Table of Content

15 August 2022, Volume 24 Issue 8

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AGRICULTURAL INNOVATION FORUM

Innovative Mechanism and Model of Cambodia-China Tropical Eco-agriculture Cooperation Demonstration Zone

Zhaoli AN, Dongqun YANG

2022, 24(8):  1-8.  DOI: 10.13304/j.nykjdb.2021.0777

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In recent years， with the support of national policies， China’s foreign investment agricultural zone have achieved rapid development. However， there are promblems of lacking cross-border management personnel， the host country business information asymmetry， unfamiliar human environment， financing difficulties and other issues. Taking Cambodia-China Tropical Ecological Agriculture Cooperation Demonstration Zone in Hainan Province as the research object， through field investigation， the successful experience was summarized as sufficient preliminary research， enterprise group cooperation， respect for local ecological environment and customs. The main innovation mechanisms included as follows： forming an orderly development path of “one nuclear， multi-zone， N bases”； the combination of long and short industries， rapid circulation of its own funds； paying attention to personnel training， reducing management risk， etc.， Its development pattern was “the long and short industry union， the industrial chain closed-loop development.” Based on above， the paper analyzed the main problems in the development of the zone at present， and put forward 5 policy suggestions. It could provide reference for other agricultural foreign investment zones to conduct in-depth study on China’s foreign investment development better zone and sum up their development of innovative mechanisms and models， and the development of agricultural investment zones could be integrated into the local production and consumption market as soon as possible through the management mechanism system innovation， which provided important reference for promoting the sustainable development of agricultural zones invested abroad.

Analysis on Production Technical Efficiency of Mung Bean Industry Under Different Cultivating Scales —Taking Mung Bean Production in Baicheng of Jilin Province as an Example

Jiliang MA, Huijie ZHANG, Ninghui LI, Huili YUE

2022, 24(8):  9-17.  DOI: 10.13304/j.nykjdb.2022.0381

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In 2019， the Central No.1 Document proposed to actively develop the miscellaneous grain and miscellaneous bean industry， vigorously develop the mung bean industry with obvious regional characteristics， which is of great significance for improving the potential of mung bean production， establishing the advantages of characteristic agricultural products， and broadening the channels for farmers to increase income. This study analyzed the status of mung bean industry in China， and then analyzed the comprehensive technical efficiency and its influencing factors of mung bean under different operation scales based on the micro-data of mung bean planting of 233 farmers in Baicheng City of Jilin Province by using the DEA-Tobit two-stage model. The results showed that the average value of comprehensive technical efficiency in the samples was 0.49， and the relationship between comprehensive technical efficiency and operation scale was “inverted U-shaped”. The significant degree of influencing factors of comprehensive technical efficiency varied under different operation scales. Among them， small-scale and medium-scale farmers were more inclined “empirical agriculture” planting mode， while large-scale farmers were more inclined “modern agriculture” planting mode. Based on the above results， some policy suggestions were put forward， such as improving moderate scale management level of mung bean production， moderately strengthening socialized service supply of machinery， and continuously strengthening science and technology training for mung bean farmers.

BIOTECHNOLOGY & LIFE SCIENCE

Breeding Progress of Anthocyanin Corn

Wenzhu YANG, Rumei CHEN

2022, 24(8):  18-24.  DOI: 10.13304/j.nykjdb.2021.0740

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Anthocyanins are water-soluble pigment and antioxidant widespread in the nature. In recent years， the health care functions of anthocyanins， such as anti-inflammation and anti-aging， have gradually gained public concern and recognition. With the increase of sweet and waxy fresh corn market and planting area year by year， the fresh corns rich in anthocyanin are very popular with consumers. In addition to fresh food， anthocyanin corn can also be used as raw materials for industrial extraction， and the extracted anthocyanins are widely used. For the past few years， anthocyanin maize breeding has also made great progress， and genetic engineering breeding has also made a breakthrough. Here， this paper reviewed the synthesis and metabolism of anthocyanin， applications and market prospect， conventional breeding and genetic engineering of anthocyanin corn， which provided a reference for breeding and development of anthocyanin maize in future.

Current Status of Gene-edited Pigs

Limin ZHAI, Wentong LI, Zheng FENG, Hua LI, Yangli PEI

2022, 24(8):  25-34.  DOI: 10.13304/j.nykjdb.2021.0671

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Pigs are important agricultural economic animals， and pork is one of the main protein source for human population. At the same time， pigs closely resemble humans in terms of anatomy， and genetic background， physiology， disease characteristics. Therefore， pigs are not only important objects for improvement of production traits， but also biomedical research objects in the field of human diseases and xenotransplantation. With the rapid advances in genome editing technology， there are new editing technologies that are widely available， simple to perform and safe. These new gene editing techniques can be used to quickly obtain cell lines with single-base editing， gene knock-in or knock-out， then gene-edited pigs can be obtained by somatic cloning and other techniques with those edited cell line. This paper reviewed the preparation of gene-edited pig， and the research progress of gene-edited pigs in the fields of agriculture and medicine， which was expected to provide reference for the agricultural production traits improvement and medical research of pigs.

Genetic Relationship of Wheat Derivatives Variety （Line） from Yannong 74（11） Using High-density 90K SNP Array

Xiaoling ZHAI, Ruixia WANG, Lian ZHANG, Juan JIAO, Yugang LI, Shengjian WANG, Xiaolei QI, Hongmei GE, Shengquan ZHANG

2022, 24(8):  35-43.  DOI: 10.13304/j.nykjdb.2021.1049

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The wheat breeding line Yannong 74（11） was bred by Yantai Academy of Agricultural Sciences in 1970s， and it derived some varieties including Lumai 14， Lumai 13 and Yannong 19 etc， so it was being the base of the breakthrough of common wheat breeding in Shandong Province recently. Therefore， in this study， illumina 90K array were screened on 120 wheat lines including the varieties （lines） derived form 74（11） and other varieties （lines） in order to study the genetic relationship of them. After manual correction of the scatter diagram of each SNP locus， 26 026 SNP loci were obtained and there are 32.17%， 40.69% and 7.64% distributed on genome A， B and D respectively. The polymorphism information content （PIC） of the tested lines based on the SNP loci ranged from 0.18 to 0.31 and the average was 0.25， which was lower than the PIC of common SSR marker. And then， the wheat materials were divided into 2 groups， that one group consisted of the wheat lines derived from Yannong 74（11） （GroupⅠ） and the other consisted of all the test materials （GroupⅡ）. In group Ⅰ， the materials with genetic similarity coefficient from 0.61 to 0.70 accounted for 59.44%， those from 0.71 to 0.80 accounted for 32.98%， and those more than 0.91 accounted for 0.80%. In Group Ⅱ， the materials with genetic similarity coefficient from 0.61 to 0.70 accounted for 26.77%， those from 0.71 to 0.80 accounted for 53.22%， those from 0.81 to 0.90 accounted for 17.26%， and those more than 0.91 accounted for 2.75%. The data revealed that， the genetic relationship among the derived offspring of Yannong 74 （11） germplasm was relatively narrow， so it was necessary to broaden the genetic basis. In addition， several classic wheat hybrid combinations were selected to study the genetic relationship and the result showed that the genetic similarity between offspring and superior parents was from 0.68 to 0.87 with an average of 0.79； the genetic similarity coefficient between sister lines was from 0.84 to 0.87 and that between breeding parents was from 0.65 to 0.71. The genomic information would provide reference for cross parent selection in wheat breeding and it was suggested that the genetic similarity coefficient of parents should be controlled below 0.8 in the establishment of medium and short-term breeding objectives； in the establishment of medium and long-term breeding objectives， the genetic similarity coefficient of parents should be controlled below 0.7.

Cloning and Expression Analysis of Wheat Heat Shock Protein Gene TaHSP90-1

Qing LU, Ting LIANG, Weiwei WANG, Dezhou WANG, Xian WU, Xiaoyan WANG, Yimiao TANG

2022, 24(8):  44-54.  DOI: 10.13304/j.nykjdb.2022.0393

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Heat shock proteins （HSPs） are a kind of stress proteins widely exist in plants and play important role in the response of plants to stress. In order to further understand the wheat HSP90-1 gene and explore its related biological functions，this paper searched the wheat genome sequence database， and obtained the homologous gene sequences on wheat A， B and D subgenomes， which were named as TaHSP90-1-A， TaHSP90-1-B and TaHSP90-1-D， respectively. TaHSP90-1 DNA sequences were obtained from 12 wheat varieties through homologous cloning and sequence analysis showed that the complete open reading frames of TaHSP90-1-A， TaHSP90-1-B and TaHSP90-1-D were 2 121， 2 136 and 2 130 bp， encoding 707， 712 and 710 amino acids， respectively. The C-terminal sequence of TaHSP90-1-A， TaHSP90-1-B and TaHSP90-1-D contained an HSP90 domain， which were members of HSP90 subfamily in HSP family. SNP loci were found among different wheat varieties， which were located in the second intron region of TaHSP90-1-B and the promoter region of TaHSP90-1-D. Phylogenetic analysis showed that TaHSP90-1-A and two grain wheat were in the same branch， and TaHSP90-1-B and TaHSP90-1-D were in the same branch. Cis acting element analysis showed that the promoter regions of TaHSP90-1-A， TaHSP90-1-B and TaHSP90-1-D contained drought response element （MBS element） and thermal response element （HSE element）. RT-PCR showed that TaHSP90-1-A， TaHSP90-1-B and TaHSP90-1-D had high expression in leaves at seedling and mature stages of wheat. Under drought stress， the expression level of TaHSP90-1 was higher in drought tolerant wheat varieties， which was 150 times compared with varieties of drought sensitive. Under heat stress， TaHSP90-1 was up-regulated in both heat sensitive and heat resistant varieties， while TaHSP90-1-A and TaHSP90-1-D were significantly up-regulated in heat-resistant varieties of wheat.

Effect of Different Sowing Dates on the Expression of Grain DUS Testing Characteristics

Xiongfei JIAO, Jin YU, Leyong FENG, Yaodong GUO, Lisheng FAN

2022, 24(8):  55-64.  DOI: 10.13304/j.nykjdb.2021.0610

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With the rapid development of modern breeding technology， the speed of variety renewal is increasing and the protection of new millet variety rights has become an urgent need for improvement. In this study， 5 spring foxtail millet varieties， 5 summer foxtail millet varieties and 5 hybrid foxtail millet varieties were used as materials and planted at 3 different sowing dates to study the effect of sowing date in Xinzhou region on the DUS （distinctness， uniformity and stability） test characteristics of foxtail millet. The results showed that different sowing dates had no significant effect on the qualitative， pseudo-qualitative and visual observation characteristics of foxtail millet. The effect of the sowing dates on the measurement quantitative characteristics of foxtail millet were different， and the order of variation coefficient of each characteristics was： number of spike stems > rate of grain > number of single-code grain > length of the single-spike heavy > spike neck > thickness of the spike > thickness of the stalk > length of the spike > width of the inverted second leaf > number of elongation sections between > elongation sections of the spike period > length of the inverted second leaf > length of the stalk. For a single trait， the degree of influence on each variety varied under differently by different sowing dates. the length of the spike neck was affected by the most varieties during the sowing dates， and 15 varieties had significant differences at 3 sowing dates （P<0.05）； number of inverted second-leaf length， number of spiked stems， rate of valley out and the number of spiked stems were the least affected varieties during the sowing dates， with significant differences of 12 varieties for each trait （P<0.05）. There were differences in the effect of the sowing dates on the test characteristics of millet DUS， and the stability of visual traits was higher than quantitative traits. The above results provided reference and theoretical basis for the scientific and rational screening of DUS test standard varieties in different sowing dates.

Analysis of Genetic Diversity of Albino Tea Cultivars （Strains） Using 2b-RAD Technology

Shengchuan LIU, Yingfen XU, Jie WEI, Donghai YAN, Zhixiong CHEN, lin XU, Yan LIU, Yufeng ZHOU

2022, 24(8):  65-73.  DOI: 10.13304/j.nykjdb.2021.0621

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To reveal the genetic diversity of albino tea cultivars （strains）， 23 tea germplasms （20 albino， 3 evergreen） were analyzed using 2b-restriction site-associated DNA （2b-RAD） sequencing. The genetic diversity， genetic relationship and population structure of 23 tea germplasms were analyzed. The results showed that 576 193 750 high-quality reads and 56 498 high-quality single nucleotide polymorphisms （SNPs） were obtained. The phylogenetic tree and principal component analysis showed that 23 tea germplasms were divided into 3 groups. GroupⅠhad 1 strain （Dayezhong） from Guizhou. Group Ⅱ had 6 germplasms originated from Guizhou local populations. GroupⅢhad 14 germplasms from Zhejiang， 2 germplasms from Anhui and Fujian， respectively. All genetic parameters of 3 groups based on the phylogenetic tree were showed group Ⅰ>groupⅡ>groupⅢ， and moderate and high genetic differentiation between group Ⅰ with groupⅡand group Ⅲ were observed， respectively. Generally， there was moderate or high genetic differentiation among albino tea cultivars （strains）， and the higher genetic differentiation was observed among germplasms from different geographical regions， which provided a theoretical basis for identification， utilization and breeding of albino tea plant （Camellia sinenis）.

Analysis of Chloroplast Genome Characteristics and Codon Usage Bias of Fissisfigma polyanthum Merr.

Qiwei YAN, Xianglan LIANG, Qiuyun TAO, Qiuxiang LUO, Song GUO

2022, 24(8):  74-86.  DOI: 10.13304/j.nykjdb.2022.0114

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To study the structure characteristics， phylogeny and codon usage bias ofchloroplast genome in Fissisfigma polyanthum Merr.， the chloroplast genome of Fissisfigma polyanthum Merr. wassequenced and analyzed. The results showed that the chloroplast genome was composed of large single-copy region， small single-copy region and a pair of reverse repeat regions. The total length was 189 920 bp， which included 118 genes （99 genes encoding protein， 11 tRNA genes and 8 ribosome rRNA genes）， and 71 simple sequence repeats （SSRs） were also identified. The phylogenetic analysis showed that F. polyanthum Merr. was closely related to Annona muricata. The codon preference analysis showed that the codon usage bias of F. polyanthum Merr. was weak， and the codon preference was mainly affected by selection factor. Finally， 11 optimal codes were selected， 10 of which ended with A/U. These results provided scientific basis for phylogeny and construction of expression vector of F. polyanthum Merr.

INTELLIGENT AGRICULTURE & AGRICULTURAL MACHINERY

Evaluation of Plant Self-rotation Multi-view Reconstruction Technique in 3D Phenotype Acquisition of Wheat Plants

Wenqi ZHANG, Sheng WU, Xinyu GUO, Weiliang WEN, Xianju LU, Chunjiang ZHAO

2022, 24(8):  87-98.  DOI: 10.13304/j.nykjdb.2022.0100

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The high-throughput acquisition system of crop phenotypes based on multi-view 3D reconstruction technology with low cost and high acquisition efficiency has attracted more and more attentions. The plant self-rotation capture platform is easy to build and low cost， but the jitter generated during plant rotation has an impact on the point cloud 3D reconstruction and phenotype resolution accuracy. To evaluate the applicability of plant rotational multi-view imaging in 3D phenotype resolution of wheat plants， designed a portable 3D phenotype high-throughput acquisition system for wheat plants based on plant self-rotation， and wheat plants of different varieties at the spike stage were selected as experimental samples for point cloud reconstruction， and the accuracy error of the reconstructed point cloud was evaluated based on Hausdorff distance； the accuracy of the extracted phenotypic indicators was evaluated based on manual measurement data. The experimental results showed that the point clouds reconstructed by plant self-rotation had high consistency with those reconstructed by camera rotation， and the difference of point cloud accuracy was basically controlled below 0.4 cm； the root mean square errors （RMSE） of obtained leaf length， leaf width and plant height were 0.79， 0.13 and 0.53 cm， and the mean absolute percent errors （MAPE） were 3.26%， 7.63% and 0.74%， respectively， indicating that this approach was suitable for phenotypic reconstruction of wheat plants at the spike stage and had high accuracy of point cloud reconstruction and phenotype extraction， which provided a low-cost solution for wheat plant phenotyping.

Precise Recognition Method of Cotton Top Buds Based on YOLOv4 Network

Haitao LIU, Xin HAN, Yubin LAN, Lili YI, Baoju WANG, Lihua CUI

2022, 24(8):  99-108.  DOI: 10.13304/j.nykjdb.2021.0536

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In order to achieve non-contact， low-cost accurate detection of cotton top buds， this paper proposed a recognition method based on the YOLOv4 network to detect the cotton top buds in a complex environment. The K-means algorithm was used to cluster the cotton top buds data set， and the anchors was optimized to improve the precision and speed of network detection， and the optimal model was selected through analysis. Compared with the performance of model before and after optimization， and the optimal weight model was compared with other object detection models in the detection performance of cotton top buds. The results showed that the average precision （AP） of optimal model in the test set， precision （P）， recall （R）， F₁ value of the optimize model increased 0.36%， 1.73%， 0.52%， 1.16% compared with the original YOLOv4 model， and the average detection time of a single image shortened 0.28 s； compared with SSD， YOLOv3， Tiny-YOLOV4 models， the optimize model had the highest F₁ value and recognition precision， and its performance was more balanced. The top buds at a backlight state in natural scenes had no effect on model detection， and the detection accuracy of each model decreased at different degrees under occlusion conditions.

Operating Performance of Self-propelled Silage Cassava Stem and Leaf Harvester

Fengguang HE, Ganran DENG, Zhende CUI, Shuang ZHENG, Guojie LI, Ling LI, Shuangmei QIN

2022, 24(8):  109-115.  DOI: 10.13304/j.nykjdb.2021.0392

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Cassava stem and leaf have important silage value， the field performance of 4JMG-190 self-propelled cassava stem and leaf silage harvester was studied to solve the current low level of mechanized harvesting of cassava stems and leaves silage. Using binary quadratic regression orthogonal rotation combined design test method， the regression equations were established between disc cutter speed and forward speed with loss rate and breakage rate. The anahysis of variance showed that disc cutter speed and forward speed had extremely significant influence on loss rate and breakage rate. The minimum loss rate parameter combination conditions were the disc cutter speed 500 r·min^-1 and the forward speed 2.6 km·h^-1， under which the theoretical loss rate was 10.04%， and the theoretical breakage rate was 6.19%. The minimum loss rate parameter combination was tested through the verification test， and the results showed that the relative error between the actual and theoretical values of the loss rate and the broken head rate were both within 5%， and the optimization results were reliable. The harvester could meet the requirements of mechanized harvesting of cassava stem and leaf silage， and the combination of the lowest loss rate parameters provided references for its field operation parameters.

ANIMAL AND PLANT HEALTH

Effect of BC98-Ⅰ and B96-Ⅱ Fermentation Broth on Potato Disease Prevention and Growth and Its Effect on Soil Enzyme Activity

Bianqing HAO, Liping MA, Yongsheng ZHAO, Wenxin SHI, Jianxiong WANG, Yuchuan JING

2022, 24(8):  116-123.  DOI: 10.13304/j.nykjdb.2021.0404

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To study the control effect of the fermentation broth of Bacillus cereus BC98-Ⅰ（T1） and Bacillus subtilis B96-Ⅱ （T2） on potato late blight， a plate culture method was used to study the inhibitory effects of the fermentation broth of T2 and T1+T2 mixture on Phytophthora infestans in potato. The control effects of the fermentation broth of T2 and T1+T2 on potato late blight and potato growth were studied through pot experiment and field experiment. The results showed that 2 fermentation broths could significantly inhibit the mycelial growth of potato late blight pathogen. In the pot experiment and field experiment， it was found that the two fermentation broths could significantly promote the growth of potato plants and increase the potato yield， which the promoting rate reached 54.74% and the yield of potato increased 35.51% compared with CK. At the same time， it was also found that the 2 fermentation broths had good control effects on potato late blight with the highest control efficiency 78.98%. In addition， the activities of peroxidase， urease， phosphatase and sucrase in soil significant increased after application of two fermentation broths. In conclusion， the fermentation broths of T2 and T1+T2 could not only increase potato yield， but also had a better control effect on potato late blight， and had potential value for developing biological pesticide against potato late blight， which provided theoretical and technical support for effective control of potato late blight in Shanxi.

Selection of Cotton Fusarium Wilt and Culture Conditions

Yan LIU, Hongshuai BAO, Hongyan SHANG, Guoning WANG, Yan ZHANG, Xingfen WANG, Zhiying MA, Jinhua WU

2022, 24(8):  124-132.  DOI: 10.13304/j.nykjdb.2021.0958

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Fusarium wilt is one of the main diseases in cotton production. The cultivation of Fusarium wilt is very important for the identification of resistance to Fusarium wilt. In this study， based on 5 Fusarium wilt races （Quzhou， Jize， Baoding of Hebei Province， and Urumqi， Institute of Plant Protection of CAAS， named as QF， JF， BF， WF， PF， respetively）， 8 culture media and 2 culture temperatures were set up to study the growth rate， the number of spores and the pathogenicity of the spores， so as to select suitable Fusarium wilt and cultivation conditions of pathogens. The results showed that BF produced spores of largest quantity. Jimian 11 as the control inoculated by QF， JF， BF and WF， respectively， were not obviously susceptible after 35 d. PF was the strongest pathogenic. And Jimian 11 inoculated by PF showed Fusarium wilt symptoms after 25 to 30 d. The colony growth rate of Czapek solid medium was 1.29 cm·d^-1， which was significantly higher than other media； the spore production of Fusarium wilt on PSA-200 solid medium was significantly higher than that of PSA-75 and Czapek. The total number of spores on solid PSA-200 was the largest， and the number on solid Czapek was the smallest. The number of spores cultivated on Czapek medium was significantly higher than that on other ones， and the optimal cultivation time was 4 d. The number of spores had no obvious difference between the culture temperature of 25 and 30 ℃. The results provided reference for the selection and cultivation of cotton Fusarium wilt.

Optimization of Serratia marcescens BRC-CXG2 Fermentation Medium Based on Response Surface Methodology

Jinrong LI, Tong ZHOU, Yiqi LIN, Zuohua HUANG, Liangjing SHENG, Feiping ZHANG, Songqing WU

2022, 24(8):  133-143.  DOI: 10.13304/j.nykjdb.2022.0422

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In order to develop the application of Serratia marcescens in the control of Monochamus alternatus， the medium formulation of Serratia marcescens was optimized in this study. The carbon source， nitrogen source and inorganic salt of S. marcescens fermentation medium were screened by single factor test， and 3 main influencing factors were determine by Plackett-burman design. The composition of the medium was optimized by the steepest climbing test combined with Box-Behnken Design and response surface analysis， and the optimal medium formula and fermentation conditions were obtained： glucose 23.27 g·L^-1， soybean cake meal 22.37 g·L^-1， yeast extract 10 g·L^-1， MgSO₄ 2 g·L^-1， Na₂HPO₄ 3 g·L^-1， NaCl 2 g·L^-1. At 28 ℃， 150 r·min^-1 for 36 h， the volume fraction of liquid was 50 mL/250 mL， the inoculation amount was 4.73 %， pH 7.1~7.3. Finally， according to the optimal culture conditions， the number of bacteria growing in the optimized medium was 6.0×10⁹ cfu·mL^-1， 9.42 times of the initial medium， which was consistent with the predicted value of the model. These results provided theoretical basis for the fermentation production of S. marcescens and provide a new approach for the control of pine wilt disease.

BIO-MANUFACTURING & RESOURCE AND ECOLOGY

Evaluation of Pollution Risk and Source Analysis of Heavy Metals in Greenhouse Soils in Wumeng Mountain Area， Guizhou Province

Guanqun CHAI, Guihua LIU, Wei ZHOU, Xiujin ZHANG, Longpin LI, Chengwu FAN

2022, 24(8):  144-153.  DOI: 10.13304/j.nykjdb.2021.0890

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To evaluate the degree of heavy metal pollution and ecological risks in the soil of vegetable greenhouses in Wumeng mountain area of Guizhou province， 4 vegetable bases in Wumeng mountain area of Guizhou province was taken as the research object. 144 soil samples form greenhouse field and 68 soil samples from nearby open field were used to determined the pH and contents of Cd， Hg， As， Pb， Cr， Cu， Zn and Ni. The degree of soil heavy metal pollution and ecological risk in the study area were evaluated. Multivariate statistics and profile differentiation were used to comprehensively analyze the main sources of heavy metal pollution in the topsoil of greenhouse in the study area. The results showed that vegetables cultivation in greenhouse fields accelerated soil acidification. Soil pH in greenhouse decreased 0.24 compared with open field soil. In the study area， the percentage of heavily contaminated soil sample points in topsoil of the greenhouse and open field were 53.57% and 42.86%， respectively， and the percentage of sample points with medium or higher ecological risk were 82.14% and 57.14%， respectively. The Cd was the most important ecological risk factor in the study area. In topsoil of the greenhouse， the As， Pb， Cr， Cu and Ni were mainly derived from the weathering of parent materials， while the Cd， Hg and Zn were mainly derived from the weathering of parent materials and agricultural inputs. In conclusion， the degree of heavy metal contamination in the greenhouse was higher than that in the open field， so the input of exogenous Cd， Hg and Zn should be controlled and the monitoring of heavy metal in agricultural products should be strengthened in greenhouse fields of study area， which provided theoretical support for the safe production of agricultural products in the Wumeng mountains of Guizhou.

Effect of Low Phosphorus Stress on Cadmium Uptake in Wheat

Ruiqi JIA, Ziang GUO, Chen YAO, Pu LI, Guixiao LA, Xiazi LU, Hongyu GUO, Xuanzhen LI

2022, 24(8):  154-160.  DOI: 10.13304/j.nykjdb.2022.0115

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In order to explore the changes in the physiology and morphology of wheat roots under low phosphorus stress and its effect on the uptake capacity of cadmium， this paper investigated the morphological and exudate changes of wheat roots under low phosphorus stress with Ca₃（PO₄）₂ as the phosphorus source， and the effects of these changes on the mobilization and uptake of insoluble cadmium （CdCO₃） through sand culture study. The results showed that low phosphorus treatment decreased the biomass of wheat by 27.3% compared to the control （P<0.05）， as well as decreased root length， root surface area and root volume significantly （P<0.05）. In addition， low phosphorus treatment reduced the plant phosphorus contents of aboveground and underground by 35.4% and 23.1% （P<0.05）， respectively， but promoted the dissolution of insoluble phosphorus （P<0.05）. It was also found that low phosphorus stress significantly increased the cadmium content and total mobilization of cadmium in wheat plants by 190.8% and 82.8% （P<0.05）， respectively. The pH of the medium reduced by 0.3 under low phosphorus stress， while the oxalate and malate contents in the roots significantly increased by 1 588.1% and 37.7% （P<0.05）， suggesting that wheat might promote phosphorus mobilization， as well as cadmium， through secreting proton and carboxylate roots under low phosphorus stress， which caused the increase of cadmium uptake in wheat. These results elucidated the mechanism by which low phosphorus stress affected cadmium uptake in wheat.

Effect of Mowing Treatment on the Main Season Whole Plant Biomass and Silage Quality and Yield in Regeneration Season of Ratooning Rice

Yuanwei CHEN, Huabin ZHENG, Weiqin WANG, Na KUANG, Youyi LUO, Dan ZOU, Qiyuan TANG

2022, 24(8):  161-171.  DOI: 10.13304/j.nykjdb.2021.0117

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To evaluate the effects of mowing time and stubble height on biomass， silage quality of main season rice and yield of regeneration season， Xiangliangyou 900 and Yongyou 4149 were used as cultivars， and a field experiment was conducted at Datonghu District， Yiyang City， Hunan Province. The mowing times were set including 10 （P10）， 15 （P15）， 20 （P20）， 25 （P25） and 30 d （P30） after full ear， while the stubble heights were set including 10 （H10）、20 （H20） and 30 cm （H30）. The biomass， silage quality of main season rice and yield of regeneration season in different treatments were determined. The results suggested that delaying harvesting time by 10~15 d significantly improved the dry matter production and the quality， V-score， fermentation quality of silage in main season rice. Compared different treatments， P10H20 treatment showed the highest dry matter production， appearance， fermentation and nutrient quality. The yield of regeneration season showed a downward trend with the delay of cutting time， and the yield of the regeneration season in P10H15 treatment was significantly higher than those in P20 and P30 treatments， and the yields of the regeneration season in H20 and H30 treatments were significantly higher than those in H10 treatments. Therefore， for the purpose of harvest whole plant silage， the main season should adopt the mowing time at 25~30 d after full ears with stubble height 10~20 cm， which had high biomass， better sensory quality， fermentation quality and nutritional quality； for the purpose of harvesting rice in the regeneration season， the first season should be mowed at 10~15 d after full ears with stubble height 20~30 cm， which had high yield.

Effects of Machine Harvesting Planting Methods on Photosynthetic Characteristics and Dry Matter Accumulation of Different Plant Types of Cotton

Ling LI, Helin DONG, Pengcheng LI, Liwen TIAN, Chunmei LI, Yunzhen MA, Na ZHANG, Fang WANG, Wenxiu XU

2022, 24(8):  172-181.  DOI: 10.13304/j.nykjdb.2021.0122

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In order to study the suitable mechanized cotton planting methods for different plant types of cotton， with Zhongmiansuo 96A （loose plant type） and B9 （compact plant type）as materials， 3 planting methods were set up： one film with three rows（R3）， one film with four rows（R4） and one film with six rows（R6）. The change characteristics of leaf area index （LAI）， net photosynthetic rate （P_n）， dry matter accumulation and yield of cotton under different planting methods were studied. The results showed that LAI and P_n were better under the treatment of R3 in Zhongmiansuo 96A. Compared with the other two planting methods， the dry matter accumulation duration of reproductive organs under the treatment of R3 in Zhongmiansuo 96A prolonged 5 d， and the yield of seed cotton increased 4.76% and 6.73%， respectively. P_n of B9 was higher under the treatment of R6. Compared with the other two planting methods， the duration of dry matter accumulation in reproductive organs of B9 under R6 treatment prolonged 2 d， the dry matter accumulation in reproductive organs increased 8.52% and 4.23%， and the yield increased 9.00% and 12.16%， respectively. The suitable planting methods of cotton with different plant types were different. The loose type Zhongmianuso 96A was suitable for one film three rows planting mode， and the compact type variety B9 was suitable for one film six rows planting mode.

Effects of Different Sowing Rates and Sowing Methods on the Nutrient Absorption， Utilization and Yield of Winter Rapeseed in Yellow Soil

Quanquan WEI, Ying GAO, Jiulan GOU, Meng ZHANG, Yong RAO, Bin YANG, Di FAN, Wenhao FENG, Huagui XIAO

2022, 24(8):  182-191.  DOI: 10.13304/j.nykjdb.2021.0271

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To study the effects of sowing methods and sowing rates on nutrient utilization and yield of winter rapeseed in yellow soil， taking ‘Yangguang 131’ as material in Qianxi county of Guizhou province， the sowing methods were set including sow broadcast （SB）， sowing in drill （TB） and sowing in hole （XB）， and the sowing rates were set including 3.0， 4.5， 6.0， 7.5 and 9.0 kg·hm^-2 to determine the biomass， nutrient absorption and utilization， yield and its components of different treatments. The results showed that， under the same sowing rate， the biomasses， accumulations of nutrients， fertilizer use efficiencies and yields under TB treatments were higher than those under SB and XB treatments， and firstly increased and then decreased with the increase of seeding rates under same sowing method， which were higher with sowing rate 6.0 kg·hm^-2. The biomasses of TB6.0 treatment in 2018—2019 and 2019—2020 were 9 798 and 10 351 kg·hm^-2， respectively， which were higher than other treatments by 615~3 196 and 254~2 714 kg·hm^-2. The average accumulations of nitrogen， phosphorus and potassium of TB6.0 treatment were 129.8， 32.6 and 213.9 kg·hm^-2， respectively， which were higher than other treatments. And the average yield of TB6.0 treatment were 2 657 kg·hm^-2， which increased by 14.6% and 7.6%， respectively， compared with SB6.0 and XB6.0 treatments. In conclusion， in the case of non-thinning and uneven seedlings， the suitable sowing method for winter rape in Guizhou was sowed in drill with seeding rate 6.0 kg·hm^-2， which provided theoretical and scientific basis for scientific planting of winter rapeseed in yellow soil of Guizhou.

Effect of NaOH Pretreatment on Anaerobic Fermentation Characteristics of Hulless Barley Straw

Li LIU, Zhongping DU, Yi LI, Laisheng CHEN, Rui HAN

2022, 24(8):  192-200.  DOI: 10.13304/j.nykjdb.2022.0304

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In order to increase the comprehensive utilization rate of hulless barley straw， NaOH was used to pretreat hulless barley straw. The effects of different level NaOH and pretreatment time on anaerobic fermentation performance were studied， and the feasibility of NaOH in anaerobic fermentation of hulless barley straw was explored. The results showed that compared with the untreated hulless barley straw， the hulless barley straw pretreated with NaOH could significantly improve the performance of methane production （P<0.05）， and the production rate of methane gas was faster and the fermentation period was shorter. The cumulative methane production of hulless barley straw treated with 5% NaOH for 12 h was higher than most lignocellulosic wastes， reaching 250.03 mL·g^-1. It indicated that the hulless barley straw was an excellent raw material for anaerobic fermentation. NaOH pretreatment increased cellulose content （13.37%~39.31%） in hulless barley straw and effectively degraded lignin （12.89%~64.34%） and hemicelluloses （0.96%~30.30%）. The study showed that NaOH pretreatment was an effective method to improve the performance of methane production by anaerobic fermentation of hulless barley straw.

Effect of Fox Raccoon Manure on the Growth and Development of Black Soldier Fly

Shuxin QI, Xiaolei WEN, Tingfeng JI, Zengzhi SI, Chunming ZHAO, Yake QIAO, Yanmin WANG, Aijun CAI, Haihua ZHANG, Zhixin JI

2022, 24(8):  201-206.  DOI: 10.13304/j.nykjdb.2021.0632

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In order to study the effect of fox raccoon manure on the growth of black soldier fly， pre-pupa and pupal development， adult duration， and feed coefficient， they were feeded at 20~25 ℃ with humidity of 70%~80% taking fox raccoon manure as the main feed and adding different proportions of basic materials （wheat bran， soybean meal and corn flour）. The results showed as followed：under the treatment of 30% fermentation mixture + 70% base material， the weight of mature larvae， pre-pupa weight， and pupa weight were 156.0， 108.8 and 60.2 mg， respectively， which were significantly higher than those of the control group， and the pre-pupa period and the pupa period were 7 and 6 d， respectively， which were significantly shorter than those in the control group； the survival rate， pupation rate， and emergence rate of the black water fly with 30% fermentation mixture + 70% base material were higher， which were 93%， 88% and 91%， respectively； under the 50% fermentation mixture + 50% base material treatment， except for the larvae body weight significantly lower than the 30% fermentation mixture + 70% base material treatment， there were no significant differences in other indicators.Comprehensive analysis believes that 30%~50% fermented mixture was the most suitable for the growth and development of black solider fly.

MARINE AGRICULTURE & FRESHWATER FISHERIES

Research on the distribution and Types of Fishing Vessels in the North Pacific Based on Satellite Ship Position Data

Yongwen SUN, Shengmao ZHANG, Fenghua TANG, Shuxian WANG, Wei FAN, Xiumei FAN, Shenglong YANG

2022, 24(8):  207-217.  DOI: 10.13304/j.nykjdb.2022.0001

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Satellite data can accurately obtain real-time vessel positions， but cann’t intuitively reflect the dynamic distribution of and type of fishing vessels during operation. In order to understand the distribution of fishing grounds and the types of fishing vessels in the high seas of the North Pacific Ocean， this article analyzed and discussed the dynamic distribution changes of fishing vessels operation and its identification based on the satellite data of fishing vessels in the North Pacific from March to December in 2019 and the actual production data of purse seiners and squid fishing vessels in the North Pacific during the same period， using hot spot analysis in local spatial autocorrelation method， using the actual production data to superimpose and verify. The results showed as follows： in 2019， fishing vessels operation in the North Pacific were mainly distributed in 37°—44°N， 154°—176°E； most fishing vessels first moved from southwest to northeast in the main operating distribution area， then turned back to northwest， and then turned back to southwest in September and later； the overlapping rate of hot spot distribution and actual squid fishing vessels operating point reached to 83.7%， the overlapping rate of the cold spot distribution and the actual purse seiner operating point was 78.1%. By observing the overall trajectory change of the distribution of fishing vessels in each month， it was initially judged that the distribution of hot spots should be squid fishing vessels， and the distribution of cold spots should be purse seine fishing vessels， but other technical means or data were still used to further verify and improve the overlap rate， such as the luminous remote sensing technology or combined with the maritime mobile service identifier （MMSI） of the fishing vessels correspond to the verification of the fishing vessels type. This paper proposed a method to visually display the dynamic changes of fishing vessels operation and the degree of their overlap rate based on satellite fishing vessels data and production data. This method preliminarily explored the distribution changes and types of fishing vessels in the study area， and provided reference basis and related methods for sustainable management of fisheries.