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Plant diversity in two horticultural farms under organic and conventional management in La Plata, Argentina: A case study.


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Stupino, Susana Andrea; Frangi, Jorge Luis; Sarandón, Santiago Javier; Arturi, Marcelo Fabián and Ferreira, Ana Clara (2008) Plant diversity in two horticultural farms under organic and conventional management in La Plata, Argentina: A case study. [Diversidade de plantas em duas fazendas de horticultura em sitemas orgânico e convencional em La Plata, Argentina: um estudo de caso.] Revista Brasileira de Agroecologia, 3 (3), pp. 24-35.

PDF - Published Version - English

Online at: http://www.aba-agroecologia.org.br/revistas/index.php/rbagroecologia/article/view/7532/5439


Cultivated and associated plant diversity, were compared (the last at 3 scales: alpha, beta and gamma), in 2 farms under conventional and organic management in La Plata. The relevé method was used for associated species recording in spring and summer. At farm level we assessed total spontaneous specific richness (γ diversity), genus and family richness. Richness – species total per crop- was used as index of α diversity. We also calculated the median richness per crop sample unit. A randomization method was used to assess the degree for which differences between the observed and expected median richness per crop in a management style are attributable to chance. β diversity values were compared to a random framework, separately for each farm. Results indicate that the organic farm had higher associated diversity at all levels; also, higher number of cultivated plots and species, and proportion of exclusive, perennials, native and utilitarian species. In the organic farm crops with higher or lower median richness than expected, and higher β, indicated higher spatial and seasonal heterogeneity. Conventional management limited spontaneous plants to a reduced, homogeneously distributed group. Other factors may influence associated plant diversity.

Summary translation

Se comparó la diversidad cultivada y asociada de plantas, la última a 3 escalas (alfa, beta y gamma), en 2 fincas una con manejo convencional y otra con manejo orgánico en La Plata. Se aplicó el método del relevé para las especies asociadas. A nivel finca se determinó la riqueza específica espontánea total (diversidad γ), y la riqueza de géneros y familias. La riqueza - total de especies por cultivo - se usó como índice de diversidad α. Se calculó la mediana de la riqueza por unidad muestral para cada cultivo, aplicándose un método de aleatorización para conocer la significancia de las diferencias entre las medianas observada y esperada por cultivo en un estilo de manejo. Los valores de diversidad β se compararon con un modelo al azar, en cada finca. La finca orgánica tuvo una mayor diversidad asociada en todos los niveles; un número más alto de parcelas y especies cultivadas, de proporción de especies exclusivas, perennes, nativas y utilitarias. En la finca orgánica los cultivos con una mediana de la riqueza más alta o más baja que la esperada, y β más alto, indicaron mayor heterogeneidad espacial y estacional. El manejo convencional limitó las plantas espontáneas a un grupo reducido, homogéneamente distribuido. Otros factores pueden influenciar la diversidad de plantas asociadas.

EPrint Type:Journal paper
Keywords:Horticultura, Agrobiodiversidad, Diversidad asociada, Agroecosistemas. Horticulture, Agrobiodiversity, Associated diversity, Agroecosystems.
Agrovoc keywords:
Subjects: Farming Systems
Crop husbandry
Research affiliation: Brazil > Other organizations
Related Links:http://www.aba-agroecologia.org.br/revistas/index.php/rbagroecologia/index
Deposited By: Pinto, Gabriela Franco
ID Code:27505
Deposited On:02 Apr 2015 13:24
Last Modified:02 Apr 2015 13:24
Document Language:English
Refereed:Peer-reviewed and accepted

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