Skip to main content
SpringerLink
Log in

Community-Oriented Motivations and Knowledge Sharing as Drivers of Success Within Food Assemblies

  • Conference paper
  • First Online:
Exploring Digital Ecosystems

Part of the book series: Lecture Notes in Information Systems and Organisation ((LNISO,volume 33))

Abstract

Despite the increased level of awareness and concern towards social and environmental issues, many consumers have not yet modified their consumption and lifestyle behaviour. In response to this trend, previous works have shown that social and collective actions among customers, enabled by certain food system networks, have the potential to transform passive consumers into active citizens. The aim of this paper is to analyse if community-oriented motivations and knowledge sharing within a network have a positive effect on customers’ consumption in terms of purchase frequency and quantity. To do so we collected data from Italian Food Assemblies, a particular kind of alternative food network based on a digital platform enabling the direct trade between communities and local farmers and producers. The simultaneous coexistence of online and on-site elements characterizing Food Assemblies allowed us to individuate possible differences between knowledge sharing through online and onsite interactions. We developed a quantitative analysis based on a regression model, collecting data from a questionnaire submitted to 8497 Italian food assembly customers, finally receiving 2115 valid answers. The results show that community-oriented motivations and on-site knowledge sharing appear to be statistically significant for purchase frequency, while online knowledge sharing affects both frequency and quantity.

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

Log in via an institution
Chapter
USD 29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD 84.99
Price excludes VAT (USA)
  • Available as EPUB and PDF
  • Read on any device
  • Instant download
  • Own it forever
Softcover Book
USD 109.99
Price excludes VAT (USA)
  • Compact, lightweight edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

References

  1. Carzedda, M., Marangon, F., Nassivera, F., & Troiano, S. (2018). Consumer satisfaction in alternative food networks (AFNs): Evidence from Northern Italy. Journal of Rural Studies, 64, 73–79. https://doi.org/10.1016/j.jrurstud.2018.10.003.

    Article  Google Scholar 

  2. De Bernardi, P., & Tirabeni, L. (2018). Alternative food networks: Sustainable business models for anti-consumption food cultures. British Food Journal, 120, 1776–1791. https://doi.org/10.1108/BFJ-12-2017-0731.

    Article  Google Scholar 

  3. Hinrichs, C. C. (2000). Embeddedness and local food systems: Notes on two types of direct agricultural market. Journal of Rural Studies, 16(3), 295–303. https://doi.org/10.1016/S0743-0167(99)00063-7.

    Article  Google Scholar 

  4. Ilbery, B., & Maye, D. (2005). Food supply chains and sustainability: Evidence from specialist food producers in the Scottish/English borders. Land Use Policy, 22(4), 331–344. https://doi.org/10.1016/j.landusepol.2004.06.002.

    Article  Google Scholar 

  5. Corsi, A., Barbera, F., Dansero, E., & Peano, C. (2018). Introduction. In: A. Corsi, F. Barbera, E. Dansero, C. Peano (Eds.), Alternative food networks (pp. 57–86). Cham: Palgrave Macmillan. https://doi.org/10.1007/978-3-319-90409-2_1.

    Chapter  Google Scholar 

  6. Murdoch, J., Marsden, T., & Banks, J. (2000). Quality, nature, and embeddedness: Some theoretical considerations in the context of the food sector. Economic Geography, 76(2), 107–125. https://doi.org/10.1111/j.1944-8287.2000.tb00136.x.

    Article  Google Scholar 

  7. Charatsari, C., Kitsios, F., Stafyla, A., Aidonis, D., & Lioutas, E. (2018). Antecedents of farmers’ willingness to participate in short food supply chains. British Food Journal, 120(10), 2317–2333. https://doi.org/10.1108/BFJ-09-2017-0537.

    Article  Google Scholar 

  8. Holloway, L., & Kneafsey, M. (2000). Reading the Space of the framers’ market: A case study from the United Kingdom. Sociol Rural, 40, 285–299. https://doi.org/10.1111/1467-9523.00149.

    Article  Google Scholar 

  9. Tregear, A. (2011). Progressing knowledge in alternative and local food networks: Critical reflections and a research agenda. Journal of Rural Studies, 27(4), 419–430. https://doi.org/10.1016/j.jrurstud.2011.06.003.

    Article  Google Scholar 

  10. Venn, L., Kneafsey, M., Holloway, L., Cox, R., Dowler, E., & Tuomainen, H. (2006). Researching European “alternative” food networks: Some methodological considerations. Area, 38, 248–258. https://doi.org/10.1111/j.1475-4762.2006.00694.x.

    Article  Google Scholar 

  11. Zoll, F., Specht, K., Opitz, I., Siebert, R., Piorr, A., & Zasada, I. (2018). Individual choice or collective action? Exploring consumer motives for participating in alternative food networks. International Journal of Consumer Studies, 42(1), 101–110. https://doi.org/10.1111/ijcs.12405.

    Article  Google Scholar 

  12. Rodrigo, R. E., Peña-López, I., Vega, N. (2017). Plataformas digitales: Grupos y cooperativas de consumo versus La Colmena que dice sí, el caso de Barcelona. Revista de Estudios para el Desarrollo Social de la Comunicación, 144–174. https://doi.org/10.15213/redes.n15.p145.

  13. Lyson, T. A. (2005). Civic agriculture and community problem solving. Culture & Agriculture, 27(2), 63–79. https://doi.org/10.1525/cag.2005.27.2.92.

    Article  Google Scholar 

  14. Renting, H., Schermer, M., & Rossi, A. (2012). Building food democracy: Exploring civic food networks and newly emerging forms of food citizenship. The International Journal of Sociology of Agriculture and Food, 19(3), 289–307.

    Google Scholar 

  15. Allen, J. E., Rossi, J., Woods, T. A., & Davis, A. F. (2017). Do Community Supported Agriculture programmes encourage change to food lifestyle behaviours and health outcomes? New evidence from shareholders. International Journal of Agricultural Sustainability, 15(1), 70–82. https://doi.org/10.1080/14735903.2016.1177866.

    Article  Google Scholar 

  16. Brown, C., & Miller, S. (2008). The impacts of local markets: A review of research on farmers markets and community supported agriculture (CSA). American Journal of Agricultural Economics, 90(5), 1298–1302. https://doi.org/10.1111/j.1467-8276.2008.01220.x.

    Article  Google Scholar 

  17. Bosona, T., Gebresenbet, G., Nordmark, I., & Ljungberg, D. (2011). Box-scheme based delivery system of locally produced organic food: Evaluation of logistics performance. Journal of Service Science and Management, 4, 357–367. https://doi.org/10.4236/jssm.2011.43042.

    Article  Google Scholar 

  18. Hertz, F. D., & Halkier, B. (2017). Meal box schemes a convenient way to avoid convenience food? Uses and understandings of meal box schemes among Danish consumers. Appetite, 114, 232–239. https://doi.org/10.1016/j.appet.2017.03.016.

    Article  Google Scholar 

  19. Lieff, S. A., Bangia, D., Baronberg, S., Burlett, A., & Chiasson, M. A. (2017). Evaluation of an educational initiative to promote shopping at Farmers’ markets among the special supplemental nutrition program for women, infants, and children (WIC) participants in New York City. Journal of Community Health, 42(4), 701–706. https://doi.org/10.1007/s10900-016-0306-3.

    Article  Google Scholar 

  20. Brunori, G., Rossi, A., Guidi, F. (2012). On the new social relations around and beyond food. Analysing consumers’ role and action in Gruppi di Acquisto Solidale (Solidarity Purchasing Groups). Sociol Ruralis, 52(1), 1–30. https://doi.org/10.1111/j.1467-9523.2011.00552.x.

    Article  Google Scholar 

  21. Migliore, G., Forno, F., Dara Guccione, G., & Schifani, G. (2014). Food community network as sustainable self-organized collective action: A case study of a solidarity purchasing group. New Medit, 13(4), 54–62.

    Google Scholar 

  22. Fonte, M., & Cucco, I. (2017). Cooperatives and alternative food networks in Italy. The long road towards a social economy in agriculture. Journal of Rural Studies, 53, 291–302. https://doi.org/10.1016/j.jrurstud.2017.01.019.

    Article  Google Scholar 

  23. Evans, A. E., Jennings, R., Smiley, A. W., Medina, J. L., Sharma, S. V., Rutledge, R., et al. (2012). Introduction of farm stands in low-income communities increases fruit and vegetable among community residents. Health Place, 18(5), 1137–1143. https://doi.org/10.1016/j.healthplace.2012.04.007.

    Article  Google Scholar 

  24. De Bernardi, P., Bertello, A., & Venuti, F. (2019). Online and On-Site Interactions within Alternative Food Networks: Sustainability Impact of Knowledge-Sharing Practices. Sustainability, 11(5), 1457. https://doi.org/10.3390/su11051457.

    Article  Google Scholar 

  25. Morgan, K. (2015). Nourishing the city: The rise of the urban food question in the Global North. Urban Studies, 52(8), 1379–1394. https://doi.org/10.1177/0042098014534902.

    Article  Google Scholar 

  26. Feola, G., & Butt, A. (2017). The diffusion of grassroots innovations for sustainability in Italy and Great Britain: an exploratory spatial data analysis. Geographical Journal, 183(1), 16–33. https://doi.org/10.1111/geoj.12153.

    Article  Google Scholar 

  27. Migliore, G., Schifani, G., & Cembalo, L. (2015). Opening the black box of food quality in the short supply chain: Effects of conventions of quality on consumer choice. Food Quality and Preference, 39, 141–146. https://doi.org/10.1016/j.foodqual.2014.07.006.

    Article  Google Scholar 

  28. Follett, J. R. (2009). Choosing a food future: Differentiating among alternative food options. Journal of Agricultural and Environmental Ethics, 22(1), 31–51. https://doi.org/10.1007/s10806-008-9125-6.

    Article  Google Scholar 

  29. Sonnino, R., & Marsden, T. (2005). Beyond the divide: rethinking relationships between alternative and conventional food networks in Europe. Economic Geography, 6(2), 181–199.

    Article  Google Scholar 

  30. Blay-Palmer, A., Landman, K., Knezevic, I., & Hayhurst, R. (2013). Constructing resilient, transformative communities through sustainable “food hubs”. Iternational Journal of Justice and Sustainability, 18(5), 521–528. https://doi.org/10.1080/13549839.2013.797156.

    Article  Google Scholar 

  31. King, C. A. (2008). Community resilience and contemporary agriecological systems: Reconnecting people and food, and people with people. Systems Research and Behavioral Science, 25(1), 111–124. https://doi.org/10.1002/sres.854.

    Article  Google Scholar 

  32. Anderson, M. D. (2008). Rights-based food systems and the goals of food system reform. Agriculture Human Values, 25(4), 593–608. https://doi.org/10.1007/s10460-008-9151-z.

    Article  Google Scholar 

  33. Goodman, D., DuPuis, E. M., & Goodman, M. K. (2012). Alternative food networks: Knowledge, practice, and politics. Routledge, London. https://doi.org/10.4324/9780203804520.

  34. Marsden, T., Banks, J., & Bristow, G. (2002). The social management of rural nature: understanding agrarian-based rural development. Environment and Planning A, 34(5), 809–825. https://doi.org/10.1068/a3427.

    Article  Google Scholar 

  35. Miralles, I., Dentoni, D., & Pascucci, S. (2017). Understanding the organization of sharing economy in agri-food systems: Evidence from alternative food networks in Valencia. Agriculture Human Values, 34(4), 833–854. https://doi.org/10.1007/s10460-017-9778-8.

    Article  Google Scholar 

  36. Bos, E., & Owen, L. (2016). Virtual reconnection: The online spaces of alternative food networks in England. J Rural Stud, 45, 1–14. https://doi.org/10.1016/j.jrurstud.2016.02.016.

    Article  Google Scholar 

  37. Brehm, J. M., & Eisenhauer, B. W. (2008). Motivations for participating in community-supported agriculture and their relationship with community attachment and social capital. Southern Rural Sociological, 23(1), 94–115.

    Google Scholar 

  38. Corsi, A., & Novelli, S. (2018). Determinants of participation in AFNs and its value for consumers. In: A. Corsi, F. Barbera, E. Dansero, & C. Peano, (Eds.), Alternative Food Networks. Cham: Palgrave Macmillan, pp. 57–86. https://doi.org/10.1007/978-3-319-90409-2_4.

    Chapter  Google Scholar 

  39. Cox, R., Holloway, L., Venn, L., Dowler, L., Hein, J. R., Kneafsey, M., et al. (2008). Common ground? Motivations for participation in a community-supported agriculture scheme. Local Environment, 13(3), 203–218. https://doi.org/10.1080/13549830701669153.

    Article  Google Scholar 

  40. Pascucci, S., Dentoni, D., Lombardi, A., & Cembalo, L. (2016). Sharing values or sharing costs? Understanding consumer participation in alternative food networks. Njas-Wageningen Journal of Life Sciences Impact, 78, 47–60. https://doi.org/10.1016/j.njas.2016.03.006.

    Article  Google Scholar 

  41. Kneafsey, A. M., Venn, L., Schmutz, U., Balázs, B., Trenchard, L., Eyden-Wood, T., Sutton, G., Blackett, M., Santini, E. F., & Gomez, S. (2013). Short food supply chains and local food systems in the EU. A state of play of their socio-economic characteristics; EUR—Scientific and Technical Research Series. Publications Office of the European Union, Luxembourg.

    Google Scholar 

  42. Blay-Palmer, A., Santini, G., Dubbeling, M., Renting, H., Taguchi, M., & Giordano, T. (2018). Validating the city region food system approach: enacting inclusive, transformational city region food systems. Sustainability, 10(1680). https://doi.org/10.3390/su10051680.

    Article  Google Scholar 

  43. Putnam, R. D. (1995). Tuning in, tuning out: The strange disappearance of social capital in America. PS, Political Science & Politics, 28, 664–683. https://doi.org/10.2307/420517.

    Article  Google Scholar 

  44. Putnam, R. D. (1995). Bowling alone: America’s declining social capital. Journal of Democracy, 6(1), 65–78. https://doi.org/10.1353/jod.1995.0002.

    Article  Google Scholar 

  45. Nahapiet, J., & Ghoshal, S. (1998). Social capital, intellectual capital, and the organizational advantage. Academy of Management Review, 23, 242–266. https://doi.org/10.2307/259373.

    Article  Google Scholar 

  46. Chow, W. S., & Chan, L. S. (2008). Social network, social trust and shared goals in organizational knowledge sharing. Information and Management, 45(7), 458–465.

    Article  Google Scholar 

  47. Cheng, J., Yeh, C., & Tu, C. (2008). Trust and knowledge sharing in green supply chains. Supply Chain Manag Journal, 13, 283–295. https://doi.org/10.1108/13598540810882170.

    Article  Google Scholar 

  48. Coleman, J. S. (1988). Social capital in the creation of human capital. American Journal of Sociology, 94, S95–S120. https://doi.org/10.1086/228943.

    Article  Google Scholar 

  49. Hau, Y. S., Kim, B., Lee, H., & Kim, Y. G. (2013). The effects of individual motivations and social capital on employees’ tacit and explicit knowledge sharing intentions. International Journal of Information Management, 33, 356–366. https://doi.org/10.1016/j.ijinfomgt.2012.10.009.

    Article  Google Scholar 

  50. Besser, T. L., & Miller, N. (2011). The structural, social, and strategic factors associated with successful business networks. Entrepreneurship and Regional Development, 23(3–4), 113–133.

    Article  Google Scholar 

  51. Jarratt, D., & Ceric, A. (2015). The complexity of trust in business collaborations. Australasian Marketing Journal (AMJ), 23(1), 2–12.

    Article  Google Scholar 

  52. McKitterick, L., Quinn, B., & Tregear, A. (2018). Trust formation in agri-food institutional support networks. Journal of Rural Studies, 65, 53–64. https://doi.org/10.1016/j.jrurstud.2018.11.008.

    Article  Google Scholar 

  53. Newbery, R., Gorton, M., Phillipson, J., & Atterton, J. (2016). Sustaining business networks: Understanding the benefit bundles sought by members of local business associations. Environment and Planning C Government and Policy, 34(7), 1267–1283.

    Article  Google Scholar 

  54. Sökjer-Petersen, M. (2010). The role of Grassroot Leaders in building Networks and organizing Learning Groups. Nordic Psychology, 62(1), 4–23. https://doi.org/10.1027/1901-2276/a000002.

    Article  Google Scholar 

  55. Chiu, C. M., Hsu, M. H., & Wang, E. T. G. (2006). Understanding knowledge sharing in virtual communities: An integration of social capital and social cognitive theories. Decision Support Systems, 42, 1872–1888. https://doi.org/10.1016/j.dss.2006.04.001.

    Article  Google Scholar 

  56. Bollinger, A. S., & Smith, R. D. (2001). Managing organizational knowledge as a strategic asset. Journal of Knowledge Management, 5(1), 8–18. https://doi.org/10.1108/13673270110384365.

    Article  Google Scholar 

  57. Civi, E. (2000). Knowledge management as a competitive asset: A review. Marketing Intelligence & Planning, 18(4), 166–174. https://doi.org/10.1108/02634500010333280.

    Article  Google Scholar 

  58. Loebbecke, C., van Fenema, P. C., Powell, P., & Managing, (2016). Inter-organizational Knowledge Sharing. The Journal of Strategic Information Systems, 25, 4–14. https://doi.org/10.1016/j.jsis.2015.12.002.

    Article  Google Scholar 

  59. Meso, P., & Smith, R. (2000). A resource-based view of organizational knowledge management systems. Journal of Knowledge Management, 4, 224–234. https://doi.org/10.1108/13673270010350020.

    Article  Google Scholar 

  60. Inkpen, A. C., & Tsang, E. W. (2005). Social capital, networks, and knowledge transfer. Academy of Management Review, 30(1), 146–165. https://doi.org/10.2307/20159100.

    Article  Google Scholar 

  61. Beckie, M. A., Kennedy, E. H., & Wittman, H. (2012). Scaling up alternative food networks: Farmers’ markets and the role of clustering in western Canada. Agriculture and Human Values, 29(3), 333–345. https://doi.org/10.1007/s10460-012-9359-9.

    Article  Google Scholar 

  62. The Food Assembly Team. (2017). Reinventing local food supply in connected cities: The example of The Food Assembly. Field Actions Science Reports, 16, 44–49.

    Google Scholar 

  63. Bell, D. R., Gallino, S., & Moreno, A. (2014). How to win in an omnichannel world. MIT SMR, 56, 45–53.

    Google Scholar 

  64. Brynjolfsson, E., Yu, J. H., & Rahman, M. S. (2013). Competing in the age of omnichannel re-tailing. MIT SMR, 54, 23–29.

    Google Scholar 

  65. Manser Payne, E., Peltier, J. W., & Barger, V. A. (2017). Omni-channel marketing, integrated marketing communications and consumer engagement: A research agenda. Journal of Research in Interactive Marketing, 11, 185–197. https://doi.org/10.1108/JRIM-08-2016-0091.

    Article  Google Scholar 

  66. van Dijk, G., Minocha, S., & Laing, A. (2007). Consumers, channels and communication: Online and offline communication in service consumption. Interacting with Computers, 19, 7–19. https://doi.org/10.1016/j.intcom.2006.07.007.

    Article  Google Scholar 

  67. Benkler, Y. (2006). The wealth of networks: How social production transforms markets and freedom. New Haven: Yale University Press.

    Google Scholar 

  68. Kostakis, V., Latoufis, K., Liarokapis, M., & Bauwens, M. (2018). The convergence of digital commons with local manufacturing from a degrowth perspective: Two illustrative cases. Journal of Cleaner Production, 197, 1684–1693. https://doi.org/10.1016/j.jclepro.2016.09.077.

    Article  Google Scholar 

  69. Randelli, F., & Rocchi, B. (2017). Analysing the role of consumers within technological innovation systems: The case of alternative food networks. Environmental Innovation and Societal Transitions, 25, 94–106. https://doi.org/10.1016/j.eist.2017.01.001.

    Article  Google Scholar 

  70. Goldman, A. E. (1962). The group depth interview. Journal of marketing, 26, 61–68. https://doi.org/10.2307/1248305.

    Article  Google Scholar 

  71. Carey, M. A., & Smith, M. W. (1994). Capturing the group effect in focus groups: A special concern in analysis. Qualitative Health Research, 4(1), 123–127. https://doi.org/10.1177/104973239400400108.

    Article  Google Scholar 

  72. Morgan, D. L., & Kreuger, R. A. (1993). When to use focus groups and why. In: D. L. Morgan (Ed.), Sage focus editions. Successful focus groups: Advancing the state of the art (vol. 156, pp 3–19). Thousand Oaks: Sage Publications. https://doi.org/10.4135/9781483349008.n1.

  73. Aiken, L. (1996). Rating scales and checklists: Evaluating behavior, personality, and attitudes. New York: Wiley.

    Google Scholar 

  74. Aldridge, A., & Levine, K. (2001). Surveying the social world: Principles and practice in survey research. Buckingham, Philadelphia.

    Google Scholar 

  75. Rea, L. M., & Parker, R. A. (2014). Designing and conducting survey research: A comprehensive guide. Hoboken: Wiley.

    Google Scholar 

  76. Brown, E., Dury, S., & Holdsworth, M. (2009). Motivations of consumers that use local, organic fruit and vegetable box schemes in Central England and Southern France. Appetite, 53(2), 183–188. https://doi.org/10.1016/j.appet.2009.06.006.

    Article  Google Scholar 

  77. Nie, C., & Zepeda, L. (2011). Lifestyle segmentation of US food shoppers to examine organic and local food consumption. Appetite, 57(1), 28–37. https://doi.org/10.1016/j.appet.2011.03.012.

    Article  Google Scholar 

  78. Vasquez, A., Sherwood, N. E., Larson, N., & Story, M. (2017). Community-supported agriculture as a dietary and health improvement strategy: A narrative review. Journal of the Academy of Nutrition and Dietetics, 117(1), 83–94. https://doi.org/10.1016/j.jand.2016.09.029.

    Article  Google Scholar 

  79. Tecco, N., & Peano, C. (2018). The environmental quality factors sought by consumers in alternative and conventional market channels. In: A. Corsi, F. Barbera, E., Dansero, C., Peano (Eds.), Alternative Food Networks, (pp 119–136). Palgrave Macmillan, Cham. https://doi.org/10.1007/978-3-319-90409-2_6.

    Chapter  Google Scholar 

  80. De Bernardi, P., Bertello, A., & Shams, S. M. R. (2019). Logics hindering digital transformation in cultural heritage strategic management: Evidence from Turin museums. Tourism Anal, 24.

    Google Scholar 

  81. Alkali, Y. E., & Amichai-Hamburger, Y. (2004). Experiments in digital literacy. Cyberpsychology Behavior, 7(4), 421–429. https://doi.org/10.1089/cpb.2004.7.421.

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Management, University of Turin, C.so Unione Sovietica, 218/bis, Turin, Italy

    Paola De Bernardi & Alberto Bertello

  2. ESCP EUROPE Turin Campus, C.so Unione Sovietica, 218/bis, Turin, Italy

    Francesco Venuti

Authors
  1. Paola De Bernardi
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Alberto Bertello
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Francesco Venuti
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Paola De Bernardi .

Editor information

Editors and Affiliations

  1. Department of Social and Political Sciences, University of Milan, Milan, Italy

    Alessandra Lazazzara

  2. Department of Management, University of Turin, Turin, Italy

    Francesca Ricciardi

  3. Management and Business Administration, University of Chieti-Pescara, Pescara, Italy

    Stefano Za

Rights and permissions

Reprints and permissions

Copyright information

© 2020 Springer Nature Switzerland AG

About this paper

Check for updates. Verify currency and authenticity via CrossMark

Cite this paper

De Bernardi, P., Bertello, A., Venuti, F. (2020). Community-Oriented Motivations and Knowledge Sharing as Drivers of Success Within Food Assemblies. In: Lazazzara, A., Ricciardi, F., Za, S. (eds) Exploring Digital Ecosystems. Lecture Notes in Information Systems and Organisation, vol 33. Springer, Cham. https://doi.org/10.1007/978-3-030-23665-6_32

Download citation

Publish with us

Policies and ethics

Search

Navigation