Effects of fire and three fire-fighting chemicals on main soil properties, plant nutrient content and vegetation growth and cover after 10 years.

摘要

The study addresses a knowledge-gap in the long-term ecological consequences of fire and fire-fighting\udchemicals. Ten years after a prescribed fire and the application of three fire-fighting chemicals, their effects\udon the soil-plant system were evaluated. Five treatments were established: unburnt soils (US) and burnt\udsoils treated with water alone (BS), foaming agent (BS+Fo), Firesorb (BS+Fi) and ammonium polyphosphate\ud(BS+Ap). Soils (0-2 cm depth) and foliar material of shrubs (Erica umbellata, Pterospartum tridentatum and\udUlex micranthus) and trees (Pinus pinaster) were analysed for total N, 15N, and soil-available and plant total\udmacronutrients and trace elements. Soil pH, NH4\ud+-N and NO3\ud--N; pine basal diameter and height; and shrub\udcover and height were also measured. Compared with US plots, burnt soils had less nitrates and more Mo.\udAlthough differences were not always significant, BS+Ap had the highest levels of soil available P, Na and\udAl. Plants from BS+Ap plots had higher values of 15N (P. pinaster and E. umbellata), P (all species), Na (P.\udtridentatum and U. micranthus) and Mg (E. umbellata and P. tridentatum) than other treatments; while K in\udplants from BS+Ap plots was the highest among treatments for P. pinaster and the lowest for the shrubs.\udPines in US plots were higher and wider than in burnt treatments, except for BS+Ap, where the tallest and\udwidest trees were found, although half of them were either death (the second highest mortality after BS+Fi)\udor had a distorted trunk. BS+Ap was the treatment with strongest effects on plants, showing E. umbellata\udthe lowest coverage and height, P. tridentatum the highest coverage, U. micranthus one of the lowest\udcoverages and being the only treatment where Genista triacanthos was absent. Consequently, it is concluded\udthat both fire and ammonium polyphosphate application had significant effects on the soil-plant system\udafter 10 years.