Relationships between Agriculture, Riparian Vegetation, and Surface Water Quality in Watersheds

Tiago Broetto,Carlos Gustavo Tornquist,Ben-Hur Costa De Campos,Júlio Cézar Schneider

doi:10.1590/18069657rbcs20160286

Abstract

ABSTRACT Agricultural land use and degradation of natural vegetation in riparian zones can impair water quality. This study was conducted in seven agricultural watersheds in Ibiruba, RS, Brazil, with the following objectives: identify relationships between concentrations of soluble phosphorus (Psol) and nitrate (NO−3) in surface water and agricultural use of soil and current vegetation in riparian zones, and assess the risk of eutrophication. Water samples from the main watercourses in each watershed were collected monthly from 10/2013 to 6/2014. Current [...]

Highlights

Human population growth and the increased demand for food has led to expansion and intensification of agricultural production in Brazil, one of the few countries with large non-agricultural areas that could be converted to cropland (Conab, 2015; IBGE, 2015)
Nitrate concentrations were highest in W6 watershed, whereas Psol was highest in W1 and W5 watersheds on 50 % of the sampling dates
Psol concentrations did not differ from those observed in other watersheds

Summary

Introduction

Human population growth and the increased demand for food has led to expansion and intensification of agricultural production in Brazil, one of the few countries with large non-agricultural areas that could be converted to cropland (Conab, 2015; IBGE, 2015). In several cases, this context has encouraged farmers to expand into environmentally fragile areas, often with disregard for conservation of natural resources. Grain production is mainly conducted under the no-tillage system (NT), which in its original definition precludes tillage operations. Farmers that adopted no-tillage have removed terraces to facilitate farm equipment operations, ignoring that these auxiliary conservation practices are still required to avoid soil, water, and nutrient losses (Denardin et al, 1999; Gilles et al, 2009)

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