Data Citation

Daubenmire, J. 1997. NPP Grassland: Cañas, Costa Rica, 1969-1970. Data set. Available on-line [http://www.daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A.

Description

The Cañas study site (10.4 N 85.1 W) was situated 8 km northwest of the town of Cañas in Guanacaste Province, 1.8 km from the Cañas (La Pacifica) weather station operated by the Servicio Meteorologico Nacional. It was an exclosure containing 65 quadrats 0.5 m x 2.0 m, within a relatively uniform area of a stand dominated almost exclusively by Hyparrhenia rufa, a grass introduced extensively throughout the tropics. The original vegetation cover was closed semi-deciduous forest characterized by a dry season from late November to April, with little seasonal differences in temperature. The study area was deforested and converted to a grass savanna around January 1947, 22.5 years before the start of the present study. Light grazing by cattle and horses was accompanied by annual burning of the savanna between December and April. Evidence of grazing by insects and non-domestic vertebrates was rare.

A volcanic explosion one year before the present study deposited a light layer of ash over the study site, and may have contributed to available P and K. Limited experiments with N fertilization resulted in little change in N content of above-ground biomass, although production was increased. A sample from an unburned stand contained twice as much N at the end of the growing season, suggesting that burning significantly depletes N in the ecosystem.

Above-ground net primary production was estimated by two methods: maximum standing crop (peak live + dead matter) was 968 g/m2, whereas the sum of monthly estimates of production (including estimated mortality) was 1387 g/m2. A single end-of season estimate of live root biomass is available for November 1969; 1220 g/m2 (0-20 cm) or 2254 g/m2 (0-100 cm).

Contact Information

Telephone +1 (352) 383-7075

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