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United States Department of Agriculture

Agricultural Research Service

Title: Delineation and Discrimination of Soil Fungal Communities under Different Land Management and Tomato Production Practices

Authors
item Wu, Tiehang - UNIV. OF FLORIDA
item Chellemi, Daniel
item Martin, Kendall - WILLIAM PATERSON UNIV.
item Graham, Jim - UNIV. OF FLORIDA
item Rosskopf, Erin

Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 20, 2007
Publication Date: N/A

Interpretive Summary: Soil fumigation with methyl bromide is considered essential for the production of fresh market tomato in the southeastern United State. However, methyl bromide is classified as a Class I Stratospheric Ozone Depleting Substance and its use in the United States is being phased out. Biological information regarding the long-term effects of alternative land use practices is critical to developing crop production systems that minimize dependence on broad-spectrum soil fumigants to manage soilborne pests. This study examined the effect of alternative agricultural land management and tomato production practices on diversity and composition of soil fungal communities. Molecular techniques (length heterogeneity polymerase chain reaction or LH-PCR were used to generate genomic fingerprints of soil fungal communities in the various land management and crop production treatments. Three and four years after land management practices were initiated, analysis of genetic richness and diversity failed to detect differences among soil fungal communities in plots managed organically, conventionally or maintained free of vegetation (disk fallow). However, the composition of fungal communities from organically managed plots could be readily distinguished from communities in conventional and disk fallow plots using multivariate statistical methods. Subsequent cultivation of tomato did not affect the similarity of communities in organic plots or in plots previously maintained as a perennial pasture grass (Paspalum notatum var Argentine bahiagrass). Divergence of the fungal communities composition in disk fallow, conventional and undisturbed (weed fallow) plots increased following cultivation of tomato. Changes incurred through tomato production extended beyond completion of the crop. Divergence of the fungal communities in the disk fallow, weed fallow and conventional plots became more pronounced following two major hurricanes (Francis and Jeanne, September, 2004). Communities in the organic and pasture grass plots remained similar within their respective land management treatment. This trend continued following the completion of an additional tomato crop. Thus, soil fungal communities within an organically-managed system and a perennial pasture grass rotation were more resilient to anthropogenic and climatic disturbances than communities in soil maintained as weed or disk fallow or subjected to conventional tomato production practices.

Technical Abstract: The structure of fungal communities was examined in soil subjected to different agricultural land management and tomato production practices using length heterogeneity polymerase chain reaction (LH-PCR). Three and four years after land management practices were initiated, univariate analysis of genetic richness and diversity failed to detect differences among soil fungal communities in plots managed organically, conventionally or maintained free of vegetation (disk fallow). Nonparametric multivariate analysis indicated communities from organically managed replicate plots remained similar to each other and could be distinguished from communities in conventional and disk fallow plots. Subsequent cultivation of tomato did not affect the similarity of communities in organic plots or in plots previously maintained as a perennial pasture grass (Paspalum notatum var Argentine bahiagrass). Divergence of the fungal communities composition in disk fallow, conventional and undisturbed (weed fallow) plots increased following cultivation of tomato. Changes incurred through tomato production extended beyond completion of the crop. Divergence of the fungal communities in the disk fallow, weed fallow and conventional plots became more pronounced following two major hurricanes (Francis and Jeanne, September, 2004). Communities in the organic and pasture grass plots remained similar within their respective land management treatment. This trend continued following the completion of an additional tomato crop. Thus, soil fungal communities within an organically-managed system and a perennial pasture grass rotation were more resilient to anthropogenic and climatic disturbances than communities in soil maintained as weed or disk fallow or subjected to conventional tomato production practices.

Last Modified: 12/22/2014
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