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Category: Ecological Research

Title: Nitrogen and phosphorus status in a ponderosa pine forest after 20 years of interval burning

Author: Wright, R.J. , Hart, S.C.

Subject: Nutrient cycling, Ponderosa pine (Pinus ponderosa), Prescribed burns, Soil

Abstract: We examined the cumulative effects of 20 years of two-year interval prescription burning on available nitrogen (N) and total N and phosphorus (P) pools in the upper 15 cm of mineral soil of a southwestern ponderosa pine (Pinus ponderosa Dougl. ex Laws.) forest over a complete two-year burn cycle. Repeated burning reduced anaerobically mineralizable N up to 25(percent). However, burned and control plots had similar monthly ammonium and nitrate pool sizes in the mineral soil during both years of the two-year bum cycle. Mineral soil total N in the upper 15 cm was reduced by 110 kg N/ha (about a 7(percent) reduction) after 20 years of prescription burning at this site. This estimate, coupled with a calculated 470 kg/ha loss of N from the forest floor, indicates repeated burning has substantially depleted soil N stocks at this site. In contrast to N, mineral soil total P in burned plots was similar to control plots. Our results suggest that repeated prescription burning at two-year intervals may have deleterious long-term effects on N cycling in southwestern ponderosa pine forests.

Date: 1997

Type: Journal

Source: Ecoscience

Identifier: 494):526-533

Publisher: Ecoscience

Format: PDF

Language: English