Title:	Use of hand-held radiometers to evaluate the cover and hydrologic characteristics of semiarid rangelands.
Authors:	POST, D. F. MARTIN, E. S. SIMANTON, J. R. SANO, E. E.
Affiliation:	DONALD F. POST, UNIVERSITY OF ARIZONA; E. SCOTT MARTIN, UNIVERSITY OF ARIZONA; J. R. SIMANTON, AGRICULTURAL RESEARCH SERVICE; EDSON EYJI SANO, CPAC.
Date Issued:	1999
Citation:	Arid Soil Research and Rehabilitation, Hants, v. 13, p. 201-217, 1999.
Description:	Abstract: The spectral reflectance characteristics of11 rainfall simulator plots were measured with a hand-held radiometer on semiarid rangeland surfaces, of the U.S. Department of Agriculture, Agricultural Research Service, Walnut Gulch Experimental Rangel and Watershed, Tombstone, Arizona. Rainfall simulations were made in May and June 1984 for plots characterized by natural vegetation, natural vegetation clipped and removed, and natural vegetation clipped and rock fragments > 5 mm removed. In 1994, reflectance and cover data were collected on the same plots to evaluate changes over time. Measurements were taken at 38-43° and 74-77° sun elevation angles with a four-band hand-held radiometer (blue 0.45-0.52 um, green 0.52-0.60 um, red0.63-0.69 um, and near-infrared 0.76-0.90 urn). Correlation and regression relationships were computed between spectral reflectance and percent soil, rock, and vegetative cover; percent runoff; and eroded sediments. Highly significant correlations were measured between vegetative cover and percent runoff; relationships with soil-rock cover and eroded sediment were poorly correlated. The normalized difference vegetation index (NDVI) was the best predictor of percent vegetative cover, with shrubs-forbs being most strongly correlated to reflectance. The regression relationships between 1984 and 1994 spectral reflectance and vegetative cover were very different, even though cover percentages were similar. The amount of standing live and dead biomass and the proportion of green biomass strongly affect spectral reflectance, and the 1984 and1994 conditions were quite different spectral.
Thesagro:	Sensoriamento Remoto Espectrometria Cobertura do Solo
NAL Thesaurus:	Reflectance spectroscopy Rainfall simulation
Keywords:	Simulação de chuva Semiarido
Type of Material:	Artigo de periódico
Access:	openAccess
Appears in Collections:	Artigo em periódico indexado (CPAC)