期刊
EARTH SURFACE PROCESSES AND LANDFORMS
卷 40, 期 11, 页码 1524-1532出版社
WILEY
DOI: 10.1002/esp.3738
关键词
deforestation; infiltration; runoff; soil and water conservation; USLE
资金
- Fundacao de Amparo a Pesquisa do Estado de Sao Paulo -FAPESP [10/18788-5, 11/14273-3, 12/03764-9]
- Conselho Nacional de Desenvolvimento Cientifico e Tecnologico - CNPq [470846/2011-9]
- Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [12/03764-9] Funding Source: FAPESP
The Brazilian savanna (cerrado) is a large and important economic and environmental region that is experiencing significant loss of its natural landscapes due to pressures of food and energy production, which in turn has caused large increases in soil erosion. However the magnitude of the soil erosion increases in this region is not well understood, in part because scientific studies of surface runoff and soil erosion are scarce or nonexistent in the cerrado as well as in other savannahs of the world. To understand the effects of deforestation we assessed natural rainfall-driven rates of runoff and soil erosion on an undisturbed tropical woodland classified as 'cerrado sensu stricto denso' and bare soil. Results were evaluated and quantified in the context of the cover and management factor (C-factor) of the Universal Soil Loss Equation (USLE). Replicated data on precipitation, runoff, and soil loss on plots (5 x 20m) under undisturbed cerrado and bare soil were collected for 77 erosive storms that occurred over 3 years (2012 through 2014). C-factor was computed annually using values of rainfall erosivity and soil loss rate. We found an average runoff coefficient of similar to 20% for the plots under bare soil and less than 1% under undisturbed cerrado. The mean annual soil losses in the plots under bare soil and cerrado were 12.4 t ha(-1) yr(-1) and 0.1 t ha(-1) yr(-1), respectively. The erosivity-weighted C-factor for the undisturbed cerrado was 0.013. Surface runoff, soil loss and C-factor were greatest in the summer and fall. Our results suggest that shifts in land use from the native to cultivated vegetation result in orders of magnitude increases in soil loss rates. These results provide benchmark values that will be useful to evaluate past and future land use changes using soil erosion models and have significance for undisturbed savanna regions worldwide. Copyright (C) 2015 John Wiley & Sons, Ltd.
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