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- Abstract：To tackle the problem of uneven consumption of soil nutrient resources caused by continuous winter wheat-summer maize cropping pattern in North China Plain, a 3-year field experiment(from 2016 to 2019)containing five different crop rotation patterns was carried out. The five crop rotation patterns included spring maize → winter wheat-summer maize, winter wheat → winter wheat-summer maize, potato-silage corn → winter wheat-summer maize, winter wheat-summer peanut → winter wheat-summer maize, spring peanut → winter wheat-summer maize, and winter wheat-summer maize continuous cropping pattern as control. In order to analyze the improvement potentials of soil fertility and reduction of leaching loss, the leakage pool and the ceramic cup extraction methods were adopted to research the distribution of soil nutrients and the leaching condition for the different crop rotations. The results were as follows: 1)Appropriate rotation patterns improved fertility status of surface soil. The soil inorganic nitrogen content of winter wheat → winter wheat-summer maize and spring maize → winter wheat-summer maize were 0. 7-2. 8 times higher than that of the control. The content of available phosphorus in 0-50 cm showed a decreasing trend, and the decreasing range of spring peanut → winter wheat-summer maize and winter wheat → winter wheat-summer maize patterns were small. Therefore, input of phosphorus fertilizer should be increased appropriately in each pattern. The soil available potassium of winter wheat → winter wheat-summer maize and winter wheat-summer peanut → winter wheat-summer maize had no significant difference compared with the control, and were significantly higher than that of other rotation patterns. 2)The leaching of soil nutrients in each pattern was different, and there was a risk of underground water pollution. The concentration of total phosphorus and potassium in 0-70 cm soil solution of spring peanut → winter wheat-summer maize was higher, which was beneficial to meet the demand of crop nutrition. The concentration of inorganic nitrogen, total phosphorus and potassium in soil solution below 1 m soil layer of winter wheat-summer peanut → winter wheat-summer maize was higher, which increased the risk of groundwater pollution. From the perspective of land conservation and investment reduction, winter wheat → winter wheat-summer maize and spring peanut → winter wheat-summer maize had the best performance. Field management measures should be improved to decrease the nutrient leaching loss of winter wheat → winter wheat-summer maize.Keywords：nutrient variety;nutrient leaching;leakage;ceramic cup;rotation7|12|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To explore and utilize storability gene resources, 216 F2 ear seeds of waxy maize combination N7 × N32 were stored at room temperature for 2 years. The electroconductibility per weight and germination percentage of F2 seeds after storage were used as storability indexes, and the DNA pool of extreme storability was formed. Primers with polymorphism between the two BSA pools were screened, molecular marker linkage map was constructed by adding primers on chromosomes of polymorphic primers using F2 as the mapping population. Furthermore, combined with the seed storability data of 216 F2 individuals, QTL related to storability were detected by composite interval mapping. The results showed that: 1)Two SSR primers with polymorphism between DNA pools were found from 600 primers, which were located on chromosomes 4 and 6, respectively; 2)A SSR linkage map containing 39 markers with a total length of 234. 9 cM was constructed by adding 200 primers on chromosomes 4 and 6; 3)Seven QTL were detected on chromosomes 4 and 6. Among them, two QTL(qCE-4-1 and qGP-4-1)of two indexes were simultaneously located in the region of bnlg1265~bnlg1755 on chromosome 4, with LOD values of 19. 3 and 18. 1, accounting for 30. 5% and 25. 9% of phenotypic variation, respectively. Moreover, two QTL(qCE-6-1 and qGP-6-1)were simultaneously screened in umc1014~bnlg1154 of chromosome 6, with LOD values of 11. 2 and 8. 2, accounting for 15. 0% and 10. 3% of phenotypic variation, respectively. This study provides a theoretical basis for the fine mapping of QTL and molecular marker assisted selection of new storability varieties.Keywords：waxy corn;storability;QTL7|10|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to study the salt tolerance of different wheat varieties in Shanxi Province and screen wheat varieties suitable for planting in saline-alkali land in Shanxi Province, 40 wheat varieties mainly promoted in different wheat regions of Shanxi Province were used as materials. These wheat varieties were treated with salt stress(1. 2% NaCl)at the germination and seedling stages, respectively. The effects of salt stress on various morphological indexes of wheat were analyzed at the germination and seedling stages. The salt tolerance comprehensive evaluation value(D)was adopted to evaluate the salt tolerance of tested materials. The results showed that: Except the root fresh weight at the germination stage and the number of roots at the seedling stage, all morphological indexes at the germination stage and seedling stage of wheat were affected by salt stress, but the sensitivities of different indexes to salt stress were different. A total of nine salt-tolerant varieties at the germination stage were identified(accounting for 22. 5% of the tested materials), eleven salt-tolerant varieties at the seedling stage(27. 5%), and five salt-tolerant materials, ‘Shinong086' ‘Linnuo88' ‘Pinyu8161' ‘Donghei1206' ‘Pinyu8012', were salt-tolerant at both the germination and seedling stages This study provides material basis for the production of wheat seeds in saline-alkali land and the cultivation of salt-tolerant wheat in Shanxi Province.Keywords：Shanxi Province;wheat;salt tolerance;comprehensive evaluation10|11|11<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to identify and screen the cold-resistant of rice germplasm resources at the seeding stage, principal component analysis method combined with morphological and photosynthesis physiological indicators was used to comprehensively evaluate the cold tolerance of 52 rice germplasm resources at seedling stage. The results show that: According to the correlation analysis, there is a negative correlation between the 6 photosynthetic physiological indicators and the yellow leaf rate of morphological indicators; The principal component analysis result converts 7 individual indicators into three independent comprehensive indicators with a cumulative contribution rate of 83. 991%; According to the comprehensive cold tolerance evaluation value(D), the 52 rice varieties are divided into 5 categories including extremely strong cold-resistant, strong cold-resistant, medium-resistant, weak-resistant and cold-sensitive. Rice varieties ‘Donong 4', ‘Hejiang 4' and ‘Jinyuan 85' with strong cold tolerance at seedling stage were identified. The regression analysis results show that the equation can be used to predict the cold tolerance of the tested materials, and the result is consistent with the result of D, indicating that the comprehensive evaluation method can be used in the rice seeding stage screening and comprehensive appraisal of cold-tolerant germplasm resources.Keywords：rice;cold resistance;principal component analysis;membership function7|11|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To study the effects of shading treatments on the photosynthesis and yield of potato, 12 potato virus-free varieties were taken as experimental materials. After the seedling emergence, the control group(CK)was planted under normal light, treatment Z1 was covered by a single-layer shading net, and treatment Z2 was covered by a double-layer shading net. The sampling interval for was 14 days, and the relative content of chlorophyll(SPAD), fluorescence parameters(Fv/Fm), photosynthetic physiological indexes(transpiration rate Tr, stomatal conductance Gs, net photosynthetic rate Pn and intercellular CO2 concentration Ci), yield per plant, dry matter content and weight of dry matter per plant tuber were measured, respectively. The results showed that: The SPAD of leaves was decreased in treatments Z1 and Z2, and the leaves of some varieties withered earlier. Fv/Fm of the leaves of plants in treatments Z1 and Z2 in the early stage was higher than that of CK, while with the extension of treatment time, the Fv/Fm of leaves of plants in Z1 and Z2 was significantly lower than that of the control. Tr, Gs and Pn of other varieties except “Atlantic” decreased in Z1 and Z2, while Ci was the opposite. Pn of Z2 was significantly lower than that of CK 12. 20%-82. 69%, and Ci was significantly higher than that of CK 11. 52%-76. 55%. Moreover, the yield per plant of Z1 and Z2 was 38. 44%-100. 00% lower than that of CK, the tuber dry matter content of Z2 was 66. 88%-100. 00% lower than that of CK, and the weight of dry matter per tuber of Z1 and Z2 was 42. 06%-100. 00% lower than that of CK.Keywords：potato;light intensity;photosynthesis;fluorescence parameters;yield2|9|8<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To study the effect of temperature and humidity conditions of storage environment during overwintering on cassava seed-stem, this study set up seven storage methods including manual climatic box(N1), indoor(N2), outdoor(CK1), inside karst cave(YD), outside karst cave(CK2), inside earth cave(TD), outside earth cave(CK3). The effects of temperature and humidity changes on the physiological changes of cassava seed-stem and storage quality overwinter were investigated. The results indicated that: 1)During overwinter storage, the temperature variation of the seven storage methods respectively were 0. 7, 11. 0, 20. 1, 1. 7, 24. 6, 2. 9, and 20. 8 ℃, and the humidity variation were 8. 5%, 23. 7%, 42. 0%, 65. 4%, 0 and 45. 4%. The temperature and humidity conditions were relatively stable for N1, YD and TD; 2)The contents of proline, malondialdehyde, soluble protein and soluble sugar in cassava seed-stem increased with the prolonging of storage time, the rate of increase was shown as N1>N2>CK1; 3)After overwinter storage, the order of storage quality was N1>TD>YD>N2>CK1>CK3>CK2. N1 was significantly higher than the other six treatments, and CK3 and CK2 were significantly lower than the other five treatments. In conclusion, during overwinter storage, relatively suitable and stable temperature and humidity conditions can weaken the physiological activities of cassava seed-stem, which is beneficial to improve the storage quality. It is suggested that the temperature of cassava seed-stem overwinter storage should be controlled at 15-18 ℃, and the humidity should be kept above 85%.2|11|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to explore the cold resistance of different peach varieties and provide scientific basis for species selection of peach in north area of China, one-year-old branches of twelve peach varieties were used as the experimental materials. The relative electrical conductivity(REC), germination rate, the ratio of bound and free water content, malondialdehyde(MDA)molalities, the mass fractions of soluble sugar, soluble protein and proline were investigated under low temperature stress(-10、-15、-20、-25、-30、-35 and -40 ℃). The cold resistance of each variety was evaluated by using membership function method. The results showed that: The REC of the twelve peach varieties increased displaying an S-curve shape with the decrease of temperature. The semi-lethal temperatures(LT50)were between -24. 30 and -17. 88 ℃; The germination rate gradually decreased. The ratio of bound and free water content and the mass fractions of soluble protein and MDA molalities increased at first and then decreased; The change trend of mass fractions of soluble suger and proline was ascending-descending-ascending-descending; The cold resistance of twelve peach varieties was in order of ‘Qiulian'>‘Wanmi'>‘Qiuyan'>‘03-49-079'>‘Chengde-2'>‘Chengde-1'>‘Okubo'>‘Qingfeng'>‘02-13-140'>‘03-22-034'>‘Spring Snow'>‘Jinao'. In summary, the membership function could be used to accurately identify cold resisitance of peach varieties. ‘Qiulian' ‘Wanmi' ‘Qiuyan' varieties can safely overwinter with strong cold resistance. ‘Spring Snow' ‘Jinao' varieties are not suggested to be introduced and cultivate in north area of China, or they need special attention against cold in winter.Keywords：peach;freezing treatment;cold resistance;evaluation4|10|9<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The aims of this study were to clarify the change characteristics of fruit texture and anatomical structure and the relationship between them during the ripening of ‘Muscat Hamburg' grapevines. The characters of fruit texture and anatomical structure were analyzed by texture profile analysis(TPA)(including firmness, cohesiveness, springiness, chewiness)and paraffin section method, respectively. The basic fruit characters were also measured. The results indicated that during fruit ripening, the thickness of pericarp(epidermis and sub-epidermis)cells decreased, the areas of pericarp cells increased, flesh cells size parameters(area, vertical diameter, horizontal diameter)also increased in varying degrees. The greatest changes were in veraison: The texture of the fruit was also changing dramatically, the fruit firmness and chewiness decreased significantly, the fruit cohesiveness and springiness increased significantly. Further correlation analysis showed that fruit firmness and chewiness had significant positive correlations with the thickness of pericarp and significant negative correlations with the area of pericarp cell and morphological parameters(area, perimeter, vertical diameter, horizontal diameter, aspect)of flesh cells at 0. 01 level. Fruit cohesiveness and springiness were significantly negatively correlated with the thickness of pericarp at 0. 01 level and significantly positively correlated with morphological parameters of flesh cells. The correlation coefficients between fruit texture and epidermal cell thickness and the vertical diameter of the flesh cells were higher. In conclusion, this study provided references for analyses on the cytological basis of texture changes during grape ripening.Keywords：grapevines;fruit;texture;cell morphology4|9|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To lay a scientific basis for alfalfa soil testing and fertilizer recommendation in the northwest desert oasis(NDO)of China, scattered experimental data integration method and the method of nutrient balance and target yield minus soil fertility yield were employed to study the rich-lack index(RLI)of soil N and the recommended N fertilizer application rates(RNFAR)for alfalfa in the natural regions. The results showed that the RLI of soil alkaline hydrolysis nitrogen for the first growing year alfalfa(FGYA)in the NDO of China for the 1st to 7th level were ≥77, 57-77, 42-57, 31-42, 23-31, 17-23 and <17 mg/kg, respectively. The RLI of soil organic matter for the FGYA for the 1st to 7th level were ≥15, 9-15, 5-9, 3-5, 2-3, 1-2 and <1 g/kg, separately. The RLI of soil alkaline hydrolysis nitrogen for the second and more growing years alfalfa(SAMGYA)for the 1st to 5th level were≥74, 40-74, 22-40, 12-22 and <12 mg/kg, respectively. The RLI of soil total nitrogen for the SAMGYA for the 1st to 5th level were ≥1. 4, 0. 7-1. 4, 0. 3-0. 7, 0. 2-0. 3 and <0. 2 g/kg, separately. The RLI of soil organic matter for the SAMGYA for the 1st to 6th level were ≥21, 10-21, 5-10, 2-5, 1-2 and <1 g/kg, respectively. The RLI of soil total nitrogen for the whole growing year alfalfa for the 1st to 5th level were ≥1. 9, 0. 8-1. 9, 0. 3-0. 8, 0. 2-0. 3 and <0. 3 g/kg, separately. As the target yield was 12-27 t/hm2 and the N fertilizer use efficiency was 40%, the RNFAR of the 1st to 7th level soil for alfalfa were 0, 90-203, 180-405, 270-608, 360-810, 450-1 013 and 540-1 215 kg/hm2, respectively. This study preliminary established the system of recommended nitrogen application rates for alfalfa in the NDO of China based on soil nitrogen RLI and provided scientific basis for soil testing and N-fertilizer recommendation of alfalfa in the NDO of China.Keywords：alfalfa;soil testing and fertilizer recommendation;rich-lack index;fertilization index;fertilizer application rate5|10|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to solve the problems of heavy workload and low accuracy of traditional estrus identification method in pig production, the estrous cycle of multiparous large white sows was divided into three stages: three days before oestrus(PE), three days after oestrus(E)and three days after oestrus(AE). Saliva protein was extracted from oral saliva of multiparous sows. Lable-free quantitative proteomics technique was used to detect the salivary proteome of the three stages by mass spectrometry, and the qualitative and quantitative algorithm maxquant was used for proteomics analysis. The results showed that: 1)A total of 405 proteins were identified in the three stages, including 149 co-existing proteins and 160 specific proteins, and 45 differential proteins were significantly screened(P<0. 05). There were 54, 25 and 81 specific proteins in PE, E and AE, respectively; 2)GO and KEGG enrichment analysis showed that they were involved in the major metabolic pathways, including glucagon signaling pathway, pyruvate metabolism, endopeptidase inhibitor activity and protein hydrolysis regulation(P<0. 05); 3)Further interaction analysis showed that P79263, F1SFI7, Q29549, F1SS24, Q9GMA6 and Q2EN74 proteins had interaction relationship, among which F1SS24、Q9GMA6 and P79263 were PE phase proteins, F1SFI7、Q29549 and Q2EN74 were E-phase proteins. In conclusion, through the analysis of salivary proteome in different stages of estrus, multiple target differential/specific proteins were screened, which provided a reference for revealing the changes of salivary protein content in sow estrus cycle, and the development of estrus identification Kit/strip in the next step.Keywords：large white sow;estrus identification;salivary proteomics;protein interaction4|11|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The aims of this study were to understand the drug resistance and drug resistance genes of Enterococcus faecalis from different animals in Xinjiang, and to guide the clinical rational drug use for different animals. A total of 564 feces from pigs, cattle, sheep, camel, chicken and pigeon were collected from 9 farms in Xinjiang. The minimum inhibitory concentrations of 11 antibiotics were determined by agar dilution method recommended by CLSI, and 10 drug resistance genes were detected by PCR. The results showed that: 1)A total of 242 strains of E. faecalis were isolated from different animals, and the isolation rate from high to low was chicken(95. 2%, 40/42), pig(61. 1%, 55/90), cattle(35. 9%, 55/153), sheep(34. 5%, 38/110), pigeon(34. 0%, 34/100)and camel(29. 0%, 20/69). 2)The severity of resistance of E. faecalis from different animal sources was cattle, pig, pigeon, chicken, camel, and sheep. The drug resistance rates of 242 strains of E. faecalis to erythromycin, tetracycline, rifampicin and doxycycline were over 80. 0%. They were highly sensitive to enrofloxacin and florfenicol. Vancomycin and ampicillin resistant strains were not detected. About 84. 7% of the 242 srains were resistant to three drugs at the same time, and most of them were resistant to five or six drugs at the same time. 3)The cfr and poxtA genes were not detected, and the carrying rates of tetM, aac(6′)/aph(2″), aph(3′)-III and ermB resistance genes of isolates were all higher than 70. 0%. In addition, a newly discovered oxazolidinone resistance gene optrA (9. 1%, 22/242)was detected. In conclusion, E. faecalis from different animal sources in Xinjiang has the characteristics of high multidrug resistance rate, wide drug resistance spectrum and high carrying rate of drug resistance genes. It is suggested to strengthen the standardized use of antibiotics and rationally use antibiotics for different animals based on the results of drug sensitivity tests.Keywords：different animal origin;Enterococcus faecalis;drug resistance;drug resistance gene2|11|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The structural development of the bursa of fabricius is closely related to its immune function, and they are directly related to the healthy development of poultry industry. To understand the research statutes of development and the immune function of the bursa of fabricius recently, the research progress of bursa development and immune is described by literature review and summary. The results showed that: 1)The development of the bursa of fabricius begins with primordium formation, which is related to the endoderm and the ectoderm; The specific factors affecting the directional migration of hematopoietic stem cells to bursa of fabricius have not been fully clarified. However, chemokine plays an important role. For example, the CXCL12-CXCR4 axis is involved in the colonization of B lymphocytes colonization; At present, the mechanism of involution of the bursa changes with age is attributed to the hormone levels in the body, mainly the sexual hormone, growth hormone, and corticosteroid hormone, but which hormone plays the dominant role is still controversial. 2)The key to the selection of B lymphocytes by bursal of Fabricius is the rearrangement of immunoglobulin on the surface of B lymphocyte precursors and the binding of the receptor complex on the surface of B lymphocyte to intestinal antigen; The peptides secreted by the bursa of fabricius play an essential role in promoting the proliferation and differentiation of B lymphocytes, and 19 bursa peptides have been identified at present; The immune function of the bursa of fabricius is affected by a variety of factors easily and the common influencing factors include pathogenic microorganisms and environmental stressors, which can directly or indirectly cause the damage of bursa structure and damage to lymphocytes, thus causing the immune suppression of the body. In view of the current situation, the problems still to be solved are put forward in this study: The bursa can interact with other organs and tissues, but the screening and validation of key factors regulating this process are still in the exploratory stage. With the development and innovation of technology, it will promote further research on the immune function of the bursa of fabricius, and provide multi-dimensional theoretical guidance for practical production.Keywords：bursa of fabric;development;immune function;research progress7|11|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to develop the fowl adenovirus serotype 4(FAdV-4)subunit vaccine, the fermentation process of the Fiber-2 protein of FAdV-4 in Pichia pastoris was optimized. Firstly, the Fiber-2 gene was optimized according to the codon preference of yeast, and the recombinant eukaryotic expression vector pPIC9K-Fiber-2 was constructed. The plasmid was transformed into GS115 strain and the high copy recombinant strain was obtained by screening with different concentrations of G418. Then the temperature, time and methanol concentration of induced fermentation were optimized in a shaking flask. The recombinant Fiber-2 protein was obtained by fermentation under the optimized conditions and the supernatant was purified by nickel column. Finally, the protein was mixed with ISA-201-VG oil adjuvant and 21-day-old SPF chickens were immunized for the immune protection test. The results showed that Fiber-2 protein was successfully secreted and efficiently expressed in Pichia pastoris, and its molecular weight was about 60 ku. The optimal methanol concentration, time and temperature in shake flask fermentation were 1. 0%(v/v), 72 h, and 30 ℃, respectively. After optimization, the total protein in the supernatant of the fermentation broth was about 50 mg/L, and the recombinant Fiber-2 protein reached 8. 7 mg/L. SDS-PAGE and Western blot showed that the recombinant Fiber-2 protein with a single band and good reactivity could be obtained by purifying the protein with a nickel column. Immune protective tests showed that the subunits vaccine prepared by the optimized optimized P. pastoris expressing Fiber-2 protein could induce high antibody levels and provide up to 100% attack protection against hypervirulent FAdV-4(GD616). This study laid a foundation for the research and development of FAdV-4 subunit vaccine using recombinant Fiber-2 protein expressed in P. pastoris.Keywords：fowl adenovirus serotype 4;Fiber-2 protein;Pichia pastoris;subunit vaccine1|9|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In response to the problem of traditional rice lodging monitoring methods are time-consuming, labor-intensive and subjectively affected by manual field measurement, the advantages of low cost, simple operation and high resolution of drones are used. The rice planting base of Qixing Farm in Jiamusi City, Heilongjiang Province is taken as the research object, and the rice lodging recognition method of the UAV remote sensing image combined with the improved DeepLabV3+ model is studied. The results show that: 1)Compared with other methods, the improved DeepLabV3+ network model achieves higher accuracy and faster recognition speed in this research method. 2)The improved DeepLabV3+ network model has an accuracy rate of 0. 99 on the test set of rice lodging images, the Kappa coefficient is 0. 98, the pixel accuracy rate is 0. 99, the recall rate is 0. 99; the balanced F score is 0. 99, the cross-combination ratio for the recognition of the complete lodging state of rice is 0. 96, and the average cross-combination ratio for the recognition of the different lodging states of the three rice varieties is 0. 97. In conclusion, the UAV equipped with RGB camera load platform to take remote sensing images combined with the improved DeepLabV3+ deep learning model can accurately identify rice lodging, providing a method for large-area, high-efficiency, low-cost rice lodging monitoring and recognition research.Keywords：rice;lodging;UAV;deep learning13|16|9<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To investigate the effect of the gate opening on the flow velocity and sediment distribution near the water diversion when the control gate adjusts the water level and flow of the bleeder. In this study, the variation of water depth along the main channel in front of the gate and the effect of the gate opening on the velocity near the diversion under different gate opening were investigated by combining numerical simulation of hydraulic characteristics at the diversion with different discharge and gate opening. The results show that: 1)The determination coefficient(R2), Nash coefficient(NSE), and root mean square error(RMSE)of the simulated and measured values of the water depth of the main channel are respectively 0. 898, 0. 687 and 0. 361, suggesting that the simulated values are in good agreement with the measured values and the model is more reliable. 2)When water discharges at the lateral gate, the water depth at the diversion of the main channel is basically the same under different gate opening, which decreases first, then increases and then decreases. When the discharge is in the range of 20-30 L/s, the critical value of discharge at the lateral gate and weir flow appears in the range of gate opening is 9-12 cm(relative opening is 0. 78-0. 81)indicating that the boundary between discharge at the lateral gate and weir flow is not a constant value, and also affected by the discharge of the main channel. With the increase of the opening of the gate, the horizontal distribution of the longitudinal velocity gradually returns to the pairwise distribution, and the transverse velocity at the diversion changes more sharply than the longitudinal velocity and the vertical velocity. 3)With the increase of gate opening, the horizontal distribution of the longitudinal velocity gradually returns to the logarithm distribution, and the transverse velocity changes more dramatically than the longitudinal velocity and the vertical velocity at the diversion. 4)The variation of surface velocity in the diversion area is greater than that at the bottom. With the increase of the gate opening, the velocity value in the area closer to the center of the diversion area is smaller, and the vortex and backflow are easy to form in this area.Keywords：control gate;gate opening;diversion;hydraulic characteristics;numerical simulation4|13|4<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To solve the problem that fish is easy to spoilage during storage, the method of drying is applied. The grass carp fillets were placed in a drying oven and dried at 50 ℃ for 0, 44 and 87 minutes, and the control, 6% dehydrated and 12 dehydrated treatment groups were prepared. The grass carp fillets with different dehydration degrees were then put into polyethylene bags for storage at 4 ℃. Sensory score, total viable counts, total volatile base nitrogen(TVB-N), trichloroacetic acid(TCA)-soluble peptides, adenosine triphosphate(ATP)-related compounds, K-value, biogenic amines, and microbial composition were used as indexes to investigate the alterations of storage quality of fresh prepared grass carp fillets with different dehydration degrees. The results showed that: The TVB-N mass fraction and TCA-soluble peptides molality of the 6% dehydrated group were lower than those in the other two groups at the end of storage(day 13). The texture, overall acceptability score, and HxR molality of the 6% dehydrated group in the late storage were significantly higher than those in the control group(P<0. 05). The putrescine and cadaverine mass fraction of the 6% dehydrated group were significantly lower than the control group(P<0. 05). In the 12% dehydrated group, the texture, overall acceptability scores, and HxR molality of fish flesh were significantly higher than the control group(P<0. 05)at the end of storage, and the putrescine mass fraction of the 12% dehydrated group was lower than that of the control group. In addition, the high-throughput sequencing results showed that the dominant spoilage bacteria in the control group was Shewanella, while the dominant spoilage bacteria in the 6% and 12% dehydrated groups was Pseudomonas. In conclusion, the 6% dehydrated group could maintain a better quality of grass carp during storage indicating a certain degree of drying and dehydration was helpful to delay the spoilage of grass carp fillets.Keywords：fresh prepared grass carp flesh;drying;physicochemical quality;microbial composition2|16|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to ensure the actual effect of high-standard farmland construction, literature research methods and cases investigation were used to analyze the current supervision and management mechanism of high-standard farmland and the experience of typical project supervision mechanism. To solve the problems, the whole-process supervision and management system of high-standard farmland were constructed by the whole life cycle management theory. The results showed that: 1)Current supervision and management mechanism of high-standard farmland has some shortcomings: imperfect full-process-multi-level supervision system, insufficient public participation, and inadequate post-construction management and protection. 2)Third-party monitoring, mine geological environment restoration fund system, the compensation and reward system for returning farmland to forests, and participation of social forces in management and protection of farmland water conservancy are what have positive significance to prefect supervision system and quality assurance system of the high-standard farmland construction and promote multi-subject cooperative supervision. 3)The whole-process supervision and management mechanism of high-standard farmland was structured from four aspects including fund guarantee, main responsibility, mechanism system and incentive mode, which improves the supervision and management mechanism of high-standard farmland construction. Funding sources for the quality, progress, and management of projects are stably obtained. A system with clear responsibilities, strong professionalism, and multi-party participation in supervision is constructed.Keywords：high standard farmland construction;the-whole-process;supervision and management mechanism;mechanism reconstruction;the whole life cycle management8|11|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to clarify the development process, research hotspot and frontier of farmland soil pollution, the relevant literature in the core database of web of science and CNKI are taken as study object, and the bibliometric analysis method of literature co-citation, keyword co-occurrence and keyword outburst are adopted to analyze the research process of farmland soil pollution. The results show that: This research field has received extensive attention both domestically and internationally, among which total literature publish in China and the United States accounts for more than 47. 00% of international publications; Internationally, the knowledge groups in this field mainly focus on heavy metals, agricultural irrigation, organochlorine pesticides, eutrophication, soil and water conservation assessment tools, polycyclic aromatic hydrocarbons, phosphorus, polymerase chain reaction, nitrate, etc; Developing with international researches, domestic researches focuse on heavy metal pollution, pollution assessment, soil remediation, sources, prophylactic treatment measures etc. Therefore, exploring the relationship between farmland soil health and quality improvement, expanding the utilization technology of contaminated farmland soil to ensure the safety of agricultural products, and forming a multi-disciplinary and integrated pattern of all factors are crucial to improve the research of farmland soil pollution and deal with the problems of farmland soil environment.Keywords：farmland soil pollution;soil science;visualization analysis;bibliometrics2|16|5<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to further clarify the role and mechanism of biochar in mitigating soil N2O emissions from agro-ecosystems, this study was based on CNKI, Springer, Wiley, and Science Direct databases with “biochar OR agro-ecosystems” and “N2O OR nitrous oxide”(researches published during 2008 to 2021)as keywords, related literatures were summarized and analyzed. The results show that: Soil N2O can be produced through a variety of microbial processes, among which nitrification and denitrification are the main processes. Non-biological processes such as denitrification by nitrifying bacteria, dissimilation and reduction of nitrate nitrogen to ammonium, and chemical denitrification can also produce N2O. Conclusions on the impact of biochar addition on soil N2O emissions are different. Most studies believe that biochar is beneficial to reduce soil N2O emissions, while a few believe that biochar stimulates or has no effect on soil N2O emissions. Two mechanisms on how biochar involves in slowing down soil N2O emissions are proposed, including the difference in the physical and chemical properties of biochar itself and the influence of biochar on the physical and chemical properties of soil and the process of nitrogen conversion. The potential of biochar to reduce N2O emissions from composted soils and biochar to promote acidic soils plant productivity were also analyzed. In conclusion, it is necessary to establish a database of biochar characteristics, systematically strengthen the estimation of biochar's N2O emission reduction potential and to conduct long-term field trials.Keywords：biochar;agro-ecosystem;soil N;2;O emission;nitrification and denitrification;nitrogen transformation process3|12|6<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To explore the evolution characteristics and reasons of “people, environment and land” in rural areas in loess hilly region, and to diagnose and classify whether villages move or not, Mizhi County of Shaanxi Province is taken as an example. Participatory rural assessment and remote sensing interpretation of cultivated land changes methods are used. The evolution characteristics of the rural human-land system in loess hilly region is identifed and the law of rural decline is explored. And the diagnosis method of moving and merging villages according to local conditions was then proposed. The results show that: 1)The loss rate of the rural population surveyed in Mizhi County from 2001 to 2020 reaches 54. 75%, and the proportion of aging population and low education level in the village resident population are 58. 44% and 72. 79%, respectively. The vacancy rate of the cave dwellings in the surveyed villages is 51. 78%. There is lack of infrastructure, and the medical treatment rate in the villages is only 25. 78%. The water resources per capita agricultural are only 39. 53 m3. The cultivated land of agricultural carriers is reduced by 61. 67% due to the abandonment of farmland and conversion of farmland to forests and grasslands. 2)The main reasons for the above situation include the internal factors such as low agricultural output in loess hilly area, low level of agricultural production efficiency, less cultivated land per capita, poor quality of life in rural areas, and the external factors such as the large employment income gap between urban and rural areas, farmers' pursuit of quality of life. 3)A diagnostic index system is established based on five dimensions including population, housing, urban-rural relationship, water resource, and cultivated land. In conclusion, the diagnostic index system established in this study can be used to optimize the layout of rural settlements in territorial spatial planning and this study provides a reference for scientific and effective village relocation.Keywords：loess hilly area;rural revitalization;movement and merger of village;village classification;rural decline;mizhi county8|14|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Based on the perspective of green total factor productivity, this study uses the SBM-Global-Super model to measure the level of agricultural green development in the prefecture-level cities in China from 2000 to 2017. Dagum Gini coefficient, σ convergence and β convergence methods are adopted to investigate regional differences and convergence. The results showed that: Firstly, the level of agricultural green development shows a fluctuating upward trend, and there are obvious regional differences, the level of agricultural green development in the eastern region is the leading type, and the distribution in other regions is relatively scattered. Secondly, the regional differences in the level of agricultural green development are gradually increasing. The regional differences in the northeast and central are small, and the inter-regional differences between the east and the west is the largest. The differences in the level of agricultural green development mainly come from inter-regional differences, hypervariable density and regional differences are relatively small. Thirdly, the level of agricultural green development in the country and four major regions does not show obvious σ convergence and absolute β convergence characteristics, but there is a significant conditional β convergence trend.Keywords：agricultural green development;green total factor productivity;SBM-Super-Global model;Dagum Gini coefficient;convergence1|10|6<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The aims of this study were to understand farmers' adoption behavior of green production technology, promote agricultural sustainable development and increase farmers' income. Based on the survey data of 634 farmers in the main tea producing area of Wuling Mountain, the Heckman sample selection model was constructed to analyze the factors affecting farmers' green production technology adoption behavior. The quantile regression model was used to further explore the impact of technology adoption behavior on farmers' different tea income levels. The results show that: 1)The adoption rate of individual technology for variety improvement, soil improvement and biological pesticides is relatively high by farmers, but the overall adoption rate of the three technologies under investigation needs to be improved. 2)There are significant differences in the factors that affect the adoption of green production technology by farmers. Among them, the family size, proportion of farmers, proportion of tea income, technology convenience perception, number of relatives and friends, and accessibility to information have positive impact on farmers' intention to adopt technology, while age has a negative impact; The education level, technical efficiency cognition, technology or financial support have positive effect on the technology adoption degree of farmers, while the child dependency ratio is the opposite. 3)The technology adoption behavior has a significant role in promoting the increase of farmers' tea income, and its impact effect shows certain differences due to the different levels of farmers' tea income. The income-increasing effect of technology adoption behavior on lower income farmers is significantly greater than that of middle and high income farmers, which is conducive to narrow down the income gap between farmers. According to the actual situation of farmers' technology adoption behavior and its effect on the difference of the income, it is necessary to improve farmers' awareness of green production technology, promote the intensive and large-scale operation of tea production, increase technical training and fund subsidies, and promote the adoption of green production technology by farmers, so as to strengthen the effect of increasing production and income of technology.Keywords：technology adoption behavior;Heckman model;quantile regression;income effect2|11|7<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to understand the family farm business behavior since corn storage system reform, based on the panel survey data of 22 provincial model family farms of H County in Liaoning Province, this study analyzes the change situation of family farm business behavior and its influencing factors since 2016 from three aspects including corn planting behavior, corn sales behavior and quality and risk awareness. The results showed that: 1)Due to the smaller scale of cultivated land and the requirement of land concentration, family farms need to transfer most of the land because the soil quality and irrigation conditions are generally poor and the planting corn production is faced with higher natural risk; 2)Due to the greater fluctuation of other agricultural products' market price, the rising trend of corn price and the time and labor saving of corn planting, the corn production of family farms have certain rigidity; 3)Due to the smaller scale and the lack of driving capacity of the new agricultural management main body, family farms still choose to sell corn to the door-to-door purchase of small traders; 4)Facing of market uncertainty, the risk awareness of family farms have been significantly enhanced, which manifested by the farmers' willingness to buy agricultural insurance and pay the most attention to the corn market price information, but the quality awareness needs to be improved.Keywords：storage system reform;corn;family farm;business conduct;change7|10|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To understand and adjust the consumers' deviation towards the qualitative safety risk of domestic infant milk powder, based on 559 consumers' data obtained by scenario simulation experiment, this study uses ordered logistic model to conduct an empirical study on the perceived deviation of domestic infant milk powder qualitative safety risk and its influencing factors. The results show that: 1)About 89. 98% of consumers' subjective perception of the qualitative safety risk of domestic infant milk powder is higher than the objective risk level, and there is a risk perception deviation. 2)Product knowledge, brand, certification label, traditional word-of-mouth, government regulation, education level, occupation, monthly family income and purchase experience display significant negative effects on consumers' perception deviation of domestic infant milk powder qualitative safety risk. 3)Problem experience, price and involvement degree have significant positive effects on the perceived deviation of domestic infant milk powder qualitative safety risk. Therefore, on the basis of the government strengthening the disclosure of domestic infant milk powder qualitative safety supervision information and increasing the supply of supervision information, the processing enterprises should improve the marketing strategy of domestic infant milk powder and enhance the effectiveness and pertinence of information transmission while strengthening the popularization of infant milk powder qualitative safety knowledge and improving the ability of consumers to search and process information.Keywords：consumers;infant milk powder;risk perception deviation;influencing factors;scenario simulation experiment5|10|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to explore the timing decision-making mechanism for agricultural enterprises to enter the online market, this study builds a theoretical model for the timing of agricultural enterprises' online entry based on real option theoretical framework. Taking small and medium-sized tea enterprises as the research object, the matching data between Alibaba Tmall Member Database and National Enterprise Credit Information Publicity System Database were obtained by using Python data collection method, and the decision influencing factors of agricultural enterprises' online market entry timing were empirically tested by using Cox and Probit models. The results show that: 1)Reducing uncertainty can promote early entry of agricultural enterprises into the online market, which is reflected in the fact that having online experience and a higher degree of diversification helps agricultural enterprises enter online sales more quickly. 2)When the network effect is stronger than the crowding effect, agricultural enterprises tend to enter early, which shows that the delay time of entry in the online market growth stage of agricultural enterprises is shorter than that in the emerging stage of the market. 3)The positive external effect of online market can weaken the negative effect of uncertainty on agricultural enterprises' market entry. There is significant heterogeneity in the effects of online experience, product diversification and market development stage on the timing of online market entry of agricultural enterprises with different sizes and business models. Therefore, agricultural enterprises should pay attention to accumulate online experience and enrich product diversity, be according to the law of online market development, actively make use of the advantages of network effect and avoid the disadvantage of congestion effect, and combine their own resource endowment to achieve the effect of the most optimal timing to enter the online market.Keywords：tea enterprises;online market;entry timing;decision-making mechanism;real option theory4|10|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In the context of the overall victory of the China's national poverty alleviation campaign in 2021, in order to objectively evaluate the implementation effect of the “photovoltaic poverty alleviation(PPA)” policy in rural areas. Based on the county level panel data in China from 2011 to 2018, this study analyzes the socioeconomic effect of the PPA policy by using a difference-in-differences strategy and conduct a back-of-envelope cost-benefit analysis for PPA policy. The results show that: 1)The PPA policy results in increasing the number of employees in the secondary industry by 10. 37% and 6. 04% in the household saving deposit; 2)Western counties with more light advantages and autonomous counties, deep poverty areas with less employment options show larger poverty alleviation impact than their counterparts; The economic benefits of non-autonomous counties and non-deep poverty areas become more significant after the implementation of PPA policy; 3)The behind mechanisms are the dual employment opportunities of “self-owned positions & public welfare positions”, government financial subsidies, income from power generation and internet access, regular dividends for the village collective, and the development mode of “photovoltaic & industry”. Based on above findings, a few suggestions are put forward as follows: The government should ensure the sustainability of completed photovoltaic power stations through multiple channels, strengthen the propaganda and education of PPA in both directions, focus on mobilizing the enthusiasm of construction; and implement the construction of photovoltaic power stations in accordance with local conditions and strengthen the capacity to respond to large-scale construction of photovoltaic power stations.Keywords：photovoltaic poverty alleviation;socioeconomic effect;difference-in-differences model3|10|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
