Spatial-temporal soil-water content dynamics in toposequences with different plant cover in a tropical semi-arid region

Resumo

Anthropogenic effects on the natural environment and on soil moisture in the tropical semi-arid region have not yet
been determined. As such, the temporal variability of soil moisture was investigated in two toposquences under different types of
plant cover: i) Caatinga under regeneration since 1978 (CReg); ii) Caatinga thinned by 40% (CThn). The research was carried out
in two catchment located in the northeast of Brazil, with an area of 2.06 and 1.15 ha for CReg and CThn respectively. Soil moisture
was determined using the gravimetric method. Three random soil samples were collected daily from the upper, middle and lower
section of each catchment, giving a total of nine daily collections and 1620 collection in the period. CThn displayed higher values
and a longer period for soil moisture. The lower section of the catchment showed values for soil moisture that were higher and
statistically different (p < 0.05) from the other sections. The increasing value for the correlation between moisture and the seven
days of antecedent rainfall indicates a low rate of decrease for soil moisture.