Issue Ebookcover storyIssue CoverIssue Contents
List of IssuesDocument Types
- Abstract：In order to improve understanding of the global regulatory status of GM and gene-edited crops, biosafety management relevant articles since 2004—2022 from CNKI, Google Scholar, Web of Science and other websites were obtained. In this study, an overview of the regulatory framework for biotechnology in our country was presented. Comprehensively comparisons with regulations regarding GMO and gene-edited crops across different countries were then conducted. The results suggest that regulatory attitudes towards GM and gene-edited crops vary across countries. Rather than copying the experience of GMO management system, more and more countries have adjusted legislation or issued new regulations on gene editing technology. In 2022, the “Guidelines for Safety Evaluation of Gene-Edited Plants for Agricultural Use(Trial)” was promulgated in China, which promoted the commercialization of gene-edited plants. Finally, the commercialization of GMOs in China still has some problems such as complicated and time-consuming approval process. Based on the above findings, it is proposed that regulatory agencies and academic groups should strengthen exchanges, establish and improve safety management systems, and promote basic research towards practical applications.Keywords：agricultural biotechnology;crops;transgene;gene editing;safety assessment33|34|8<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：In order to clarify China's role in the innovation chain of gene editing crop breeding, this study systematically analyzed the evolution logic and latest development trend of the global gene editing breeding innovation chain from three dimensions as follows: knowledge principle, application technology and product development. The results show that: 1)Most of the global R&D resources are mainly concentrated in the development of applied technology and the creation of germplasm resources in the intermediate links. There are relatively few commercially applied products at the end of the innovation chain, especially in China, where there is no commercialized gene editing varieties; 2)The scope for further fundamental knowledge innovation of gene editing is very limited. As a popular technology, gene editing will focus on creating breeding materials and germplasm resources with new functions by using gene editing tools in the future; 3)Commercial product development is currently the weakest link in the gene editing innovation chain, and only the development of gene editing results that can meet the market demand and have significant social and economic benefits is meaningful. Some countermeasures and suggestions are put forwarded to establish an efficient gene editing crop breeding innovation system and accurately locate the development goals in our country. This study provides a reference for decision-making in building an innovation value chain with Chinese characteristics.18|24|3<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：To investigate the role of the CDS region and promoter sequence of the GbHCT14 gene in cotton fiber development, the CDS region and the upstream non-coding region of the GbHCT14 gene -2 000 bp were retrieved from the database of the Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Cotton. fragment, clone the CDS region and promoter, and detect the promoter activity. The cDNA library was constructed, positive clones were screened using yeast single hybridization technique to obtain candidate transcription factors, and bioinformatics analysis was performed. The results showed that: 1)The CDS region of GbHCT14 gene is 1 144 bp long, and its translation product is a hydrophilic stable protein predicted to be localized on chloroplasts without signal peptide and transmembrane structural domains. 2)The promoter of GbHCT14 gene predicts five MYB binding sites involved in the regulation of plant phenylpropane metabolic pathway, one TCA-element involved in salicylic acid regulation, and six ABA response elements. 3)The GbHCT14 promoter is able to drive GUS protein expression with initiation activity. 4)Yeast single hybridization initially screened 16 candidate genes, including Gbar_D01G020710, Gbar_A09G017360, Gbar_A09G009680, Gbar_A11G003660, Gbar_A12G004430, Gbar_D04G021210, GbM_D09G1212, GbM_A11G0186, GbM_A03G0171, GbM_A09G1247, GbM_D10G0411, GbM_D10G1024, GbM_D02G1379, GbM_A11G1190, GbM_D12G0471 and genome_Gbar-ZJU_D08. Using bioinformatics analysis, these candidate genes were predicted to be involved in fiber cell wall elongation, ubiquitination response, cell division, flower development, and fruit ripening, with GbM_A09G1247 being a similar gene to WAK2, and the WAK2 functional protein binding to GbM_A09G1247 and WAK2 are similar genes, and WAK2 functional protein binds to pectin to promote cell wall elongation, while HCT family genes are one of the key factors affecting pectin synthesis. 5)GbHCT14 and WAK2 genes are highly expressed in cotton within 25 d post-anthesis, and there is a correlation between them for the regulation of cotton fiber development. In summary, the CDS region and promoter sequence of GbHCT14 gene were obtained for the first time, and the promoter of GbHCT14 gene was identified to have driver activity, and 16 candidate transcription factors related to lytic enzymes, transferases, phytohormones, proton pumps and functional proteins were screened.Keywords：Gossypium barbadense;HCT;gene;promoter;transcription factor17|26|0<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：The aim of this study was to determine the appropriate amount of drip irrigation for spring corn planting in the central and western regions of Inner Mongolia. Based on the long-term positioning experiment started in 2018 conducted by the experimental base of the Academy of Agriculture and Animal Husbandry Sciences of Inner Mongolia Autonomous Region, six different drip irrigation treatments, 312(W1), 645(W2), 945(W3), 1 275(W4), 1 605 m3/hm2(W5)and rain-fed without irrigation(W0), were designed to determine the soil water characteristics in 0-60 cm soil layer at different growth periods of maize and the yield differences in 2019 and 2020. The results showed that: With the increase of drip irrigation amount, the water consumption of maize increased gradually during the whole growth period, and the economic yield increased first and then decreased. The utilization efficiency of irrigation water decreased gradually with the increase of drip irrigation amount. The yield and water use efficiency of W4 were better than those of other treatments. The maximum economic yield of maize reached 16 952. 9 kg/hm2 in 2019 and 16 802. 84 kg/hm2 in 2020. Among all treatments, the yield of W4 treatment was the highest in both years. The economic yield of W4 treatment in 2019 was significantly higher than that of other treatments, and the economic yield of W4 treatment in 2020 was 77. 2% and 7. 3% higher than that of W0 and W5 treatment, respectively. The water use efficiency of W4 was significantly higher than that of W5 treatment in 2019, which ranked the third place among all treatments. In 2020, maize in W4 treatment had displayed the highest water use efficiency among all treatments, which was significantly higher than that of W0, W1 and W5 treatments. In conclusion, the 1 275 m3/hm2 drip irrigation can effectively improve spring maize yield and the water use efficiency in the central and western regions of Inner Mongolia.Keywords：drip irrigation;corn;water consumption;yield;water use efficiency36|36|5<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：To clarify the impact of straw returning to the field and increasing nitrogen fertilizer application on rice yield and nitrogen uptake and utilization in cold regions, a two-factor fully randomized pot experiment was designed. Rice yield, nitrogen accumulation, nitrogen production efficiency, and nitrogen utilization efficiency were measured under four different treatments including straw leaving the field(S1), returning to the field(S2), conventional nitrogen(N1)and tillering fertilizer increasing nitrogen treatments(N2). The results showed that: Under S2 condition, the biological yield and grain yield of rice respectively decreased by 3. 18% and 3. 90%, and the nitrogen accumulation and spike nitrogen increase respectively decreased by 9. 34% and 6. 48%, respectively. Nitrogen dry matter production efficiency and nitrogen rice production efficiency respectively increased by 6. 87% and 6. 34%. Under the condition of returning straw to the field, the biological yield and yield under the treatment of tillering fertilizer and nitrogen respectively increased by 4. 60% and 4. 38%. Compared with those under the conventional nitrogen application, the nitrogen accumulation and the increase of nitrogen spike respectively increased by 13. 69% and 11. 69%, and the nitrogen dry matter production efficiency decreased by 7. 98%. Compared with S1, the agronomic utilization efficiency, absorption utilization efficiency, and partial factor productivity of nitrogen in S2 respectively decreased by 8. 54%, 15. 77% and 3. 93%. The physiological utilization efficiency increased by 9. 52% compared to that of straw removed from the field. The effect of the interaction between the two factors of straw return and tiller fertilizer nitrogen increase on nitrogen agronomic utilization, absorption utilization and bias productivity reached a highly significant level. Under the condition of returning straw to the field, the nitrogen utilization efficiency of conventional nitrogen application increased by 5. 53% compared with that of tiller fertilizer, and the absorption utilization efficiency and partial factor productivity did not change significantly. Therefore, the tiller fertilizer nitrogen enrichment(N2)under straw return(S2)conditions could significantly increase nitrogen accumulation and spike nitrogen content, significantly improve nitrogen agronomic use efficiency, and thus increase biological yield and rice yield. It is an effective technical approach to achieve high yield and efficient use of nitrogen fertilizer in cold regions of rice.Keywords：rice in cold region;straw return;tillering fertilizer increase nitrogen;nitrogen fertilizer utilization rate22|38|3<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：In order to verify the scientific nature of the advanced decision irrigation model in soil cultivation and screen the optimal irrigation quantity combination based on the advanced decision irrigation model, the Penman-Monteith model(PM treatment)was used as the control. Three levels(0. 8 ET, 1. 0 ET, 1. 2 ET)of irrigation quantity(ET)calculated by advanced decision irrigation models were set at flowering stage and fruit expansion stage of tomato with a total of 10 treatments. The effects of different irrigation models on soil water content, physiological indexes, yield, quality and water use efficiency of tomato were analyzed and compared, and the comprehensive indexes of tomato under different treatments were evaluated by entropy weight-topsis method. The results show that: Compared with the control, the fluctuation of soil water content was smaller under the advanced decision irrigation model, and the photosynthetic capacity, plant yield and water use efficiency were significantly improved. The results of entropy-topsis comprehensive analysis showed that the T2-3 treatment(1. 0 ET irrigation at flowering stage, 1. 2 ET irrigation at fruit expansion stage)ranked the first, the PM treatment at autumn crop tomato(PM model irrigation)ranked the eighth, and the PM treatment at spring crop greenhouse tomato ranked the 10th. Compared with the PM treatment, the net photosynthetic rate of greenhouse tomatoes under the optimal treatment of treatment T2-3 in autumn and spring stubble was 9. 7% and 24. 3% higher, respectively. The transpiration rate decreased by about 16. 5% and 14. 6%, and the yield and water use efficiency increased by 4. 7%, 8. 7% and 0. 8%, 9. 5%, respectively, compared with PM treatment. Therefore, the irrigation precision of advance decision irrigation model was higher than that of the PM model in greenhouse tomato cultivation in spring and autumn. In addition, 1. 0 ET irrigation at flowering and fruiting stage and 1. 2 ET irrigation at fruit expansion stage were the optimal irrigation quantity combination for the advanced decision irrigation model.Keywords：advanced decision irrigation model;Penman-Monteith model;greenhouse tomato soil cultivation;entropy weight TOPSIS comprehensive analysis17|27|2<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：Although there are many methods for constructing crop development stage models, only a few studies were on constructing the models for chili peppers. And the research on development stage models focuses on the accuracy of simulation and ignores the applicability. To address above problems, two crop experiments and two pepper varieties were explored. Four methods with effective accumulated temperature method, linear subsection function, exponential function and power exponential function and two calculation steps(days and hours)were adopted to establish and validate a simulation model of pepper development period. The correlation between the best model and the price of pepper was established. The results show that: 1)The effects of models constructed by the four methods from high to low were power index function>linear segmentation function>exponential function>effective accumulated temperature method. The root mean square error of the power index function model between 5. 77 to 8. 10 d, the mean relative error was from 5% to 7%, and the mean absolute error is between 3. 33 to 5. 00 d; 2)In addition to effective accumulated temperature method, improving the calculation accuracy can effectively reduce the simulation error by taking h as a step size of each model; 3)The simulated days from planting to harvesting of pepper at different time points are between 56-159 d, and the corresponding average price of harvesting period was between 2. 93-6. 48 yuan/kg. When pepper variety ‘Donglang' was planted on September 16th, the average price during the harvest period was the highest, at 6. 48 yuan/kg. Pepper variety ‘Huanle' had the highest average price during the harvest period when it was planted on October 1 st, at 6. 40 yuan/kg. This study provides a reference for the majority of researchers to choose a suitable model, and a theoretical basis for growers to reasonably measure the planting time and obtain the maximum benefit.Keywords：pepper;greenhouse;simulation model;physiological development time;price13|24|1<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：In order to screen high-affinity persimmon hybrid parental combinations, a total of 19 hybrid combinations were designed with 4 excellent sweet persimmon varieties as female parents and 8 persimmon specific male germplasms(varieties)as male parents, and artificial control cross pollination was carried out. The compatibility of hybrid parents was analyzed by counting the fruit setting rate and the number of seeds obtained at 8 weeks after flowering of each hybrid combination, and the immature embryo of immature seeds was rescued by embryo rescue tissue culture. After obtaining hybrid F1 seedlings, the female and male and sweet and astringent traits were identified by molecular markers. The results show that: 1)There were significant differences in pollen viability among the 8 male parents, among which, the pollen viability of the wild male plant(Male 8)carrying the Chinese persimmon gene was the strongest, reaching 90. 38%, and the in vitro germination rate was 45. 89%. The pollen viability of monoecious ‘Nishimurawase' was the worst, its germination rate was only 35. 29%. 2)The pollen of male 8 and ‘Taishuu' could germinate normally on the stigma of ‘Youhou', ‘Fuyu' and ‘Luotian-tianshi'. 3)The compatibility of different hybrid combinations was significantly different. The fruit setting rate and compatibility index of ‘Youhou' × Male 8 hybrid combination were the highest, which were 48. 39% and 1. 56, respectively. The fruit setting rate and affinity index of the hybrid combination of ‘Fuyu' × ‘Nishimurawase' were the lowest, which were 5. 53% and 0. 05, respectively. 4)The immature seeds were cultured by embryo rescue tissue culture, and 705 in total hybrids were obtained. After early identification of female and male and sweet and astringent molecular markers, a total of 359 female plants and 346 male plants, 363 complete sweet persimmons and 342 incomplete sweet persimmons were identified, of which 181 were female plants that met the breeding objectives. This study provided a theoretical guidance and material basis for cross breeding and new germplasm innovation of sweet persimmon.Keywords：persimmon;hybrid offspring;parent selection;affinity;affinity index20|34|3<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：To establish an in vitro isolation, culture and identification system for chicken chondrocytes, 15-day-old chicken embryos were selected as the test material and chicken embryo cartilage tissue was digested by two-step digestion method of 0. 25% trypsin and 0. 2% type II collagenase; chondrocytes were identified by cytomorphological observation and immunofluorescence detection of the chondrocyte marker protein Col II. The growth curve of chicken primary chondrocytes was determined by CCK-8 method to observe the growth pattern of chondrocytes. The differentiation medium was used to induce the differentiation of chondrocytes into osteoblasts in a targeted manner, and then the differentiation ability of chondrocytes was identified by alizarin red staining; Finally, the relative expressions of key genes in the osteogenic process were detected by fluorescence quantitative PCR(qPCR). The results showed that: 1)Chondrocytes with high purity were isolated, and the freshly isolated cells were spherical, and the cells were shuttle-shaped or polygonal after apposition. 2)The chondrocyte-specific marker protein Col Ⅱ was identified as positive, confirming that the isolated cells were chondrocytes. 3)The growth curve of chondrocytes was roughly “S”-shaped, and the cell proliferation process went through latent phase, growth phase, plateau phase and finally reached the decay phase, which was consistent with the normal chondrocyte proliferation process. 4)After inducing osteogenic differentiation, the cell morphology became irregular and round opaque calcified nodules were visible by alizarin red staining, and the number and density of cells increased significantly, indicating that chondrocytes were successfully induced to osteogenic differentiation. 5)The marker genes of osteogenesis, RUNX2(RUNX Family Transcription Factor 2), SOX9(SRY-Box Transcription Factor 9), NELL-1(Neural EGFL Like 1)and GDF-5(Growth Differentiation Factor 5)were highly significantly increased(P<0. 01). In conclusion, a two-step digestion-based method was established for the isolation of chicken embryonic chondrocytes, and the isolated chondrocytes were of high purity and good proliferation ability, which laid the foundation for further investigation of the role of chondrocytes in poultry skeletal development and cartilage-like disease treatment.Keywords：chicken;chondrocytes;isolation and culture;identification;osteogenesis differentiation14|24|1<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：To explore the potential function of miR-370-3p associated with reproductive function and its targeting relationship with COL4A3 in the thyroid tissue of Small Tail Han(STH)sheep, this study predicted the target genes of miR-370-3p using the miRDB website and Targetscan website, and took their intersections for functional enrichment analysis, and the binding site of sheep miR-370-3p to candidate target genes were predicted by the RNAhybrid and Targetscan website. Subsequently, the relative expression levels of miR-370-3p and COL4A3 in the thyroid tissue of STH sheep were detected. The psiCHECK2-COL4A3-3′UTR wild-type(WT)/mutant-type(MT)Dual- luciferase reporter vectors were constructed, and co-transfected with miR-370-3p mimics/ mimics NC into HEK293T cells to detect fluorescence activity. The results showed that: 1)The target genes of miR-370-3p were enriched in progesterone-mediated oocyte maturation, oocyte meiosis, HIF-1 signaling pathway, MAPK signaling pathway, mTOR signaling pathway, Ras signaling pathway, FoxO signaling pathway, and other signaling pathways related to animal reproduction. 2)RT-qPCR results showed that the expression of miR-370-3p and COL4A3 in the thyroid tissue of STH sheep showed an opposite trend. 3)The luciferase activities of co-transfected psiCHECK2-COL4A3-3′UTR-WT and miR-370-3p mimics were significantly lower than co-transfected psiCHECK2-COL4A3-3′UTR-WT and miR-370-3p NC mimics group, co-transfected psiCHECK2-COL4A3-3′UTR-MT and miR-370-3p mimics group, co-transfected psiCHECK2-COL4A3-3′UTR-MT and miR-370-3p mimics NC group(P<0. 05). There was no significant difference among the other three groups(P>0. 05). The above results indicated that miR-370-3p targets and binds COL4A3-3′UTR and inhibits its transcriptional activity, suggesting that miR-370-3p can target binding to COL4A3-3′UTR region, providing a basis for further studies on the molecular mechanism of miR-370-3p affecting sheep thyroid function and sheep fertility.Keywords：sheep;miR-370-3p;COL;4;A;3;thyroid gland;high fertility31|30|3<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：In order to study the cashmere fineness of Tibetan cashmere goats and understand the effects of related candidate genes on cashmere production performance of cashmere goats, this study verified the screening of chi-miR-105a target genes. Taking Tibetan cashmere goats as the research object, RNA sequencing data and proteomics data were combined to screen key candidate genes related to cashmere fineness, and the regulatory effects of candidate genes were verified by real-time fluorescence quantification and dual luciferase reporter gene assay. The results showed that: 1)384 DE mRNAs, 12 DE miRNAs and 29 DEPs were obtained from transcriptome and proteome data. Through multi-omics joint analysis, it was found that CXCL10, SRC, CXCL9, FOS, ETV6, GMPS, PIP5K1B genes were associated with wool fineness. 2)Through the DEG-DE miRNA interaction network diagram, it was found that chi-miR-105a and target genes ETV6 and PIP5K1B appeared in the network. Therefore, the regulatory factor was verified and analyzed. According to the target gene expression level test, it was found that the mRNA expression of ETV6 gene in dermal papilla cells was significantly decreased after transfection of chi-miR-105a mimics(P<0. 001), while the expression of PIP5K1B gene was not significantly changed. 3)Double luciferase reporter gene assay showed that ETV6 enzyme activity was significantly decreased after overexpression of chi-miR-105a, that is, chi-miR-105a could bind to the 3′UTR region of ETV6. In summary, CXCL10, SRC, CXCL9, FOS, ETV6, GMPS and PIP5K1B related to wool fineness were screened by multi-omics combined analysis. The target of chi-miR-105a and its predicted target genes ETV6 and PIP5K1B was verified by dual luciferase reporter gene, and chi-miR-105a was identified as a potential regulator of ETV6. This study provided a theoretical basis for accelerating the cultwation of new varieties(lines)of high-quality cashmere goats.Keywords：Cashmere goats;joint multi-omics analysis;chi-miR-105a;ETV;625|27|2<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：To study the secretion of plasma progesterone(P4)and the expression of progesterone receptor(Progesterone receptor, PGR)in the HPO axis of Ganjia Tibetan sheep(Ovis arise)during the estrus cycle, and to analyze its regulatory effect on the reproductive activity of Tibetan sheep, in this study, enzyme-linked immunosorbent assay(ELISA), Western blotting, Real-time fluorescence quantification and immunohistochemistry staining were used to detect the dynamic changes of progesterone in plasma of Ganjia Tibetan sheep during estrus cycle and the expression and distribution of PGR mRNA and its protein in HPO tissues. The results showed that: 1)The secretion of progesterone in the plasma of Ganjia Tibetan sheep showed fluctuating and pulsed secretion during the estrus cycle, with the highest value in diestrus and the lowest in estrus, with significant differences(P<0. 05). 2) PGR mRNA and its protein were expressed in HPO tissues. In hypothalamus, the relative expression level of PGR mRNA and its protein was the highest in diestrus, significant differences among different periods(P<0. 05). In pituitary, PGR mRNA reached the highest in metestrus, which was significantly higher than that in proestrus and diestrus(P<0. 05), and the relative expression level of proestrus protein was higher than that in other periods. Among the ovaries, PGR mRNA was the highest in estrus, which was significantly different from that in diestrus(P<0. 05), and the protein expression level was the highest in proestrus. 3)PGR immune reactive products were expressed in hypothalamic glial cells and large neuronal bodies, in the cytoplasm of eosinophils and basophils in adenohypophysis, and in the cytoplasm of granular layer cells, theca cells and luteal cells of growing follicles in ovaries. In summary, the dynamic changes of plasma progesterone content and the differential expression of PGR mRNA and protein in the HPO axis indicate that progesterone regulates the periodic estrus and reproductive organ function of Ganjia Tibetan sheep during the estrus cycle by binding to PGR receptors distributed on the reproductive axis of HPO.Keywords：Ganjia Tibetan sheep;progesterone;progesterone receptor;estrus cycle;hypothalamus-pituitary-ovary axis18|29|2<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：In order to simplify the multi-needle heat-pulse technique for measuring ground heat flux, a simplified heat-pulse sensor for monitoring ground heat flux dynamics under field conditions was proposed in this study based on the theory and design criteria of heat pulse technique. The simplified sensor first measured the heat storage changes in the 0~50 mm soil layer and the soil heat fluxes at the 50 mm depth, and then obtained the dynamic ground heat flux via the sum of heat storage changes and fluxes. Finally, the field data measured by the sensor were compared with the data obtained by the traditional combination method(based on de Vries heat capacity model and heat flux plate method). The results showed that the simplified multi-needle heat-pulse sensor could provide reliable in-situ dynamics of ground heat flux density results. Compared with the results from the independent combination method, the linear regression of the results obtained from the two methods gave a slope of 1. 09 and a coefficient of determination of 0. 98, leading to a MAD value of 12. 33 W/m2 for the measured ground heat fluxes by the simplified sensor. In conclusion, the simplified sensor proposed in this study is effective in monitoring ground heat flux dynamics accurately and can provide reliable research tools for studying the heat and water processes.Keywords：ground heat flux;heat storage;multi-needle heat-pulse technique;combination method22|30|1<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：In order to improve the precision performance for mung bean seeding under the condition of high density planting, a new air-suction mung bean precision seed-metering device was designed in this study. Based on the physical characteristic parameters of mung bean seeds and the agronomic requirements of precision densety planting, the key structural and working parameters affecting the single-seed precision sowing of seed-metering device were determined. By taking ‘Chuanyu Lv No. 1' mung bean variety as research object, single factor test was carried out to explore the influence of working pressure, diameter and number of holes on seeding performance with the qualified rate, multiple rate and leakage rate as evaluation indexes. The structural and working parameters were optimized and verified by central composite design of three factors and five levels of quadratic orthogonal rotation center. The results showed that: The working pressure of 6. 234 kPa, hole diameter of 2. 255 mm and hole number of 60 are the optimal combination. The qualified rate of 98. 75%, multiple rate of 0. 58% and leakage rate of 0. 67% met the design requirements. The qualified rate was more than 97%, multiple rate was less than 1. 5% and leakage rate was less than 2% when the working speed was within 7 km/h. The qualified rate of different varieties of more than 97. 5%, the multiple rate of less than 1% and leakage rate of less than 2% met the technical requirements of mung bean precision sowing under the condition of high density planting and had good variety adaptability. This study provided reference for the design of precision metering device for dense planting of mung bean.Keywords：mung bean;air-suction type;densely-planted;seed-metering device;optimization29|32|4<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：Aiming at indoor shadow, skeleton load increasing and other problems of caused by the rolled up thermal quilt of the external thermal arch shed parked at the top of the arch shed, a conical reel type over-top rolling machine was designed in this study. This machine uses the auxiliary climbing mechanism based on the rope drive principle to climb over the top of the arch shed to roll up and lay insulation thermal quilt. According to the functional requirements, the overall design of the over-top rolling machine was carried out. The over-top rolling machine was mainly composed of four parts as follows: coiling shaft, rocker, main engine and auxiliary climbing mechanism. The design methods of the key parts of the machine for different types of thermal quilts in different structural forms of external thermal arch shed was established, and the calculation method of the structural parameters of the conical reel was designed according to the rolling rules of the thermal quilt. By analyzing the movement and force in the rolling process of the thermal quilt, the calculation method of the maximum working load was obtained, and the selection method of the motor and reducer was determined. The mechanical model of the coiling shaft was established, and the checking method of the coiling shaft is given. Finally, the over-top rolling machine was installed on an external thermal arch shed with the span of 10 m and the length of 48 m. The results show that: The thermal quilt was laid flat and rolled neatly with a good operation effect; The actual running time of the over-top rolling machine was stable and the machine had stable working state. The feasibility of the design scheme was verified by the test under the actual working condition. In conclusion, the conical reel type over-top rolling machine in this study can solve the problems of indoor shadow and skeleton load, and provide new technical support for the performance improvement and application of external thermal arch shed.Keywords：external thermal arch shed;over-top rolling machine;conical reel;structural design18|26|1<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：In order to objectively evaluate the degree of organic matter conversion during composting, the literature published in recent years were searched in China Academic Journal Network Publishing Database(CNKI)and Web of Science Core Collection with “organic solid waste”, “biotransformation” and “organic matter conversion rate” as keywords. The literature related to the research on organic matter conversion were reviewed and summarized. The results show that: 1)Organic matter is mainly transformed by mineralization and humification during composting, and improving the humification degree of organic matter is beneficial to the preservation of carbon. 2)At present, the evaluation methods for organic matter conversion include organic matter loss rate, oxygen consumption, organic matter fraction degradation rate, carbon mass balance method and organic matter degradation model, but these methods still have limitations in practical application. 3)An evaluation method of organic matter conversion is proposed in this study, which was oriented by the target product of composting and the carbon in unstable humus as an indicator. The evaluation method can be used to determine the degradability of composting raw materials, process of composting and quality of composting products and it is scientific, accurate and practical. The results provides method support for the evaluation of organic solid waste recycling effect and promotes the development of composting science and technology.Keywords：composting;organic matter conversion;mineralization;huminification;gaseous emission13|30|3<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：To investigate the spatial and temporal variability of soil hydraulic characteristics parameters under field-scale irrigation conditions, HYDRUS-2D model was used to estimate soil hydraulic parameters at different depths at different growth stages based on soil water content data in the vineyard of Shiyanghe Experimental Station in Wuwei, Gansu Province. The effect of soil water content simulation by inversion parameters was evaluated and its spatial and temporal variability were analyzed. The results showed that: The inversion parameters simulated the variation of soil water content at different depths at the field scale were better than those predicted by the Rosetta model under the same conditions. The values of RMSE and MAE decreased from 0. 04-0. 05 cm3/cm3 and 0. 03-0. 04 cm3/cm3 in the Rosetta model to 0. 03-0. 04 cm3/cm3 and 0. 02-0. 03 cm3/cm3, respectively; Moreover, the soil hydraulics characteristics of the inversions were only applicable to simulations under similar conditions to those involved in the inversion process, and the accuracy of the simulations was significantly reduced when applied to scenarios with different conditions. The three parameters derived from inversion, which were soil saturation hydraulic conductivity(Ks), soil water suction equation parameter(α), and soil pore size distribution coefficient(n), all showed some degree of spatial and temporal variability. Ks and n showed small spatial and temporal variability, and α ranging from 0 to 10 m-1 showed large spatial and temporal variability. In conclusion, this study can provide a scientific basis for accurately predicting changes in soil water content in agricultural fields developing reasonable irrigation systems, and improving water use efficiency.Keywords：soil hydraulic parameters;HYDRUS-2D inversion;parameter evaluation;spatial and temporal variability analysis6|24|0<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：In order to study the influence of policy incentives on rice farmers' willingness to control heavy metal pollution, based on the survey data of typical heavy metal pollution areas in southern China, Binary selection model and mediation effect model was used to study rice farmers' willingness to control heavy metal pollution in major rice producing provinces in southern China. The results show that: 1)The policy incentives of farmland fertility protection subsidy have a significant role in promoting the intention of heavy metal pollution control of rice farmers, and the subsidy funds can directly improve the budget constraints of rice farmers; 2)The subjective norms of farmland land use protection subsidies can change the income expectations of rice farmers, and then affect the willingness of rice farmers to control heavy metal pollution. 3)The effect of farmland land use subsidy policy incentives varies according to the type of farmers. Pure farmers are more vulnerable to the impact of the amount of farmland land use protection subsidies, and part-time farmers are more vulnerable to the impact of the subjective norms of the policy. Based on this, the following countermeasures and suggestions are put forward: Firstly, improving the promotion mode of subsidies and strengthen the subsidies; Secondly, implementing the farmland fertility protection subsidy policy according to the differences of group characteristics; finally, creating conditions to promote the transformation of rice farmers' governance will into behavior.Keywords：farmland fertility protection subsidies;subjective norms;revenue expectations;willingness to control heavy metal pollution;intermediary effect6|24|3<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：Photovoltaic power generation is an important clean energy development strategy in China, and it is also an important way to help the poor, reduce carbon emissions and improve the ecological environment in rural areas. This study takes the 150 MW rural distributed photovoltaic project in Shunyi District, Beijing as an example. The economic and social benefits of rural photovoltaic projects are studied using the levelized cost of electricity(LCOE)model and levelized social benefits of electricity(LSBOE)model. The research is carried out using the levelized cost of electricity(LCOE)model and levelized social benefit of electricity(LSBOE)model, and attention is concentrated on exploring the dependence of PV projects on PV subsidy policies and the sensitive factors affecting their sustainable economic stability. It results show that: The case project can achieve economic benefits, but the level of economic benefits depends on the strength of PV subsidies, which are highly dependent on PV subsidies. Affordable online access can only be achieved under dual photovoltaic subsidies; There is still uncertainty about the long-term economic benefits of the case project under the current subsidized on-grid electricity price, and this uncertainty has been strengthened with the introduction of the policy of “retrograding” of the feed-in tariff subsidy for photovoltaic power generation; The factors affecting the long-term economic stability of PV projects are ranked as follows: policy factors, technical factors and economic factors; In the meantime the photovoltaic system has good social benefits, the social benefit of levelized kilowatt-hour electricity in its service life is 12. 63 yuan/kWh; Based on the price of photovoltaic subsidies in Beijing or Shunyi District it is necessary to increase the average annual utilization hours of the PV system by 8. 45%, or reduce the unit cost by 11. 02%, or increase the amount of PV subsidies in the previous five years to 0. 768 yuan/kWh from the existing basis; When coal-fired power generation is used to achieve electricity price parity it is essential to increase the average annual utilization hours of PV system by 40. 14%, or reduce the unit cost by 52. 35%, or increase the amount of PV subsidies in the first five years to 1. 398 yuan/kWh from the existing basis; Therefore, in order to continuously realize the economic benefits of rural PV projects, the government should appropriately increase the amount of rural PV subsidies or slow down the reduction of subsidies. There has been a focus on reducing the impact of PV subsidy “recession” policy on the economic benefits of PV projects, and attention should be paid to photovoltaic-related technology research and development as well as reducing construction, operation and maintenance cost.Keywords：rural PV system;levelized cost of electricity(LCOE)model;economic benefits;social benefits;ensitivity analysis8|26|2<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：In order to explore the spatial and temporal evolution law of coupling and coordination of “production-living-ecological” functions in the central-southern Liaoning and Harbin-Changchun urban agglomerations, a total of 30 indicators were selected from 9 aspects of agricultural production, non-agricultural production, economic development, space carrying, living standard, public service, ecological pressure, ecological maintenance and environmental purification to calculate “production-living-ecological” functions. The revised coupling coordination model and the grey relational model were combined to analyze the temporal and spatial differentiation and influencing factors of the “production-living-ecological” functional coupling coordination in urban agglomerations from 2000 to 2020. The results show that: 1)The “production-living-ecological” functions of the central-southern Liaoning and Harbin-Changchun urban agglomerations are improved as a whole, and only the development of ecological function of Harbin-Changchun urban agglomeration is better than that of the central-southern Liaoning urban agglomeration. Among them, high-value areas with production, living and comprehensive functions are mainly the core or coastal cities such as Shenyang and Dalian; The areas with high ecological function are mainly inland or border cities such as Mudanjiang and Jilin. In addition, after 2015, the expansion of “production-living-ecological” functions advantage areas tend to slow down or even stagnate, the production function and living function of some cities are significantly reduced, and the “production-living-ecological” function at the intersection of urban agglomerations continues to be low. 2)The coupling and coordination of "production-living-ecological" functions of urban agglomeration has gradually improved, the coordination of the central-southern Liaoning urban agglomeration is better than that of the Harbin-Changchun urban agglomeration. The coordination degree of the “production-living-ecological” functions of the core cities were mainly intermediate, non-core cities have changed from mildly maladjustment to general coordination. The spatial distribution of mildly imbalanced cities transfer from south to north, and finally distributes around the two core cities of Harbin and Changchun. 3)The calculation results of the nine impact indicators selected in this study show that: the top three influencing factors of the spatial and temporal differences in the coupling and coordination of “production-living-ecological” functions of urban agglomerations include the green total factor productivity, fiscal decentralization and average annual rainfall. In summary, this study can provide scientific basis for the coordinated optimization of “production-living-ecological” functions in Northeast China in the new era.Keywords：“production-living-ecological” function;coupling and coordination;influencing factor;central-southern Liaoning and Harbin-Changchun urban agglomeration11|23|3<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：To solve the problem of whether the use of rural internet can effectively promote the development of agricultural mechanization, based on the micro data, an OLS model is used to estimate the impact of farmers' access to agricultural information through the internet on their adoption of the socialized service of agricultural machinery. The instrumental variable method and the treatment effect model are used to control the endogenous. A variety of robustness tests and heterogeneity analysis are carried out. The results show that: 1)The relationship between access to agricultural information through the internet and the adoption of socialized service of agricultural machinery by farmers is negative. The coefficients obtained by using two different methods to control endogenous are -2. 3 and -1. 8, respectively; 2)Heterogeneity test shows that the coefficients between internet information access and agricultural machinery service outsourcing adoption are not significant in the sample of elderly farmers and small-scale farmers; 3)The mechanism test shows that internet information acquisition has a significant promotion effect on farmers' self-purchase of agricultural machinery. Internet information acquisition inhibits farmers' adoption of the socialized service of agricultural machineryg, but promotes farmers purchase agricultural machinery by themselves. There is a deeper digital gap between obtaining information through the internet and benefit from internet information.Keywords：the socialized service of agricultural machinery;internet information;agricultural mechanization;farmers' adoption15|28|4<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：In order to explore the mechanism of the farmers' subjective cognition on the “non-grain production” of cultivated land(NPCL), a structural equation model was constructed based on the theory of planned behavior(TPB). The field research data of Dafang County, Bijie City, Guizhou Province were used to study the factors influencing farmer's NPCL. The results showed that: 1)The degree of household income from growing food crops, the influence of friends and relatives, and the distance between farmland to residence have greater impact on the farmer's NPCL; 2)The mediation impacts of the intention to engage in farming(digging fish ponds)and the intention to cooperate with industrial and commercial capital are significant, which are the main paths to form the farmer's NPCL; 3)There are differences in the influencing factors of the NPCL of different types of farmer. Behavioral attitudes, subjective norms and perceptual behavioral control display significant effects on farmers who make independent decisions. Their behavioral intentions have a significant impact on farmers who make behavioral decisions with the intervention of third parties such as industrial and commercial capital. Finally, solutions such as intensify the political propaganda, measures and proposals of industrial and commercial capital to the countryside, and differentiated farmer management measures were proposed.Keywords：non-grain production of cultivated land;theory of planned behavior;farmers;behavioral decision-making;influencing factors9|22|9<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：In order to explore the low-carbon development of the animal husbandry under the “dual carbon” goal, the carbon emissions of China's animal husbandry were calculated(The data do not include those of Hong Kong, Macao and Taiwan regions. The same below). The spatial-temporal dynamic evolution and influencing factors were explored with the help of kernel density estimation and LMDI decomposition model. The results show that: 1)The total carbon emissions of China's animal husbandry first increased and then decreased, the carbon emission intensity of animal husbandry showed a downward trend, and the inter-provincial gap narrowed significantly. 2)The inhibitory effect of the intensity effect is the most obvious, and the evolution trend presents a “strong-stable-strong” inhibition level; The agricultural structure effect presents a change characteristic from a promotional effect to an inhibitory effect; The inhibitory effect of the industrial structure effect is only inferior to the intensity effect; The promotion effect of the population size effect is the largest, and its evolution trend presents an inverted “U”; The promotion effect of the population size effect is small. 3)There are regional differences in the factors affecting the carbon emissions of the national livestock and poultry breeding industry and its main species. Beef cattle and mutton sheep in pastoral areas and some grassy areas in the south, as well as the inhibitory effect of the intensity effect and industrial structure effect of pigs in the Northeast, are insufficient to reduce the promotion effect brought by the economic effect, which promotes the increase of carbon emissions. Therefore, the government needs to actively guide farmers to carry out clean production, increase investment in scientific research on breed improvement and feed ratio optimization for leading livestock enterprises, and promote the development of low-carbon livestock and poultry farming according to local conditions.Keywords：animal husbandry;carbon emissions;LMDI decomposition model;space-time evolution;factors20|25|19<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
- Abstract：In order to analyze the influence and mechanism of economic forestry compound management technology adoption on farm household income, and to clarify the constraints on the income-increasing benefits of economic forestry compound management technology, this study applies an econometric model to do empirical analysis of data from a sample of 568 farm households, collected in Zhejiang, Fujian and Jiangxi provinces. The results show that: The adoption of economic forestry compound management technology can significantly increase the agricultural income of farm households, especially significant for low-endowment farmers, and is achieved by increasing agricultural labor time for farmers. The counterfactual estimation reveals that the income-increasing effect of compound management technology is present in farm households with different technology adoption statuses. For farmers who have adopted the technology, the income-increasing effect of economic forestry compound management technology occurs only among high-endowment farmers. For farmers who have not adopted the technology, the income-increasing effect of the economic forestry compound management technology occurs in all endowed farmers. This study provides new empirical evidence for understanding the mechanism of the impact of compound management technology on farmers' income, and also provides reference for further technology promotion.8|24|0<HTML><L-PDF> <Meta-XML>Updated：2023-12-22
