Nutrient changes in surface soils after an intense fire in jarrah (Eucalyptus marginata Donn ex Sm.) forest

Abstract

The effects of an intense fire on the nutrient status of jarrah ^Eucalyptus marginata Donn ex Sm.) forest soils were investigated. At seven experimental sites, representing a range of soil and vegetation types, surface soils were sampled to a maximum depth of 20 cm before, immediately after, and 1 year after the fire.Immediately after the fire, concentrations of total and extracted nutrients in surface (0-3 cm) soils mcreased markedly. One year later, concentrations of extracted nutrients in surface soils had returned to levels close to pre-burn concentrations. During this period, some properties of sub-surface (3-20 cm) soils also changed: Bray-extractable phosphorus and electrolytic conductivity decreased, whereas e.xtractablepotassium andpH increased relative to pre-burn concentrations. Initial increases in concentrations of extractable forms of nutrients were determined largely by the amounts of nutrients deposited in fine ash, whereas the changes after 1 year depended more on the leaching of ions and their reactions with the mineral soil.Increases in total amounts of major nutrients in surface soils arising from additions offi ne ash were generally well correlated wtth amounts in pre-burn litter and with amounts in the components of organic matter likely to be consumed in the fire. Significant quantities of all nutrients are redistributed from aboveground sources to the soil surface during intense fires, including nutrients which are most susceptible to losses through volatilization. This redistribution of nutrients is discussed in relation to short-term and long-term effects on plant growth and functioning of the jarrah ecosystem.

Nutrient losses during a winter low-intensity prescribed fire in a Mediterranean forest

“…However, although most nitrogen is volatilized and lost, the remaining ammonia and nitrate nitrogen is settled to the soil surface. This is why some studies report on total N increase on the surface soil, and many studies on increase in inorganic forms of N immediately after the fire (Christensen, 1973;Covington and Sackett, 1986;De Bano et al, 1979;Grove et al, 1986;Hunt and Simpson, 1985;Khanna and Raison, 1986;Kovacik et al, 1986;Schoch and Binkley, 1986;Stock and Lewis, 1986;White, 1986).…”

“…All these nutrients, returning to the soil surface, are mostly in mineral and partly in extractable form (Brown and Mitchell, 1986;Christensen, 1977;Covington and Sackett, 1986;De Bano and Klopatek, 1988;Grove et al, 1986;Lewis, 1974;Lloyd, 1971;Walker et al, 1986) and are easily available for the uptake by plants and microorganisms. As most plants and microorganisms are not killed during these low-intensity burnings (Gillon et al, 1987), they are able to immediately utilize these nutrients.…”

“…These data give useful indications on nutrient losses during burning, but always under artificial conditions. Attempts in the field were based on differences in the nutrient content of fuels before burning and of the remains after the fire (De Bano and Conrad, 1978;Grove et al 1986;Harwood and Jackson, 1975;Schoch and Binkley, 1986). In these studies, plant and litter nutrient and biomass were sampled before burning and after fire, sometimes with inclusion of the surface soil layer.…”

The coupling of recruitment and disturbance by fire in two resprouting Proteaceae species

“…Other changes to the habitat in the first few years after fire may be more important to plant recruitment in these large seeded species, such as soil properties (Grove et al 1986;Certini 2005). Examination of the conditions in microsites where seedlings have and have not been established may provide insights into other possible mechanisms influencing establishment (e.g., Lamont et al 1993;Garcia and Houle 2005).…”

Site management and productivity in tropical plantation forests: progress report: workshop proceedings 7-11 December 1999, Kerala, India

“…Increases in plant availability of the cations and P after fire is one of the most common responses found (Grove et al 1986). In our study, these effects tended to be relatively short lived, with most soil properties returning to their pre-fire levels within the first or second year after fire.…”