Soil conservation practices in a watershed in Southern Brazil

Abstract: The aim of this study was to determine how often rural farmers in a watershed use no-tillage systems combined with crop rotation, contour farming and agricultural terraces. The study area was Paraná Watershed III (PB3) in the western region of Paraná State, and data from the 2006 Agricultural Census of the Brazilian Institute of Geography and Statistics were used. A frequency distribution analysis of farms as a function of the no-tillage (NT) area was conducted in combination with a cluster analysis of soil and water conservation practices (adoption of crop rotation, contour farming and agricultural terrace practices). The results showed that the farms in PB3 adopt adequate soil and water conservation practices, with 73% adopting NT combined with at least 2 other conservation practices; however, agricultural terracing was found to be the most neglected practice in the region. In addition, based on the soil and water conservation practices in the watershed, 5 groups of farms were identified, the worst of which, those located in the municipalities that mainly neglect conservation practices, live in areas with highly erodible soils.

摘要：本研究旨在探明某流域内农村农户采用免耕（no-tillage, NT）系统结合轮作、等高耕作与农业梯田措施的实施频率。研究区域为巴拉那州西部的巴拉那流域III区（PB3），所用数据来源于巴西地理与统计研究所2006年农业普查。本研究以免耕面积作为变量开展农场频率分布分析，并结合轮作、等高耕作及农业梯田等水土保持措施的采用情况展开聚类分析。结果显示，PB3区域内的农场普遍采用了较为完善的水土保持措施，其中73%的农场采用免耕结合至少2项其他水土保持措施；但农业梯田是该地区最常被忽视的措施。此外，基于流域内水土保持措施的采用特征，研究共划分出5类农场群体，其中表现最差的群体主要分布于忽视水土保持措施的县域，其所在区域土壤极易发生侵蚀。