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- Abstract：Harvest index (HI) and residue factor (RF) are essentially significant for crop production research and crop residue quantity assessment.Data in this research were collected from original papers on cereals which were mainly published between 2006 and 2010 in the main production provinces of mainland China.Results indicated the average of HI and RF of rice were 0.50 and 1.00,respectively.In 16 provinces,HI of rice varied between 0.43 and 0.54 and RF between 0.85 and 1.33.The average of HI and RF of maize were 0.49 and 1.04,respectively.HI of maize varied between 0.42 and 0.53 and RF between 0.89 and 1.38 in 12 provinces.The average of HI and RF of wheat were 0.46 and 1.17,respectively.Wheat had HI with the range of 0.42 and 0.50 and RF 1.00 and 1.38 in 11 provinces.For the other cereal crops,the range of HI was 0.17 and 0.49,and RF 1.04 and 4.88.The HI of the cereals was significantly improved during the past 20 years.In the near future grain yield of cereals will be improved mainly through a substantial increase in biomass,instead of HI.Keywords：cereal crop;crop residue;harvest index;residue factor;residue/grain ratio6|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Harvest index (HI) and residue factor (RF) are of essentially significance for crop production research and crop residue quantity assessment.HI and RF of non-cereal crops in their main production provinces of China are reviewed according to field data collected from original papers published mainly during 2006-2010.HI of soybean varied between 0.35 and 0.47 whereas RF between 1.13 and1.86 across six provinces,and the average was 0.42 and 1.50,respectively.Tubers including potato,sweet potato,and cassava had HI between 0.55 and 0.77 whereas their between 0.30 and 1.17 across eleven provinces.The average HI and RF was 0.59 and 0.71 for potato,0.69 and 0.45 for sweet potato,and 0.64 and 0.50 for cassava,respectively.The average HI and RF for cotton were 0.15 and 2.91,with a range of 0.12－0.18 and 2.41-4.09 respectively.Peanut had HI between 0.41－0.54 and RF between 0.85－1.43 across six provinces,and the average was 0.50 and 1.14,respectively.Canola had HI 0.24－0.28 and RF 2.57－3.17 across six provinces,and the average HI and RF were and 2.87,respectively.Sunflower had HI between 0.21 and 0.40 whereas RF between 1.50 and 3.76 across four provinces in Northwest and North China,and their average HI and RF were 0.32 and 2.63 respectively.In Henan and Hubei provinces,the average HI and RF were 0.34 and 2.01 for sesame.Sugarbeet had a higher average HI 0.71 with a range of 0.60－0.85,its RF varied between 0.18－0.67,with an average of 0.43.HI and RF of sugarcane was 0.70 and 0.43 for Fujian province only.Tobacco had HI between 0.52－0.67 and RF between 0.49－0.92 across seven provinces,the average HI and RF was 0.61 and 0.71,respectively.In near future,there will be a potential trend to decrease the HI to approach higher crop residue yields,along with substantial improvement of the economic product yield due to increase in biomass yield.Keywords：crop;harvest index;crop residue;residue factor;residue/grain ratio4|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Nine sweet sorghum cultivars were observed for salinity tolerance in climate incubator and irrigated with four NaCl concentrations of 0、70、140 and 210 mmol/L with three replications.Comprehensive evaluation on salt tolerance was studied by fuzzy mathematics.Effects of salt stress on POD isozyme of sweet sorghum seeding were studied by PAGE.As a result,there are significant (P＜0.05) differences between all treatments and control in germination rates,germination index,germination energy,bud length,root length,bud fresh weight,root fresh weight.Moreover,averages of the above eight indicators decrease along with the increase of salt concentrations.The order of salt-tolerance for nine varieties was:Thesi＞Tian132＞BJK156＞Cowley＞Jitian3＞Wray＞Keller＞Dale＞Jitian2.In the meantime,Pattern of POD isozyme bands became stronger and stronger with increase of salinity concentration,a novel isozyme band (P1) was induced at 210 mmol/L NaCl for BJK156,at 140,210 mmol/L NaCl for Dale,under all salt stress for Wray,Tian132,Keller,Jitian2,Thesi,Jitian3,Cowley.The isozyme band P4 disappeared at 70 mmol/L and appeared at 140,210 mmol/L NaCl for Jitian3.The changes of peroxidase isoenzyme profiles may be related to the salt tolerance in sweet sorghum.Keywords：sweet sorghum;NaCl;germinate;peroxidase isozyme (POD)1|5|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Four microbial communities named WSD-5, N,M and D,which with stable wheat straw-degradation capability,were constructed at normal temperature using the restricted cultivation technology.Compared with other three groups,WSD-5 exhibited the potential higher wheat straw-degradation ability during the process of continuous cultivation.On the 15th day,WSD-5 displayed the maximum wheat straw-degradation rate up to 75.6%,compared to N(65.0%),M(69.4%) and D(67.5%).Based on the results,up to 94.2% of cellulose,81.9% of hemicellulose,and 21.3% of lignin could be decomposed by WSD-5.The activities of cellulase,xylanase,and filter paper were detected for all the four communities and the results demonstrated that WSD-5 showed the highest enzyme activity (filter paper activity,1.30 U/mL;cellulose endonuclease activity,4.35 U/mL;exonuclease,0.60 U/mL;β-glucosidase activity,0.43 U/mL;xylanase activity,15.16 U/mL).The result of specific primer PCR showed that WSD-5 was consisted of fungi and bacteria together.Keywords：lignocellulose;microbe;degrading community;enzyme activity2|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：A two-year field experiment was conducted to study the effect of nitrogen on grain yield and yield components of aerobic rice,HD297.The objective was to clarify the constraints for improving grain yield when amount of applied nitrogen reached a certain level.The grain yield was 2.8,3.5 and 3.5 t/hm2 respectively over two years under 0,75 and 150 kg/hm2(N) treatments.Compared with 0 kg/hm2(N),N input increased the grain yield significantly,but there was no difference between 75 and 150 kg/hm2(N).With N input,the productive tillers and grains per panicle increased significantly and there was no difference of thousand grain weight and harvest index among the nitrogen treatments,while the percentage of filled grains decreased and the ratio of non-productive tillers increased especially under N150 treatment.The dry matter accumulation reached maximum at the middle stage of grain filling followed by a poor dry matter production after anthesis.Moreover,nitrogen input had little effect on the dry matter production after anthesis.The N uptake at maximum tiller stage could improve tiller numbers and promote spikelet formation at panicle initiation.Therefore,there was no difference of the grain yield between N75 and N150 treatment;compared with N75 treatment,the lower ratio of productive tiller,lower percentage of filled grains and poor dry matter production after anthesis were three major factors for improving the grain yield of HD 297 under 150 kg/hm2(N) treatment.Keywords：aerobic rice;nitrogen;productive tillers;percentage of filled grain;grain yield2|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：DELLA proteins in plants are transcriptional regulators involved in GA signal pathway.Mutation of the DELLA proteins induces dwarf phenotypes.MdRGL1a gene is a member of the apple MdDELLAs.In order to elucidate its physiological functions, the full length of MdRGL1a gene isolated from 'Wijcik’ apple was cloned to construct an MdRGL1a-GFP transient expression vector and a 35S::MdRGL1a expression vector.The MdRGL1a subcellular localization in the particle bombardment transformed onion epidermal cells was observed under a confocal laser scanning microscope.The Agrobacterium-mediated transgenic method was used to introduce the MdRGL1a gene into Nicotianna tabacum.Transgenic plants were identified by PCR amplification and GUS histochemical staining.Transgenic tobacco plants were characterized.The endogenous hormones of tobacco were quantitatively analyzed by ELISA.Our results showed that MdRGL1a-GFP fusion protein was localized in the cell nucleus.The root system of in vitro transgenic plantlets carrying 35S::MdRGL1a was generally smaller and shorter than those of control plantlets.The transgenic tobacco displayed dwarf phenotypes when transplanted into the greenhouse and 75% flowered earlier than non transgenic control.Compared to control, the concentrations of endo-auxins and cytokinins in most transgenic plants were lower while the ABA level was higher.The dwarf phenotypes and the change in blooming time may probably result from the MdRGL1a overexpression induced changes in the concentrations of the endogenous IAA,ZR,and ABA in the transgenic plants.Keywords：apple;MdRGL1a;gene;DELLA protein;GA;genetic transformation0|6|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Akihime’ strawberries(Fragaria×ananassa Duch.)were planted in grooves of an A-frame with the mixed substrate in three different greenhouses (medium-scale glass greenhouse,medium-scale plastic greenhouse and large-scale plastic greenhouse).The effects of greenhouse conditions on photosynthetic characteristics were evaluated.The results showed that the root temperature of plants in upper tier was higher than middle and lower tiers’ on an A-frame.The daily variation of net photosynthetic rate showed double-peak in upper tier,while single-peak in middle and lower tiers.The daily variation of net photosynthetic rate and photosynthetic active radiation displayed great discrepancy between facing east and facing west in middle tier and lower tier.The leaf photosynthetic active radiation in middle and lower tiers were 51.21%-62.49%,33.64%-44.86% of upper tier,while their net photosynthetic rates could reach to 62.42%-77.98%,42.14%-53.51% of upper tier.It indicated that 'Akihime’ strawberry had some adaptive capacity under low light environment.Correlation analysis indicated that the leaf net photosynthetic rate was closely related to photosynthetic active radiation and air temperature,but almost not related to root temperature.1|8|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Bacterial communities of sediments from Guanting Reservoir (Beijing) and Rupa Lake (Nepal) were studied using method of 16S rDNA clone library.In the sediments,pH and concentration of total phosphorus and phosphorus fractions were obviously different.Bacterial communities of the two samples were both dominant by phylum of Proteobacterium,in which the percentage of β-proteobacterium was highest (>50%).The second dominant bacteria cluster of sediment from Rupa Lake is α-Proteobacterium,other than γ-Proteobacterium in that from Guanting Reservoir.δ-Proteobacterium in both samples was much less.In sediment from Guanting Reservoir,percentage of Chloroflexi(9.21%) was much higher than that of Rupa Lake (1%),and Gemmatimonadetes (12.2%),Acidobacteria (1.3%) and Bacilli (0.8%) were peculiar.Sediment of Rupa Lake is peculiar of Spirochaetes (2%),Chlorobi (1%),Clostridia (1%) and Verrucomicrobiae (0.3%).There were less Actinobacteridae in sediment of Guanting Reservoir and Rupa Lake.Keywords：water resource;bacterial community;sediment;eutrophication1|9|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：This research was engaged in study on synergistic effect of Probiotics and Astragalus on production of broilers.In this experiment,broilers lactobacillus microcapsule,bacillus subtilis powder,bacillus licheniformis powder and Astragalus were mixed by the mass ratio of 3∶1∶1∶3 to prepare the Probiotics-Astragalus complex biological reagent.2 g/kg Probiotics reagent,4 g/kg Astragalus and 4、5 and 6 g/kg Probiotics-Astragalus complex biological reagent were added respectively in the based diet of 3 days old of AA broilers.The result showed that Probiotics-Astragalus had better effect than Probiotics and Astragalus groups:1) Broiler product performances in Probiotics-Astragalus group were significantly increased compared with Probiotics and Astragalus groups,such as daily weight gain increased 14.01%-24.90% and 13.40%-24.24%,and the ratio of feed to meat decreased 14.56%-7.28% and 14.15%-6.83% respectively.2) Immunity ability in Probiotics-Astragalus group increased significantly compared with Probiotics and Astragalus groups,for example,bursal index increased 23.53%-28.10% and 29.45%-34.25%,and spleen index increased 31.65%-34.53% and 46.4%-49.6% respectively.3) Increased the production of antibody for broilers newcastle disease and improving intestinal flora (P＜0.05).Synergistic effect achieved the best when adding 5 g/kg supplement in Probiotics-Astragalus group.Probiotics and astragalus had better synergistic effect in improving the performance,immunity ability and intestinal flora of the broilers.Keywords：broiler;astragalus;composite biological preparations;probiotics1|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To test the effect of immunological challenge on performance and meat quality of broiler chickens,108 7-d broiler chickens were divided into control group (CK) and experimental group (LPS).Birds in LPS group were injected with 500 μg/kg BW LPS dissolved in saline on Monday,Wednesday and Friday since 8-d of age for continuous 2 weeks,meanwhile,birds in CK were injected with saline.The performance and serum corticosterone and IL-1β level of broiler chickens were evaluated on 21-d.The performance,percentage of pectoralis and thigh muscle (with bone) and abdominal fat;the drip loss rate,pH value and shear force of pectoralis and thigh muscle;the protein and fat content,protein/fat ratio and myofiber area of pectoralis of broiler chickens were assayed on 42-d.Results showed that LPS challenge had no significant effect on serum corticosterone and IL-1β level and growth performance (P>0.05).The percentage of abdominal fat,protein/fat ratio of pectoralis of birds in LPS were about 17.81% and 36.94% higher than those in CK,respectively (P<0.05),while pH value of pectoralis were about 2.23% lower than those in CK (P<0.05).In conclusion,immunological challenge had no effect on growth performance,but had significant negative effects on the carcass quality and meat quality of broiler chickens.Keywords：broiler chicken;LPS;immunological challenge;carcass quality;meat quality1|5|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The objective of this study was to investigate the characteristics of different breeds of cattle in China and provide technical parameters for the production of superior quality beef and breed selection.Fiber characteristics of longissimus dorsi ,musculi psoas major and biceps femoris in six Chinese breeds of cattle were studied using cryostat section and enzyme succinate dehydrogenase (SDH) staining.1) The percentage of red muscle (R type ) of longissimus dorsi in Luxi cattle and Limousine(32.7% and 29.5%) is significantly higher than that of others breeds (P<0.05);While,the percentage of R muscle fiber types of musculi psoas major and biceps femoris is the highest in Jinnan cattle and Luxi cattle (42.7% and 48.7% respectively). 2) The diameter of all the three muscle fiber types of longissimus dorsi (60.009,61.109,67.800 μm) in Qinchuan is significantly thicker than that of the other breeds cattle(P<0.05);The diameter of Red and Intermediate types of muscle fiber of musculi psoas major and biceps femoris in Qinchuan and Jinnan cattle is significantly thicker than that in other four breeds of cattle (P<0.05). 3) The density of all the R (216.667 and 189.583 num/mm2) and W (200.926 and 261.11 num/mm2) muscle fiber types of the musculi psoas major in Piemontese and Limousine is significantly higher than the one in other breeds of cattle (P<0.05);The density of the R muscle fiber types of the longissimus dorsi and biceps femoris in Luxi cattle is higher than that in other breeds of cattle. 4) For the same breed,the percentage of the three muscle fiber type in different part of the body in six breeds of cattle has no obvious consistency.The diameter of longissimus dorsi muscle fiber is significantly thicker than that of musculi psoas major in the five breeds of cattle (P<0.05),except for Jinnan breed whose biceps femoris has the thickest diameter of muscle fiber.Also,the density of muscle fiber of musculi psoas major in the other five breeds is significantly higher than that of longissimus dorsi and biceps femoris (P<0.05) except for the Jinnan.The percentage,diameter and density of muscle fiber of the same part have differences in different breeds.With one exception for Jinnan,the density of muscle fiber of musculi psoas part is highest and the diameter of longissimus dorsi muscle fiber is thicker than that of musculi psoas in other five cattle breeds,but the Jinnan cattle has its own characteristics.Keywords：beef cattle;muscular tissue;muscle fiber type;diameter of muscle fiber;density of muscle fiber0|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To determine enzymological characteristics of feruloyl esterase (FAE) and acetyl esterase (AE),rumen fluids collected from Holstein steers intalled flexible ruminal cannula were centrifuged at 1 000g at 4 ℃ for 10 min to prepare crude enzyme solutions.The optimal pH is 9.0 and optimal temperature for FAE is 40-50 ℃;and the Michaelis constants (Km) is 0.76 mmol/L and maximum velocities (Vmax) against methyl ferulate is 5.43 mU at pH 6.0 and 39 ℃ .The optimal pH for AE is 8.0 and optimal temperature for AE is 50 ℃,and the Km and Vmax against p-nitrophenyl acetate at pH 7.0 and 39 ℃ were 0.64 mmol/L and 91.00 mU.Cations such as Mg2+,Zn2+,K+,Cu2+,Co2+,Ca2+ and Mn2+ in this study inhibited the activities of esterases for FAE while Fe2+ has opsite effects.The cations of Mg2+,K+,Co2+,Ca2+ and Mn2+ had a stimulatory effect on AE.In general,FAE showed relatively more stable than AE in the rumen though both pH and temperature in rumen fluids may not be optimum for both esterases to exert their enzymological potentials in plant cell wall degradation.Keywords：cattle;rumen fluid;feruloyl esterase;acetyl esterase;enzymological characteristics1|6|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Hydrogen production from poultry farms and rice bran was studied by using heated anaerobic sludge as inoculums of hydrogen-producing bacteria.The effects of the carbon nitrogen ratio of fermentation liquid on hydrogen production,the liquid fermentation products,COD removal rate and hydrogen production kinetics were investigated.The results indicated that poultry dung wastewater could produce hydrogen by anaerobic fermentation and the cumulative gas yield was 1.855 L under the conditions of carbon nitrogen ratio 50,pH 5.0,and temperature 36 ℃.Under above conditions the hydrogen production was 1.128 L,the maximum hydrogen production rate 370.46 mL/(g·d),and the maximum COD removal rate 32.6%.The COD removal rate ascended first and then descended as the carbon nitragen ratio increased.Most of the substrate was transferred into intermediate metabolization products such as acetic acid and butyric acid.A modified Gompertz model can adequately describe the H2 production.Keywords：poultry farms wastewater;rice bran;anaerobic sludge;hydrogen production;carbon nitrogen ratio3|6|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：A high-performance liquid chromatography-fluorescence detection (HPLC-FLD) method was developed for determination of Moxidectin in pork.The target compound was extracted by acetonitrile,diluted by water and pH was moderate with triethylamine.The solution was purified by C18 Column of solid-phase extraction (SPE),derived by trifluoroacetic anhydride and N-methylimidazole.Determination was performed by reverse phase HPLC-FLD with acetonitrile and water,with the Excitation spectra of 365 nm and Emission spectra of 475 nm.Between 0.01 and 1.00 μg/mL,the chromatographic peak area of Moxidectin showed linear correlation to their concentration,with the correlation coefficients of 0.99.At the spiked levels of 5、50 and 250 ng/g ,recoveries ranged from 92.16% to 99.39%,with the intra-day coefficient variation (CVd) of 2.8%－4.1%(n=5) and inter-day coefficient variation (CVr) was 6.4%－8.5% (n=3).The limit of detection (LOD) of Moxidectin in pork was 2 ng/g,and the limit of quantitation (LOQ) was 5 ng/g.The method was accurate and sensitive.It could be used for determining the residues of Moxidectin in pork.Keywords：pork;HPLC;FLD;Moxidectin;residues determination5|6|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The solid-state fermentation medium of Ganoderma lucidum was optimized by the response surface methodology.And the nutrient component of powder fermentated by Ganoderma lucidum was tested,so as to provide a reference for further development of functional food.The results showed that the optimal medium formulations of solid-state fermentation by Ganoderma lucidum were 24% wheat,12% soybean flour and 64% corn powder of 8 mesh.The result of validation test indicated that the polysaccharide content was 3.27% under the optimum conditions.The analysis of nutritional components of substrate before and after fermentation showed that the solid-state fermentation of Ganoderma lucidum could reduce the content of starch and crude fat in the substrate by 43.27% and 9.76%,respectively ,and increase the content of reducing sugar,protein and vitamine B1 by 684%、35.94% and 167%,respectively.According to amino acid analysis,it was found that the amino acid content increased by 7% after Ganoderma lucidum fermentation,moreover the content of all the essential amino acids except lysine increased.Keywords：Ganoderma lucidum;solid-state fermentation;optimization;nutrition component analysis2|9|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Antioxidant activity and functional properties of protein hydrolysates from grass carp (Ctenopharyngodon idellus) meat,hydrolyzed by Alcalase 2.4L(HA) and Papain (HP) with different (10%,20%)degrees of hydrolysis(DH) were investigated.With the DH rising,the metal chelating activity increased while the reducing power and DPPH radical scavenging activity decreased of both HA and HP(P<0.05).At the same DH test,HP possessed a better DPPH radical scavenging activity and reducing power than HA did (P<0.05).The solubilities,emulsion activity index and foaming capacity were lowest at pH 4.When the DH increased,the solubilities of hydrolysates increased,but the foaming capacity decreased in the pH range of 3-8.And HP displayed higher emulsion activity index but lower solubility and foaming capacity than HA did.The result revealed that the antioxidant activity and functional property of protein hydrolysates from grass carp meat were determined by the DH and types of the enzymes.Keywords：grass carp;meat;degree of hydrolysis;protease;antioxidant activity;functional properties3|10|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The objective of this study is to test the performance of time domain reflectometry (TDR) based on phase difference detecting with independent intellectual property rights measuring soil water content.A laboratory calibration experiment using soil column was conducted to obtain the calibration equations for TDR measuring soil water content,and field test was also conducted to validate these calibration equations.The results showed that,there was no significant effect of bulk density on the calibration relationship between time measured by TDR and soil water content,but the soil texture had a significant effect.It could be calibrated using three calibration formulas in sandy soil,loamy clay soil and clay soil,respectively.All of R2 were greater than 0.98,and the estimated standard errors were less than 0.020 cm3/cm3.The root mean square errors were less than 0.035 cm3/cm3 for TDR measuring soil water content in the field.Therefore,this new TDR instrument was reliable to measure soil water content in the field using calibration equations from the laboratory experiments.Keywords：soil water content;time domain reflectometry;phase difference1|8|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Vegetation restoration on surfaces destroyed by engineering at a section of Tongliao-Chifeng Expressway was investigated.Temporal observations of surface temperatures were made using infrared imaging thermometer and the effect of vegetation restoration on surface temperature was analyzed.Results show that for surfaces destroyed by engineering in semi-arid area,stone slope-protection on southern slopes yielded higher surface temperature than that of bare natural rocks.This would exacerbate the high temperature if it were applied in the summer.In contrast,vegetation restoration could significantly reduce the surface temperature on southern slopes,which consequently improved the microclimate.Moreover,the difference in surface temperature between southern and northern slopes was mitigated by a decrease of 5-10 ℃ in summer,fall and winter.Furthermore,soil moisture also significantly affects surface temperature.Keywords：semi-arid regions;surfaces destroyed by engineering;vegetation restoration;surface temperature;temperature effect3|6|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：During the operation of pad and fan system for greenhouse cooling,fog wafts appeared inside the greenhouse.If the fog adheres to a sensing part of a thermometer,measurement of air temperature through pad will decrease and cause errors.The study was conducted by three measurement methods which were non-aspirated thermocouple with shelter,aspirated psychrometer and bare thermocouple without the shelter.It was found that the result of the non-aspirated thermocouple with shelter provided the most accurate measurement values;the measurement result of the aspirated psychrometer was lower than the actual temperature and the error rang was 0.1-3.2 ℃;the measurement of the bare thermocouple was affected by environmental factors easily and the error rang was -2.7-3.9 ℃.Keywords：greenhouse;pad and fan cooling system;temperature;measurement method2|10|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：With Munjiza's 2-d code Y2D based on the so-called combined finite-discrete element method (FE/DE),two examples,i.e.rupturing of a concrete beam under transverse impact and fracturing of a concrete column under axial impact,were simulated.It illustrated that,the cracking pattern in the former example is coincided with the high stress bands in the contour chart predicted by ANSYS,and the patterns of cracking,crack propagation,fracturing and multi-fracturing of the column in the later example were in general rational.Thus it is verified that the FE/DE method enables to predict the process from a solid continuum to discontinuum.Limitations of the code were also discussed.Keywords：concrete;rupture;finite element method;Discrete Element Method3|8|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Based on the cost-income data of farm products and the China Agricultural Yearbook,the changes of land use and output in the period of 1980－2007 were analyzed,with examples of three provinces,Zhejiang,Henan and Sichuan,representing different economic levels.The results showed that: 1) The decrease rate of the proportion of cereal crops area in total sown-area was accordant with the order of economic levels,being Zhejiang>Henan>Sichuan.The sown area proportion of vegetables and fruits in Zhejiang was much higher than that of the other two provinces. 2) The labor intensity decreased rapidly,with a decreasing order of Zhejiang>Henan>Sichuan.In 2007,there was an inverse relationship between the intensity and economic level. 3) Machinery input was proportionally related with economic level.The developed area didn't have significant increases in the inputs such as seeds,chemical fertilizer and pesticide,for increasing cereal yield.The increasing rate was in the order of Henan>Zhejiang>Sichuan. 4) The increase rate of labor productivity was much higher than that of land productivity,especially in Zhejiang,indicating that the farmers in the developed area paid more emphasis on labor productivity.Keywords：agricultural land use;cropping structure;labor intensity;input output1|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The research on the productivity lose of the cultivated land was mostly put emphasis on land use conversion and few on the elastic loss of grain productivity.The method of the calculation was made to analyze the elastic loss of grain productivity in this paper,and methods as econometrics analysis,Arc GIS’s spatial analysis and a case study of Daxing district in Beijng were employed.The result shows that comparative benefits of farm land could be the main reason to lead to the land use pattern change and land use intensity declining.Land use pattern conversion was calculated by change of grain planting area and the intensity change was calculated by grain yield difference.In the case study of Daxing district,the figures of the quantitative values of samples show that the regional distributing regularity is that the elastic loss of potential production was correlated with the economomic developed degree.Keywords：cultivated land use;grain production capacity;resilient loss;household4|10|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：It is fertilizering the crops that is a major resource of agricultural non-point pollution in China.Basing on provincial panel data from 1996 to 2009,using Stochastic Frontier Production Function approach we calculate fertilizering technical efficiency of wheat and corn in China,and using Tobit model,we analyze the factors that determine the technical efficiency of fertilizing.The result showed,the low efficiency of fertilizering not only affects its production technical efficiency,but is the major reason of agricultural non-point pollution;fertilizer price,income of farmers,planting scale and technology training for farmers are important factors affecting technical efficiency of fertilizer.The policy of improving income of farmers and encouraging land transfer can increase technical efficiency of fertilizer and decrease agricultural non-point pollution;subsidies policies for producing factors with pollution go against the governance of agricultural non-point pollution;Chinese Agricultural Technology Extension should be strengthened and perfected in order to increase fertilizering technical efficiency and reduce agricultural non-point pollution.Keywords：fertilizer;fertilizering technological efficiency;influencing factors;policy implications1|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The purpose of this paper is to research the dynamic relationship between hog price and corn price.The results indicate that there is a positive correlation between the two prices and the corn price is the Granger cause of the hog price.Cointegration test shows that there exists a linear cointegration between hog price s and corn price.Besides,Enders-Siklos test suggests an inertia long-run equilibrium relationship with a threshold exited between them-adjustment speed is higher when the spread of hog prices and corn prices diminishes.The main reasons for that phenomenon include the effect of law of value,different government countermeasures,and the features of hog production process.The paper puts forward some measures for a good market expectations,such as improving Information Publishing Platform of hog market price,widely releasing relevant information to the grassroots pig farmers and the masses of consumers.Besides,it is also vital to give a thorough consideration on asymmetric adjustment between hog prices and corn prices before making any decision s affecting hog prices and guiding pig farmers.Keywords：corn;hog;price;threshold autoregression;momentum threshold autoregression2|9|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
