Time-stability of soil water content (SWC) in an Atlantic Forest - Latosol site

Abstract

Time-stability of the soil water content (SWC) under influence of a native forest has great interest, however, it has been little scientifically explored in tropical and subtropical regions. This study aimed to monitor in a systematic way the SWC at soil depth to analyze its space-time variability and time-stability under conditions of an Atlantic Forest remnant, a native environment of southeastern Brazil. Time-stability was monitored at five soil depths (0.10 m, 0.20 m, 0.30 m, 0.40 m and 1.0 m), analyzing the statistical dispersion measures (SDM). Based on SDM, we also aimed to infer about the time-stability locations that are most representative for the study site. The sampling effort for SWC comprised a monthly recording time step at 32 points in the site from June/2013 to January/2016. We observed a decrease in the variability of the following SDM with increase of soil depth: mean relative difference (δij), standard deviation and Temporal Stability Indicator (TSI). It was possible to infer that local topographic elements induced the time-stability. It was not possible to select only one location representative for SWC since the statistical criteria did not adequately converge for all soil depths at the same location. However, the point locations selected for each depth produced adequate statistics of validation. We were able to identify the relation between the points and the landscape representation indicators, which can help in the endeavor of identification of point locations which are more stable and the time-stability of SWC in a native forest site.