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ARS Home » Plains Area » Temple, Texas » Grassland Soil and Water Research Laboratory » Research » Publications at this Location » Publication #324371
Title: A long-term study of burning effects on a plant pathogen in tallgrass prairie

Author
item DENDY, S - Kansas State University
item TONG, B - Kansas State University
item ALEXANDER, H - University Of Kansas
item Fay, Philip
item MURRAY, L - Kansas State University
item BLAIR, J - Kansas State University
item GARRETT, K - University Of Florida

Submitted to: Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/5/2017
Publication Date: 3/5/2017
Publication URL: http://handle.nal.usda.gov/10113/5803495
Citation: Dendy, S.P., Tong, B., Alexander, H.A., Fay, P.A., Murray, L., Blair, J., Garrett, K.A. 2017. A long-term study of burning effects on a plant pathogen in tallgrass prairie. Plant Pathology. 66:1308-1317.

Interpretive Summary: Management prescriptions for rangelands often incorporate fires to stimulate plant growth and improve forage quality. Fire stimulates growth by removing previous year standing dead growth, reducing light limitation and accelerating warming of the soil in spring. Fire may also indirectly stimulate plant growth by decreasing the abundance of plant natural enemies, including fungal pathogens. Pathogen abundance is influenced by weather and soil fertility; however, the effects of fire on pathogens is not well understood. This study reports a long-term survey of pathogen populations on a common plant species in tallgrass prairie, Erigeron strigosa, which sustains populations of the rust fungus Puccinia dioicae. The rust was surveyed for eight years in experimental plots with long-term histories of burning or fertilization with nitrogen or phosphorus. Rust population size varied greatly among years, and in most years fire reduced rust infection rates. Nitrogen fertilization reduced rust populations, possibly because plants were more robust, but phosphorus fertilization caused small but measurable increases in rust populations. However, fertilization effects were much smaller than effects from fire and year-to-year variability. The results suggest that positive effects of fire on plant growth may be reinforced by reduced abundance of plant pathogens.

Technical Abstract: Tallgrass prairie species have evolved with regular exposure to fire. Yet burning has been used as a management tool for reducing plant disease in agricultural systems, posing the question of how plant pathogens of tallgrass prairie will be affected by burning. We studied the rust fungus Puccinia dioicae infecting Erigeron strigosus (Asteraceae) for eight years in long-term experiments to evaluate burning effects in native tallgrass prairie. This experiment also allowed us to evaluate the effects of nutrient additions, although E. strigosus was rare in the nutrient addition plots in most years. Burning reduced rust severity in most years. Effects of nutrient additions were rarely observed. There was high inter-annual variation in rust severity, suggesting weather may be the most important of these three abiotic factors in determining infection. High inter-annual variation also suggests that the effects of this pathogen on its host would be sporadic and difficult to study in short-term experiments.