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    15 July 2023, Volume 25 Issue 7
    AGRICULTURAL INNOVATION FORUM
    Recent Advances in Sensor Technology of Modern Poultry Production
    Xing LI, Ning ZHAO, Yong JIANG, Zhixiu WANG, Guohong CHEN, Hao BAI, Guobin CHANG
    2023, 25(7):  1-11.  DOI: 10.13304/j.nykjdb.2022.0247
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    Poultry industry is the second largest industry of animal husbandry and plays an important role in the development of animal husbandry. The fine farming of poultry is gradually gaining attention in recent years, and timely and effectively obtaining information on individual poultry body temperature, behaviour, movement posture and physiology and other indicators through effective means has become the focus of fine poultry farming. This paper expounded the research and application of sensors in poultry growth physiology, and mainly from the aspects of poultry breeding environment, body temperature, behavior and physiological indicators, and summarized the research and application of sensors in poulty production at home and abroad in recent years, put forward the problems existing in the field of sensors, and the prospect of comprehensive and efficient application of sensors in poultry breeding in the future.

    BIOTECHNOLOGY & LIFE SCIENCE
    Research Advances on Plant Root Exudates in Response to Cadmium Stress
    Xiang WU, Juan LI, Yan CAO, Yanrong CHENG, Xuyu YAN, Ling LI
    2023, 25(7):  12-20.  DOI: 10.13304/j.nykjdb.2022.0619
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    With the rapid development of industry and agriculture and the the casual discharge of waste, heavy metal pollution has been serious in farmland soil. Cadmium (Cd) pollution is more serious in heavy metal pollution. The technology of in situ remediation by hyperaccumulative plants is the main means to remediate cadmium and other heavy metal pollution. Root is the first part of plants to contact with heavy metals such as Cd. As an important carrier, root exudates can conduct material exchange and energy transfer between plants, soil and microorganisms, and it can effectively regulate the rhizosphere microenvironment, affect the behavior of heavy metals in the rhizosphere environment, ultimately affect the absorption and transport of heavy metals by plants, and then affect the growth and development of plants themselves. This paper briefly described the effects of Cd stress on plant growth and development, analyzed the response of different kinds of root exudates under Cd stress, as well as the effects of root exudates on soil physical and chemical properties, rhizosphere microorganisms, the accumulation and transport of Cd,and analyzed the expression of genes pathways related to cadmium stress. In addition, regarding heavy metal pollution, this paper looked forward to the research trend of root exudates in order to explore the response mechanism of plant root exudates to cadmium stress in the future.

    Lodging-resistance Comparison Among Sumer Maize Varieties with Different Growth Period in North of Huang-Huai-Hai Plain
    Yajun YUAN, Jiaxing FENG, Qifan YANG, Xue BAI, R A J PUSHPA, Dahong BIAN, Yanhong CUI
    2023, 25(7):  21-28.  DOI: 10.13304/j.nykjdb.2021.1058
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    In order to resolve the serious lodging promblem of summer maize in the Huang-Huai-Hai Plain under current trend of full mechanized cultivation,7 summer maize varieties (2 early-maturing varieties, 3 medium maturing varieties and 2 late maturing varieties) with different growth period were used to compare the lodging-resistance at grain filling period. The results showed that the plant height, ear height, ear height coefficient, length and K content of the basal 3rd internode of summer maize were not related to growth period. The contents of water soluble carbohydrate in middle and early maturing varieties were significantly higher than that in late maturing varieties. The diameter and puncture strength of the basal 3rd internode, the number of nodes near the ground and the total plant, the bending strength and the vertical root-pulling resistance of the plant in middle and late maturing varieties were significantly higher than those of the early maturing varieties. Correlation analysis showed that there was significantly negative correlation between plant bending strength and ear height coefficient, and significantly positive correlation between plant total root number per plant. Puncture intensity of the basal 3rd internode was positively correlated with K content. Therefore, we should not only pay attention to faster grain filling and dehydration rate, but also pay attention to appropriate plant height, lower ear height and higher diameter of the basal internode, at the same time, suitable cultivation measures with inhibition of basal internode elongation, promoting the internode enlargement and enrichment and root development, which should be used to improve the ability of plant resistance to lodging. Above results provided theory basis for breeding with high yield, lodging resistance and grain harvest mechanization of summer maize.

    Mining of QTLs and Candidate Genes for Pod and Seed Traits via Combining BSA-seq and Linkage Mapping in Soybean
    Yaqian SUN, Shiliang CHEN, Jiahao CHU, Xihuan LI, Caiying ZHANG
    2023, 25(7):  29-42.  DOI: 10.13304/j.nykjdb.2022.0089
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    Pod and seed are important organs for yield formation in soybean, while pod and seed traits are also important characteristics of soybean appearance quality, which directly influence the commercial values of soybean product. In view of this, a recombinant inbred line (RIL) population was evaluated for the pod and seed related traits (pod length, pod width, pod weight, seed length, seed width and seed weight) under different environments, and the bulked segregant analysis sequencing (BSA-seq) was conducted to identify the genetic loci for pod and seed traits in 2 DNA pools (large pool, LP; small pool, SP) with extremely significant differences on related traits. Subsequently, by combining linkage mapping results and transcriptome data of RIL parents in previous study, the consistent genetic loci and candidate genes related to pod and seed traits across multiple environments via different methods and controlling diverse traits were discovered. The results showed that there were significant differences in the pod and seed related traits between the 2 DNA pools, LP and SP, under different environments. The average blasting percentage and coverage percentage of DNA sequences obtained from BSA-seq were above 98% and 94% with Williams 82 reference genome. Based on this, 27, 41 and 51 associated genome regions at 0.95 confident level were identified through the SNP-index, Euclidean distance (ED) and G-statistic methods, and 5, 15, 16 associated genome regions on 11 chromosomes (chromosomes 1, 3, 4, 6, 7, 12, 13, 15, 17, 19 and 20) at 0.99 confident level were obtained. Further analysis showed that the consistent genetic loci under multiple environments through the BSA-seq and linkage mapping methods were detected on chromosomes 7, 19 and 20. Moreover, some SNP markers, such as ss715637629 on chromosome 20 and ss715635705, ss715635755, ss715635827 and ss715635844 on chromosome 19, were detected by BSA-seq and linkage mapping, simultaneously. Furthermore, 40 candidate genes in the consistent association regions were found to present non-synonymous mutations in exons, and 15 of them showed high expression levels in the pod and seed of RIL parents. Among these 15 genes, 3 of them showed increasing expressions with the developmental stages of soybean pod and seed, which might have important functions in the formation of soybean pod and seed traits. Thus, the results in the present study provided novel insight for the genetic basis dissection of soybean pod and seed traits, and also provided the useful markers and genes for the genetic improvement of pod and seed traits in soybean breeding programme.

    Analysis on miRs Expression Profiles of Alfalfa and Screening of Trans-border Potential miRs
    Jingying JIA, Yahui LI, Bingzhe FU, Yun MA, Xiaoyan CAI
    2023, 25(7):  43-53.  DOI: 10.13304/j.nykjdb.2021.1090
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    To explore miRNA expression profile of ‘Xinyan 52’ (XY52), a new drought tolerant alfalfa line cultivated in Ningxia, and screen microRNA (miR) with cross-border research value, ‘Zhongmu 1’ (ZM1) was as the reference. ZM1 and XY52 were sequenced and analyzed by high-throughput miRs (RNA-seq); the bioinformatics technology was used to screen differential expressed miRs and predict target genes, and the predicted target genes were enriched and analyzed by GO and KEGG; then 10 miRs were detected and analyzed by RT-qPCR. The results were as follows: ① the miRs expression profiles of 2 kinds of alfalfa were successfully constructed, and 656 and 703 miRs were detected in ZM1 and XY52, which the number of newly predicted miRs were 233 and the known miRs were 433 and 480; ② a total of 21 differential expressed miRs were detected in the two alfalfa varieties, among which 3 miRs including novel-miR54, miR156f and miR166a were expressed higher, and the expression of novel-miR54 in XY52 was significantly higher than that in ZM1 (P<0.01), and the expression of miR156f in ZM1 was significantly higher than that in XY52 (P<0.01); ③ among the five miRs which had cross-border regulatory functions, miR166a had the most expressive level in ZM1 and XY52, while the expression of miR166a in XY52 was significantly higher than that in ZM1 (P<0.01); ④ a total of 623 target genes were predicted by the KEGG pathway and GO function enrichment analysis of 21 miRs with differential expression, which were mainly related to signaling pathways such as RNA transport, ABC transporter and ubiquitin-mediated proteolysis. These results laid a preliminary foundation for the analysis of miRs in differences of alfalfa and the regulation of genes in dairy cows.

    Leaf Color Characteristic Value and Nitrogen Diagnosis Model of Tobacco During Growth Period
    Yingxue ZHU, Qi WANG, Xianfa MA, Yusheng JIAO, Jinxu GAO, Weijia MAO, Jia FU, Xuedong SUN, Ye YUAN
    2023, 25(7):  54-62.  DOI: 10.13304/j.nykjdb.2021.1074
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    In order to clarify the color characteristic parameters significantly related to the total nitrogen content of tobacco leaves, the relationship between the leaf color characteristic value and the total nitrogen content and chlorophyll (expressed by SPAD value) of tobacco leaves under different nitrogen application rates was analyzed, and the color characteristic value diagnosis model of total nitrogen content of tobacco leaves was established by multiple stepwise regression analysis. The results showed that, under different nitrogen application rates, the most sensitive period to the change of nitrogen content was fast growing period. There was a significant negative correlation (P<0.05) between color characteristic values (red, R; green, G; blue, B; lightness, L) and leaf SPAD values, which the correlation coefficient showed as rR (0.728)>rL (0.706)>rG(0.649)>rB(0.477). There was significant correlation (P<0.05) between total nitrogen content and color characteristic values L, R, G, L/(R+G), B/R, B/G, L/B, R+B, B+G, R+B+G+L, R/(G+B) and R+B/(R+B+G). The nitrogen diagnosis model was established by multiple stepwise regression analysis using the characteristic values of leaf total nitrogen content and color characteristic values, which was significant at P<0.05 level. The model was verified, and the correlation between the measured value and the simulated value reached significant at P<0.01 level. The model of leaf color characteristic and leaf total nitrogen content of flue-cured tobacco could be used to guide the nitrogen nutrition diagnosis of flue-cured tobacco during the growth period, which provided a theoretical basis for smart agriculture in the future.

    Research of the Photosynthetic Characteristics of 7 Table Grape Varieties Under Compound Salt-alkali Stress
    Qianqian LU, Abuduwaili Abulimiti, Yixing HOU, Zhihui LI, Shuang WANG, Long ZHOU
    2023, 25(7):  63-76.  DOI: 10.13304/j.nykjdb.2021.0847
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    In order to screen out table grape varieties with more salt-alkali tolerance, 7 new introduced grape varieties were used as experimental materials. Under the condition of pot control experiment, 3 concentrations of compound salt-alkali stress of 0.29%, 0.58% and 0.87% were carried out. On the 30th day after the stress, the SPAD value and daily changes of photosynthetic parameters and fluorescence parameters were measured, and the principal component analysis method was used to rank the salt-alkali tolerances of the 7 varieties. The results showed that diurnal variation curves of net photosynthesis rate in ‘Blackcrunchy Seedless’ exhibited a unimodal peak, and the other 6 varieties showed a bimodal peak, which the highest peak of the day all appeared at 11∶00. Among the 6 varieties that had midday depression of photosynthesis, ‘Crimson Rose’ ‘Wagamichi’ and ‘Sweet Sapphire’ were mainly restricted by non-stomatal factors, while Silk road red rose, Shine muscat and Zaoxiawuhe were mainly restricted by stomatal factors. With the increase of salt-alkali stress concentration, SPAD value, net photosynthetic rate, stomatal conductance, intercellular carbon dioxide concentration, transpiration rate, water use efficiency, initial fluorescence, maximum fluorescence, actual efficiency of PSⅡ photochemistry, maximum efficiency of PSⅡ photochemistry all showed a downward trend, while non-photochemical quenching coefficient showed an upward trend. 4 principal components were extracted by principal component analysis, and their cumulative contribution ratio was 94.26%. According to the principal component comprehensive model, the salt-alkali tolerances of 7 varieties were obtained with ‘Zaoxiawuhe’>‘Shine Muscat’>‘Silk Road Red Rose’>‘Wagamichi’>‘Crimson Rose’>‘Blackcrunchy Seedless’>‘Sweet Sapphire’, which provided a theoretical basis for the further popularization and application of 7 newly introduced table grape varieties in Xinjiang.

    Effects of Overexpression of veA Gene on Secondary Metabolism of Eurotium cristatus
    Yunsheng WANG, Yincui CHEN, Zai CHENG, Jin ZHANG, Chuanbo ZHANG
    2023, 25(7):  77-86.  DOI: 10.13304/j.nykjdb.2022.0170
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    Eurotium cristatus is a dominant fungus in the process of Fuzhuan tea, the extracellular enzymes and abundance of secondary metabolites affect the quality and taste of finished tea. To explore the regulation mechanism of veA on secondary metabolism of Eurotium cristatus, the veA overexpressed mutant was successfully constructed by seamless cloning and agrobacterium transformation technology, and the effect of overexpression of veA on E. cristatus was evaluated by high performance liquid chromatography (HPLC) and transcriptomic sequencing technology. The results showed that the contents of various compounds in the fermentation products of the mutant strain were significantly different from those of the wild type, 3 new compounds were detected and the absorption peak of compound 1 increased by 4.09 times. Also, there were significant differences in gene expression profiles between wild type and mutant strain. A total of 737 differentially expressed genes (DEGs) were detected, among which 282 genes were significantly up-regulated and 455 genes were significantly down-regulated. KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway showed that DEGs were mainly enriched in amino acid metabolism, proteasome and terpenoid backbone biosynthesis. AntiSMASH software annotated 545 genes related to secondary metabolite synthesis, of which 10.64% genes were significantly differentially expressed between wild type and mutant strain, including polypentenyl synthase gene, isoprene diphosphate δ-isomerase gene and farniki pyrophosphate synthase gene were significantly up-regulated. It suggested that overexpression of veA activated some secondary metabolite genes, which provided new insights and methods for further mining novel compounds of E. cristatus.

    INTELLIGENT AGRICULTURE & AGRICULTURAL MACHINERY
    Simulation of Pepper Cleaning Based on DEM-CFD Coupling
    Dejun ZHANG, Xiaoming ZHANG, Di WU, Shuyun LIN, Taihua ZHANG, Weiping XU
    2023, 25(7):  87-96.  DOI: 10.13304/j.nykjdb.2022.0008
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    Due of pepper harvested by pepper harvester contains high rate of impurity, the effect of wind sorting is poor. In order to reduce the pepper impurity rate and improve the pepper air selection’s effect, a pepper wind-separation device was designed. Using the coupled research method of computational fluid dynamics (CFD) and discrete element method (DEM), the separation process of pepper wind sorting was simulated, the separation mechanism and motion state of the pepper mixture in the flow field were analyzed, and the effect of wind speed on pepper wind sorting was discussed. The results of the simulation showed that the average impurity rate of pepper was 11.774%, 4.624% and 1.676% at wind speeds of 15, 20 and 25 m·s-1, respectively, and the loss rate of pepper was 0.959%, 1.798% and 6.476%, respectively. The above results showed that the wind speed had a great influence on the wind sorting effect of pepper, when the simulated wind speed was increased to 20 m·s-1, the average rate of impurity of pepper decreased by 7.15% and the average loss rate increased by 0.839% compared to that at 15 m·s-1 wind speed; when the simulated airflow speed of wind sorting was adjusted to 25 m·s-1, the average impurity rate of pepper in the cleaning process decreased by 2.948% and the average loss rate increased by 4.678% compared with the airflow speed of 20 m·s-1. Combining the impurity content and loss rate of pepper air sorting, it can be seen from the comparative analysis that when the wind speed was 20 m·s-1, the sorting effect was better, with the pepper impurity rate of 4.624% and the pepper loss rate of 1.798%. The results provided reference for the designing and optimization of the wind sorting device of the pepper harvester.

    Research and Construction of Pinus massoniana Lamb. Volume Model in Chongqing Area by Non-destructive Method
    Zhuang YU, Zhongke FENG, Biao ZHANG, Tiantian MA
    2023, 25(7):  97-104.  DOI: 10.13304/j.nykjdb.2022.0102
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    The volume model of Sichuan masson pine has been used in Chongqing, so it is not completely applicable to the actual situation. It is necessary to establish a new volume model. It is difficult to collect data by logging, so lossless method is used to collect data. The volume of trees was measured by photogrammetry,the samples were divided into modeling and validation samples, with 80% for modeling and 20% for validation. Various one-dimensional and two-dimensional timber volume models were established using the modeling samples, while the validation samples were used to compare and analyze the models using relevant indexes from the Technical Regulations for the Preparation of Binary Standing Timber Volume Tables. The results showed that when data was obtained by photogrammetry, the values of deviation, root mean square error, relative deviation, and relative root mean square error of single wood diameter at breast height and single wood height were low,which indicated that the research and development of timber volume models could be carried out by photogrammetry, and the results fully satisfied the investigation needs. Among the multiple timber volume models determined by the combination of multiple indicators, the model with the best results had an R2 of 0.966 and a prediction accuracy of 97.69%. Therefore, the newly developed binary wood volume model in this study was more effective than the traditional Sichuan masson pine wood volume model in terms of total relative error, relative error average, and prediction accuracy. As a result, it could be used as the basis for establishing the wood volume table of Mawei pine stumpage in Chongqing.

    Study on Hot Air Drying System for Implantable Alfalfa Bales
    Yaqiang HU, Ya YUAN, Luwei YANG, Xuelai ZHANG, Shaopeng QIU, Xinyao YU
    2023, 25(7):  105-112.  DOI: 10.13304/j.nykjdb.2022.0044
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    In order to reduce the impact of sunlight, field operation and rain on the quality of alfalfa, a planting bale hot air drying equipment was developed. Based on the processing technology of wet harvest, the hot air drying experiment of alfalfa bale was carried out. It was found that the moisture content of bales reduced from 27% to 14% within 40 min under the condition of hot air temperature of 90 ℃. In the drying process, the energy efficiency of the system was 90%. In the implantable drying, the heat inside the bale was evenly diffused from the inside to the outside to complete the drying of the whole bale. After the test, most of the inside of the bale had been completely dried, and the leaves were intact and emerald green. Compared with alfalfa baled after natural air drying, crude protein and relative feed value of alfalfa increased by 10.98% and 19.72% respectively after implantable hot air drying. This study provided case reference and technical support for the drying process of wet harvesting bales.

    ANIMAL AND PLANT HEALTH
    Effect of ECF-Sig16 on Avermectin Production in Streptomyces avermitilis
    Shuai LUO, Yaqin WEN, Hua ZHU, Rong ZHANG, Xiaowen WANG, Lili LIU, Jianya ZHU
    2023, 25(7):  113-121.  DOI: 10.13304/j.nykjdb.2022.0105
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    Streptomyces avermitilis produces avermectin, which is a kind of anthelmintic antibiotics with broad-spectrum, low toxicity activities and high potency and widely used in agricultural and medical fields. Extracytoplasmic function Sigma (ECF-Sigma) regulators play key roles for adaptation to changes of living environment and activating stress responses efficiently. To investigate the function of ECF-Sig16 regulator in avermectin biosynthesis, shaking flask fermentation of sig16 gene deletion, complementary, and overexpression strains were test. The results indicated that Sig16 inhibited avermectin biosynthesis, but exerted no function on cell growth. Phenotype observation experiment showed that Sig16 didn’t affect Streptomyces avermitilis morphological differentiation in some conditions. Electrophoretic mobility shift assay (EMSA) showed that Sig16 binded to the promoter of branched-chain amino acid ABC transporter operon SAV1190~SAV1194, which indicated Sig16 could inhibit avermectin production by affecting avermectin precursor supply.

    Effects of Chemical Fertilizer Reduction Combined with Bio-organic Fertilization on Tobacco Soil Characteristics and Tobacco Bacterial Wilt Control
    Xingsheng YIN, Lingfeng BAO, Yongyu PU, Jiali SUN, Qing ZHANG, Haiping LI, Mingying YANG, Yueping LIN, Huaixin WANG, Yonghong HE, Peiwen YANG
    2023, 25(7):  122-131.  DOI: 10.13304/j.nykjdb.2021.1092
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    To analyze the relationship between the tobacco planting soil quality and the occurrence and development of tobacco bacterial wilt, and the control effect of chemical fertilizer reduction combined with bio-organic fertilization on tobacco bacterial wilt, 4 nitrogen reduction levels (5%, 10%, 15% and 20%) combined with bio-organic fertilizer were set up, with conventional nitrogen application as the control. The effects of each treatment on the main physiochemical properties of soil, the yield and quality of tobacco and the control effect of tobacco bacterial wilt were investigated. Based on the correlation analysis, the correlation between soil physiochemical factors and disease index was further analyzed. The results showed that the soil bulk density and pH of each treatment decreased. But the ratio of soil carbon and nitrogen, organic carbon, carbon storage, nitrogen storage, sucrase activity, urease activity, microbial biomass carbon and microbial biomass nitrogen increased. The yield, the proportion of high-grade tobacco and the proportion of medium and high-grade tobacco also increased significantly. The results of correlation analysis showed that the disease index was extremely negatively correlated with soil C/N ratio, organic carbon content, carbon storage, nitrogen storage, sucrose activity, urease activity, microbial biomass carbon and microbial biomass C/N ratio (P<0.01), extremely positively correlated with soil pH (P<0.01), negatively correlated with microbial biomass nitrogen (P<0.05), positively correlated with soil bulk density, alkali hydrolyzable nitrogen, available phosphorus and available potassium, and negatively correlated with microbial biomass nitrogen. Under the experimental conditions, appropriate nitrogen reduction and combined application of bio-organic fertilizer could improve soil quality, tobacco yield and quality, and reduce the occurrence of tobacco bacterial wilt.

    BIO-MANUFACTURING & RESOURCE AND ECOLOGY
    Effects of Nitrogen Application Rate and Density on Growth and Yield of Orderly Machine-thrown Early Rice
    Zhigang ZHENG, Li XIANG, Gongyi LIU, Cai XU, Bin QIN, Weiqin WANG, Huabin ZHENG, Qiyuan TANG
    2023, 25(7):  132-143.  DOI: 10.13304/j.nykjdb.2021.1076
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    In order to explore the effects of nitrogen application rate and throwing density on the growth and development characteristics and yield formation of early rice under the orderly machine-throwing mode, Xiangzaoxian 24 was used as the test material, and a split-plot test design was adopted. The nitrogen application rate was the main area (N1: 120 kg·hm-2, N2: 150 kg·hm-2), and the throwing density was the sub-area (D1: 22.2×104 holes·hm-2; D2: 25.0×104 holes·hm-2; D3: 30.8×104 holes·hm-2; D4: 33.3×104 holes·hm-2; D5: 38.5×104 holes·hm-2). The yield, yield component factor, tillering rate, dry matter accumulation, leaf area index and leaf SPAD value of each treatment were analyzed. The results showed that proper nitrogen addition and density could significantly increase the yield of orderly machine-throwing early rice. Compared with the N1 treatment, the N2 treatment significantly increased the yield by 5.33%~6.75%, and the D3, D4, D5 treatments significantly increased the yield by 11.97%~15.05% compared with the D1 treatment. The main reason for the increase in yield was more effective spikes. In terms of population structure, proper nitrogen addition and proper throwing density could significantly improve the dry matter assimilation and accumulation capacity and leaf area index of the population, promote the ability of tillering into panicles, form more effective panicles, and significantly increase the total spikelet per unit area. The increase of nitrogen fertilizer could significantly increase the leaf SPAD value and improve the photosynthetic production capacity of rice; while increasing the throwing density clould significantly reduce the SPAD value of rice leaves. In conclusion, the high yield could be obtained in the range of 30.8×104~38.5×104 holes·hm-2 for orderly machine-throwing early rice. Considering the principle of cost saving and increasing efficiency, the recommended throwing density was 30.8×104 holes·hm-2, which provided a theoretical basis for orderly machine-throwing early rice production in Hunan province.

    Effect of Selenium Fertilizer Application Position on Physiological Characters and Selenium Accumulation in Wheat
    Feifan HOU, Xiaowen ZHANG, Jiaqi WANG, Jianzhen ZHANG, Kaiquan LI, Xuebin YIN
    2023, 25(7):  144-152.  DOI: 10.13304/j.nykjdb.2021.1104
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    Different application positions in soil of selenium-enriched organic fertilizer (Se-fertilizer) will lead to various effects on physiological characters and selenium (Se) accumulation in wheat. ‘Xinmai 296’ was used as the material, and Se-fertilizer was applied at the horizontal distances of 5 and 10 cm from the wheat rhizosphere and at the vertical depths of 5, 10, 15 cm from the soil surface. The agronomic traits, yield factors, selenium content and selenium accumulation of wheat were determined under each treatment condition. By using the membership function, the fertilizer efficiency was better than others when Se-fertilizer was applied at 5 cm horizontal distance from wheat rhizosphere and 5 cm vertical depth from soil surface(T1 treatment). Under this condition, the height of wheat plant was 67.18 cm, the dry matter quality of each plant was 20.30 g, the yield was 820.17 g·m-2, the accumulation of selenium in each plant was 10.85 μg, which were significantly higher than those of other treatments, and selenomethionine and selenocystine were the main types for selenium element in plant. Therefore, this location for applying Se-fertilizer could be recommended for the production of selenium-enriched wheat to obtain better yield and Se accumulation effect, which provided a theoretical reference for precise fertilization of selenium-enriched wheat production.

    Study on the Response Factors of Maize Yield to Nitrogen Fertilizer
    Yaxuan MENG, Wei MA, Xuhang YAO, Yingqi SUN, Xin ZHONG, Shan HUANG, Qiaoyun WENG, Yinghui LIU, Jincheng YUAN
    2023, 25(7):  153-160.  DOI: 10.13304/j.nykjdb.2021.1032
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    To clarify the effect of nitrogen application on maize yield under different ecological conditions in China, a literature search was conducted through CNKI, CQVIP, and Wanfang data base. At last total 78 papers were obtained and constructed 525 independent data. Used an integrated analysis method the effect of nitrogen application on maize yield were analyzed under different nitrogen fertilizer model (N application rale, N; dressing ratio, DR), geographical areas, climatic factors(average annual temperature, Ta; average growing season temperature, Tg; average annual precipitation, Pa; average growing season precipitation, Pg), and soil organic matter, SOM. Meta-analysis results showed that application N significantly increased maize yield by 17.64%. Nitrogen application at 250~300 kg·hm-2 with a ratio of base fertilizer to top dressing 1∶2 gained the highest yield. Application of nitrogen could increase maize yield at different ecological regions, and the highest yield increase (28.15%) was observed in the southwest region, while the lowest yield increase (7.86%) was observed in the southeast region. Climatic factors effected the efficiency of nitrogen on maize yield also, the highest yield was gained in the condition of 5<Ta≤10 ℃, 400<Pa≤800 mm, Tg≤25 ℃ and Pg>400 mm. The effect of N application was closely related to soil organic, the highest yield increase was achieved with 15<SOM≤25 g·kg-1. On the whole, high rainfall and soil organic content and suitable temperature in regions were favorable for efficient of N application. The suitable and efficient nitrogen application mode was 250~300 kg·hm-2 with the dressing ratio 1∶2.

    Effects of Intercropping Pinellia ternata on Growth, Yield and Quality of Flue-cured Tobacco
    Wen ZHOU, Xiaoheng GUO, Rui XU, Xiaoli WANG, Huiwei NIU, Dan HAN, Huifang SHAO
    2023, 25(7):  161-169.  DOI: 10.13304/j.nykjdb.2022.0009
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    To explore the influence of flue-cured tobacco intercropping with Pinellia ternata on the yield and quality of flue-cured tobacco and economic benefit, 4 treatments were set up including flue-cured tobacco monoculture (CK) and flue-cured tobacco intercropping with Pinellia ternata according to 1∶2 (C1), 1∶3 (C2) and 1∶4 (C3). The agronomic characters, disease resistance, yield, quality and economic characters of flue-cured tobacco were determined. The results showed that, compared with CK, the model of flue-cured tobacco intercropping with Pinellia ternata had significant effects on the agronomic traits of flue-cured tobacco, which significantly increased plant height and maximum leaf area, and improved canopy morphology. In terms of controlling diseases and insect pests, the intercropping model with Pinellia ternata could significantly reduce the occurrence of red spot disease, which the relative control effect was 45% (C1), 30.7% (C2) and 38.2% (C3), respectively. Compared with CK, the intercropping model with Pinellia ternata increased the total amount of neutral aroma substances in the upper leaves, middle leaves and lower leaves, and improved fine tobacco ratio and high economic benefit. Among 3 intercropping treatments, C1 treatment showed that the comprehensive benefit increased by 6.1% than CK treatment, which provided a new way to reduce obstacles of tobacco continuous cropping and increase economic income of farmers.

    Effects of External Application of α-Ketoglutarate on Growth, Carbon, Nitrogen and Phosphorus Accumulation and Their Stoichiometric Relationships in Kosteletzkya virginica Under Salt Stress
    Yulu WU, Jiaxin HU, Yuxi CHEN, Bingsong ZHENG, DaoLiang YAN
    2023, 25(7):  170-177.  DOI: 10.13304/j.nykjdb.2022.0276
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    In order to study the effects of organic carbon fertilizer α-ketoglutarate on the growth, carbon(C), nitrogen(N) and phosphorus(P) accumulation and their stoichiometry of Kosteletzkya virginica under salt stress, the seedlings of K. virginica (with 3~4 true leaves) were used as experimental materials, and the cultivation medium and soil were watered with different concentrations of salt solution (NaCl, 0, 5, 15 g?L-1) and α-ketoglutarate solution (KG, 0,10, 20 mg?L-1) was sprayed on the leaves. After 45 d of treatment, these indexes were measured and analyzed, including the plant height, biomass, relative growth rate, root shoot ratio, specific leaf weight, total carbon (C), total nitrogen (N), total phosphorus (P), sodium (Na+), potassium (K+) content and their stoichiometric ratio. The results showed that exogenous spraying KG did not significantly affect the relative growth rate of K. virginica plants under salt stress, but promoted the total biomass of plants under non salt stress; under high salt stress (15 g?L-1 NaCl), exogenous 20 mg?L-1 KG significantly increased the root biomass, root shoot ratio and specific leaf weight of K. virginica. At the same time, 20 mg?L-1 KG significantly increased the contents of C and N in leaves. For K. virginica under high salt stress, KG had more obvious accumulation of C in leaves. KG had no significant effect on the accumulation of N and P under salt stress. External application of 20 mg?L-1 KG could significantly increase the C/N and C/P of K. virginica under 15 g?L-1 NaCl treatment, and the utilization efficiency of N and P was significantly improved; under the treatment of 5 g·L-1 NaCl, the application of 10 mg?L-1 KG significantly increased the K+ content of leaves, which showed that KG could promote the absorption of K+ under salt stress, but had no significant effect on the absorption of Na+. Correlation analysis showed that leaf N was significantly positively correlated with leaf P (P<0.01), negatively correlated with leaf N/P (P<0.01), and positively correlated with leaf K+/Na+P<0.01). Leaf P content was negatively correlated with leaf Na+ content and positively correlated with leaf K+ content. The above research results showed that a certain concentration of organic carbon fertilizer KG could alleviate the inhibition of salt stress on the growth of K. virginica, which provided a new fertilization idea for improving the biomass and normal growth of K. virginica in saline alkali land.

    Effects of Long-term Biochar Application on Greenhouse Gas Emission and Its Temporal Effect in Huang-Huai-Hai Plain
    Hongyuan LIU, Zhihua ZHOU, Guangxin ZHAO, Qinrui SHEN
    2023, 25(7):  178-186.  DOI: 10.13304/j.nykjdb.2021.1081
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    To study the temporal effect of biochar on greenhouse gas emissions, the soil of the Huang-Huai-Hai plain was as the research object. The amount of biochar was added with 0.00 (CK), 2.25 (C1),4.50 (C2),9.00 (C3),13.50 t·hm-2 (C4) per year and 13.50 t·hm-2 (CS) at one time for 3 years. The differences in soil greenhouse gases and soil physicochemical properties of the wheat-maize rotation farmland ecosystem in the Huang-Huai-Hai plain were studied. The results showed that CS treatment could significantly suppress CO2 emission of soil, with the decrease of 38.5% and 25.75% in wheat and corn seasons, respectively. The C2, C3 and C4 treatments significantly suppressed CO2 emission of soil by 17.7%~24.6% in the maize season. Biochar had no significant effect on CH4 emission of soil. The application of biochar could significantly inhibit N2O emission of soil, reaching 37.5%~60.1% and 24.9%~39.3% in wheat and maize seasons, respectively. Only CS treatment significantly reduced the comprehensive warming potential by 30.4%, which indicated that the one-time application of a large amount of biochar had a better inhibitory effect on greenhouse gases. Correlation analysis showed that soil CO2 emission flux was significantly positively correlated with soil temperature, moisture, NH4+-N and NO3--N. Soil CH4 emission flux was negatively correlated with soil temperature, moisture, NH4+-N and NO3--N. Soil N2O emission flux was positively correlated with soil temperature, moisture, NH4+-N and NO3--N. In summary, biochar could inhibit soil greenhouse gas emissions. Under the conditions of this experiment, a one-time application of 13.5 t·hm-2 of biochar could maximize environmental benefits.

    Study on Soil Moisture Dynamics in Growing Season of Sand-fixing Haloxylonammodendron Forest in Ulan Buhe Desert
    Xuting HAO, Yaru HUANG, Yingbin MA, Shuai ZHANG, Chunxia HAN, Jiacheng PANG, Guangfu XU, Huizhong HAO, Yajing LIU
    2023, 25(7):  187-196.  DOI: 10.13304/j.nykjdb.2022.0862
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    Soil moisture is the main limiting factor for the growth and development of desert vegetation in arid sandy areas. In order to understand the dynamic change characteristics of soil moisture in the sand-fixing Haloxylon ammodendron forest in Ulan Buhe Desert, the drying method was used to measure the soil moisture of Ammodendrus ammodendrus forest during the growing season from April to September in 2021. The results showed that, 0—20 cm of Haloxylonammodendron ammonium forest was shallow dry sand layer with soil moisture content 0.23%~2.13%, 20—80 cm was middle layer with severe changes with soil moisture content 0.36%~3.59%, and 80—120 cm was deep stable layer with soil moisture content 0.45%~1.63%. The month change of soil moisture content showed that the soil water consumption was weak in April, was vigorous from May to August, and was slowly restored and stabilized in September. There was an obvious logarithmic function relationship between the soil moisture content and soil water potential (R2 is greater than 0.514 2)。In conclusion, the soil moisture in Saxoul woodland had obvious character of vertical distribution and stratification, and the variation degree of time was higher than that of space, which was of great significance for the construction of artificial vegetation in this area.

    Temporal and Spatial Variation of Xinjiang Natural Grassland and Their Responses to Climate Factors
    Weikang ZHAO, Changqing JING, Chen CHEN
    2023, 25(7):  197-206.  DOI: 10.13304/j.nykjdb.2021.0931
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    Based on remote sensing data such as net primary productivity (NPP), normal difference vegetation index (NDVI) and climate factors (temperature and precipitation), the temporal and spatial variation of grassland NPP and grassland NDVI in Xinjiang and their responses to climate factors were analyzed by the unary linear regression model, correlation analysis and other methods. The results showed that the annual average values of grassland NPP and NDVI both showed an upward trend. The spatial distribution of grassland NPP over the years showed a trend of high in the north and low in the south, and the spatial distribution of grassland NDVI showed a trend of gradually decreasing from northwest to southeast. From 1985 to 2015, the average annual temperature and precipitation both showed an upward trend. Overall, the average annual temperature in the basin was higher than that in the mountainous area, and the average annual precipitation in the mountainous area was more than that in the basin. From the perspective of spatial correlation, whether it was grassland NPP or grassland NDVI, the area of grassland positively correlated with precipitation was larger than that of grassland positively correlated with temperature, and the correlation coefficient with precipitation was higher than that with temperature. It showed that precipitation was the main influencing factor of grassland vegetation in Xinjiang, which deepened the understanding of Xinjiang grassland’s response to climate factors and provided data support for the response to climate change.

    MARINE AGRICULTURE & FRESHWATER FISHERIES
    Study of Volcanic Rock Deposition on the Running of Aquaponics
    Denglong CHEN, Yuxiang ZHANG, Jiajia SONG, Pengyu CHEN, Xiangzhen WEN, Yaling LI
    2023, 25(7):  207-214.  DOI: 10.13304/j.nykjdb.2022.0074
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    In an aquaponics, excessive accumulation of fish excreta and bait residues on the bottom of the pond may cause further pollution of the water, so the experiment was conducted to investigate the effect of volcanic rocks on the growth of fish and vegetables, water purification and nitrogen and phosphorus utilization efficiency of the Aquaponics. 4 treatments were set up for this experiment: farming carp (F), farming carp and adding volcanic rocks to the bottom of the pond (Fv), planting lettuce on the pond of Fv (Fvs) and planting lettuce on the pond of F (Fs). The results of the 45 d trial showed that the addition of volcanic rocks effectively reduced nitrite nitrogen concentrations and contributed to the accumulation of nitrate nitrogen, and had no effect on fish production, but significantly increased lettuce production by 33.95%(P<0.05); the integrated aquaponics culture system with volcanic rocks (Fvs) had the highest nitrogen and phosphorus utilization efficiency NUE, PUE), up to 36.80% and 26.14% respectively. In conclusion, it was concluded that the addition of volcanic rocks to an integrated aquaponics could effectively reduce the concentration of nitrite nitrogen, decrease the accumulation of toxic substances in the water, promote the accumulation of nitrate nitrogen and then increase lettuce production, and enhance the utilization efficiency of nitrogen and phosphorus, which could provide a theoretical basis for the effective operation of aquaponics systems.

    INNOVATIVE METHODS AND TECHNOLOGIES
    Effects of Atmospheric Pressure Cold Plasma Continuous and Interval Treatments on Oat Seed Germination
    Peng REN, Xiaogui LYU, Lei SHI
    2023, 25(7):  215-221.  DOI: 10.13304/j.nykjdb.2022.0126
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    To study the effect of cold plasma treatment on oat seed germination and seedling growth, oat seeds were treated with a cold plasma jet at atmospheric pressure and argon AC discharge. The effects of continuous treatment and interval treatment on oat seed germination and seedling growth were compared and analyzed at a voltage of 4 kV and a total treatment time of 40 and 60 s, respectively. The results showed that interval treatment could significantly improve the germination potential of seeds compared with the continuous treatment (P<0.05), and the 10 s treatment for 4 times had the greatest improvement, which was about 27.16% higher. Interval treatment could improve seed germination rate, root length, shoot length and dry matter accumulation of seedlings, but the change was not significant. Moreover, the hydrophilicity of oat seeds was significantly improved by interval treatment (P<0.05), and the hydrophilicity changed the most when treated 4 times 10 s, which increased about 39.07% compared with continuous treatment. Compared with continuous treatment, interval treatment could significantly improve the germination potential, hydrophilicity and water uptake of oat seeds, which could provide a theoretical reference for shortening the soaking time of seeds and increasing the uniformity of germination when planting oats.

    Optimization of Liquid Culture Conditions for the Production of Deoxynivalenol and Its Derivatives by Fusarium graminearum Using Response Surface Methodology
    Xiuying ZHAO, Qingwen HUANG, Haojie CAO, Jie WANG, Ruijiao LI, Dongxia NIE, Zheng HAN, Zhihui ZHAO
    2023, 25(7):  222-233.  DOI: 10.13304/j.nykjdb.2021.1055
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    To investigate the effects of different liquid culture conditions on the production of deoxynivalenol (DON) and 15-acetyldeoxynivalenol (15-ADON) by Fusarium graminearum, the single factor experiment and response surface methodology were used. The results showed that the production of DON was significantly influenced by incubation time, initial pH and their interactive effect, while the production of 15-ADON was significantly influenced by incubation time, incubation temperature and their interactive effect. The optimal conditions for DON production was followed with incubation time 22 d, temperature 26.3 ℃, initial pH 6.35, which the highest amount of DON was 5 739.69 μg·L-1. The highest production of 15-ADON with 10 453.41 μg·L-1 was achieved when the incubation time, the temperature and the initial pH were set as 21 d, 26.3 ℃ and 5.58, respectively. The above results provided theoretical basis and data support for the biosynthesis, routine supervision and control of DON and 15-ADON.