.38%， respectively. The results of Alpha diversity showed that the abundance of fungal community in susceptible stems of mung bean was higher than that of adzola bean， and the diversities of fungal community in adzio bean and mung bean were similar， which provided a theoretical basis for further study the pathogenic mechanism of fungal communities in the stem susceptible parts of adzio bean and mung bean.

Identification and Biological Characteristics of the Pathogen Causing Root Rot of Atractylodes chinensis

Jiahuan HUO, Xiaolei WEN, Shuangmin LI, Lina FENG, Shuhui LAN, Lixin DONG, Sirou GUO, Jianing LI, Jianhua WANG, Huixia QI

2022, 24(5):  137-144.  DOI: 10.13304/j.nykjdb.2021.0468

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Root rot seriously affects the production of Atractylodes chinensi，which occurrs from seedling to mature periods. In order to clarify the pathogen causing Atractylodis chinensi root rot in Qinhuangdao area of Hebei Province， tissue isolation， morphological and molecular biological identification were used to isolate and identify the pathogen， and the pathogenicity was identified. At the same time， the effects of temperature， nitrogen source and carbon source on the growth of the pathogen and the lethal temperature of the mycelium were analyzed. The results showed that the pathogen causing root rot of Atractylodis chinensi in Qinhuangdao area was Fusarium oxysporum （MK849925）. The colony of the pathogen on PDA medium was nearly round， radial， villous， pink purple and dry. Mycelium lateral branched with septum， the conidia were all colorless and the large conidia were acuminate sickle with 1~5 septations， the small conidia were mostly oval with 1~2 septations. The chlamydospores were round and colorless. Its pathogenicity was strong， and the disease showed dark brown dehydration dry after inoculation for 10 d. The pathogen grew better at 25 ℃ and on the medium with yeast extract powder as the nitrogen source. After 5 d culture， the colony diameter reached 7.17 cm. Among different carbon sources， the utilization rates of glucose and sucrose were high， while the utilization rate of soluble starch was low. The mycelium lost its vitality after treated at 75 ℃ for 10 min.

BIO-MANUFACTURING & RESOURCE AND ECOLOGY

Observation Analysis on Atmospheric Turbulence Characteristics Over A Small Fish Pond

Zhihao QIN, Wei WANG, Wei XIAO, Ning HU, Mi ZHANG, Jiayu ZHAO, Chengyu XIE

2022, 24(5):  145-156.  DOI: 10.13304/j.nykjdb.2021.0082

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To understand the atmospheric turbulence characteristics and evaluate the performance of eddy covariance for measuring fluxes at a small fish pond， this study investigated the atmospheric stability， variance similarity， power spectra and cospectrum， turbulence intensity and turbulence kinetic energy， based on eddy covariance and micrometeorological observations in 2018 at a small fish pond in Guandu Village， Quanjiao County， Chuzhou City， Anhui Province， this study investigated the atmospheric stability， variance similarity， power spectra and cospectrum， turbulence intensity and turbulence kinetic energy. The results showed that atmospheric instability prevailed over the small fish pond. Atmosphere kept unstable in about 21 h during 1 d. Monin-Obukhov similarity theory was applicable to the agricultural breeding pond. The relationship between normalized standard deviations of three wind speed components and stability parameter followed the 1/3 power law. The fitting was better under unstable conditions， especially for vertical wind speed. Similarly， normalized standard deviations of temperature and water vapor density followed the -1/3 power law under unstable condition. The normalized power spectra of three wind speed components followed the -2/3 power law in the inertial subrange. The cospectrum of vertical wind speed and temperature， water vapor， CO₂ density followed -4/3 power law in the inertial subrange. The eddy covariance system could be used to observe sensible heat， latent heat and CO₂ fluxes on the fish pond. Over this fish pond， turbulence intensity decreased with wind speed faster than that over large lakes. It approached a constant when wind speed larger than 1 m·s^-1. Turbulence intensity of horizontal wind components were larger than that of vertical wind speed. Turbulence kinetic energy over the fish pond was mainly produced by wind shearing and reached a maximum of 3.0 m²·s^-2 under neutral condition， and it increased with wind speed quadratically， the strongest and lowest turbulence kinetic energy was observed around noon time and midnight， respectively. The results of this study provided a theory base for clarifying the characteristics of atmospheric turbulence on small water bodies and the mechanism of energy and mass exchange between small agricultural ponds and atmosphere.

Effect of Emitter Spacing on Nitrogen Transport Characteristics of Intersecting Two Point Sources in Bubbled-root Irrigation

Zhenjia HE, Tongle SHI, Yuliang FU, Liangjun FEI

2022, 24(5):  157-169.  DOI: 10.13304/j.nykjdb.2021.0107

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In order to optimize the relevant technical elements of the bubbled-root irrigation， a dual-point source intersection infiltration test was carried out at Yuanzhishan experimental station of Northwest A&F University to study the influence of different irrigator spacing on the characteristics of the wet body and the law of water and nitrogen transport. Three levels of irrigator spacing （40， 50， and 60 cm） were set in this experiment， the mass concentration of fertilizer solution was 10 g·L^-1， and the flow rate of bubbled-root irrigation irrigator was 5 L·h^-1， the effects of different distance of irrigators on the infiltration characteristics of fertilizer solution， the migration law of wetting front， soil moisture， and distribution characteristics of ammonium nitrogen （NH{}_{\mathrm{4}}^{+}-N） and nitrate nitrogen （NO{}_{\mathrm{3}}^{-}-N）. The research showed that the cumulative infiltration amount and the increased infiltration amount of free infiltration and intersection infiltration under different conditions of the bubbled-root irrigation or the distance of the wetting front in different directions of the bubbled-root irrigation， which all had a positive proportional power function relationship with the distance between irrigators （R²>0.9， P<0.01）. The larger the distance between the irrigators， the smaller the migration distance of the wetting front moving upward and downward on the intersection surface （P<0.05）， and the reduction of soil moisture content on the infiltration side of the intersection was smaller than that on the free infiltration side， the larger the distance between the irrigators， the lower the wetness degree of the intersection surface （P<0.05）. Under the condition of free infiltration， the greater the distance from the water outlet of the irrigator， the decrease of NH{}_{\mathrm{4}}^{+}-N content was more significant （P<0.05）， while the decrease of NH{}_{\mathrm{4}}^{+}-N content on the convergent infiltration side was smaller than that on the free infiltration side. The NO{}_{\mathrm{3}}^{-}-N content varies greatly at different times and positions. After irrigation， the NO{}_{\mathrm{3}}^{-}-N content of the surface soil in the humid area decreased slightly. The longer the water distribution time， the higher the NO{}_{\mathrm{3}}^{-}-N content at different soil depths （P<0.05）. A mathematical model of the cumulative infiltration volume of the bubbled-root irrigation intersection infiltration， the migration distance of the wetting front with time and the distance of the emitters was established. The model parameters K and α， which varied with the distance of the irrigators in a power function relationship， and the value of K decreased with the increase of the distance， while the value of α increased with the increase of the distance. The relationship model about soil moisture content， NH{}_{\mathrm{4}}^{+}-N， NO{}_{\mathrm{3}}^{-}-N contents and the distance of the irrigators was established， and the soil moisture content， soil NH{}_{\mathrm{4}}^{+}-N and NO{}_{\mathrm{3}}^{-}-N contents at any point from the infiltration soil to the distance r from the irrigator center were quantitatively estimated， and the deviation of the estimation results was within ±10%. The results laid a scientific foundation for the further improvement of the water-saving irrigation technology of the bubbled-root irrigation.

Effects of Nitrogen Topdressing on Yield and Photosynthetic Fluorescence Characteristics of Different Forage Oat Varieties

Xin WANG, Yuxia ZHANG, Weidong CHEN, Congying LIN, Wenhui HOU, Guleng SIRI, Baiming CONG

2022, 24(5):  170-179.  DOI: 10.13304/j.nykjdb.2021.0067

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In order to explore the response of yield， chloroplast content， fluorescence characteristics and photosynthetic characteristics of different forage oat varieties to nitrogen application， taking forage oat varieties suitable for planting in Kerqin sandwishes as materials， this paper studied the effect of nitrogen fertilizer on photosynthetic physiological characterics and yield of oat. Using randomized block experiment design， 4 main planting forage oat vaieties planted in the Kerqin sandwishes， Yanwang， Muwang， Tianyan 1 and Mulesi， 0（N0，CK）、100（N100）、200（N200）、300 kg·hm^-2 （N300） nitrogen fertilizer （pure N） were applied according to the proportion of 15%， 40%， 25%， 20% at the tillering stage， jointing stage， heading stage and flowering stage of oats， respectively. Chlorophyll content， carotenoid content， fluorescence parameter index and photosynthetic index were measured at grain filling stage， and yield was measured at maturity stage. Yanwang and Muwang had the highest yield under N200 nitrogen application level， which were low nitrogen and high efficiency forage oat varieties； Tianyan 1 and Mulesi had the highest yield under N300 nitrogen application level， which were high nitrogen and high efficiency forage oat varieties. With the increase of nitrogen application level， the chlorophyll content， potential photochemical efficiency （F_v/F_m）， actual photochemical efficiency （ΦPSⅡ）， photochemical quenching coefficient （qP）， net photosynthetic rate （P_n）， stomatal conductance （G_s）， transpiration rate （T_r） of different forage oat varieties showed a trend of increasing first and then decreasing or increasing. The NPQ and C_i showed opposite trends with the increase of fertilization amount. Yield was significant positively correlated with chlorophyll a， chlorophyll b， F_v /F_m （P<0.01）， extremely significant negatively correlated with NPQ （P<0.01）， significantly positively correlated with T_r （P<0.05）， but there was no significant correlation with carotenoid content， ΦPSⅡ， qP， P_n， G_s and C_i（P>0.05）. Nitrogen fertilizers could increase yield by increasing chlorophyll content， enhancing F_v /F_m， reducing NPQ， and improving photosynthetic performance， so as to achieve the purpose of increasing production.

Effect of Glyphosate on Soil Nutrient and the Functional Enzyme Activities in Soybean Fields

Kuiyuan CHEN, Hui LIU, Wei DING

2022, 24(5):  180-188.  DOI: 10.13304/j.nykjdb.2021.0781

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To investigate the effects of glyphosate on soil nutrients and the functional enzyme activities in soybean fields， this paper investigated the effect of 1.2， 2.4 and 3.6 kg·hm^-2 of glyphosate on soil nitrogen（N）， phosphorus（P）， potassium （K） and the functional enzyme activities in soybean fields using a field experiment with transgenic glyphosate-resistant soybean Hujiao 06-698 as material. The results of 2 years of trials showed that the content of soil alkaline nitrogen and available phosphorus， and the enzyme activities of urease， cellulase， phosphatase and nodule nitrogenase activities were significantly reduced with peaks of 10.57%， 11.30%， 67.66%， 40.62%， 45.88% and 74.49%， respectively， and catalase activity was significantly increased with peaks of 131.93% in the two years in soybean fields at 2.4 kg·hm^-2 and 3.6 kg·hm^-2 of glyphosate use rate， while available potassium content was not affected by glyphosate. However， this effect gradually returned to normal with time the extension of time after glyphosate application and did not bring adverse effect on soil nutrients and the functional enzyme activities for a long time. The soil quality analyzed by principal component and integrated evaluation methods with soil N， P and K nutrients and the functional enzyme activities as the main components was higher than that of CK at 2.4 kg·hm^-2 and 3.6 kg·hm^-2 of glyphosate use rate.The results of the research can provide a theoretical basis for sustainable utilization of farmland ecosystem and commercial planting of transgenic glyphosate-resistant soybeans.

Effects of Organic Fertilizer and Calcium Fertilizer on Peanut Rhizosphere Bacterial Community Structure in Saline-alkali Soil

Liangxiang DAI, Guanchu ZHANG, Hong DING, Yang XU, Zhimeng ZHANG

2022, 24(5):  189-201.  DOI: 10.13304/j.nykjdb.2021.0119

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To Study the effects of organic fertilizer and calcium fertilizer on the microbial community structure and function in the peanut rhizosphere of saline-alkali soils， the peanut rhizosphere soils with different salinity contents （slightly and severely saline-alkali soils） were performed experiments with control （no fertilization， CK）， calcium fertilizer （C）， organic fertilizer （M） and organic fertilizer+calcium fertilizer （CM）. Then the peanut rhizosphere soils were used to extract DNA for constructing bacterial 16S rRNA gene library， and high-throughput sequencing was performed for sequencing and bioinformatics analysis. The results showed that the application of organic fertilizer， calcium fertilizer and the combination of organic fertilizer and calcium fertilizer had significant effects on the diversity and richness of rhizosphere microbes in slightly saline-alkali soil， but had no significant effects in severely saline-alkali soil. PCoA analysis showed that the OTUs diversity was closely related to the salinity contents of soil， and the structure of the rhizosphere microbial community treated with calcium fertilizer was significantly different from those of other treatments. The rhizosphere microbial structures of the two kinds of coastal saline soils were affected by organic fertilizer， calcium fertilizer and the combination of organic fertilizer and calcium fertilizer. The dominant bacterial communities of different treatments were similar， while the relative abundances of dominant bacterial communities were difference in different treatments. On the order and family levels， OTUs of new species accounted for 76.3%~82.5% of the total bacteria， which indicated the rhizosphere in the coastal saline soil of the Yellow River Delta contained a large number of new microbial species resources. The analysis of 16S rRNA function prediction indicated that the application of organic fertilizer， calcium fertilizer and the combination of organic fertilizer and calcium fertilizer increased the abundances of genes on carbohydrate transport and metabolism， amino acid metabolism， energy production and conversion， metabolism of cofactors and vitamins， nucleotide metabolism， translation and membrane transport. In conclusion， the application of calcium fertilizer and organic fertilizer could be beneficial to improve the rhizosphere microecological environment of saline-alkali soil and enhance plant stress tolerance.

Effects of Straw Mulching on Shallow Water Soil on Alleviating Soil Salinization and Growth of Aquatic Vegetables

Hui LIU, Jiezeng JIANG, Hao ZHANG, Yongxian ZHANG, Jiayu QIAN, Dongsheng LI, Yan LYU, Huanrui WU

2022, 24(5):  202-208.  DOI: 10.13304/j.nykjdb.2021.0362

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In order to explore the effects of straw mulching in shallow water on mitigation of soil salinization and growth of water spinach， 5 treatments were set useing a plastic cultivation box with a nitrate nitrogen content of more than 1 200 mg·kg^-1 to grow water spinach in the greenhouse， which included 150 g （7 500 kg·hm^-2） rice straw with 5 cm （R150₅），150 g （7 500 kg·hm^-2） wheat straw with 40 cm （W150₄₀），150 g （7 500 kg·hm^-2） whole wheat stalk （W150）， 300 g （15 000 kg·hm^-2） wheat stalk with 10 cm （W300₁₀） and no mulching straw （CK）. The contents of soil nitrate nitrogen， organic carbon， total nitrogen， total phosphorus， total potassium， and water spinach yield and quality were determined. The results showed that the contents of soil nitrate nitrogen in straw mulching treatments were significantly lower than that of CK， and the decrease ranges were all above 50%. Except for W300₁₀ treatment， the soil organic carbon contents in the other treatments all decreased， but the decrease ranges were smaller than that of CK. The contents of available potassium in the soil of straw mulching treatments increased except for the W150₄₀ treatment. The total yields of water spinach in straw mulching treatments were higher than that of CK， and the R150₅ treatment showed higher yield. In conclusion， straw mulching in shallow water could alleviate soil salinization， increase the contents of soil organic carbon and available potassium， and significantly increase the yield of water spinach.

Analysis of Bacterial Diversity in the Rhizosphere Soil of Salsolapasserina and Its Correlation with the Soil Physical and Chemical Properties

Yanchen WEI, Jixiang CHEN, Yonggang WANG, Tongtong MENG, Yalong HAN, Mei LI

2022, 24(5):  209-217.  DOI: 10.13304/j.nykjdb.2021.0015

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In order to understand the ecological adaptation mechanism of Salsolapasserina， high-throughput sequencing of bacterial 16S rDNA， pure culture and fluorescence staining laser confocal microscope counting methods were used to study the bacterial groups in the rhizosphere soil of Salsolapasserina and their correlation with soil physical and chemical properties in Jingtai desert steppe of Gansu Province. The results showed that the number of OUTs in the rhizosphere soil was 5 655， while that of non-rhizosphere soil was 4 665， and the bacterial diversity of the rhizosphere soil was significantly higher than that of the non-rhizosphere soil. The numbers of cultivable bacteria and the total bacteria in rhizosphere soil were 1.62×10⁶ CFU·g^-1 and 1.33×10⁷·g^-1，^{respectively， which were higher than those in non-rhizosphere soil （5.40×105 CFU·g-1 and 1.12×107·g-1）. The dominant phyla included Actinobacteria， Planctomycetes， Proteobacteria， Gemmatimonadetes， Acidobacteria， Chloroflexi， Bacteroidetes， Firmicutes and Verrucomicrobia， which accounted for 97.7% of the total number of bacteria. The dominant genera were Rubrobacter， RB41， Nocardioides， Streptomyce， Pir4_lineage， Bacillus， Solirubrobacter， Gemmatimonas and Pirellula. The correlation analysis of the main flora and soil factors showed that the soil physical and chemical properties were the key determinants affecting the composition of soil bacterial community.}