Conversion to soy on the Amazonian agricultural frontier increases streamflow without affecting stormflow dynamics

TitleConversion to soy on the Amazonian agricultural frontier increases streamflow without affecting stormflow dynamics
Publication TypeJournal Article
Year of Publication2011
AuthorsHAYHOE, SHELBY J., Neill Christopher, PORDER STEPHEN, MCHORNEY RICHARD, LEFEBVRE PAUL, COE MICHAEL T., Elsenbeer Helmut, and Krusche Alex V.
JournalGlobal Change Biology
Volume17
Pagination1821 - 1833
Date Published05/2011
KeywordsAmazon, baseflow, Hydrology, land use change, soybean cultivation, water yield
Abstract

Large-scale soy agriculture in the southern Brazilian Amazon now rivals deforestation for pasture as the region’s predominant form of land use change. Such landscape-level change can have substantial consequences for local and regional hydrology, but these effects remain relatively unstudied in this ecologically and economically important region. We examined how the conversion to soy agriculture influences water balances and stormflows using stream discharge (water yields) and the timing of discharge (stream hydrographs) in small (2.5–13.5 km2) forested and soy headwater watersheds in the Upper Xingu Watershed in the state of Mato Grosso, Brazil. We monitored water yield for 1 year in three forested and four soy watersheds. Mean daily water yields were approximately four times higher in soy than forested watersheds, and soy watersheds showed greater seasonal variability in discharge. The contribution of stormflows to annual streamflow in all streams was low (