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- Abstract：In this study, the identification of the genetic basis of Yumai 13 cytoplasm was conducted using chloroplast microsatellite SSR markers. Wheat cultivar Yumai 13 and its derived progenies were identified with 24 wheat chloroplast microsatellite SSR markers, among which wild ecotype oat (Avena fatua),bread wheat varieties (Chinese Spring and Xuezao) and 30 alloplasmic lines belonging to the genus Triticum and Aegilops were taken as references. By SSR marker analysis, it was shown that the cytoplasms of Yumai 13 and its derived progenies and bread wheat varieties displayed polymorphism in the PCR products of 5 SSR markers. This indicated the cytoplasm types of Yumai 13 and its derived progenies were different from that of bread wheat. By comparing the cytoplasm genotype of A. fatua with Triticum timopheevii, 15 molecular markers displayed polymorphism. Among these markers, the PCR bands of Yumai 13 and its derived progenies were exactly the same as that of T. timopheevii,whereas drastically different from that of A. fatua. The cytoplasm genotype of Yumai 13 was also compared with other 29 alloplasmic lines and Yumai 13 showed to be unique. This indicated that the cytoplasm type of Yumai 13 and its derived lines may be T-type. The results would provide valuable basis for the utilization of Yumai 13 in wheat breeding.Keywords：wheat;chloroplast SSR marker;T-type sterile line;cytoplasm male sterility0|8|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to analyze the antioxidative mechanism of glutathione peroxidase (GPX) in Brachypodium distachyon, a 681 bp cDNA of BdGPX4 gene is cloned, which encodes a protein of 261 amino acids residues with predicted relative molecular mass of 24.49 ku. The protein is presumably localized to the chloroplasts and mitochondria. Bioinformatics analysis show that the promoter of BdGPX4 gene contains many cis-acting elements related with stress such as cold, drought as well as plant hormone and light. Combining microarray data and RT-PCR expression results, BdGPX4 gene is found expressing in root, stem, leaf, leaf sheath, sprouts, spikes and seeds. Its expression in photosynthetic tissues and the active growing organs are significantly higher than that of non-photosynthetic and senescence parts. BdGPX4 is also induced by SA in roots. Recombinant plasmid is successfully constructed and the recombinant protein is purified. BdGPX4 protein shows high enzymatic activities towards the substrates H2O2 and COOH, and low enzymatic activities towards tBOOH. BdGPX4 protein is functionally differentiated compared to the orthologous protein OsGPX4 in rice. The characterizations of its expression patterns and enzyme activities indicate that the BdGPX4 gene plays an important antioxidative role in photosynthetic organs and under stress conditions.Keywords：Brachypodium distachyon;glutathione peroxidase;expression;enzyme activity0|6|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to exploit GDSL esterase/lipase gene of Helianthus annuus L, GDSL esterase/lipase genes were screened based on the Unigenes obtained from H. annuus's transcriptome sequencing data in this study. The selected GDSL esterase/lipase gene and analysis on its physicochemical properties and sequence structure was conducted by Bioinformation. The results showed that:Seven GDSL esterase/lipase genes were selected from H. annuus, with the molecular size ranged from 255 to 396 aa. The ranges of molecular weight and isoelectric point were respectively 28.75~42.61 ku and 4.91~8.89. Besides unigene60916, most proteins had more transmembrane regions and higher phosphorylation levels; The alpha helix and the irregular curl were the primary secondary structure. The constructed phylogenetic tree indicated that the 7 genes were well grouped into three categories. The 7 genes are more conservative. Among which, unigene 58624 was highly conservative with AT4G01130.1 on the same branch. Unigene 60916was speculated to be related to lipid metabolism in seeds, which had the highest similarity with AT1G74460.1 and contained multiple alpha helix and beta sheet.2|8|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Based on the observed daily meteorological data and agro-meteorological data from 1986 to 2015 from 47 normal meteorological stations and agro-meteorological stations in cotton-growing area of North China Region, the cotton water requirements (ETc), effective precipitation(Pej), irrigations demand(ETaw) were calculated by SIMETAW model. The results showed that the water requirement of cotton declined in recent 30 years, but effective precipitation was risen in the same period. The ETc in Jun to Aug was maximum during cotton growth period, which was from 80 to 160 mm. However, ETaw demand of Jul and Aug were minimum, which was almost zero, and the maximum irrigation demand month of cotton growth period is Jun, the mean of North China Region was 56.50 mm. The mean of ETaw of cotton in funnel area and normal area were respectively 144.41 and 70.41 mm due to the difference of precipitation. The mean ETc, Pej and ETaw during cotton growth period were 560.19, 467.32 and 98.75 mm in North China area, respectively. The water requirement of continuous cotton was lower than winter wheat-summer maize, and the continuous cotton had better benefits than continuous spring maize. In conclusion, replacing the traditional crop rotation with continuous cotton was promising for alleviate water shortages in funnel area.Keywords：cotton;water requirement;funnel area;cotton-growing area of North China Region1|8|4<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to investigate the influences of alternative irrigation between brackish water and fresh water on greenhouse gas emission from spring maize soil, drip irrigation experiments with four kinds of water quality and two different irrigation methods were conducted. The results showed that:The average daily emission of CO2 and N2O flux of 1:2 alternative irrigation were respectively reduced by 10.26% and 8.74% compared with that of 1:1 alternative irrigation. The average emission of CO2 and N2O flux were 27.82% and 31.16% lower than that of 2.0 g/L and the average emissions flux of N2O gas were 4.46% and 8.23% lower than that of 2.0 g/L, respectively. Compared to 2.0 g/L brackish water treatment, the corn yield of 3.5 g/L and 5.0 g/L treatment respectively decreased by 5.92% and 11.05% on average. The corn yield of 1:2 alternative irrigation treatment was 2.00% lower than that of 1:1 on average. The results significant difference analysis showed that:The water quality had a significant effect on the daily average emission of CO2 flux and maize yield (P<0.05), whereas the water quality did not have significant effects on N2O emission flux (P>0.05); The effect of alternative irrigation on CO2 and N2O emission fluxes and maize yield were not significant (P >0.05).Keywords：maize;brackish water;alternative irrigation;CO;N;2;O;soil3|11|7<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：American walnut industry occupies an important position in the world walnut industry with its large nut, thin shell and high yield. Xinjiang is one of the main producing areas of China's walnut and has a long history of cultivation. However, in recent years, cultivation and management techniques were not updated in time, which resulted in unstable yield, uneven quality, poor overall efficiency of walnut and other issues in the walnut production in Xinjiang. In this study, the introduced American walnut varieties ‘vina’, ‘Amigo’ and Xinjiang local varieties ‘Wen 185’ and ‘Xinxin2’ were used as materials to compare the botanical and biological characteristics of different varieties of flower buds differentiation process and expression of related flowering genes. The results showed that there was no significant difference among the four cultivars in tree growth, development characteristics of buds, astern stage, as well as flower rate and fruit setting rate. However, the ability to create double fruit, three fruit or more in the same branch of fertile branch of ‘Xinxin2’ was significantly higher than thatof ‘vina’. The size and fruit weight of ‘Xinxin2’ were lower than ‘vina’. The average flower buds on the shoots and fruit setting rate of ‘vina’ was higher than that of ‘Xinxin2’. At the same time, the expressions of JrFT and JrLFY genes in mixed buds from bud to flower stage of ‘vina’ were also higher than those of ‘Xinxin2’, while the expression of JrFLC gene in the bud was relatively lower. The results showed that ‘vina’ increased the expressions of JrFT and JrLFY genes during flower bud differentiation and flower organ formation, and formed a large number of lateral flower buds on the shoots. The use of a large number of lateral buds results fruiting branches, the formation of larger fruits with low expression of JrFLC gene. So its final yield produced was not lower than the ‘Xinxin2’ of the same set of fruit parts with two or more fruits.4|8|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to study the pathogenicity and phylogeny of Tibetan yak-derived Escherichia coli, and relationship with other animal sources of E. coli. A total of 240 samples of Tibetan yak diarrhea stool samples were collected and the bacteria were isolated, serotyped and pathogenic tested by microbiological methods. 16S rRNA was identified, sequenced and phylogenetically analyzed by molecular biology method. The results showed that among the 16 yak-derived pathogenic E. coli isolates:Three strains were closely phylogenic to swine-origin pathogenic E. coli. Two strains were closely phylogenic to the pathogenicity of avian pathogenic E. coli. Two strains were closely phylogenic to calf source E. coli and four strains were closely phylogenic to E. coli derived from cattle. One strain of yak pathogenic E. coli formed a distant separate branch. One yak-derived pathogenic E. coli and Shigella and human hemorrhagic E. coli were in the same phylogenetic tree and might become the potential pathogens of yak and human. There were close phylogenetic relationships among the Tibetan yak source E. coli and bovine, poultry, pig, human derived E. coli, which meant the risk of interspecies transmission. Animal experiments showed that the Yak-derived E. coli, with caused 95% mortality of the experimental animals, should be paied more attention. This study would provide references for the prevention and control of yak source E. coli disease.Keywords：Tibet yak;Escherichia coli;pathogenicity;phylogenetic0|8|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To investigate the effects of different pH and SCFAs on the expression of SCFAs transport proteins and GPR41 in rumen epithelial cells of dairy cows. Six groups of experiment were designed, after 24 h culturing, cells were collected and RNA was extracted. The results showed that with SCFAs supplementation:There was no significant difference in the expression levels of MCT1 among pH 6.2, 6.8 and 7.4 (P>0.05). The expression of MCT1 in pH 6.8 was significantly higher than that in pH 6.8 and 7.4 (P<0.05); The expression of MCT4 in pH 6.2 was significantly higher than those in pH 6.8 and pH 7.4 (P<0.01); The expression of MCT4 was significantly higher than those of SCFAs (P<0.01). The expressions of NHE1, NHE2 and NHE3 were significantly higher than those without SCFAs supplement (P<0.01). With the decreasing of pH, the expressions of NHE1, NHE2 and NHE3 increased gradually; Without additional SCFAs, GPR41 was not expressed. After the SCFAs supplementation, the expression of GPR41 was greatly activated. In conclusion, SCFAs could significantly enhance the expressions of SCFAs transport proteins and GPR41 in rumen epithelial cells of dairy cow. It was proved that the cell uptake of SCFAs was mainly depended on SCFAs transporter and GPR41.Keywords：dairy;short chain fatty acids;monocarboxylate transporter;G protein-coupled receptors1|8|7<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The objective of this study was to investigate the effects of dietary supplementation of SCD inhibitor (phoenix tree seed oil) and accelerator (rosiglitazone) on the key lipid metabolism regulator and related enzyme's mRNA expressions in the longissimus muscle and subcutaneous adipose tissues of fattening sheep. Eighteen crossbreed ram (Merino sheep♂×Thin-tail Han sheep♀), which were similar in body weight[(27.71±2.64) kg] and body condition, were randomly divided into 3 groups with 6 sheep in each group. The sheep in control group (C group) were fed a basal diet + 4.8% linseeds; those in phoenix tree seed oil group (W group) were fed the C group diets supplemented with 15 g/d phoenix tree seed oil and those in rosiglitazone group (L group) were fed the C group diets supplemented with 8 mg/d rosiglitazone. The trial period lasted 50 d including 10 d of transition period, 5 d of pretrial period and 35 d of trial period. The results showed that:1) Compared to animals in control diet, the expression of PPAR-γ mRNA in the longissimus muscle and subcutaneous adipose of animals in W group were increased by 42% and 28%, respectively. The expression of SREBP-1 and SCD mRNA in the longissimus muscle were decreased by 20% and 24% respectively(P<0.05); 2) Compared to animals in control diet, The mRNA expression levels of PPAR-γ and SREBP-1 in the longissimus muscle of animals in L group were significantly increased by 93% and 35%, respectively (P<0.05). The expression of FAS, LPL and SCD mRNA were increased 36%, 56% and 22%, respectively (P<0.05). and the expression of PPAR-γ and FAS mRNA in subcutaneous adipose of animals in L group were significantly increased by 25% and 32%, respectively (P<0.05). These results proved that the phoenix tree seed oil increased the expression of PPAR-γ mRNA in longissimus muscle and subcutaneous adipose, and decreased the expression of SREBP-1 and SCD mRNA in longissimus muscle. The rosiglitazone increased the expression of PPAR-γ,SREBP-1,FAS,LPL and SCD mRNA in longissimus muscle and the expression of SREBP-1 and FAS mRNA in subcutaneous adipose.Keywords：sheep;stearoyl-CoA desaturase;phoenix tree seed oil;rosiglitazone;gene expression1|8|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The aim of this study was to investigate the effects of nisin and rhubarb compounds on the endocrine regulation and colon inflammation of rats with endometritis, and to further reveal the relationship between endometritis and the colon. Excluding the blank control, the models in other groups were established by using Escherichia coli. ELISA kit was applied to detect MPO and OXT in rat's uterus. The IL-1 β and TNF-α in the colon of rat with endometritis were detected and the changes of colon flora to determine the therapeutic effect were also investigated. The results showed that:There was no significant difference in concentrations of MPO and OXT between groups at 0 h before modeling. At 24 h after modeling, the concentration of MPO in the middle and high dose of rhubarb compounds groups and nisin group were decreased. The concentration of OXT in the high dose of rhubarb compounds and the positive control group was higher than that in the negative control group and the blank control group, while that was decreased in the negative control group. After 48 hours of modeling, the concentration of OXT in the negative control group was significantly reduced. At 72 hours after the establishment of model, MPO in the negative control group was increased, and the concentration of OXT was decreased. In uterus, the concentration of MPO and OXT in high dose of rhubarb compounds and positive control group were significantly increased. 2) In the colon, the levels of IL-1 β and TNF-α in the negative control group were significantly increased during the 0 to 72 h. The concentrations of IL-1 β and TNF-α in high dose of rhubarb compounds groups, the nisin group, and the positive control group were significantly reduced. 3) In colon, the number of Lactobacillus and Bifidobacterium in high dose of rhubarb compounds groups and the nisin group increased, and the number of Escherichia coli and Enterococcus were decreased. In conclusion, the concentration of MPO and OXT were decreased in rats by applying the nisin and rhubarb compound. In rats with endometritis, the concentration of IL-1 β and TNF-α in the colon were increased. High doses of rhubarb compounds and the nisin group could regulate the structure of colonic microbiota.Keywords：rats;nisin;rhubarb compound;endometritis;colon;sex hormone;Escherichia coli0|8|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to obtain the full-length cDNA sequences of Ghrelin Cervus elaphus in total RNA was extracted from abomasum mucosa and the cDNA was obtained by RT-PCR, RACE and cloning technology. The results indicated that:A 539 bp (GenBank accession no. KX857494) amplicon of Cervus elaphus Ghrelin cDNA was cloned successfully. It was consisted by a 46 bp 5' UTR, 351 bp ORF encoding a preproghrelin of 116 amino acids, 128 bp 3' UTR and ploy(A)14. The amino acid homology analysis of Ghrelin showed that the full-length Ghrelin cDNA in Cervus elaphus was highly homologous to the reindeer, Cervus nippon, goat, sheep and cattle, and the phylogenetic tree analysis is consistent with its genetic relationship. This study provided basis for further analysis of the expression and regulation of Ghrelin gene in Cervus elaphus.Keywords：Cervus elaphus;Ghrelin;cDNA;clone;sequence analysis0|8|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To find new cellulase-producing microbial resource, fungus LYW-1 was isolated from wet wood chips by selection medium with CMC (Carboxyl methyl cellulose) as sole carbon source. Conserved ITS (Internal transcribed spacer) sequence of LYW-1 was amplified from genome and sequenced at Invitrogen. The verified ITS sequence was subjected to online BLAST analysis with other selected fungi. Phylogenetic analysis was then performed by MEGA 4.0. Combining the results of molecular analysis with morphological observation, LYW-1 was identified as a fungus belongs to Trametes. The cellulose activity of LYW-1 was assayed by 3',5'-dinitrosalicylic acid (DNS) method. The effect of different pH, temperature and carbon or nitrogen source on enzyme activity was assayed. The result showed that enzyme activity reached maximum when the fungus was cultured in fluid medium by using starch as carbon source and ammonium acetate as nitrogen source. The optimal pH and temperature for enzyme producing was pH 7.0 and 37℃, respectively.Keywords：Trametes;cellulase;enzyme activity;condition of cellulase production3|7|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The study aims to investigate the spatial characteristics and influence of patch landscape pattern of the grassland in Hal town, Wuchuan county, Inner Mongolia. Designating the grassland in the Farming-Pasturing interlocked areas as the object, the research is based on binary Logistic regression model, utilizing the landscape pattern index and influential factors from natural geography and human society.The grassland landscape of Hale Town shows obvious regional difference. The patch scale is larger in the southeast and smaller in the northwest; the patch form is dense in the southeast and sparse in the northwest;the fragmentation of patch distribution is low in the southeast and high in the northwest.Natural geography and humanistic society are crucial factors during the study of grassland landscape patch characteristic in this region, incentivizing the diversification of grassland landscape.The main influential factors of grassland patch scale diversity are related to elevation, distance to the nearest road, distance to the nearest river, and distance to the nearest residential area; the intrinsic inducement of morphological differentiation of grassland patch is involved in elevation, slope, and distance to the nearest river; the driving factors of the difference in the distribution of grassland patches are elevation, distance to the nearest road and distance to the nearest residential area.Keywords：grassland;grassland landscape pattern;influencing factors;Logistic regression model;Farming-Pasturing Interlocked Areas0|9|6<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To quantitatively study the carrying capacity of ecological environment in Tianjin, make effective use of natural resources and promote sustainable development, based on the current situation of ecological environment and the characteristics of social and economic development, a evaluation index system and grading standards of ecological environment carrying capacity according to P-S-R model is constructed in this study. A combination of subjective and objective weighting method and fuzzy cluster analysis are adopted to investigate the ecological environment carrying capacity in Tianjin level from 2000 to 2014 years and provide scientific basis for the construction of ecological environment in Tianjin. The results show that:The membership value of ecological environment carrying capacity in Tianjin is on the rise, and the carrying capacity level rises from the overloaded state to the bearing state; The pressure and response level of ecological environment carrying capacity increased steadily, and reached the bearing state in 2009 and 2010 respectively; The level of ecological environment carrying capacity of the state layer is fluctuating. The development trend is not optimistic. The problems of over-consumption of resources, environmental pollution and ecological destruction are the main factors that restrict the further carrying capacity of ecological environment. The research results provide reasonable suggestions for the future development of Tianjin and references for the research on the carrying capacity of ecological environment in other regions.Keywords：ecological environment carrying capacity;fuzzy cluster analysis;P-S-R model0|7|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Research on the spatial and temporal variation of surface temperature is crucial to establish appropriate urban heat island mitigation strategies and improve the environmental quality. The radiative transfer algorithm was used to retrieve land surface temperature (LST) in Harbin City in summer of 2001, 2008, 2013 and 2016. Density segmentation, orientation quadrant, buffer analysis and regression analysis method were adopted to perform inversion and classification of land surface temperature, analyze the land surface temperature space change characteristics, reveal and expound the correlation between land surface temperature and the normalize construction index NDBI. The results showed that:From 2001 to 2016, significant high temperature regions were mainly in the Harbin urbanized area and industrial area, and significant low temperature were mainly in water bodies, green land and arable land; High temperature regions continuously increased during 2001 to 2016, while the expanding trend, extent and model differed from each other; The spatial distribution of the high temperature area and the urban construction land was consistent. The process of urbanization and population movements accelerated the expansion of the range of the high temperature area. A significant positive correlation between surface temperature and NDBI was discovered, which meant that NDBI was good indicator for marking surface thermal characteristics.Keywords：land surface temperature;normalized difference building index;space-time evolvement;urban expansion;remote sensing0|9|4<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Firstly, by combining theoretical analysis with literature review, the current research of tractor body leveling system at home and abroad is studied. Secondly, the literatures are summarized and classified from two aspects, tractor rear suspension technology and the adaptive technique of leveling slope. The results show that:1) The tractor leveling system can adjust the tractor to the horizontal state when the body is bumpy or tilted, which ensures driving safety and comfort; the operation stability and traffic ability are closely related to the degree of the automatic leveling when tractors operate on hilly areas.2) The suspension mechanism plays a crucial role in the tractor leveling system and the rear suspension implements leveling system, the technical structure of suspension mechanism impacts the research of the body leveling system and rear suspension technology directly. 3) The key issue of the tractor leveling system research is the research on tractor rear suspension technology and equipment leveling slope adaptive technology. Finally, it is proposed that the research of tractor rear suspension technology and equipment leveling slope adaptive technology should be based on building tractor leveling system and optimizing suspension mechanism. Under the premise of tractor operation quality and efficiency on hilly areas, the research on tractor body leveling system and rear suspension implements leveling system, which realizes the suspension implements' trailing operation to hilly land, will be the main research trend of tractor automatic leveling system.Keywords：mountain tractors;hilly mountain;implement;leveling system;suspension;stability1|7|4<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To solve the problem that the object was difficult to segment from complex background in the sheep images and the illumination interference on images, an improved C-V active contour model based on YCbCr space was used to study sheep images segmentation in complex backgrounds. The results showed that:1) According to color feature of the sheep images, conversion from RGB space to YCbCr space was done for each pixel, which was necessary to overcome illumination factors influencing sheep images. 2) A new level set was constructed by sketching the rough outline of sheep manually in order to distinguish an outer region from inner region, and the curve evolution was halted at the object contour border. It was proved that the improved C-V model could segment the sheep images in complex background and the segmentation results could be applied to succeeding sheep measurement point identification.Keywords：sheep;image segmentation;YCbCr space;Chan-Vese model0|9|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to solve the problem of segment difficulty caused by seeds adhesion during automatic seeds test, a new segmentation method was proposed in this study. Image segmentation algorithms combing genetic algorithms (GA) and improved pulse coupled neural net (PCNN) model were adopted. To improve contrast between the adhesive corn seeds and image background,adhesive corn seeds were pretreated to remove noise by using mathematical morphology and wiener method, multi-scale decomposed based on wavelet transform, and reconstruct images by using data fusion. The optimal parameters of β、αE and VE in the PCNN model were obtained by genetic algorithm. Small distracter of the segmented image were removed with the PCNN's automatic porter sign. The adhesion grain segmentation image was finally obtained. The results showed that:1) The accuracy of image segmentation algorithm by combing GA and adaptive pulse coupled neural net (PCNN) was 98% (the highest); 2) The cross entropy, regional uniformity, shape measure dimension and region contract indexes proposed in this study were respectively 0.079 4, 0.975 4, 0.878 5 and 0.869 2, which were superior to OTSU, improved watershed algorithm, iteration method global threshold algorithm and not improved PCNN algorithm; 3) The running time of GA+improved PCNN algorithm was 22.07 s, which was longer than the rest, but the segmentation effect of GA+improved PCNN algorithm program was the best.Keywords：corn seeds;automatic seeds test;grain adhesion;image segmentation0|7|5<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In view of the problems of low separation efficiency and high damage rate existed during using astragalus excavator, the working parameters of typical astragalus excavator were optimized to meet the requirement of astragalus mining operations. Mechanism analysis on vibration separation was conducted. The core parameters of the vibration mechanism were optimized through the Mathlab optimization toolbox. Experiment was carried out by taking the eccentric wheel angular velocity, eccentric distance and effective length parameters as central influencing factors and the obvious stem rate and the damage stem rate as experimental index. The results showed that when the speed was 0.64 m/s, the vibrational frequency was 8Hz and the digging shovel angle was of 15°, the obvious stem rate reached 95.62% and the damage stem rate reached 0.73%. The results from field experiment showed that:Under the same conditions, the obvious stem rate was 93.62%, the damage stem rate was 0.82%, and the operation of the whole machine was stable and reliable. The optimized vibration excavator could meet the agronomic requirements of astragalus.Keywords：astragalus;excavator;vibration separating sieve;parameter optimization2|7|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：China's agricultural machinery purchase subsidy introduced in 2004 is an important financial agriculture supporting policy. In order to make a systematic evaluation of the policy, from the points of background, target and means of agricultural machinery purchase subsidy policy, the article summarizes and reviews researches on the policy and its effect, and focuses on the property of the policy under WTO framework and the related mechanization policy. The results show that:The subsidy policy is multi-objective, and its implementation has attracted wide attention. It is the core content of policy research and the focus of controversy. Most scholars make a positive assessment of the policy and think the subsidy has stimulated the farmers' purchasing demand, changed the structure of agricultural machinery equipment; promoted the level of agricultural mechanization and regional balance. It is conducive to increasing agricultural output and farmers' income, promoting the development of agricultural machinery industry and the upgrading of agricultural machinery products. The machinery purchase subsidy belongs to yellow box policy. It is different with subsoiling operation subsidy and should be implemented separately. Under the background of improving the system of agricultural support and protection, attentions should be paid to the effect of subsidies on the using efficiency of agricultural machinery and preventing potential conflicts between policy objectives to continue to implement the subsidy policy.Keywords：agricultural machinery purchase subsidy;agricultural supporting policy;agricultural equipment structure;agricultural mechanization;research review1|10|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to clarify the relationship between the aging agricultural labor force and wheat production, this study investigates the impact of aging agricultural labor on mechanization and technical efficiency under different landform. The 2010 China Rural Fixed Point Survey data is adopted in the analysis. The results show that aging agricultural labor stimulates the use of wheat machinery, and the impact varies across different landforms. In particular, a greater impact is detected for machinery use in wheat production in hilly and mountainous areas. Moreover, aging agricultural labor has a negative impact on technical efficiency of wheat production in plain area. To the contrary, a positive impact is found in hilly and mountainous areas. Therefore, in order to cope with the aging of agricultural labor force, and further improve the technical efficiency of wheat production, agricultural policy should focus on increasing the substitution elasticity of machinery and labor according to local conditions, stimulating innovation and R&D, and promoting cross-region operation market for agricultural machinery.Keywords：aging agricultural labor;wheat;landform;mechanization;technical efficiency1|7|5<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：By establishing an extended C-D production function model and using the rice production and meteorological data of China's 15 rice-producing provinces from 1984 to 2014, an empirical analysis of the influence of climate change in rice's growing seasons on rice production was conducted and the nonlinear and regional difference of climate factors' effects was observed. The results showed that increasing precipitation had a significantly negative impact on rice yield. However, the impacts on different regions were different. Meanwhile, quadratic precipitation had a significantly negative impact on rice yield. On the whole, the precipitation had a negative impact on the northeast, eastern, central and southern regions of China, while had a positive impact on the southwest region. Besides, rising temperature had a significantly negative impact on rice yield and there existed a "U" shape relationship between temperature change and rice yield. On the whole, the temperature had a negative impact on the eastern, central, southern and southwest regions of China, while had a positive impact on the northeast region.Keywords：rice;climate change;yield;C-D production function3|9|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The daily climate observation materials of Yanqing Met.station (54406 station), which is located at Beijing International Horticultural Exposition in 2019, are adopted to analyze the monthly average, annual average and annual difference of daily temperature, precipitation, relative humidity, sunshine hours and wind speed. The curves of annual temperature inter-annual variation, extreme temperature inter-annual variation, annual precipitation inter-annual variation are calculated by the statistics, and the linear regression equation of the least square method is used to fit the same element during 1961 to 2014 and 2000 to 2014. The meteorological factors of this area in 2019 are pre-evaluated respectively. According to the evaluation results, the annual average temperature in the 2019 Beijing Exposition area is about 10℃, the extreme temperature is 35.03 to 36.21℃, and the extreme low temperature is -18.16 to -19.51℃, the active accumulated temperature is 3 806.65 to 3 858.10(℃·d), accumulated temperature of 195 to 196 d, the number of sunshine hours for the Year 2 545.93 to 2 708.65 h. The annual rainfall is 411.11 to 466.35 mm, the maximum rainfall of the day for the 37.00 to 45.65 mm, the relative humidity is 52.80% to 55.57%, and the average wind speed of 1.34 to 1.44 m/s. The maximum wind speed is 9.99 to 10.56 m/s. These results would provide scientific basis for the introduction, distribution, planting and maintenance of horticultural plants and prediction of natural disaster weather.Keywords：meteorological factor;regression analysis;forecast;Beijing International Horticultural Exposition0|8|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To investigate the interactive relationships between land finance and land urbanization, based on theoretical analyses, this study used econometric analysis methods to analyze the relevant data of China from 1999 to 2015 at provincial level. The results showed that there were bidirectional interactive relationships existing between land finance and land urbanization. They could be divided into three phases:driving land-use demand, land urbanization expanding and land finance replenishing. And the results from empirical studies argued that land finance and land urbanization statistically motivated each other. In the short term, the land urbanization led to the gradual increase of land finance, and the land finance had a long-term positive impact on land urbanization, which was consistent with the three phases in theoretical analysis. It was revealed that land urbanization was very sensitive to the disturbance of land finance in both impulse response function and variance decomposition. In conclusion, the land finance significantly affected the process of land urbanization of China. Local governments should actively promote the reform of land finance and taxation system, control urban growth boundary and maximize the value of urban land.Keywords：interactive relationships;land finance;land urbanization;VAR model0|10|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：order to promote efficient and rational use of logistics land, the data envelopment analysis model was used to estimate the relative efficiency of input and output of logistics land in 31 provinces (cities). The Global Moran'I and Gi* index spatial econometric models were adopted to analyze the global and local characteristics of the temporal and spatial pattern of land use efficiency. Gray relational analysis model was also used to explore the main influencing factors of land use efficiency of logistics. The results showed that:1) The comprehensive efficiency, the pure technical efficiency and the scale efficiency of the national logistics land use showed an unsteady rise trend of fluctuation with significant spatial differences from 2009 to 2016. 2) The utilization efficiency of inter-provincial logistics land use generally showed significant spatial autocorrelation, overall spatial pattern of comprehensive efficiency had a little change. And significant changes existed in the spatial pattern of pure technical efficiency and scale efficiency; 3) The main factors affecting the utilization efficiency of inter-provincial logistics land use included urbanization level, economic development level, industrial structure, institutional factors and transportation level, of which the most prominent impacts were urbanization level and institutional factors. The three major efficiencies of logistics land showed a spatial difference in ascending orders was eastern, central, western regions in China. In conclusion, the comprehensive efficiency of logistics land should be enhanced by focusing on improving technical efficiency.Keywords：logistics land;land use efficiency;data envelopment analysis;temporal spatial pattern;driving factors0|8|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to help farmers deal with livelihood risk more effectively in their daily process of production and life, the role of livelihood risk on risk-coping strategies was explored in this study. Using information collected through semi-structures interview in 483 households in Shiyang river basin in China, this study identified the effect of livelihood risk on livelihood strategies. By the establishment of index system with livelihood risk evaluated by Entropy Method and livelihood strategies, its effect was measured by use of Multinomial Probit Regression. The results from indicated that:1) Health risk, Environmental risk, Financial risk, Social risk, Information and connectivity risk had become main livelihood risk problem faced by farmers in Shiyang river basin. However there was a significant difference existed in different regions; 2) The main risk-coping strategies, which were preferred and chosen more by local farmers are ‘Use loans’, ‘Go out to work’ and ‘Reduce consumption’; 3) Health risk, environmental risk, financial risk, social risk, information and connectivity risk presented a significant correlation with the option of livelihood strategies. The health risk had a negative impact on ‘Letting children drop out of school’ and a positive impact on ‘Go out to work’; The environmental risk had a positive impact on ‘Convert assets into cash’, ‘Use loans’, ‘Reduce consumption’, ‘Let children drop out of school’ and ‘Go out to work’; The financial risk showed a negative impact on ‘Reduce consumption’ and ‘Let children drop out of school’; The social risk had a positive impact on ‘Reduce consumption’; Information and connectivity risk had a positive impact on ‘Convert assets into cash’, ‘Use loans’ and ‘Go out to work’; ‘Distance from the county’ had a negative impact on ‘Use loans’ and ‘Go out to work’ and has a positive impact on ‘Reducing consumption’. In order to control livelihood risks and ensure farmers' sustainable livelihoods more effectively, findings presented in this study could be used for evidence-based policies on introducing farmers to resist livelihood risk more reasonably, enhancing their livelihood approach to improve their capacities and improving their well-being, at the same time constructing early warning system and prevention mechanism, which could help to form efficacious security mechanism against livelihood risks.Keywords：sustainable livelihood;livelihood risk;risk-coping strategies;Shiyang river basin0|8|5<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
