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- Abstract：A field experiment was conducted to study the impact of biochar on soil water and grain yield of winter wheat under wheat-maize cropping system in the North China Plain.Four treatments,including 7200 (BH),3600 (BM),1800 (BL) and 0 (CK) kg/hm2 biochar addition rates,were conducted during 2014-2017 at Wuqiao Experimental Station of China Agricultural University,Hebei Province.The results showed that:Compared with the CK,BH,BM and BL increased the grain yield of winter wheat by 1.84%,7.28% and 5.03% on average for 3 years,respectively.In addition,additionial biochar reduced the water consumption and improved the water use efficiency by 5.96%-14.86%,9.42%-19.18% and 5.96%-13.50%,respectively.The application of biochar also increased the soil water content.Compared with the CK,the increase amplitude of BM was the largest in the upper layer of 0-60 cm.The increase amplitude of BL was the largest in the middle layer of 60-120 cm and the lower 120-200 cm,respectively (P<0.05).In summary,biochar addition can increase soil water content and grain yield.Statistical analysis showed that the soil water content and grain yield were the highest under 3389-3882 kg/hm2 and 3500-4357 kg/hm2 biochar addition rates,respectively.Moreover,there was a positively significant correlation between soil water content of 0-60 cm soil layer and grain yield (P<0.05).Therefore,the application of biochar not only increased soil water content and reduced water consumption,but also increased grain yield and water use efficiency of winter wheat.Application of 3000-4500 kg/hm2 biochar under the conditions of this experiment was optimal.Keywords：North China Plain;biochar;soil water content;water use efficiency;grain yield1|8|5<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The objective was to study the impact of variation of rainfall on broomcorn millet yield in arid region,measured the date of rainfall and broomcorn millet yield of Hequ County from 2012 to 2017.The results showed that:July was the most critical month of water demand during the growth period of broomcorn millet,and extremely significant positive correlation with the yield of broomcorn millet,directly determined the broomcorn millet whether could achieve high yield,and the rainfall proportion accounted for about 38.03%-39.92% of the total rainfall during the growth period;The rainfall of June was no significant positive correlation to the yield of broomcorn millet,which determined the seedling emergence rate of broomcorn millet,and the rainfall proportion accounted for about 22.49%-22.65% of the total rainfall during the growth period.The rainfall of August and September was significantly negatively correlated with the yield of broomcorn millet.Therefore,under satisfying rainfall condition of June and July,the suitable rainfall during the growth period of broomcorn millet was 409.3-472.2 mm.Keywords：rainfall;broomcorn millet;dry land;yield6|8|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to ascertain the growth and development of pods and the characteristics of grain filling and material accumulation after mung bean flowering,this study used mung bean cv.‘Xilv 1’ and ‘Anlv 7’ as tested materials.The color of pod and seed,length of pods,width of pods,volume of pods,grain volume,grain number,fresh weight of pod shell,fresh weight per hundred pod,dry weight per hundred pod,fresh weight of one hundred and dry weight per hundred were measured.The changes of dry matter distribution and grain filling rate of pod shell and grain during the development of mung bean pod were analyzed using Logistic Equation to fit grouting process and correlation analysis was conducted.The results showed that in the process of mung bean grain formation,pod color changed from dark green to green to black,and the color of seed changed from translucent turquoise to tender green to dark green.The pod length and pod width increased first and then kept steady.The trend of pod volume and grain volume increased first and then decreased and finally stabilized,the grain water content decreased continuously,and the pod shell dry matter distribution index decreased while the dry matter partitioning index of grain increased continuously,the grain filling rate changed slowly-fast-slowed and reached the peak value about 15 days after flowering.The grouting process was in line with Logistic equation.Correlation analysis showed that there were a extremely significant positive correlation between 100-grain dry weight of mung bean and 100-pod dry weight,a extremely significant positive correlation between 100-grain fresh weight and grain volume,and a significant positive correlation with pod width,pod volume and pod shell dry weight,and a significant negative correlation with pod number.The 100-grain dry weight and maximum grain filling rate displayed extremely significant negative correlation.A significant negative correlation with the average filling rate and a significant positive correlation with the active growth period were discovered.Therefore,mung bean breeding should adopt varieties of large pods,pay attention to the supply of fertilizer and water around 15 days after flowering in order to ensure grain's full filling and finally achieve high yield and quality.Keywords：mung bean;pod developmental rules;filling characteristics;correlation analysis1|9|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to provide a theoretical basis for breeding erect varieties of compact plant type,the main plant type characters in mung bean were explored.Six generations (P1,P2,F1,F2,B1 and B2) produced from a cross between semi-erect variety Taolyu 218 and erect variety Jilyu 10 were used to analyze inheritances of plant height (PH),number of branches (BN),node number of main stem (MSNN),and branch angle (BA) by the mixed major gene plus polygene inheritance model.The results showed PH,BN,and BA were dominated by two pairs of major gene with additive-dominance-epistasis effects plus polygenes with additive-dominance-epistasis (E-1 model).The additive effects of the two major genes of PH were both 7.27,and the dominance effects of the two major genes were 0.03 and -0.13,respectively,the heritability in B1,B2,and F2 was 59.35%,8.23%,and 41.45%,respectively for the major genes,and 2.40%,0%,and 0%,respectively for the polygenes.The additive effects of the two major genes of BN were both 0.33,and the dominance effects of the two major genes were -0.74 and -1.55,respectively.The heritability of major genes in B1,B2,and F2 were 3.26%,7.69%,and 53.10%,and were 51.39%,56.36%,and 0%,respectively for the polygenes,respectively.The additive effects of the two major genes of BA were both 2.10,and the dominance effects of the two major genes were -0.94 and -1.38,respectively.The heritability of major genes in B1,B2,and F2 was 48.11%,32.45%,and 64.54%,respectively.The heritability for polygenes was 0%.MSNN was dominated by a pair of major gene with additive-dominant effects plus polygenes with additive-dominance-epistasis effects (D-0 model).The additive and dominant effects of major gene of MSNN were 0.10 and -0.01.The heritability for major gene in B1,B2,and F2 were 1.39%,1.27%,and 0.63%,and were 65.39%,10.81%,and 47.08% for polygenes,respectively.It was found that BN and BA with high total heritability in ‘Taolyu 218’בJilyu 10’ should be selected in early generation.PH and BA were mainly dominated by major genes,and BN and MSNN were mainly dominated by polygenes.The roles of major genes and polygenes,and environmental conditions should be comprehensively considered in plant type breeding of mung bean.Keywords：mung bean;plant type;mixed inheritance modal;genetic analysis1|8|5<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The aim of this study was to investigate the best harvesting time of Fagopyrum dibotry as dual-purpose (medicine and food) vegetable.A high-epicatechin Fd species ‘Jinqiao No.I’,which was selected from mutation breeding,was used as materials.The contents of active ingredients and nutrition ingredients were detected in the two species,and the best harvest time of Fd leaves was studied at different growth stages.The results showed that the contents of flavonoids and anthocyanin in ‘Jinqiao No.I’ were significantly higher than those in control.The contents of flavonoids,anthocyanin and polyphenol of Fd leaves reached the highest point at 60 d of seedling stage.Compared with normal leaf vegetable,the contents of protein,dietary fiber and VC in the leaves of ‘Jinqiao No.I’ increased,while the contend of fat decreased.In conclusion,according to the indexes of medicine and food quality,the best harvest time of Fd leaves was 60 d after seedling-emerging.1|9|4<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To explore the effects of water stress on the water consumption and water use efficiency of post-cultivation facility grapes,a three-year experiment of facility cultivation was carried out from 2012 to 2014 at the experimental center for water saving irrigation of Zhangye City,Gansu Province.The growth cycle of grape was divided into five growth stages including germination,shoot growth,flowering,fruit enlargement,and coloring maturity.The 55% field water holding capacity (FC),which is the lower limit of soil moisture,was set as the moderate water stress at each growth stage.65% FC was set as the mild water deficit level.In addition,the lowest limit of 75% FC was used as control.Daily water consumption intensity,water consumption,water consumption module and water use efficiency of grape under water supply level were investigated.The results showed that:1) The grapes intensity of water consumption,amount of water consumption,water consumption model coefficients reached maximum value in fruit enlargement period,and three indicators were up to 45.84%,220.55 mm and 3.14 mm/d indicating fruit enlargement period is a critical period of water requirement for the facility grape.2) In addition to the flowering period,the moderate water stress in the rest of the growth period significantly decreased the water consumption intensity of the grapes during the stress period.The moderate water stress in coloring maturity period also significantly reduced the water consumption intensity.The mild water stress in the two long growth period (fruit enlargement,and colored maturity) also significantly affected the daily water consumption intensity.3) The moderate water stress in germination stage improved grape yield and water use efficiency (WUE) advantageously.The annual yield of three test years was 15% higher than CK,WUE increased by 20.5%.In conclusion,water stress had an important effect on the yield and water use efficiency of grapes.Water stress in the germination period saved water and increased the yield of grapes.The fruit expansion period was the critical period of water demand for grapes,which should be fully irrigated.Keywords：grapes;greenhouse planting;water stress;daily water consumption intensity;yield;water use efficiency2|8|5<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Annual dormant branches of 10 chestnut cultivars were taken as the experimental materials.Relative electrical conductivities (REC),freeze injury index,dyeing degree,the contents of malondialdehyde (MDA),proline,and soluble sugar under different low temperature treatments,as well as the anatomical structures indexes of branches were determined in this study.Semi lethal temperature (LT50) was assessed with REC and Logistic equation.The physicochemical and morphological structural indexes,which had significant relationship with LT50,were screened by correlation analysis.The membership function was used to determine the average subordinate level of the indexes,the comprehensive evaluation and cold resistance of main cultivars were sorted by comparing the average subordinative indexes.The results showed that:The relative electrical conductivities of 10 chestnut cultivars were in approximate "S" trend as temperature decreased.The LT50 based on the REC of 10 chestnut varieties (strains) were quite different,ranging from －26.64 to －17.73 ℃.The significant correlations were found between LT50 and the indexes including REC,freeze injury index,dyeing degree,the contents of MDA under －20 ℃ treatment,as well as phellem layer thickness and phellem layer ratio of the branch.These characters could be used as physicochemical and morphological structural indexes.The membership function based on 6 indexes could be used to accurately identify the cold resistance of the chestnut.The order of cold resistance of 10 chestnut cultivars,from the strong to the weak,was Yankuan,Yanshanzaofeng,Yankui,Chushuhong Zipo,Niandiban,Luotian 1,Hongli,Yanhong and Za 35.Keywords：Chinese chestnut;cold resistance;index;comprehensive evaluation1|8|12<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The objective of this study was to explore a ascorbate peroxidase (APX) gene in Lycium chinense by the methods of Reverse-Transcription PCR and RACE,and deduce the structure of this gene by bioinformatics,and analyze gene expression by real time PCR.The full-length cDNA of L.chinense APX (designated as LcAPX) was 1 047 bp (Genbank No.KX981601),and contained a complete open reading frame (ORF) of 753 bp,which encoded 250 amino acid residues.Sequence analysis showed that LcAPX protein contains the heme binding site,substrate binding site,and K+ binding site.Homology analysis indicated that the deduced LcAPX protein was highly homologoud to other APX proteins from different species.LcAPX protein had closer relationship with APXs from Solanaceae plants than from other plants.The expression of LcAPX gene was the strongest in the mature leaves of L.chinense,and the least in flowers.Furthermore,LcAPX transcription level was induced under the treatment of PEG and NaCl stresses,and LcAPX played a role in resistance to drought and salt stress processes.1|9|6<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To systematically analyze the nutritional components of Cantharellus cibarius Fr.and evaluate its nutritional value,the contents of water,crude protein,ash,crude fat and total sugar of wild C.cibarius Fr.were determined by national standard methods.The mineral elements,alpha tocopherol,fatty acids and volatile components were determined by Atomic absorption spectrometry,Liquid chromatography,Gas chromatography and Solid phase microextraction and Gas chromatography/mass spectrometry.The contents of water,crude protein,ash,crude fat and total sugar in C.cibarius Fr.were 90.36%±0.82%,21.82%±0.21%,3.54%±0.34%,2.12%±0.14% and 37.72%±0.28% respectively.The contents of K,Ca,Mg,Zn,Fe and Mn were 366.10±2.76,48.47±0.83,84.30±2.99,7.73±0.48,22.35±0.80,and 1.78±0.24 mg per 100 g,respectively.The total amount of amino acids was 11.19%,the total amount of essential amino acids in human body was 3.95%,and the ratio of essential amino acids to non essential amino acids was 0.55.The composition of amino acids was similar to the standard model of FAO/WHO protein,and the AAS,CS and EAAI were 1.13,0.84 and 0.81,respectively.The content of alpha tocopherol was up to 9.56 ±0.36 mg per 100 g.There were 23 fatty acids in C.cibarius Fr.,including 12.92% of saturated fatty acids,7.19% for monounsaturated fatty acids and 79.89% for polyunsaturated fatty acids.67 kinds of volatile components were detected and 25 compounds were identified that accounting for 77.60% of the total distillate composition.And the main components are beta lonone (26.02%) and gamma nonanoic lactone (11.96%).This study showed that C.cibarius Fr.was a valuable edible fungus with high development and utilization value.1|8|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to study the muscle meat quality of Mongolia cattle in Xilinguole Grassland,eight Mongolia cattle and eight Simmnetal cattle in Xilinguole Grassland were selected as study objects.The longissimus dorsi muscle of slaughtered cattle was collected for muscle meat quality analysis and mineral content measurement.The results showed that:1) The muscle redness a*,yellowness b*,water holding ratio,cooked meat rate,shear force,dry matter and ash in Mongolia cattle muscle were significantly higher than those in Simmental cattle (P < 0.05).The drip loss rate and pH were significantly lower than those of Simmental cattle (P < 0.05).Although the brightness,crude protein and crude fat in meat were higher than those in Simmental cattle,there were not significant differences (P > 0.05).2) The contents of mineral elements,Ca,P,Cr,Cu,Fe,Mn,Zn and Se,in Mongolia cattle were significantly higher than those in Simmental cattle (P < 0.05).The Mg and K contents were significantly lower than those in Simmental cattle (P < 0.05),while Mo content in Mongolia cattle was higher than that in Simmental cattle,the difference was not significant (P > 0.05).In conclusion,the Mongolia beef had better muscle quality and a higher mineral content than Simmental beef.It had better edible and processing potential.Keywords：Mongolia cattle;Simmental cattle;meat quality;minerals1|8|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To reveal the roles of CYP11A1,CYP17A1 and CYP19A1 genes in the high fecundity of sheep,Real-time fluorescence quantitative PCR (RT-qPCR) was performed to detect CYP11A1,CYP17A1 and CYP19A1 mRNA expressions in seven different tissues (brain,cerebellum,hypothalamus,pituitary,uterus,ovary and oviduct) of multiparous and uniparous Small Tail Han sheep.The results showed that CYP11A1 was expressed in ovary,oviduct and uterus of Small Tail Han sheep.The expression of CYP11A1 in ovary of multiparous Small Tail Han sheep was extremely significantly higher than that of uniparous Small Tail Han sheep (P<0.01).However,the expression of CYP11A1 in the uterus of multiparous Small Tail Han sheep was extremely significantly lower than that of uniparous Small Tail Han sheep (P<0.01).The CYP17A1 gene was mainly expressed in ovary,oviduct and hypothalamus of Small Tail Han sheep.The expression of CYP17A1 in hypothalamus,uterus of multiparous Small Tail Han sheep was significantly lower than that of uniparous Small Tail Han sheep (P<0.05).The CYP19A1 gene was mainly expressed in ovary and hypothalamus of Small Tail Han sheep.In conclusion,the results suggested that CYP11A1 and CYP17A1 might be involved in the regulation of multiple births in Small Tail Han sheep.Keywords：Small Tail Han sheep;prolificacy;CYP11A1;CYP17A1;CYP19A1;tissue expression2|10|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To study the substitution effects of cinnamylaldehyde for antibiocs in broiler diet,360 healthy 1 day of age broilers were selected and randomly divided into 4 groups:Group 1 (the control),the experimental group 2,3 and 4 with 3 replicates per group and 30 broilers per replicate.The control group broilers were fed basal diet supplemented antibiotics (1-3 weeks of age:kitasamycin premix 50 mg/kg and salinomycin premix 75 mg/kg;4-8 weeks of age:kitasamycin premix 10 mg/kg);Group 2,3 and 4 broilers were fed basal diet supplemented with 40,80 and 120 mg/kg of cinnamaldehyde premix,respectively.The feeding experimental period was 56 d.The broiler health status,weight gain,serum biochemical indexes,intestinal flora and meat quality were observed.The results showed that:1) At 1-8 weeks of age,the average daily gain of the Group 3 broilers increased by 5.68% compared with the control group.The feed weight ratio (2.14±0.17) of the experimental Group 3 was the lowest.2) Compared with the control group,the activities of the glutamic-pyruvic transaminase in serum of the Group 3 and 4 broilers decreased respectively by 43.66% and 61.97%.The activities of the glutamic-oxaloacetic transaminase in serum of Group 4 broilers decreased by 9.27%;The total protein in serum of Group 2 broilers increased by 14.34%.The urea nitrogen in serum of Group 2,4 broilers decreased both by 24.32%.IgA in serum of Group 3 broilers increased by 31.03%.IgG in serum of Group 3,4 broilers increased respectively by 61.47% and 66.97%.IgM in serum of Group 2,3 and 4 broilers increased respectively by 169.09%,283.64% and 300.00%.3)The water loss rate of pecloralis muscles of Group 3 and 4 broilers decreased respectively by 17.21% and 14.10%.This study showed that cinnamaldehyde promoted the growth of broilers,improved the metabolism of nutrition and biochemistry,enhanced immune function and improved the quality of chicken meat.The application effects of cinnamaldehyde in broilers were better than antibiotics,and the optimal supplementation of cinnamaldehyde premix in broiler diet was 80-120 mg/kg.Keywords：broiler;cinnamaldehyde;antibiotic;substitution;application effect1|8|5<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To analyze the correlation of plasmid-mediated quinolone resistance (PMQR) genes/quinolone resistance determining region (QRDR) mutations with quinolones resistance in Aeromonas,116 Aeromonas isolates were taken as study object.PMQR genes including qnrA,qnrB,qnrS,qepA and aac(6')-Ib-cr in Aeromonas were detected by PCR.The target genes of gyrA and parC were also amplified by PCR to analyze the mutations in QRDR.The minimal inhibitory concentrations (MICs) of all 116 isolates against nalidixic acid (NAL),enrofloxacin (ENR) and ciprofloxacin (CIP)of quinolones were evaluated by micro broth 2-fold dilution.The results showed that:Eighteen (15.52%) isolates were detected carrying PMQR gene.Among those strains,8 (6.90%) and 9 (7.76%) strains carried qnrS2 gene and aac(6')-Ib-cr gene,respectively.One strain carried both of these two genes;qnrA,qnrB and qepA genes were not detected in this study;Mutations in the QRDRs of gyrA and parC were found in 56 strains (48.28%) of all isolates with GyrA:Ser83Ile and GyrA:Ser83Ile + ParC:Ser87Ile combination being the most common mutations.The resistance rates of 116 Aeromonas isolates to NAL,CIP and ENR were 47.41%,12.07% and 11.21%,respectively;With the exception of one strain carrying qnrS2 gene alone was resistant to CIP,7 strains were susceptible to the 3 drugs of quinolones examined;No mutations in QRDR.The MICs of NAL,CIP and ENR were less than 4.00,0.50 and 1.00 mg/L,respectively;Ten aac(6')-Ib-cr positive strains were found mutations in QRDR and resistant to NAL (MIC>128.00 mg/L), and eight strains were resistant to CIP and ENR (MIC≥4.00 mg/L).Strains with either gyrA single mutation or gyrA + parC double mutation were resistant to NAL (MIC≥64.00 mg/L).The MICs of CIP and ENR for the strains with QRDR mutation,some strains were less than 4.00 mg/L,and there were more than 4.00 mg/L.In conclusion,QRDR target gene mutation may contribute to the susceptibility decrease of NAL,and the fluoroquinolone resistance in Aeromonas might be attributed to the mutual cooperation between PMQR and QRDR mutations.Keywords：Aeromonas;PMQR;QRDR mutation;quinolones;resistance1|9|4<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To solve the problem of dust during the operation of the forage seed pelletizing,a 3-stage dust removal system was designed.Theoretical analysis,numerical simulation and test were combined to study the dust removal system of the forage seed pelletizing coating machine.The results showed that:1) Based on Fluent,the flow field distribution of the internal space of the dust removal system was obtained and the airflow attachment effect was obvious.The gas followed the designed route.The airflow changed obviously with sudden changes in the volume.The average inlet airflow speed was 10 m/s.The average speed of the dust removal airflow was 0.2 m/s,which was conducive for the collection of dust particles;2) The primary,secondary and tertiary dust removal systems were designed separately according to the gravity principle,centrifugal force principle and bag isolation principle to be used for dust collection of different particle sizes.The test reached a dust removal efficiency of 92.56%,which basically met the dust removal requirements for the seed pellet coating operation of forage grass.Keywords：dust removal system;seed pellet coating machine;Fluent;collection efficiency2|9|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In view of the problems of deep substituting resistance,small width and low efficiency of the existing deep shovel in the red soil plough,a pneumatic deep shovel based on air pressure splitting was designed.CFD software was used to establish the model of the red soil plow bottom of the southern cultivated land to carry out the calibration of the deep gas pressure range,and the diffusion characteristics of the bottom layer of different volumetric plows under the same pressure of 2 MPa were studied.The results showed that the effective enthalpy pressure of the bottom layer of 1.8 g/cm3 red soil was 1.6-2.4 MPa;The crack of the bottom layer of the plough was mainly diffused horizontally,while the crack of the bottom of the plough with smaller bulk density is also vertical.In conclusion,by using the pneumatic deep shovel designed in this study,the direction and the horizontal direction were diffused,the bottom of the plow was larger,and the deeper pine effect was better.Keywords：deep shovel;pneumatic deep loose;plow bottom;air pressure split1|9|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to increase the heat energy utilization efficiency of direct-expansion solar-assisted heat pump (DX-SAHP),a mechanism was designed by using DX-SAHP as collection system and rhizosphere-air heating as releasing system. The heating effect,coefficient of performance (COP) and heat-collecting efficiency were tested.The operation mode under different weather conditions was optimized.The results showed that:Under the conditions of consecutive cloudy days and consecutive sunny days,the heat utilization efficiency of the heat releasing system was higher than 97.2% and 92.7% correspondly;Under different weather conditions,the rhizosphere temperature and air temperature in the experimental area were above 17.9 and 11.6 ℃ respectively,which were 1.5 and 3.6 ℃ higher than those of the control area;The relative humidity in the experimental area was below 90.8%,which was 3.2% lower than that of the control area;The energy-saving rate R of the whole system under different weather conditions was higher than 47.2%,and the coefficient of performance (COPtotal) was above 1.9;Under different weather conditions,the heat collecting system could reach the set temperature objective for heating within the set time while keep the coefficient of heat-collecting performance (COPc) above 2.3 and the heat-collecting efficiency μ higher than 149.6%;Additionally,from 9:30 am to 11:30 am,with the increase in solar radiation intensity,the COPc of the heat collecting system also increased from 1.4 to 3.0;from 11:30 am to 14:50,the COPc of the heat-collecting system was above 3.8;After 15:10 when the temperature of water in the thermal storage tank was higher than 47 ℃,the COPc finally dropped from 3.2 to 0.8.In conclusion,this study clarified that the DX-SAHP heating rhizosphere-air could not only improve the heating effect of greenhouse,but also improve the heat energy utilization rate and the COPc of the DX-SAHP.Additionally,it could realize the greenhouse energy conservation goal by using the operating mode of DX-SAHP,which could be adjusted in accordance with variations in solar radiation intensity and the water temperature in the tank.1|11|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The steel skeleton structure of solar greenhouse is a light and long-span structure,and its dynamic response is strong under wind load.Based on the theory of Timoshenko beam,a investigated lump method is presented for the dynamic response analysis of plane frame solar greenhouse under wind load.Firstly,according to the concept of Timoshenko beam micro-body,the spatial discrete segments of steel skeleton are used to model the investigated lumps.Based on Timoshenko beam theory,the governing equations of the skeleton structure of the plane frame solar greenhouse are derived,and the algorithm is also given.Secondly,the accuracy and effectiveness of the proposed numerical method are verified by a bending wave of variable cross-section beam with free ends propagates.Finally,the dynamic response of steel skeletons of plane frame solar greenhouses is respectively analyzed under the effect of simulation wind speed and actual wind speed,and the position of the node maximum displacement and the section maximum stress of the steel skeleton are obtained.The computational results and comparisons show that:The two peaks of displacement are respectively near the windward height 1 and 3 m;The most dangerous section in the steel skeleton is near the left end,and the maximum stress is 321 MPa,where the bending stress is the main factor of the rapid increase in stress.In addition,the maximum of both node displacement and cross-sectional stress caused by fluctuating wind loads are bigger than the values caused by average wind loads.Keywords：solar greenhouse;wave propagation method;dynamic response;fluctuating wind speed;investigated lump1|10|5<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In this study,the process of transporting granular materials by double-shaft screw conveyor was simulated with discrete element method and compared the results of experiments and simulations of single-shaft screw conveyor.Based on the accuracy validation of numerical model and parameters with experiments,the quantitive relationship between shaft distance,screw pitch and mass flow rate (Ṁ ) was fitted with a binary quadratic polynomial function of the fit goodness of R2=0.964 6.The results showed that:1)Rotating directions of two shafts did not affect the Ṁ;2)Ṁ was evidently influenced by shaft distance and screw pitch.Ṁ increased with the increasing of shaft distance obviously,and it decreased after reaching the maximum value under the larger pitch.Ṁ increased with the increasing of pitch and decreased after the maximum value.3)The behavior of the particles was influenced by the shaft distance and screw pitch.Tnd the minimum velocities of particles at the central position of the double-shaft decreased linearly as the shaft distance increased,and the decrease tendency was more obvious with larger screw pitch.Keywords：screw conveyor;twin-shaft;mass flow rate;discrete element method;optimization analysis1|9|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In view of the application of mega-city region construction to the landscape ecological pattern and its quantitative research,Beijing City was taken as research object.Landscape index was combined to quantitatively analyze the spatial pattern and dynamic changes of Beijing landscape.The threshold effect of urbanization on urban landscape was explored based on multi-temporal remote sensing change detection and grid partitioning method.The results showed that:1) From 2000 to 2015,because of the gradual increase in the level of urbanization,there was a 56% increase in Beijing's building land and a relatively low degree of plaque fragmentation.Meanwhile,urban cultivated land and Greenland were unevenly distributed and the fragmentation was increased.2) In the aspect of spatial pattern,because of the coverage and the high degree of connection of building land,the landscape fragmentation degree of the urban area was obviously lower than that of the suburb area,and the landscape diversity level was declining.3) The regression analysis showed that urbanization had a significant impact on the degree of urban landscape fragmentation with a correlation coefficient of 0.84,which was expressed as an inverted U relationship.In other words,the landscape fragmentation first rose and then declined with the urbanization level increasing,and it reached the peak when the urbanization level was between 51% and 53%.Keywords：mega-city regions;landscape pattern;landscape index;urbanization;ecological construction2|10|6<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The aim of this study is to explore the spatial distribution characteristics and differences of rural settlements under different agricultural development levels in main grain producing areas.GIS spatial analysis,geostatistics and landscape index methods are used to analyze the spatial pattern and difference of distribution,scale and morphological characteristics of rural settlement of agricultural and reclamation areas in Fujin of Heilongjiang Province.The result shows:1) In terms of spatial distribution,rural settlement in agricultural and reclamation areas all belong to agglomeration mode.The highest nuclear density of agricultural and reclamation areas are 0.93 and 0.73 km-2 respectively,and the density in agricultural areas is relatively higher.2) In terms of scale distribution,the scale of rural settlement in agricultural areas presented globally low clustering spatial distribution,which is manifested in three modes of large-scale,small-scale and random distribution.The scale of rural settlement in reclamation areas presented globally high clustering spatial distribution,which is manifested in two modes of large-scale and random distribution.3) In terms of morphological distribution,the spatial distribution pattern of morphology of rural settlement in agricultural areas shows random characteristics,random components in the spatial distribution pattern are much higher.The spatial distribution pattern of morphology of rural settlement in reclamation areas shows continuity and stability characteristics,the mechanism of the structural differentiation caused by natural correlation in the spatial distribution pattern is much higher.According to the spatial pattern characteristics of the rural settlement in the agricultural and reclamation areas,different spatial regulations and reconstruction model of rural settlements are proposed.This study provides reference for rural reconstruction and consolidation of rural residential areas under the background of urban rural integration.Keywords：rural settlement;spatial pattern characteristics;differences;agricultural areas;reclamation areas1|10|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Based on the Theil index,exploratory spatial data analysis and spatial econometric model,the regional differences,temporal and spatial patterns and driving forces of fertilization intensity in Shandong province from 1995 to 2015 are examined.The results show that:1)The total amount of fertilizer application and fertilization intensity of Shandong Province is higher,both trends are basically the same,showing a certain stage characteristic;2) In the view of absolute quantities,eastern area is the highest (annual average of 486.71 kg/hm2),central area comes second,whereas the western area shows the lowest level.The differences of fertilization intensity show a fluctuant increasing trend,which is mainly attributed to the differences among the three regions;3) The spatial distribution of fertilization intensity is unbalanced.There is a significant positive spatial correlation,and the spatial agglomeration increased.Most counties in Yantai have become stable hot spots and most counties in Jinan,Zibo,Laiwu and Liaocheng have become stable cold spots;4) By spatial error model,it is found that the fertilization intensity is influenced by many factors.The net agricultural income has a significant positive effect,the farmers' education,planting scale,agricultural production structure and the policy of soil testing and formula fertilization have a significant negative effect on spatial-temporal changes of fertilization intensity.However,the population and fertilizer prices have no significant effect.In the future,popularizing scientific fertilization techniques,formulating policies according to local conditions,speeding up land circulation,and strengthening education and training of farmers should be carried on.Keywords：fertilization intensity;spatial-temporal patterns;driving forces;spatial econometric model1|10|4<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to carry out chemical fertilizer reduction work more specifically,this study employed Cobb-Douglas production function to evaluate the degree of over fertilization during 2002—2015,and then spatial autocorrelation theory and hot spot analysis were employed to analyze the spatial correlation pattern of over fertilization,which main production regions of rice,wheat and maize were taken as research objects.The conclusions showed that:1)The degree of over fertilization about crops was distributed regularly,which the high value areas of rice's overuse fertilization mostly were concentrated in the Huang Huai Hai Area and South China,the high value areas of wheat's overuse fertilization were distributed in Northern Plateau Area,Huang Huai Hai Area and Middle Lower Yangtze Region,and the high value areas of maize's overuse fertilization were distributed in South China,Middle Lower Yangtze Region and Northeast.2)The degree of over fertilization about rice,wheat and maize showed strong spatial autocorrelation,from its clustering characteristics view,wheat is the strongest,the rice is middle and the maize is the weakest.3)The hot spot regions of rice's over fertilization were mainly distributed in Huang Huai Hai Area,Middle Lower Yangtze Region and South China,and its cold spot regions were mainly distributed in Northern Plateau Area and Northeast;the spatial distribution of wheat's cold and hot spot showed "hot in middle and cold in round",which the hot spot regions were mainly distributed in Huang Huai Hai Area and Middle Lower Yangtze Region,and its cold spot regions were mainly distributed in Northwest;the pattern of cold and hot spot about maize was changed from "hot in south and cold in north" to "hot in east and cold in west",which the hot spot regions were mainly distributed in Southwest,South China and Middle Lower Yangtze Region,and its cold spot regions were mainly distributed in Northwest.Keywords：major grain crops;the degree of over fertilization;spatial autocorrelation theory;cold and hot spot analysis3|11|11<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to further explore the effectiveness of labor transfer on anti-poverty,based on 789 survey data on poor rural households in the Former Central Soviet Area of Gannan,a mediating effect model was built by taking households income as a mediator and "Labor transfer intermediary conduction—Exit from poverty" as conduction mechanism.The impact mechanism of rural labor transfer on farmers' poverty reduction was analyzed.Taking the family income as the intermediary variable,a theoretical structure was formed.The results showed that the labor transfer was a significant positive factor of increasing the income and non-agricultural income of rural households to promote the rural households exiting poverty.It could effectively promote poverty-stricken households to get rid of poverty.But it had not obvious effect on the rural households of getting rid of poverty by improving agriculture income through non-agricultural employment feeding back agricultural operations.Suggestions were put forwarded in this study:Formulating and perfecting policies and measures for labor transfer,reasonably arranging the number of labor force transfers,and improving the social security system play an important role in promoting the anti-poverty process.Keywords：labor transfer;income structure;poverty withdrawal;mediating effect2|9|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Targeted women poverty alleviation needs a precise measure of their poverty.Multidimensional poverty measurement can reflect poverty status comprehensively.In order to understand the degree of multidimensional poverty,the A-F of MPI index is adopted to measure the multidimensional poverty of poor women in Fujian Province from 11 dimensions and then decomposed respectively from the perspective of dimensions and regions based on the data from the project of Five Years Plan of "Women's Poverty Alleviation",which was carried out by Fujian Women's Federation in 2015.The results show that the highest poverty dimension is nine,and social relationships,health,education,sanitation facilities and decision-making dimensions have the highest contribution to the multidimensional poverty indexes.Under different number of dimension values,Longyan,Quanzhou,Zhangzhou and Nanping have been proved to have greater impact on the multidimensional poverty indexes.Keywords：women's poverty;multidimensional poverty;poverty measure;A-F method1|8|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The aim of this study is to guide the land-lost peasants to efficient use land compensation and perfecting the way of Land compensation payment based on the survey and experimental data of the land-lost peasants in the suburbs of Jinan to study the characteristics and mental mechanism of household portfolio choice,and then through option design "nudge" the way of land compensation payment.The results revealed that the "Conservatism and Adventure" coexist in household portfolio choice of the peasants who have lost their land in the suburbs.The cognitive labels and emotional labels of psychological accounts have a significant impact on the choice of family assets..When the land compensation is presented by multiple accounts,the proportion of low-risk household portfolio choice increased and the proportion of household portfolio choice decreased.Keywords：household portfolio choice;mental accounting;land compensation1|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The study is to summarize researches on pricing of the farmers' land member rights quitting,and put forward future key research point and direction.Literature synthesis method and inductive summarization method are employed in this study.The results show that contracted management rights and homestead qualifying rights are origin from land member rights,and they are part of land member rights,and the two plused other land right are land member right.Since the quitting of farmers' land member rights is a deeper level of reform,more complex factors are needed to be considered in the study.Prospects suggested for research in this area are:The differentiation of rural households and the pricing of farmers' land right quitting in the new era should be further explored;The efficiency and equity of the real price of land member's right quitting in reform areas;The effect of dynamic game between the government,collectives,land owners,and quitting farmers to the process of quitting of land member rights;No-marketing pricing of the farmers' land member right;the pricing mechanism for the quitting of the farmers' land member rights.Keywords：land member rights;the quitting of land member right;contracted management rights;homestead qualifying rights;pricing mechanism1|9|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Based on the papers of Nature index journals,this study analyses the development status of life science research in China from the aspects of trends of publication,distribution of field and contribution of institutions.The results show that:1) The life science capability of China is continuously improving while the output of top papers in technologically-developed countries is declining;2) There is a convergent development in Chinese life science research with the trend of integration and interdisciplinary and the advanced technology is rapidly applied,such as CRISPR/Cas9 and RNA-Seq;3) Chinese Academy of Sciences and its directly affiliated units concentrate a lot of power in Chinese life science research,and other research teams of domestic universities are growing with the comparative advantages in some disciplines.The existing problems in the development of Chinese life science research are discussed in the end.Keywords：life science;Nature index journal;bibliometrics;Chinese scientific institutions;development status1|10|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
