Author
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Emmerich, William |
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Submitted to: Journal of Range Management
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 2/15/1999 Publication Date: N/A Citation: N/A Interpretive Summary: Wildfires and prescribed burns on rangelands remove vegetation and generally increase surface runoff and erosion. The increased runoff can change the nutrient dynamics of an ecosystem because of the loss of nutrients. The soil contained greater than 98% of the total nutrient in the ecosystem and was not significantly changed by burn treatments. The nutrient concentrations in the regrowth vegetation were generally greater. Nutrient loss in both surface runoff and sediment after one year was greater on the burned treatments. The nutrient loss in runoff and sediment was small compared to the nutrient in the vegetation and very small compared to the soil nutrient. These research results show that there could be repeated burns before a major amount of nutrient would be lost from the soil and change the nutrient dynamics of the ecosystems studied. The public and land managers can now be assured that the use of prescribed burns or natural wildfires on similar rangeland ecosystems will not change the nutrient dynamics for vegetation growth. Technical Abstract: Burning of vegetation generally increases surface runoff and erosion and potentially can change the nutrient dynamics of a ecosystem with loss of nutrients. Nitrogen, P and K nutrient status of soil and above ground biomass were determined before fall and spring burns and one year later at two different soil and vegetation type locations. Nutrient loss in surface erunoff and sediment was assessed with rainfall simulations conducted immediately after prescribed burns. The soil contained >98% of the total nutrient and was not significantly influenced by the burn treatment. The nutrient concentrations in the regrowth biomass were generally greater. Nutrient loss in surface runoff-sediment was greater at one location after the first burn on both unburned and burned treatments. After one year and a second burn, losses on the burn treatment were similar between locations. The burn treatment produced consistently greater nutrient loss than the unburned treatment at both locations for both runoff and sediment after th second burn one year later. The nutrient loss in runoff-sediment was small compared to the nutrient in the above ground biomass and insignificant compared to the soil nutrient. The implications of these results are that the locations could have repeated burns for many years before a significant amount of nutrient would be lost from the large soil pool. |
