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- Abstract：The quantitative relationship between the environmental factors and yield of crops was established by using AquaCrop model in Quzhou County, Hebei Province. A index evaluation method was used to evaluate the utilization of water and heat resources by mulching and seedling transplanting for winter wheat and summer maize. The results showed that:Firstly,the AquaCrop model well simulated the crop canopy coverage, biomass, and yield, and could be used to analyze the impact of technology on water and heat resource use efficiency. Secondly, film mulching and seedling transplanting techniques significantly affected the utilization efficiency of water and heat resources of crops (winter wheat and summer maize) at sowing-jointing stage. Thirdly, the water and heat resource utilization efficiency of winter wheat mulching and summer maize seedling transplanting increased by 0.67 and 0.5, respectively, and the output increased by 326 kg/hm2 and 972 kg/hm2. The results showed that the plastic film mulching and the seedling transplanting technology affected the utilization of water and heat resources and crop yield during the critical growth period. Above results be used as a support to enhance the efficiency and theoretical potential of other crops and further serve as a remedy for the disaster of winter wheat and summer maize and provide reference for technical adjustment in Quzhou County.Keywords：plastic film mulching technology;seedling transplanting technology;water resources;heat resources;utilization efficiency25|8|6<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To provide a method for reasonable fertilization and soil fertility improvement, the responses of rice yields to soil basic fertility and fertilization were studied in double-cropping paddy fields of Western Sichuan Plain of China, in order. Two-year field trails were conducted to investigate the effects of basic fertility and fertilization on the yields of rice by comparing the fertilization and non-fertilization of rice in high, medium and low yield fields in Mianzhu City, Sichuan Province. Two-factor randomized block design was used in the trial. The main factor was basic fertility, and the secondary factor was fertilization treatment, with 3 repetitions per treatment. The results showed:The contribution rates of basic fertility in descending order was high yield fields > medium yield fields > low yield fields. The average contribution rates of basic fertility were 84.5%, 75.7% and 72.5% in 2016, and 85.0%, 80.7% and 70.6% in 2017, respectively. There were significant positive correlations between the conventional fertilization and basic fertility (P<0.01). Under the same fertilization, growth rate of yields showed low yield fields > medium yield fields > high yield fields. Under the conventional fertilization, the average yield of high, medium and low yield fields increased by 19.3%, 34.1%, 40.0% in 2016, and 17.9%, 24.6%, 43.3% in 2017, respectively. Furthermore, under continuous non-fertilization, the base yields showed an average decline of 14.4%. Effective spike and 1 000-grain weight were the main factors of yield difference. The contribution rate of basic fertility increased with the increase of basic fertility, and the contribution rate of fertilizer decreased with the increase of basic fertility, in the trails of western Sichuan Plain. Consequently, rational fertilization under different base fertility was an important factor to ensure high and stable rice yields. This study provided references for rational fertilization under different base conditions in the paddy fields of Western Sichuan Plain.Keywords：rice;basic fertility;fertilization;growth dynamics;yield23|7|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to reveal the effect of different nitrogen application on the dry matter accumulation and transport of high yielding spring soybean under drip irrigation, the effects of 4 kinds of nitrogen application (0, 75, 150, 225 kg/hm2) on the accumulation of high yield spring soybean dry matter in drip irrigation and the transport of dry matter in stem were studied under field conditions. The results showed that:The increase of the leaf area index by increasing the amount of nitrogen application was the result of the increase of the 7-19 leaf area of the main stem; Nitrogen application increased dry matter accumulation. When the amount of dry matter accumulation reached the maximum, the increase of dry matter was mainly due to the increase of the accumulation of dry matter in the middle and upper part of the stem; Increasing nitrogen application improved the dry matter translocation amount and translocation ratio from the upper and middle parts of the stem to seed, the contribution the upper and middle parts of the stem to seed and yield. The Nitrogen application increased the middle and upper leaf area in the plant, the accumulation of dry matter in the stem, and its transfer to the seed. The transfer rate and the contribution to the seed weight was the reason to increase the soybean yield. The yield of N150 treatment was 4 889.62 kg/hm2, and the maximum dry matter mass was 1 613.38 kg/m2, among which the stem dry matter was 5 364.7 kg/hm2, stem dry matter translocation amount szx 1 830.5 kg/hm2 and transfer rate was 34.12%.Keywords：nitrogen;spring soybean;high yield;accumulation and transfer of dry matter24|9|6<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To study the effects of planting density on the stem characters, reproductive growth, yield and components of Shucaihua 1 colored peanut in Western Sichuan Plain, a field plot experiment of five planting density treatments (4.5×104,6.0×104,7.5×104,9.0×104 and 10.5×104 hole/hm2) was conducted. The results showed that:With the increase of planting density, the main stem length and lateral branch length increased significantly. The stem diameter, stem diameter coefficient, pod number, pod weight, needle number, economic coefficient, 100-pod weight, 100-seed weight and yield decreased significantly. The group yield increased first and then decreased. At the group yield of planting density 6.0×104 hole/hm2 reached the maximum, compared with that of plant density 4.5×104 hole/hm2, increased by 14.64%. Correlation analysis showed that the planting density of Shucaihua 1 colored peanut was positively correlated with the main stem length and negatively correlated with other main indicators of stem traits and yield. It was concluded that the planting density was one of the most important factors influence the characteristics, reproductive growth and yield of colored peanut. Appropriate planting density could significantly increase the group yield and economic coefficient of colored peanut, and finally improve its yield and economic benefit.Keywords：Shucaihua 1;colored peanuts;planting density;stem traits;reproductive growth;yield;Sichuan Western Plain23|9|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The aims of this study were to select better straw-decomposing bacteria strains and analyzing the biological processes of straw degradation. A total of three strains of straw-degrading bacteria, designated yj1, yj2 and yj3, were identified from soil samples. The optimal temperature and pH conditions for straw degradation were determined according to the 8-day straw degradation rate. The activities of six enzymes involved in EG, BG, xylanase, LiP, MnP, Lac were measured and compared. The results showed that:1) yj1, yj2 and yj3 strains were identified belonging to Pseudomonas, Bacillus and Brevibacterium, respectively. 2) The straw degradation efficiency of three strains reached their peak values when the three strains were respectively cultured at 37, 30 and 37℃ and the optimal pH of 8, 8 and 7 for 8 days. The straw degradation rate of yj2 reached 26.61% under alkaline conditions. 3) The yj1 and yj3 strains were found to be xylanase-free but their LiP, MnP, Lac activities were higher, which played a key role in straw degradation. All of the six enzymes in strain yj2 showed higher activity and collaboratively completed straw degradation. In conclusion, strain yj2 could be used as a candidate strain for straw degradation under alkaline soil conditions.Keywords：straw-degrading bacteria;straw degradation rate;straw optimal degradation conditions;straw-degrading enzymes25|9|8<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To analyze the antioxidant activity of Hericium caput-medusae(Bull.:Fr.) Pers (HFC), an industrial extraction of H. erinaceus polysaccharide fermentation extract was taken as study object. Using dialysis method and DEAE sepharose fast flow column purification crude polysaccharide components HFCP1 and neutral polysaccharides HFCP1-1 were obtained. The composition and structure of monosaccharides were preliminarily analyzed by PMP pre-column derivatization-high performance liquid chromatography and infrared spectroscopy. The monosaccharides were mainly composed of glucose and galactose. The results showed that the IC50 values of HFCP1 and HFCP1-1 to scavenge hydroxyl radical scavenging, superoxide anion scavenging, ABTS+ and DPPH were 7.66 and 6.77, 6.16 and 5.30, 0.63 and 0.85, 0.39 and 2.62 mg/mL, respectively. A H2O2-induced injury model was established in RAW264.7 cells, the results of anti-oxidation of cells showed that the cell viability of HFCP1 and HFCP1-1 treatment group were significantly increased compared with those the model group (P<0.05). The content of MDA was significantly decreased compared with the model group when it concentration was 100 and 200 mg/L (P<0.05). The activities of SOD and GSH-Px were significantly increased compared with those of the model group when HFCP1 concentrations was 100 and 200 mg/L (P<0.05). In conclusion, compared with model group, 200 mg/L HFCP1-1 significantly increased SOD activity (P<0.05), but also increased GSH-Px activity, but did not reach significant level (P>0.05).23|8|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：By using bisulfite sequencing and quantitative PCR methods, the effects of folate deficiency in hens on the methylation patterns and expression levels of MTHFD2 and TYMS of its progeny were studied. The results indicated that:1) Parental folate deficiency had no effect on the promoter region methylation of MTHFD2 and there were no methylation among 16 CpG sites of MTHFD2 promoter; 2) Methylation of downstream at ATG of TYMS (including 8 CpG sites) in progeny occurred mainly in the 2nd, 3rd, 4th and 5th sites. However, the methylation ratio of these 4 CpG sites showed no significant difference between the control and folate deficiency groups (P>0.05), and there was also no significant difference in the total methylation levels of TYMS either (P>0.05); 3) The expression levels of MTHFD2 and TYMS genes in liver tissues of hens progeny were significantly increased (P<0.05). Taken together, the expression levels of MTHFD2 and TYMS genes in hen's progeny were influenced under folate deficiency, but it didn't affect the methylation ratio. These results indicated that DNA methylation patterns were determined by several factors, and other regulatory mechanisms might be existed.Keywords：broiler;folate;MTHFD;2;TYMS;methylation24|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：A 2×2 factor experiment was conducted to explore the effect of rearing system and stocking density on the growth performance, meat quality and stress response of Arbor Acres broilers. The broilers were arranged in two rearing systems:Battery rearing and net rearing and two stocking densities (10 and 14 broilers per m2). The results showed that:1) The feed/gain of broilers in net rearing of low stocking density group was significantly higher than those in battery rearing in high stocking density and low stocking density. The average daily feed intake of broilers in net rearing was significantly higher than those in battery rearing. The daily gain and the average weight of broilers in net rearing were significantly higher than those in battery rearing. 2) The breast muscle rate and leg muscle rate of broiler in net rearing was significantly higher than those in battery rearing. The breast muscle and leg muscle shear force of broilers in net rearing was significantly higher than those in battery rearing. The breast muscle drip loss of broilers in net rearing was significantly higher than those in battery rearing. The leg muscle pH24 of broilers with low stocking density was great significantly higher than those with high stocking density. 3) The T-AOC, GSH-PX of broilers in battery rearing was significantly higher than those in net rearing, the T-AOC of broilers with high stocking density was significantly lower than those with low stocking density. The IL-6 of broilers in net rearing was significantly higher than battery rearing. Rearing system and stocking density had significant effect on CK. The CK of broilers in battery rearing with high and low stocking density was significantly lower than those in net rearing with high stocking density. In conclusion, the stocking density of 14 birds per m2 had no significant effect on the production performance, but increased oxidative stress response. The growth performance and meat production performance of broilers in net rearing were better than those in battery rearing, but the meat quality, feed to gain ratio, immune stress and antioxidant were relatively poor.Keywords：Arbor Acres broilers;rearing system;stocking density;growth performance;meat quality;immune stress25|8|9<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To study whether molecular chaperones could promote the expression of Mycoplasma bovis membrane protein in soluble form in Escherichia coli and the expressed protein was active or not, prokaryotic expression and Western blot methods were adopted in this study. The results showed that:1) The truncated membrane fragment of M1 from M. bovis was expressed in inclusion body in E. coli expression system. Its expression form remained unchanged by changing induction time, temperature or induction agent doses; 2) Four types of molecular chaperone, pG-KJE8, pGro7, pG-Tf2 and pTf16, were respectively combined with recombinant plasmid and expressed in BL21 with the final concentrations of 1.0 mmol/L IPTG and 0.5 mg/mL L-Arabia sugar or 5.0 ng/mL tetracycline inducer, After 5 h induction at 37℃, it was found that molecular chaperones pG-Tf2 and pG-KJE8 significantly increased the soluble expression of truncated M1 fragment, and the other 2 chaperones didn't change the expression of M1; 3) The truncated M1 fragment had specific reaction with the positive serum of Mycoplasma. In conclusion, the four types of molecular chaperones promoted the soluble membrane protein of M. bovis expressed in E. coli expression system, and didn't change its bioactivity. This result laid foundation for establishing effective serological diagnosis method and producing the subunit vaccine of M. bovis.Keywords：molecular chaperone;Mycoplasma bovis;membrane protein;soluble expression;prokaryotic expression system24|8|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The aim of this study was to examine the effects of flavonoids from alfalfa on the milk production, serum hormone and immune indexes of dairy cows. Four primiparous Holstein cows fitted with ruminal cannulas were taken as study object, and 4×4 Latin square design was conducted. The cows were fed with total mixed ration supplemented with 0, 20, 60 or 100 g alfalfa flavonoids (AF) at different periods, respectively. The experiment lasted four periods and each period contained 24 days. The results showed that:1) The dry matter intake (DMI) of dairy cows showed quadratic curve change with the increasing dose of AF. DMI was significantly higher in group Ⅱ than that in groups I and IV (P<0.05); 2) Prolactin (PRL) concentration was increased at first and then decreased with the increasing dose of dietary AF supplementation. The concentration of PRL in group Ⅲ was the highest. The concentrations of triiodothyronine and tetraiodothyronine were increased linearly with increasing dose of dietary AF supplementation and were significantly higher in group IV than that in groups I (P<0.05). 3) The count of CD4+ and the ratio of CD4+ to CD8+ in group Ⅱ were significantly higher than that in other groups (P<0.05), whereas the count of CD8+ showed the opposite result; 4) The relative expression of genes of IL-4, IFN-γ and GM-CSF colony stimulating factor in lymphocyte of group Ⅱ were significantly higher than that of other groups (P<0.05). In conclusion, the moderate supplement of alfalfa flavonoids in diet could improve cow's feed intake and regulate hormone secretion and immune performance of dairy cows. The addition of 60 g AF in the diet of dairy cows was shown to be most beneficial.Keywords：dairy cow;flavonoids;alfalfa;hormone;immune performance;milk production23|8|9<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Aiming to tentatively explore the relationship between MITF gene expression and seasonal estrus and litter size in sheep, the real-time fluorescent quantitative PCR (qPCR) method was used to detect the expression difference of MITF gene in nine tissues including hypothalamus in seasonal estrous sheep (Sunite sheep, SNT) at different photoperiods (short photoperiod, long photoperiod) and year-round estrous sheep (Small Tail Han sheep, STH) at different reproduction stages (follicular stage and luteal stage), and the expression difference of MITF gene between single birth tissues and multiple birth tissues including ovary, uterine body and oviduct of STH at follicular stage. The results showed that:The MITF gene was widely expressed in different tissues and its' expression level in ovary, uterine body and oviduct tissues were higher than that in other tissues of two breeds. The expression level of MITF gene in pituitary gland was extremely higher at long photoperiod than that at short photoperiod in SNT (P<0.01). The expression level of MITF in ovary was extremely higher at follicular stage than that at luteal stage (P<0.01), while its expression level in uterine body was significantly higher at luteal stage than that at follicular stage (P<0.05) and its expression in oviduct was extremely higher at luteal stage than that at follicular stage (P<0.01) in STH. The expression level of MITF gene in uterine body in single birth group was extremely higher than that in multiple birth group (P<0.01),while its' expression level in oviduct in single birth group was significantly higher than that in multiple birth group (P<0.05) of STH at follicular stage. In conclusion, the research results indicated that MITF gene expression may be related to sheep seasonal estrus and litter size and further biological function verification will be required.Keywords：sheep;MITF;gene;estrus;reproductive stage;tissue expression;litter size23|8|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Goat whey protein was hydrolyzed with neutrase, alcalase, trypsin, flavourzyme and papain. The hydrolysates were sampled at different time points. ACE and DPP-IV inhibitory activities were measured at the concentration of 5 mg/mL. The neutrase-generated hydrolysate was isolated by ultrafiltration, gel filtration chromatography, reversed-phase high-performance liquid chromatography (RP-HPLC) and then identified via liquid chromatography-tandem mass spectrometry (LC-MS/MS). The peptides were synthesized and assayed for bioactivities. The results showed that the hydrolysate treated with neutrase showed certain bioactivities. The dual bioactive peptide Pro-Pro-Ala-Ser-Glu-Val-Val-Lys-Pro showed inhibition against ACE and DPP-IV with IC50 values of 573.32±4.63 and 2 065.35±22.30 μ mol/L, respectively. Ile-Pro-Ala-Val-Phe-Lys-Ile-Asp had better DPP-IV inhibitory activity with an IC50 value of 964.14±4.09 μ mol/L. In conclusion, the goat whey protein hydrolysates can be used as a food-derived material for managing the diet of type 2 diabetes mellitus patients with hypertension.Keywords：goat whey protein;angiotensin-converting enzyme;dipeptidyl peptidase IV;dual bioactive peptide23|8|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In view of the single product line of probiotic strain L-DT (Bifidobacterium longum ssp. longum L-DT), and its application to be diversified, a high density culture technology with food grade raw materials was used to optimize the liquid medium and culture conditions. Single factor experiment, Plackett-Burman experiment, steepest climbing experiment and response surface analysis were adopted in this study. The results showed that:The mass fraction of each component in the medium suitable for L-DT growth was:glucose 1.5%, yeast peptone 2%, oligomeric maltose 1.5%, tomato juice 3%, lactose 2.4% and yeast extract 2.26%. The culture condition was:Inoculation quantity (volume fraction) 4.46%, pH 6 and temperature at 37℃. Under this condition, the OD600 of the bacterial liquid could reach 1.113, which had no significant difference compared to the predicted value of 1.104. And the quantity of viable bacteria could be up to 1.5×109 CFU/mL. Amplification and verification in a 7 L fermenter, the maximum number of L-DT viable bacteria reached 5×109 CFU/mL, which was 3.33 times higher than that in tube culture.Keywords：Bifidobacterium longum;food-grade ingredients;response surface analysis;magnification and culture23|8|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Because of the incremental scale of the farms and the corresponding higher number of breeding hens, it is increasingly difficult for farmers to monitor their animals over continuous 24 hours and to discover their abnormal situation timely. In this study, a type of contactless, 24-h continuous and automatic monitoring method was proposed by using Kinect synchronously to acquire images and sound data. Then, the data were analyzed through the LabVIEW software for the early warning of abnormal events occurred in the henhouse. This method combined image processing and sound processing to calculate daily activity index and sound energy for early warning study of abnormal events affecting hens' production performance. The results showed that this system reported abnormal events with an accuracy of 73.9%, the rate of missing abnormal events (PFNR) of 0, the rate of misjudging abnormal events (PFPR) of 26.1%. Compared with single image analysis or sound analysis method, this method can fully monitor abnormal events in a henhouse. In conclusion, this method can provide an effective tool for deep animal behavior study and animal welfare in the future.Keywords：breeding hens;image processing;sound processing;Kinect;animal behavior25|9|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to solve the problem that the significant reduction of inertial navigation accuracy of sea cucumber fishing device caused by random drift noise in the MEMS gyroscope output signal, the reduction issue of random drift noise of the MEMS gyroscope is studied by using time series analysis method and Kalman filtering algorithm. Taking the measured data of the MEMS inertial measurement unit and attitude angles measured by the three-dimensional electronic compass as samples, the noise reduction effect of the low-cost gyroscope is tested. The experimental results show that:1) After the noise reduction, the variance of the random drift signal of the gyroscope is reduced by one order of magnitude compared with the variance of the original sampling signal of the gyroscope, and the precision of the random drift data of the gyroscope is significantly improved. 2) Using the attitude angle measured by the high-precision three-dimensional electronic compass as a reference, the de-noised gyroscope random drift data are imported into the SINS attitude calculation program, and the RMSEs of the calculated pitch angle, roll angle, and heading angle are all less than 1° in 300 s; Compared with before noise reduction, the RMSEs of the corresponding pitch, roll, and heading angles are respectively reduced by 170.5, 97.6, and 42.5 times, which significantly improves the inertial navigation accuracy.Keywords：MEMS gyroscope;inertial navigation;AR model;Kalman filtering;sea cucumber fishing26|8|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To overcome the limitations of current static calculation method of radial force without trapped-oil pressure in gear pumps, a new quantitative method for the influence of trapped-oil pressure on dynamic radial force was built. In a trapped-oil cycle, the dynamic fluid pressure distribution of four pressure sections, suction oil, transition oil pressure, discharge oil and trapped-oil pressure, on driven addendum circle were investigated, and the dynamic trapped-oil radial force were then studied and verified indirectly. The results showed that:The first improvement rate of new trapped-oil radial force to current radial force released differently by discharge oil, suction oil and transition oil was 9.9%, -10.2% and -1.1%, respectively. Then the radial force could be improved under relief by discharge oil. However, it was intensified under relief by suction oil and weakly impacted under relief by transition oil. Therefore, the relief by discharge oil was highly recommended in practice; The second impact rate of new trapped-oil radial force to current radial force released differently by discharge oil, suction oil and transition oil was 24.5%, 38.5% and 13.8%, respectively. The radial force was strongly impacted by trapped-oil pressure, so it was necessary to release trapped-oil pressure by innovated relief groove, and the new quantitative method was recommended to radial force calculation; The third effect of trapped-oil pressure on radial force was not only itself but also more other radial force relief measures. The trapped-oil force was collectively determined by trapped-oil pressure and its action area, so the extreme position of trapped-oil pressure, radial force and trapped-oil force was not completely consistent. In conclusion, the calculation results of the new quantitative method provided an accurate external load for full fluid lubrication design of bearings and otherKeywords：gear pumps;trapped-oil pressure;radial force;liquid force;meshing force23|8|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Improving the accuracy of agricultural land classification, through establish the quality evaluation model of agricultural land (cultivated land) can classify the agricultural land (cultivated land) objectively and accurately and reduce the impact of human factors in the current agricultural classification method. The hilly area of Changtai County in Fujian Province is used as an empirical area. MATLAB software is adopted as the operating platform. Supervised network learning (BP-ANN and SVM) and unsupervised network learning (SOM) methods are combined. Firstly, a total of 2 602 group typical samples are selected by using self-organizing feature mapping network (SOM) through unsupervised network learning. Network learning about BP neural network and support vector machine (SVM) are monitored. Seven indicators (effective soil thickness, organic matter content, slope, field road accessibility, altitude, soil texture and irrigation guarantee rate) are then used as input variables. Natural grade indexes or grade are used as output variables, the evaluation model of cultivated land quality of BP neural network and support vector machine(SVM) are established. The results show that:The evaluation accuracy of BP neural network method is high. The correct rate of total evaluation result is 89%. As for the SVM method, the correct rate of total evaluation result has remarkable accuracy of 99%. Both methods can meet the accuracy requirements of agricultural land classification. In the whole, SVM method is more effective than the BP neural network. It is more suitable for agricultural land classification.Keywords：agricultural land classification;back-propagation neural network;support vector machine23|8|6<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Based on the remote sensing image data, DEM data, rainfall data and soil type data, the soil erosion modulus of Ningxiang City was calculated by using GIS and RS techniquescombined with the universal soil erosion equation (USLE). Model indexes include rainfall erosion factor, soil erosion factor, slope length factor, vegetation coverage factor, soil and water conservation measures factor. The results showed that:The average soil erosion modulus was 1 410.64 t/(km2·a) in Ningxiang City in 2015, which belonged to the moderate erosion grade. The main types of soil erosion were micro-erosion, severe erosion and slight erosion. The erosion area was 1 548.87, 434.16 and 397.91 km2, accounting for 53.84%, 15.09% and 13.88% of the total erosion area respectively. The areas with high soil erosion modulus are mainly concentrated in Weishan, Changchong and other hilly areas in Ningxiang City. In conclusion, the relationship between soil erosion and the related influencing factors of USLE model was systematically analyzed. The elevation was positively correlated with the soil erosion intensity, and negatively correlated with the erosion area. The area of micro erosion was the largest in<200 m elevation area. The largest area of soil erosion was in the slope zone below 25°, and the soil erosion area generally decreases with the decrease of slope. The soil erosion of cultivated land and forest land was the most serious in the land use types, followed by urban land, grassland, water area and bare land. According to the present situation of soil erosion in Ningxiang City, comprehensive control measures were put forward to provide a scientific basis for the government to carry out soil and water conservation.Keywords：soil erosion;GIS;RS;USLE;measures23|8|5<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The objective of this study was to select suitable switchgrass varieties for large scale cultivation in saline-alkali soil of the Yellow River Delta. The plant height, tiller number, leaf length, leaf width and yield of four switchgrass varieties (Alamo, JAp-014, CHp-005 and CAp-017) were determined during a 3-year experiment with complete randomized block design. Grey correlation analysis was applied to evaluate their adaptability. The results showed that:The plant height, leaf length, leaf width and yield of the four switchgrass varieties were significantly different throughout the 3-year experiment, with the order of Alamo > JAp-014 > CHp-005 > CAp-017. The Alamo at 3-year-old had the maximum plant height, leaf length, leaf width and yield of 211.80 cm, 54.90 cm, 1.57 cm and 7.20 t/hm2, respectively. Tiller number varied according to the plant age. There were significantly positive correlations between the above agronomic traits. Both weighted grey correlative degree and grey correlative degree of different switchgrass varieties in descending order was Alamo > JAp-014 > CHp-005 > CAp-017. Therefore, Alamo was suitable to be cultivated on large scale in saline-alkali soil of the Yellow River Delta due to its superior adaptability.Keywords：switchgrass;variety;saline-alkali soil;agronomic trait;adaptability25|7|5<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Rapid population growth and multiple competing demands for water (i.e., drinking, industrial uses) have contributed to irrigation water scarcity in many Asian developing countries including China. In order to solve the problem of increasing water scarcity caused by the food demand of a rapidly growing population, more efficient water management practices-water-saving technologies-are needed. A water-saving technology of drip irrigation approach was developed for vegetable cultivation in China. This impact of drip irrigation technique in carrot production in Yanjin County was evaluated. Endogenous Switching Regression (ESR) was applied to analyze the farm-level survey data. The results of the impact analysis using ESR indicated that drip irrigation had a significant positive impact on crop yield and increased yield by 7 961 kg per hm2, account for 21% of the average production. The educational level of the head of the household, the number of household members working outside and the experience of adopting technique had a significant impact on the adoption of drip irrigation technique. Farms with larger production capacity and participating in producing-marketing cooperation were more likely to adopt drip irrigation technique. Based on this study, four countermeasures were put forwarded at the end of this study:1) Strive to improve farmers' educational level; 2) Advance appropriate scale management actively; 3) Popularize producing-marketing cooperation; 4) Promote water-saving irrigation technique increasingly.Keywords：water-saving irrigation technique;impact assessment;endogenous switching regression;adoption behavior23|7|4<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To explore the dynamic effect of RMB exchange rate change on China's agricultural product price, this study analyzed the effects by time varying parameter vector auto regression (TVP-VAR) model based on the data from January 1999 to February 2017. The results showed that the change of RMB exchange rate pass through effect on the price of agricultural products had obvious time-varying characteristics. There were significant differences in the pass-through effect of RMB exchange rate on agricultural products. The pass-through effects on import prices of agricultural products were high. The pass-through effects on the production of agricultural products prices and consumer prices were relatively small. In the long term, the RMB exchange rate pass-through effects on the import of agricultural products prices and agricultural products prices were increasing since 1999. The effect of RMB exchange rate on the consumption price of agricultural products was increased firstly and then decreased. There were significant differences in the effect of RMB exchange rate changes on the price of agricultural products during different exchange rate system reform stages.Keywords：RMB exchange rate;agricultural product price;dynamic pass-through effects;TVP-VAR model;time varying characteristics26|8|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to study the characteristics of China's agricultural exports and explore the impact of trade costs on the dual margin of agricultural export growth in the Belt and Road(the B&R)region, a total of 64 countries along the B&R are taken as objectives, the HS-6 bit codes data of China's agricultural products export to the B&R Region from 1997 to 2016 is selected. H-K measurement method and nuclear density estimation are used to explore the source of China's agricultural exports growth in 64 countries along the B&R region and to further analyze the role of trade costs in the dual margin of the export growth of agricultural products. The results show that:The dual margin of China's agricultural exports growth have been greatly fluctuated to the B&R region and the extensive margin growth has played a major role in promoting the growth of agricultural exports of China. Economic size, geographical area and population density have a significant positive impact on the dual margin of agricultural exports; Tariff levels, geographical distances, the number of documents required for import countries, the time required for trade countries to establish warehouses, exchange rate costs and external shocks have a significant negative impact on the extensive margin of agricultural exports; The tariff levels, the number of documents required for importing each country, the time required for trade countries to establish warehouses, exchange rate costs and external shocks are significant negative impacts on the intensive margin growth of agricultural exports.Keywords：The B&R;agricultural products;extended margin;intensive margin;export growth24|8|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to explore the impact of agricultural socialization services on the efficiency of agricultural machinery operation, this study calculates the efficiency of agricultural machinery operation in 30 provinces in China in 2004-2015 years by using DEA method, and empirically studies the influence of agricultural machinery socialization services on the efficiency of agricultural machinery operation by using panel Tobit model. The results show that:The efficiency of agricultural machinery operation in 2004-2015 years is low and the regional differences are large. However, there is a trend of increasing year by year on the whole. The agricultural machinery operation service and technology extension training service significantly improve the efficiency of agricultural machinery operation, while agricultural machinery repair service has limited effect on the efficiency of agricultural machinery operation. Therefore, the efficiency of agricultural machinery can be improved by cultivating agricultural machinery operation service organization, improving agricultural machinery repair service system, strengthening agricultural machinery extension training and developing the appropriate scale management of agriculture.Keywords：agricultural machinery socialization service;the efficiency of agricultural machinery operation;DEA method;Panel Tobit model23|9|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to evaluate the effect of the new round of collective forest tenure reform in poor areas, a survey data on rural households' livelihoods in Dushan County, a concentrated destitute area in Guizhou Province in 2014 is taken as study object. Statistical analysis on the effects of collective forest tenure reform on farmers' income per capita and farmers' forestry net income per capita is conducted by adopting propensity score matching method. The results show that:After eliminating the influence of confounding factors and sample selection bias and management choice problem by propensity score matching, the effect of collective forest tenure reform on farmers' income per capita is about 0.45% indicating that the effect of collective forest tenure reform on farmers' income is not significant. However, its effect on farmers' forestry net income per capita is about 2.76, which means that collective forest tenure reform had positive and robust effect on farmers' forestry income. Furthermore, compared with propensity score matching method, the conventional descriptive statistical methods overestimated the impact of collective forest tenure reform on farmers forestry net income per capita, roughly overestimated by 5. The following policy suggestions are put forwarded:Deepening further collective forest tenure reform in poor areas, encouraging farmers to make full use of timberland resource, and promoting the sustainable growth of farmers' forestry income.Keywords：collective forest tenure reform;propensity score matching method;farmers' income;effects assessment23|8|5<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to discuss the impact of fishery technology differences and the cross-strait policy on the intra-industry trade of aquatic products, the development level of intra-industry trade (HⅡT) between Mainland China and Taiwan China in aquatic products was estimated using G-L index (GLⅡT), Horizontal Intra-industry Trade index (HⅡT) and Vertical Intra-industry Trade index (VⅡT) synthetically. The impact of technological disparity and the cross-strait policy on the ⅡT, HⅡT and VⅡT were investigated and other impact factors were empirically analyzed. The results showed that:1) Although the trade of aquatic products between Mainland China and Taiwan China was dominated by inter-industry trade, the intra-industry trade was increased. The vertical intra-industry trade was the main form of intra-industry trade; 2) Technical difference was an important reason for the intra-industry trade of aquatic products;3) The cross-strait policy displayed a great impact on cross-strait trade in aquatic products. From the aspect of "the Belt and Road" initiative background, policies on how to promote aquatic product trade and strengthen fisheries cooperation between Mainland China and Taiwan China were recommended at the end of this paper.Keywords：cross Taiwan Strait;aquatic products;intra-industry trade;technical difference;policy28|8|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Based on the conceptual framework of motivation, a structural dimension of the motivation of migrant workers' returning hometown to build houses was constructed, the motivation measurement scale for returning hometown to build houses was developed, actor analysis was conducted, and the questionnaire survey data of migrant workers in Fujian Province was used to extract the data. The factors on the migrant workers motivations of returning hometown to build houses were theoretically explained. At the same time, cluster analysis methods were used to classify the migrant workers who returned hometown to build houses. The results showed that:According to the intensity, a total of 6 types of motives for migrant workers returning to the countryside to build houses were listed from strong to weak as follows:"improve family living condition", "increasing the value of risk avoidance", "preparing for returning home in future", "get married", "showing identity", "maintain member rights". According to the external incentives and internal demand, which affected the incentives for building a house, the migrant workers were divided into three categories, namely, "external incentive-driven" migrant workers, "internal demand-driven" migrant workers, and "internal and external hybrid-driven" migrant workers. Among them, the migrant workers driven by external incentives to return hometown to build houses accounted for a relatively large proportion. In conclusion, the migrant workers returning hometown to build houses were less often because of the active arrangements for internal needs, and more often passively driven by external incentives, in other word namely helplessness.Keywords：migrant workers;returning hometown to build houses;motivation;category24|8|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
