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- Abstract：In order to study the effects of chemical regulation timing on canopy, root morphology and yield, a field experiment was conducted in the western of Jilin Province in 2017 and 2018. ‘Fumin 985' was selected as the experimental material and ethephon type reagent was sprayed for chemical regulation. In 2017, chemical regulation were sprayed at the 8 and 10 leaf stage(T(8+10)), 8 and 16 leaf stage(T(8+16)), with the planting densities of 70 000 and 90 000 plants/hm2; In 2018, chemical regulation were at 8 leaf stage(T(8)), 8 and 16 leaf stage T(8+16), 16 leaf stage(T(16)), with the planting densities of 60 000 and 90 000 plants/hm2. The results showed: 1)The lodging rate increased with the increased planting density. Chemical regulation reduced the lodging rate by reducing plant height, ear height and the internode length of the plant, particularly for T(8+16). 2)The leaf area of the leaves above the ear was decreased by chemical regulation; T(8+16)can reduce the leaf area by more than 15% compared to CK, so the light transmittance increased. 3)Chemical regulation can effectively increase root projected area and maximum expansion width and reduce the horizontal angle. In particular, T(8+16)regulation enhanced the lodging resistance to a great extent. 4)T(8+16)regulation increased the yield of maize, by up to 6. 5% compared with CK. Therefore, the application of ethephon type reagent in 8-9 and 15-16 leaf stages during the establishment period of maize population structure can improve the population structure on the ear position and above the ear, enhance the lodging resistance of stem and root, and maintain the production capacity of population structure in the later growth period.Keywords：corn;density;chemical regulation;lodging;canopy;root morphology9|15|4<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to make efficient use of the abundant maize silk resources and explore and develop new means for high added value development, this study primarily summarizes and analyzes the research progress on the chemical composition, pharmacology and health care, beauty and other functions of maize silk based on the literature published from 2001 to 2018. The results show that the chemical component of maize silk mainly includes polysaccharides, polyphenols, phytosterols, mineral elements and organic acids. Silk filament extract is shown to have important pharmacological values such as antioxidant activity, anti-tumor effect and immune function, and has wide application prospects. However, its pharmacological mechanism is not clear, and there is lack of depth in product development and utilization. Therefore, the tasks at this stage are to identify the new medicinal value and clarify the mechanism of maize silk by applying modern crop science and pharmacology research methods, and to put more effort into the research and development of maize silk product with high added value.Keywords：maize silk;chemical composition;medicinal value;beauty and health care;silk product7|13|5<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To study the role of the transcription factor GbTCP27 in cotton fiber development, RT-PCR was used to clone GbTCP27 from the island cotton ‘Xinhai 21'. The island cotton GbTCP27 gene has a 1 017 bp open reading frame encoding 338 amino acids with a predicted molecular weight of approximately 35. 37 ku, an isoelectric point of 9. 08, and a molecular formula of C1549H2511N439O483S11. The sequence contains a highly conserved TCP domain. The amino acid sequence comparison showed that the GbTCP27 gene of the sea-island cotton was quite conserved during the evolution process, and the protein sequence was highly consistent with the TCP protein sequence in other plants. Subcellular localization results showed that GbTCP27 belonged to nuclear localization gene. It is predicted that GbTCP27 might play a role in the process of replication and transcription. Phylogenetic tree analysis indicated that the island cotton GbTCP27 gene was distributed on the same branch as the Asian cotton GaTCP9 gene. Real-time PCR showed that the GbTCP27 gene was expressed most in the ovule on the day of flowering and on the day of flowering. In summary these results suggest that GbTCP27 transcription factor may be involved in the development of ovule epidermal cells in cotton fiber initiation stage.Keywords：Gossypium barbadense;TCP;transcription factor;subcellular localization;expression characteristics4|9|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：DUS test of plant varieties is the key point of the examination of plant breeder's rights, and also the technical support of varieties management. By the analysis of herbaceous flower DUS testing status to promote the examination of new varieties, and to speed up the realization “fast protection” as early as possible. Based on DUS testing practice and data analysis from the Ministry of Agriculture and Rural Affairs(MARA), the situation of herbaceous flower new varieties DUS testing is summarized. The new Plant Variety Protection Office of MARA is the authority of herbaceous flowers new varieties rights. The MARA has a relatively perfect testing organization and a high-quality testing team. Official testing is the main method of DUS testing supplement with spot inspection in China. This study introduced the organization, the test guidelines, the application and authorization and the basic situation of DUS testing on herbaceous flowers in China. At the same time, this study summarized the common problems in DUS testing and put forward some suggestions to improve the quality of DUS testing. In order to fully protect the rich flower resources of our country, herbaceous flower new varieties DUS testing has a long way to go.Keywords：herbaceous ornaments;DUS testing;situation3|9|5<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：A microcosm experiment was conducted to investigate the effects of mycorrhizal fungi and mixed minerals in vermicompost substrate on watermelon seedling growth. Pot experiment was carried out in greenhouse of China Agricultural University from 16 October to 27 November 2018. Four treatments were designed as follows: CK(inoculating sterilized mycorrhizal fungi), AM(inoculating mycorrhizal fungi), KW(adding mixed minerals and inoculating sterilized mycorrhizal fungi), AM+KW(adding mixed minerals and inoculating mycorrhizal fungi). After harvesting, the basal nutrient content, biomass, chlorophyll content and root growth index of watermelon seedlings were determined. The results indicated that the addition of mixed minerals in vermicompost decreased the bulk density by 42. 18%, while significantly increased the total nitrogen and available phosphorus(P<0. 05), which promoted plant's uptake of Ca, Fe and Mg in root by 60. 97%、21. 21% and 84. 52%, respectively. Adding mycorrhizal fungi and mixed minerals to the vermicompost significantly increased the gibberellin content of watermelon seedlings(P<0. 05)and improved the root fresh weight(P<0. 001). In summary, adding mixed minerals and inoculating mycorrhizal fungi to vermicompost could improve the root growth and the nutrient uptake in the watermelon seedlings, thus promoted the biomass of watermelon seedlings.Keywords：nutrient absorption;growth hormone;biomass;trace elements4|8|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To study the principle and adaptability of the estimation methods of breeding value for livestock and improve the accuracy of breeding value estimation, literatures related to the methods of estimating breeding value published from 2010 to 2019 are searched by using “livestock”, “estimation of breeding value”, “variance component”, “genome selection method” and “statistical model” as keywords. China National Knowledge Infrastructure, Baidu Scholar, Google Scholar and SCI-HUB are taken as data sources. It is found that different methods are suitable for different research objects, and the accuracy of estimation breeding value is different in different methods. Therefore, to estimate breeding value for livestock and improve the accuracy of estimation of breeding value of livestock, the principles of various methods and choose appropriate estimation methods should be fully considered. More accurate estimations of breeding values could be achieved by establishing genetic evaluation model for study and select suitable genetic evaluation model to assist early selection, shorten the generation interval and speed up the genetic progress in future.Keywords：livestock;breeding value;genetic evaluation method;genome2|8|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To explore the effects of Lactobacillus casei on the structure, function and development of duodenal mucosa in chicks, 450 SPF healthy chicks just hatched were randomly divided into 6 groups. Each group had 5 replicates with 15 chicks in each. Histochemical and immunohistochemical methods were adopted in this study. The results showed that: 1)The intestinal villus height of the L. casei prevention group, the treatment group and the preventive treatment group were significantly higher than that of the Salmonella challenge group by 19. 04%, 10. 68%, and 12. 21%, respectively; 2)The ratio of the villus height to the crypt depth(V/C)of the L. casei prevention group was significantly increased by 23. 94% compared with the Salmonella challenge group; 3)The proliferating cell nuclear antigen(PCNA)content of the L. casei prevention group and the treatment group was significantly higher than that of the Salmonella challenge group; 4)The number of goblet cells in the Lactobacillus prevention, treatment and prevention plus treatment groups was significantly higher than that of the Salmonella challenge group by 72. 26%, 67. 74% and 65. 32%, respectively. The results indicated that L. casei significantly increased the duodenal height, V/C value, PCNA content and goblet cell number of chicks suggesting that L. casei could effectively maintain the intestinal health of chicks and reduce the damage on intestinal mucosal tissue structure caused by Salmonella and promote intestinal development.Keywords：chick;Lactobacillus casei;Salmonella pullorum;duodenum;mucosal morphology1|9|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The purpose of this experiment was to study the effects of iron and zinc chelate of different complex amino acid on the production performance of broiler chickens. A total of 360 1-day-old Arbor Acre commercial broiler chickens of similar body weight were selected and randomly assigned to 6 groups with 3 replicates in each group, and 20 chicks of each replicate. The control group was fed with the basic diet with 100 mg/kg of zinc(ZnSO4)and iron(FeSO4·7H2O)content. The other 5 groups were experimental groups and iron and zinc came from complex amino acid chelate. The contents of iron and zinc were 25(group Ⅰ), 50(group Ⅱ), 75(group Ⅲ), 100(group Ⅳ), 125(group Ⅴ)mg/kg, respectively. At 21 and 42 days, blood sampling and slaughter were conducted. The production performance, slaughter performance and concentration of iron and zinc in different tissues were measured. The results were as follows: 1)The group Ⅱ's average body weight was significantly higher than that of the control group(P<0. 05)at 21 day; The group Ⅴ's average body weight was significantly higher than that of the control group(P<0. 05)at 42 day. 2)The average daily feed intake of the group V at 22 to 42 days of age and 1 to 42 days of age was significantly higher than that of control group(P<0. 05); The average daily weight gain of the group V from 22 to 42 days of age was significantly higher than that of the control group(P<0. 05). There was no significant difference in feed weight-to-body weight ratio between groups(P>0. 05). 3)The breast muscle rate of the group II from 21 days of age was significantly higher than that of the control group(P<0. 05), The breast muscle rate of the group V from 42 days of age was significantly higher than that of the control group(P<0. 05). Other slaughter performance indicators displayed no significances(P>0. 05). 4)The zinc and iron of group Ⅲ and group V in liver were higher than that of control group(P<0. 05). It was concluded that adding amino acid iron and zinc chelate in basal diet could improve the performance of broiler chickens, increase the effective use of iron and zinc, and indirectly reduce environmental pollution. The effects of adding 50 and 125 mg/kg in the experiment were better, but considering the low energy emission reduction problem, the addition of 50 mg/kg was optimal.Keywords：broiler chicken;complex amino acid;iron/zinc chelate;production performance4|7|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：This study was aimed to evaluate the effects of compound Chinese herbal medicine additives on the growth performance, carcass traits, blood immune indexes and meat quality of Pekin ducks. A total of 240 one-day-old Pekin ducks were randomly allocated into 4 dietary treatments, each treatment had 6 replicates and each replicate had 10 ducks. The ducks in control group were fed with a basic corn-soybean diet, the other three groups were fed with a basic corn-soybean diet with additional 0. 1%, 0. 2% and 0. 5% Chinese herbal medicine additive, respectively. At 42 d, the growth performance, carcass traits, blood immune indexes and meat quality of Pekin ducks were measured. The results showed that: Compared with the control group, the average body weight and average daily gain increased significantly(P< 0. 05)while the feed conversion ratio decreased significantly(P<0. 05)in the middle-dose experimental group; the dressing percentage, breast muscle ratio and abdominal ratio of Pekin ducks increased significantly(P<0. 05)in the middle-dose experimental group; the contents of IgA, IgM, IgG and C4 were significantly higher(P<0. 05)in the middle-dose experimental group; the L* value, shear force and drip loss decreased significantly(P<0. 05)while the a* value increased significantly(P<0. 05)in the middle-dose experimental group. In conclusion, the dietary compound Chinese herbal medicine supplementation could improve the growth performance, carcass traits, blood immune indexes and meat quality of Pekin ducks at 42 days of age, and the recommendation additional dose is 0. 2% in basal diet.Keywords：Pekin duck;Chinese herbal medicine additive;growth performance;carcass traits;meat quality3|8|6<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Aimed at the problem of mud homogenizing inefficiency in rice seedling raising tray technology at present, the orthogonal design method, computational fluid dynamics(CFD)numerical simulations and experimental analyses were used to study the homogenizing effects and power consumption of blades with different parameters during mud homogenizing operation in paddy fields. The results showed that: 1)The single-knife cutting width was the biggest factor affecting the mud movement velocity and power consumption, and the effect of bending angle was not obvious; 2)When the sliding-cutting angle was 50°, the bending angle was 115° and the single-knife cutting width was 60 mm, the effect of mud homogenizing was good. When the sliding-cutting angle was 30°, the bending angle was 135°and the single-knife cutting width was 20 mm, the power consumption was the smallest; 3)The blade homogenized mud well at the center of the blade and 0. 1 m from the bending side of the blade; 4)The average relative error of power consumption between simulation value and experiment value was 12. 16%, which was acceptable.Keywords：rice tray nursing seedlings;blade;mud homogenizing;movement velocity;power consumption3|12|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Aiming at the problems that the flow of the agricultural chimney fan is small and the energy efficiency ratio is low, a numerical simulation method is adopted in this study. Under the premise of saving investment cost, the blade shape of the chimney fan is not changed and the size of the supporting air duct structure is modified and optimized. After testing the performance of the prototype fan, the numerical simulation method is used to calculate the inner diameter d of the air duct of the chimney fan(the inner diameter ratio k is used for the ratio of the inner diameter of the modified air duct to the inner diameter of the prototype air duct), the outlet section diffusion angle α and the diffusion depth l. On the basis of single factor optimization, the orthogonal optimization method is used to synthesize the above three factors to obtain the orthogonal optimal design parameters of the air duct. The corresponding air duct prototype is prepared according to the optimal parameters obtained by orthogonalization, and the laboratory performance test is performed. The results show that: 1)Under the single factor optimization simulation, compared with the prototype fan, the air volume and energy efficiency ratio increase respectively by 4. 7% and 4. 0% when k=0. 985, the air volume and energy efficiency ratio increase respectively by 4. 7% and 5. 3% when α=28°, and the air volume and energy efficiency ratio increase respectively by 1. 8% and 3. 2% when l=250 mm; 2)Under multi-factor orthogonal numerical simulation, the air volume and energy efficiency ratio increases by 7. 9% when k=0. 988, α=28°, l=200 mm compared with the prototype fan of 8. 1%; 3)The the optimized fan test results show that the fan airflow and the energy efficiency ratio increase respectively by 4. 6% and 4. 5% compared to the prototype fan.Keywords：chimney fan;air duct type;numerical simulation;performance optimization1|9|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The application of deep learning(DL)in agriculture was summarized, organized, analyzed and forecasted in this study, so that researchers in this field could more systematically and quickly understand the application and research progress of DL in agriculture. A total of 90 publications that applied DL in agriculture from 2013 to 2019 were comprehensively reviewed. In addition, the employed models and frameworks, data augmentations, and overall evaluation of the performances were examined. All reviewed publications were categorized into 13 research areas, including the crops and organs classification(11 papers), pest identification(15 papers), fruit detection and counting(13 papers), plant recognition(6 papers), land cover classification(9 papers), identification of weeds(7 papers), behavior identification and classification(7 papers), estimation of plant nutrient content(5 papers), and plant leaf and seed phenotyping(7 papers). It is noticeable that almost all the studies(87 out of 90)were published during or after 2015, indicating a strong tendency of DL applications in agricultural field. More specifically, there were 15, 39, 21, 9 and 6 published in 2019, 2018, 2017, 2016 and 2015, respectively. Most of the studies adopted the architectures of convolutional neural networks(CNNs), such as AlexNet, VGG16 and Faster R-CNN. In terms of the framework, Caffe was the most favored by researchers, followed by Tensorflow and Keras/Theano. A possible reason was that Caffe incorporated various CNN frameworks and datasets, which could be easily adapted for multiple tasks. Besides, it was worth mentioning that most of the works could benefit from transfer learning(i. e. pre-trained networks)concerning leveraging the already existing algorithm parameters of related tasks in order to increase the learning efficiency of the modified model. Some works augmented the dataset to artificially enlarge the number of training images. The major methods of data transformation included image rotating, cropping, scaling, transposing, and mirroring. Regarding the metrics used for performance evaluation, classification accuracy(CA)was the most popular metric used, followed by F1 score and average precision(AP). As reported, the DL models outperform than other approaches(e. g. traditional machine learning)implemented for comparison purposes. CNNs based DL showed 1%-9% higher CA in comparison to support vector machines(SVM), and was superior than unsupervised feature learning with 3%-13% higher CA, as well as 2%-46% greater CA in relation to local shape and color features. Moreover, DL showed advantages in searching feature engineering(e. g. good feature extractions), which was not always an easy task being completed manually. The DL models performed robustly even under challenging conditions, such as various illuminations, complex backgrounds, different resolution, size and orientation of the images. Although DL normally costed longer time to train the dataset than other approaches, it had much higher efficiencies on testing data. However, a considerable drawback and barrier in the use of DL was the need of large datasets, which served as the input during the training procedure. Another limitation was that the DL models could learn some particular problems well, but they couldn't generalize beyond the dataset. In the future, to achieve the smarter and more sustainable farming, as well as more secure food production, the DL is expected to be applied in other areas of agriculture where it has not been adequately used yet.Keywords：deep learning;convolutional neural network;application framework;evaluation metrics;data augmentation;transfer learning15|11|20<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to further clarify the influencing factors of straw pyrolysis process and their interactions, this study systematically analyzed the current literatures on straw pyrolysis at home and abroad, and summarized the problems existing in the research of straw pyrolysis. From the perspective of numerical simulation analysis, the factors affecting the straw pyrolysis process were summarized and classified, and the factors that need to be considered in the numerical simulation and their applications were analyzed. For example, the instantaneous temperature distribution, volatile flow path, straw particle regular flow path and concentration distribution, and other transient physical quantity changes during the straw pyrolysis process can be monitored in real time based on unsteady numerical simulation. The necessity of combining CFD numerical simulation with experiments and theoretical derivation to study the pyrolysis of straw is expounded, and the feasibility of this research method is analyzed.Keywords：straw;pyrolysis;factors;thermodynamics;chemical reaction kinetics;CFD simulation4|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to objectively evaluate the ecological safety warning situation of Yarkant river plain oasis, an index evaluation system based on the PSR-EEES model suitable for the study area was constructed. The comprehensive index method was used to evaluate the ecological safety warning state of the Yarkant river plain oasis from 1990 to 2016, and the GM(1, 1)model was combined to predict the regional ecological safety situation from 2026 to 2032. The results showed that: 1)The comprehensive index of ecological safety early warning in Yarkant river plain oasis from 1990 to 2016 showed an overall increasing trend. increasing from 0. 255 8 to 0. 551 6, and the ecological warning changed from heavy alarm to moderate alarm with the warning indicator light changed from orange to yellow; 2)The forecast model of GM(1, 1)showed that the ecological safety situation of the study area in 2026-2032 was further improved, ecological security warning value increased from 0. 726 2 to 0. 891 3. A more secure statu emerged, and the safety grade was upgrated from grade Ⅱ to grade Ⅳ and Ⅴ; 3)The status of ecological safety early warning in different counties was obviously different. In the early stage of the study, the ecological safety state in the southwest was better than those in the central and eastern regions. In 2016, it showed a trend of higher in the center area and lower in the northeast and southwest areas. In conclusion, the ecological environment of Yarkant river plain oasis was restored to some extent in the past 26 years. However, the state differences of ecological safety early warning in different counties were obviously indicating that the construction of ecological civilization has a long way to go.Keywords：ecological safety early warning;PSR-EEES model;grey prediction;YarKant river plain oasis4|9|4<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Overland flow is the main source of soil erosion. Research on the hydrodynamic characteristics and its impact on soil erosion are important to deeply understand the mechanism of soil erosion. In recent years, numerous studies have focused on the characteristics of overland flow on slopes, which ignored the role of slope hydrodynamics in soil erosion mechanisms. In this study, the characteristics of overland flow and its impact on soil erosion were analyzed by conducting artificial simulation experiments in runoff plots with different slope lengths(1, 5, 10, 15 and 20 m)under different rainfall intensities(25, 50 and 75 mm/h). The results showed that the average velocity was mainly affected by the lengths of slope and the discharge per unit width, whereas the rainfall intensity indirectly affected the average velocity by influencing the discharge per unit width. The overland flow presented laminar torrent pattern when the slope length was greater than 1m and laminar subcritical pattern when the slope was 1 m. When the rainfall intensity was constant, the Reynolds number increased linearly with the increase of slope length, and the Froude number increased with the increase of the slope length as a power function. The rainfall intensity displayed a significant “drag- increasing” effect on overland flow. The slope resistance coefficient decreased in power function with the increase of slope length. The average soil erosion rate on slope increased with the discharge per unit width linearly, with the average velocity exponentially and the Reynolds numbers quadratically.Keywords：Loess Hilly Region;overland flow;hydrodynamic characteristics;soil erosion3|9|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The aim of this study was to explore the effects of vegetation cover change and human activities on the ecological environment in Guanzhong and Northwest China. By using the vegetation and land surface temperature data, combined with Sen trend and Mann Kendall test, the vegetation cover changes in Guanzhong - Tianshui economic zone from 2001 to 2016 were analyzed. According to the estimated soil moisture factor, the residual method was used to evaluate the influence degree and influence direction of human activities on vegetation cover change. The results showed that: 1)From the perspective of time change, the vegetation cover change during 2001-2016 in Guanzhong-Tianshui economic zone showed a good trend in general, and the overall performance was increasing in the constant fluctuation. It also showed that the ecological environment construction project carried out in Guantian economic zone slowly showed its ecological effect. 2)From the perspective of spatial change dimension, the area with significant increase in vegetation cover in Guanzhong-Tianshui economic zone accounted for 35. 87%, mainly concentrated in both sides of the north and the south of the study area. And the significant decline in the area accounted for 3. 21%, mainly distributed in urban centers, which were areas with active economic development, such as Xi'an, Baoji, Tianshui, Tongchuan. 3)The vegetation cover in Guanzhong-Tianshui economic zone was less affected by natural factors and greatly influenced by other factors. And the positive correlation areas accounted for 13. 43%, while the non-significant related area accounted for 85. 26%. 4)The positive effect by human activities on the change of vegetation cover in the Guanzhong-Tianshui economic zone was greater than the negative effect. Among them, the positive area was mainly distributed in the northern and southeast areas of the study area. The main reasons were the infrequent human activities, the construction of ecological barriers, the strengthening of the conversion of farmland to forests, the protection of Sanbei shelterbelt and soil and water conservation and other ecological projects to promote the growth of NDVI. The negative action areas were mainly distributed along the Weihe River, high economic activity areas, the main reasons included frequent human activities, excessive urbanization, industrialization and other factors restraining vegetation growth. 5)The growth and decline of vegetation cover areas were about the same as those of positive and negative effects of human activities on vegetation, which illustrated from the side that the vegetation cover of the Guantian economic zone was greatly influenced by human activities. In short, attentions should also be paid on vegetation construction and the protection of vegetation and ecological environment at the same time during the economic construction and development.Keywords：vegetation cover;soil moisture;human activities5|8|5<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To explore the grain development foundation of the Sustainable Development Goals(SDGs)in Africa by 2030, using the data from FAOSTAT and taking wheat, paddy rice and maize as example, the evolution tendency of grain production in Africa from 1961 to 2017 is analyzed. Taking 2017 as the reference period, the grain development potential in Africa is estimated by using the Global Agro-Ecological Zone(GAEZ)method. The results show that: 1)Both the harvested area and grain production in Africa and their proportion of the world have mainly kept increasing. However, most African countries' grain yield is still significantly lower than that of the world and China. 2)Taking 2017 as the reference period, the grain development potential in Africa is between 26 857. 81×104 and 27 579. 44×104 t, and the growth range of which is between 181. 64% and 186. 52%. The wheat development potential in Africa is between 2 112. 74×104 and 2 415. 65×104 t, and the growth range of which is between 77. 81% and 88. 96%. The paddy rice development potential in Africa is between 2 763. 77×104 and 2 817. 96×104 t, and the growth range of which is between 75. 59% and 77. 08%. The maize development potential in Africa is between 21 768. 07×104 and 22 345. 83×104 t, and the growth range of which is between 258. 67% and 265. 54%. Therefore, the grain development potential in Africa is enormous, which will provide a very solid foundation to improve food security situation and achieve the SDGs by 2030 in Africa.Keywords：Sustainable Development Goals;Millennium Development Goals;grain production;development potential;Global Agro-ecological Zone2|8|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To measure the relationship between the degree of social capital and the willingness of farmers to participate in the village ecological governance, 634 households in Hubei Province are taken as samples and the survey data are analyzed through the quantile regression method. The research results show that there is an “inverted U” nonlinear relationship between social capital and the participation willingness of farmers. It is mainly represented by that with the increase of farmers' participation willingness degree, the impact of social capital on the ecological management of farmers' village is transformed from stimulation effect to the final constraint effect, which changes from “weak incentive” to “strong incentive”, and then return to “weak incentive role” and “restraint effect”. This relationship format not only enables us to deeply understand the stage role of social capital, but also has important practical significance for the policy making of village ecological governance of peasant households.Keywords：social capital;village ecological governance;quantile regression4|9|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To analyze the impact mechanism of land scale operation(LSO)to international competitiveness in rape planting, a case study of 1 034 households based on the survey data in 2017-2018 in the five provinces of Hubei, Sichuan, Hunan, Anhui and Jiangsu is conducted. A structural equation model(SEM)was built to study the mechanism of LSO and the main impact factors affecting international competitiveness in rape planting. The results show that: Currently, LSO affecting international competitiveness in rape planting mainly lies in two feature latent variables of labor transformation and agricultural mechanization. The land intensification has weak effect on international competitiveness in rape planting. At the same time, among the main impact measurable variables, labor-input and sale price are main factors in feature latent variable of labor transformation, while machine-input play key role in agricultural mechanization and total land scale of a household is important for land intensification. In conclusion, under the background of LSO as the direction for modern agriculture, improving international competitiveness in rape planting mainly lies in three ways: The first one is to promote the rural surplus labor transformation; The second one is to improve the level of agricultural mechanization; The third one is to pay close attention to the affection of land intensification to international competitiveness in rape planting.Keywords：land scale operation;international competitiveness;mechanism;rape planting;structural equation model1|8|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to know whether the rural land contracted right mortgage loan meets the needs of households' funds, based on a households' survey data of Tongxin and Pingluo counties, Ningxia, the credit availability for rural land contracted rights mortgage loan and its impact factors are analyzed by using a bivariate Probit model. The results show that: 1)Compared with the government-led pattern of land mortgage loan, households and rural financial institutions are more active in the market-led pattern and the credit availability is also higher; 2)The middle-aged households have the highest availability to the mortgage loan; 3)Households who have the higher supply ratio, the more cash/savings and the higher production expenditure, their credit availabilities are lower. With the higher land value, the more agricultural income, the higher the non-financial assets, the more convenient transportation, the availability of the loans is also higher. Therefore, in order to further promote the development of rural land contracted right mortgage financing pilot business and improve the availability of households' loans, in areas with good financial ecological environment and households' credit, priority should be given to market-led pattern. The land value and land scale should be jointly included in the evaluation scheme of rural land contracted right mortgage. Providing differentiated financial services to meet the multi-level loan needs of households.Keywords：rural land contracted right;mortgage finance;credit availability;bivariate probit model3|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Based on the evolutionary game model, the quality control mechanism of dairy farmers and dairy processing enterprises in the dairy supply chain from the point of view of market failure and government intervention are investigated. The applicability of model and accuracy to results are verified by the related data. The results show that: Low yield and high overflow rate can lead to market failure. When dairy farmers adopt the advanced prevention strategies or dairy processing companies adopt the advanced inspection strategies, the basic prevention and basic inspection will be the optimal quality control strategy combination of both parties. At this time, the government should give sufficient subsidies to adopt advanced control strategies to encourage both sides to jointly ensure the quality of dairy products. When the dairy farmer adopts the advanced prevention strategies or dairy processing company adopts the advanced inspection strategy to increase the yield, but the overflow rate is higher, the other party will adopt the “free-rider” behavior, then the advanced prevention and basic inspection or the basic prevention and advanced inspection will be the optimal combination of strategies for both sides. At this time, the government should increase its penalties and force “free-rider” actors to conduct quality control. In conclusion, the government subsidies are more effective to dairy farmers, and the government penalty has the double effect of “positive reinforcement” and “negative reinforcement”.Keywords：supply chain management;quality prevention;quality inspection;synergy mechanisms;simulation4|7|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to explore the comprehensive impact of human and mechanical investment on farmers' willingness to make decisions on the scale of operation, this study empirically tests the inpact of different mechanical investment levels on farmers' willingness to make decisions on the scale of rice cultivation under different concurrent jobs with an ordered logistic model based on the survey data of 1080 rice growers in Jiangxi Province. The results show that: 1)The loss of labor caused by rice farmers' part-time work has a general negative impact on the farmers' willingness to expand their business scale; 2)From the perspective of pure farmers and farmers with a low degree of part-time work(Multiple occupations farmers typeⅠ), the higher the level of mechanized production, the more stronger of the farmers' intention to expand the scale of operations; 3)On the contrary, farmers who have higher degree of part-time employment(Multiple occupations farmers typeⅡ)or non-farmers, do not intend to increase mechanized inputs to maintain or expand the scale of existing rice production and operation, and the non-propensity behavior of secondary farmers is significant. Therefore, while improving the socialized machinery production service system and encouraging small scale farms to expand the scale of operation and deepen the division of labor in agriculture, it is an important measure to promote the moderate scale management of agriculture in China to reasonably guide farmers to transfer resources from rice management.Keywords：farmer concurrently;mechanized inputs;scale of operations2|8|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
