Grass and Forage Science最新文献_第4页

Factors affecting nutrient losses in hay production 影响干草生产中营养损失的因素

IF 2.7 3区农林科学

Grass and Forage Science Pub Date : 2024-07-14 DOI: 10.1111/gfs.12685

Diego Zamudio, Marjorie A. Killerby, Robert C. Charley, Eric Chevaux, Pascal Drouin, Renato J. Schmidt, Jhon Bright, Juan J. Romero

{"title":"Factors affecting nutrient losses in hay production","authors":"Diego Zamudio, Marjorie A. Killerby, Robert C. Charley, Eric Chevaux, Pascal Drouin, Renato J. Schmidt, Jhon Bright, Juan J. Romero","doi":"10.1111/gfs.12685","DOIUrl":"10.1111/gfs.12685","url":null,"abstract":"The primary objective of haymaking is to dry forage adequately to inhibit the growth of undesirable microbes and halt residual plant enzymatic activity that causes nutrient losses. During the field and storage phases of haymaking, the environment, management practices, and other factors influence the extent of dry matter losses. This review discusses these factors and the strategies that have been developed to mitigate nutrient losses. A major emphasis was placed on hay microbiome dynamics, as it has been scarcely studied despite its importance on nutrient losses during storage and harvest, especially under humid conditions. The effects of cutting height, mower type, and swath manipulation on soil contamination were discussed. Also, the impact of environmental conditions and swath manipulation on wilting time was analysed for humid and arid conditions. Special attention was given to design improvements in harvesting equipment to reduce wilting time and field losses. Furthermore, we assessed the nutrient losses during storage caused by microbial and residual plant enzymatic activity resulting from excessive moisture at baling or re-introduced moisture during storage. The spoilage extent during storage depends on bale moisture, size, density, shape, wrapping, forage type, and storage facilities. A Venn diagram analysis showed that each phase of haymaking process has a unique microbiome and that certain fungal and bacterial genera could be shared across more than one hay production phase. To take corrective actions, hay producers need to be aware of the increased susceptibility to nutrient losses associated with particular field and storage practices, environmental conditions, and forage types.","PeriodicalId":12767,"journal":{"name":"Grass and Forage Science","volume":"79 4","pages":"499-515"},"PeriodicalIF":2.7,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141649794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Forage potential of Thinopyrum intermedium through near-infrared spectrometry and grown in mixture with various legumes 通过近红外光谱分析 Thinopyrum intermedium 与各种豆科植物混合种植的饲料潜力

IF 2.7 3区农林科学

Grass and Forage Science Pub Date : 2024-07-08 DOI: 10.1111/gfs.12684

Laura Fagnant, Olivier Duchene, Jérôme Bindelle, Yves Beckers, Virginie Decruyenaere, Benjamin Dumont

{"title":"Forage potential of Thinopyrum intermedium through near-infrared spectrometry and grown in mixture with various legumes","authors":"Laura Fagnant, Olivier Duchene, Jérôme Bindelle, Yves Beckers, Virginie Decruyenaere, Benjamin Dumont","doi":"10.1111/gfs.12684","DOIUrl":"10.1111/gfs.12684","url":null,"abstract":"Intermediate wheatgrass [IWG; Thinopyrum intermedium (Host) Barkworth & D.R. Dewey] is a perennial grass, dual-purpose crop that can provide environmental services. In addition to the grain production, assessing its forage potential is crucial. We developed models for near-infrared (NIR) spectrometry prediction of the chemical composition and digestibility of IWG across various experimental sites. Among these, a Belgian field was used to compare its dual production in pure stands or in mixture with legumes. Good quality NIR predictions were observed, offering an efficient tool to characterize the forage composition of IWG. Its forage parameters were mainly influenced by the phenological stage with an increase of fiber and a decrease of protein, digestibility, and energy content (NEL) during the growing season. IWG forage at vegetative stages could be used to feed lactating dairy cattle with a NEL of 1625 kcal kg−1 of DM but, its biomass was low averaging 1.8 t of DM ha−1. At grain maturity, biomass was higher (i.e., 5.3 t of DM ha−1), representing 73%–92% of the total biomass production, and could replace straw in high-starch dairy diets with a NEL averaging 849 kcal kg−1 of DM. Although the mixture of IWG with legumes enhanced some forage parameters, its value as animal feed was not improved. In mixture, we observed a tradeoff between the increase of the forage yield and the reproductive potential of IWG. These insights can inform the on-going process of breeding and help farmers to design relevant systems to experiment this new crop.","PeriodicalId":12767,"journal":{"name":"Grass and Forage Science","volume":"79 4","pages":"557-570"},"PeriodicalIF":2.7,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141569397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Urea fertilization for potentializing beef cattle performance in agroforestry systems in the humid tropics 在湿热带农林系统中施用尿素肥料以提高肉牛的性能潜力

IF 2.7 3区农林科学

Grass and Forage Science Pub Date : 2024-06-17 DOI: 10.1111/gfs.12683

Thaís Lima Figueiredo, Valéria Xavier de Oliveira Apolinário, Janerson José Coelho, Luciano Cavalcante Muniz, Maria Karoline de Carvalho Rodrigues de Sousa, Raabe Alves Souza, Giselle Cristina da Silva Carneiro, Natannael Castro Vilhena, Joaquim Bezerra Costa, Jose Carlos Batista Dubeux Jr

{"title":"Urea fertilization for potentializing beef cattle performance in agroforestry systems in the humid tropics","authors":"Thaís Lima Figueiredo, Valéria Xavier de Oliveira Apolinário, Janerson José Coelho, Luciano Cavalcante Muniz, Maria Karoline de Carvalho Rodrigues de Sousa, Raabe Alves Souza, Giselle Cristina da Silva Carneiro, Natannael Castro Vilhena, Joaquim Bezerra Costa, Jose Carlos Batista Dubeux Jr","doi":"10.1111/gfs.12683","DOIUrl":"https://doi.org/10.1111/gfs.12683","url":null,"abstract":"This study hypothesized that urea fertilization could optimize animal performance in an agroforestry system. This study evaluated how increasing rates of N fertilization (0, 100, 200, and 400 kg N ha−1 year−1) using urea (CH4N2O) affected forage mass, nutritive value, and beef cattle (Bos indicus) performance in an agroforestry system with Massai grass (Megathyrsus maximus Jacq. cv. Massai) and legume tree (Mimosa caesalpiniifolia Benth.), in the humid tropic region of Brazil, over 2-year period. The experiment was carried out in a randomized complete block design with four treatments (N fertilizer rates) and three replications. Forage mass was positive and linearly affected by N fertilization (p = .0236, R2 = 0.92), ranging from 1297 to 1583 kg DM ha−1 under 0 and 400 kg N ha−1 year−1, respectively. There was greater average forage mass during the rainy period (1826 kg ha−1) (p < .05). Crude protein in green forage mass increased linearly (p = .0041, R2 = 0.91) in function of the N applied. Cattle average daily gain showed a positive quadratic response to the rates of N applied (p = .0298, R2 = 0.97), ranging from 0.46 kg to 0.68 kg animal day−1; and the gain per area increased linearly from 1.84 to 2.68 kg LW ha−1 day−1 (p = .0640, R2 = 0.96). The findings indicate that applying 200 kg N ha−1 year−1, split-applied during the rainy season, would yield acceptable outcomes in terms of forage mass, nutritive value, and animal performance for this type of agroforestry system.","PeriodicalId":12767,"journal":{"name":"Grass and Forage Science","volume":"79 3","pages":"423-437"},"PeriodicalIF":2.7,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141980237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Nutrient composition, fermentation characteristics and mass balance of press juice and press cake obtained from biorefining of grass-clover and red clover silage 禾本科苜蓿和红苜蓿青贮饲料生物炼制获得的压榨汁和压榨饼的营养成分、发酵特性和质量平衡

IF 2.7 3区农林科学

Grass and Forage Science Pub Date : 2024-06-02 DOI: 10.1111/gfs.12682

Reinhard Resch, Georg Terler, Manuel Winter, Michael Mandl, Lisa Baldinger, Joseph Sweeney, Kevin McDonnell, Andreas Steinwidder

{"title":"Nutrient composition, fermentation characteristics and mass balance of press juice and press cake obtained from biorefining of grass-clover and red clover silage","authors":"Reinhard Resch, Georg Terler, Manuel Winter, Michael Mandl, Lisa Baldinger, Joseph Sweeney, Kevin McDonnell, Andreas Steinwidder","doi":"10.1111/gfs.12682","DOIUrl":"10.1111/gfs.12682","url":null,"abstract":"Biorefining is seen as a potential method to produce protein-rich feed for monogastric farm animals from grassland, which does not compete with human nutrition. Therefore, a new biorefinery facility was constructed and tested in this experiment by using silages from grass clover mixture and red clover. After biorefining, press juice was stored for further use while press cake was re-ensiled. Samples from silage, press juice, fresh press cake and re-ensiled press cake were analysed for nutrient composition, fermentation parameters, amino acids (AA) and biogenic amines (BA) concentrations. Furthermore, digestibility of silage and re-ensiled press cake was tested in wethers. We found that press juice contained about 205 g crude protein (CP), more than 180 g crude ash and more than 130 g volatile organic compounds (VOC, all values per kg dry matter [DM]). Furthermore, press juice had an unfavourable AA ratio for use as a monogastric feed (methionine and cysteine were reduced). Forage type hardly affected nutritive value of press juice. Re-ensiling of press cake was successful as a sufficient decrease of pH and VOC concentration was observed. Press cake had 26–36 g/kg DM lower CP content and 0.77–1.12 MJ/kg DM lower metabolisable energy content than silage with greater differences in red clover than in grass clover mixture. Press juice can be used as feed in monogastric animals, but its use is limited due to its low CP content and unfavourable AA profile. Press cake could be an appropriate feed for ruminants, especially dry cows or heifers.","PeriodicalId":12767,"journal":{"name":"Grass and Forage Science","volume":"79 3","pages":"449-463"},"PeriodicalIF":2.7,"publicationDate":"2024-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141273437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Topics from the 2023 EGF Symposium: The future role of ley-farming in cropping systems, and other recent grassland events 2023 年 EGF 研讨会的主题：列依耕作在种植系统中的未来作用以及其他近期草原事件

IF 2.4 3区农林科学

Grass and Forage Science Pub Date : 2024-05-30 DOI: 10.1111/gfs.12676

Anjo Elgersma

引用次数: 0

Proceedings of a European Grassland Federation Symposium, held at Vilnius, Lithuania, 11–14 June 2023. By Ž. Kadžiulienė, K. Jaškūnė, E. Norkevičienė, M. Toleikienė, L. Šarūnaitė (Eds.). 2023. pp. 280. ISBN: 978-609-451-008-3 (Published as Grassland Science in Europe, Volume 28. Available as a free access pdf download from https://www.europeangrassland.org and follow the link to proceedings) 欧洲草原联合会研讨会论文集，2023 年 6 月 11-14 日于立陶宛维尔纽斯举行。作者：Ž.Kadžiulienė, K. Jaškūnė, E. Norkevičienė, M. Toleikienė, L. Šarūnaitė (Eds.). 2023. pp.ISBN: 978-609-451-008-3 （作为《欧洲草地科学》第 28 卷出版。可从 https://www.europeangrassland.org 免费下载 pdf，并点击链接进入论文集)

IF 2.4 3区农林科学

Grass and Forage Science Pub Date : 2024-05-30 DOI: 10.1111/gfs.12677

Alan Hopkins

引用次数: 0

The de-domestication of Ornithopus sativus Brot. to develop cultivars with physical dormancy (hardseed) 对Ornithopus sativus Brot.进行非驯化，以培育具有物理休眠（硬籽）特性的栽培品种

IF 2.7 3区农林科学

Grass and Forage Science Pub Date : 2024-05-14 DOI: 10.1111/gfs.12675

Robert J. Harrison, Bradley J. Nutt, Ronald J. Yates, Belinda F. Hackney, John G. Howieson

{"title":"The de-domestication of Ornithopus sativus Brot. to develop cultivars with physical dormancy (hardseed)","authors":"Robert J. Harrison, Bradley J. Nutt, Ronald J. Yates, Belinda F. Hackney, John G. Howieson","doi":"10.1111/gfs.12675","DOIUrl":"10.1111/gfs.12675","url":null,"abstract":"Ornithopus sativus Brot. (French serradella) is a forage legume that is well adapted to acidic coarse textured soils (sands) which are characterized by poor nutrition and an inability to retain water. During the process of domestication of O. sativus, there was an unintentional loss of seed physical dormancy (PY) thus compromising its self-regeneration after a cropping interval. Through mass screening of seed, we identified for the first time that heritable sources of PY exist in three populations of O. sativus. This rare genetic material was then incorporated into suitable genetic backgrounds of differing maturity through targeted hybridization. We demonstrated that the heritability of PY was dominant in the population of 97ZAF5sat but inconsistently recessive in the population of cv. Emena. Flowering time was variable in each source population, with a large variation in time to emergence of first flowers (95–175 days). Selection for early flowering maturity was heritable and stable. F6 generations selected for PY in different maturity classes were then evaluated in situ to establish whether PY would allow a proportion of seeds to survive in the soil through consecutive seasons exposed to a Mediterranean climate. The breeding lines FHS3, 7 and 23 remained dormant, thus viable, in the soil for up to 3 years, indicating the likelihood that O. sativus with PY could survive and persist in a ley farming system. The de-domestication program in O. sativus has resulted in commercially successful cultivars (most recently cv. Fran2o) suited to sustainable dryland agriculture in a Mediterranean climate.","PeriodicalId":12767,"journal":{"name":"Grass and Forage Science","volume":"79 3","pages":"366-380"},"PeriodicalIF":2.7,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gfs.12675","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140980141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Arachis pintoi Krapov. & W.C. Greg.–A multifunctional legume Arachis pintoi Krapov.一种多功能豆科植物

IF 2.7 3区农林科学

Grass and Forage Science Pub Date : 2024-05-14 DOI: 10.1111/gfs.12674

Isabela Brandão de Sousa, Renata de Oliveira Garcia, José Francisco Montenegro Valls, Georgia Pacheco, Elisabeth Mansur

{"title":"Arachis pintoi Krapov. & W.C. Greg.–A multifunctional legume","authors":"Isabela Brandão de Sousa, Renata de Oliveira Garcia, José Francisco Montenegro Valls, Georgia Pacheco, Elisabeth Mansur","doi":"10.1111/gfs.12674","DOIUrl":"10.1111/gfs.12674","url":null,"abstract":"Arachis pintoi, commonly known as pinto or forage peanut, is used mainly in consortia with grass pastures and as cover plant. In addition to increasing the productivity of livestock and plantations, it contributes to the mitigation of environmental impacts (reduction of greenhouse gas emissions) and soil improvement (nitrogen fixation, reduction of fertilizers use), as well as to pests and disease management. Several cultivars that are tolerant to specific climates and soil conditions are suitable to be used as ground covers in agroforestry and silvopastoral systems, orchards, and plantations. Biotechnological and phytochemical investigations revealed the potential of pinto peanut as a sustainable source of resveratrol and other stilbenoids. Extracts from plants grown under natural conditions and from materials obtained in vitro displayed allelopathic, anthelmintic, or antioxidant activities. Other studies revealed the potential of pinto peanut for erosion control, phytoremediation, seed and essential oils production, materials for animal tissue engineering, synthesis of nanoparticles for drug delivery, and as green biorefineries to produce proteins, biochemicals, and biomaterials.","PeriodicalId":12767,"journal":{"name":"Grass and Forage Science","volume":"79 3","pages":"343-352"},"PeriodicalIF":2.7,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140981688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Examining the role of ruminants in sustainable food systems 研究反刍动物在可持续粮食系统中的作用

IF 2.4 3区农林科学

Grass and Forage Science Pub Date : 2024-04-26 DOI: 10.1111/gfs.12673

Sara E. Place

{"title":"Examining the role of ruminants in sustainable food systems","authors":"Sara E. Place","doi":"10.1111/gfs.12673","DOIUrl":"10.1111/gfs.12673","url":null,"abstract":"Sustainable food systems provide food security while stewarding economic, social, and environmental bases in ways to meet future generations' needs. Sustainable food systems encompass the health of animals, people, and ecosystems. Healthy and productive ruminants can produce meat and milk products with fewer resources, and consequently, often fewer greenhouse gas emissions are produced. Ruminant livestock faces the dual challenge of being impacted by and contributing to climate change, while also experiencing increased demand for ruminant meat and milk products due to growing global population and increased incomes. This challenge presents different ways forward depending upon solutions and how one values certain aspects of sustainability, ranging from simply building upon past improvements in ruminant agriculture to dramatic reductions in ruminant livestock populations. Better understanding the concerns with ruminant's role in sustainable food systems is important, as is understanding the different viewpoints and interpretation of evidence both for and against ruminant agriculture. This review provides a brief overview of some of the key issues related to the role ruminant animals play in sustainable food systems, including greenhouse gas emissions, feed-food competition and land use, and human nutrition. The review also highlights how improved animal health outcomes can enhance ruminants' role in sustainable food systems. Ultimately, ruminants make unique contributions to human flourishing via providing nutrition, livelihoods, and ecosystem services from forage resources and grassland landscapes. However, the status quo is unlikely to meet the challenges of the coming decades, thus investing in research and development into sustainable ruminant systems is required.","PeriodicalId":12767,"journal":{"name":"Grass and Forage Science","volume":"79 2","pages":"135-143"},"PeriodicalIF":2.4,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/gfs.12673","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140805391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Forage accumulation, nutritive value, and grazing efficiency on rotationally stocked ‘Zuri’ guineagrass pastures as affected by pre-graze canopy height and N rate 轮牧 "Zuri "几内亚草牧场的牧草积累、营养价值和放牧效率受放牧前冠层高度和氮含量的影响

IF 2.4 3区农林科学

Grass and Forage Science Pub Date : 2024-04-23 DOI: 10.1111/gfs.12672

Otávio Goulart de Almeida, Carlos Guilherme Silveira Pedreira, Juliana Aparecida de Assis, Valdson José da Silva, Bruno Carneiro e Pedreira

{"title":"Forage accumulation, nutritive value, and grazing efficiency on rotationally stocked ‘Zuri’ guineagrass pastures as affected by pre-graze canopy height and N rate","authors":"Otávio Goulart de Almeida, Carlos Guilherme Silveira Pedreira, Juliana Aparecida de Assis, Valdson José da Silva, Bruno Carneiro e Pedreira","doi":"10.1111/gfs.12672","DOIUrl":"10.1111/gfs.12672","url":null,"abstract":"Grazing management and nitrogen fertilisation may affect forage accumulation (FA), nutritive value, and grazing efficiency (GE) of the highly productive ‘Zuri’ guineagrass [Megathyrsus maximus (Jacq.) B.K.Simon & S.W.L. Jacobs syn. Panicum maximum Jacq.]. The objective of this study was to assess the effects of pre-graze canopy heights [55 and 75 cm (H55 and H75, respectively)] and N fertilisation rates [150 and 300 kg N ha−1 year−1 (N150 and N300, respectively)] on FA, GE, grazing losses (GL), and nutritive value of Zuri under rotational stocking. The stubble height was 50% of the pre-graze canopy height. The total FA was 20% greater under H75 than H55 (22,120 vs. 18,370 kg DM ha−1 year−1), as well as the GL was greater under H75 (85%) than under H55 (79%). Regardless of pre-graze height, the upper stratum of the canopy was composed mostly of leaves contributing to similar crude protein (CP) (142 g kg−1) and in vitro digestible organic matter (IVDOM) (559 g kg−1) concentrations. Greater N rate (N300) increased FA (23,500 vs. 16,980 kg DM ha−1 year−1) and resulted in greater GE (84% vs. 80%) compared to N150. The CP and IVDOM concentrations under N300 (157 and 571 g kg−1, respectively) were greater than under N150 (128 and 547 g kg−1). Zuri guineagrass grazed at H75 has great FA and GE, maintaining a similar forage nutritive value compared to H55.","PeriodicalId":12767,"journal":{"name":"Grass and Forage Science","volume":"79 2","pages":"308-317"},"PeriodicalIF":2.4,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140670383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0