Abstract. Hydrological studies in small basins are essential for investigating the role of distinct processes on water resources conservation and to assess the impact of the natural ecosystems on improving water security especially in semiarid environments. In Brazil, the cooperative hydrological Network REHISA (“REde de HIdrologia do SemiÁrido”) comprises hydrologists from several universities of Brazil, focusing on field measurements, monitoring and modeling activities in well instrumented experimental rural catchments located at different regions and biomes in Semiarid environment. Water scarcity is a common aspect among the catchments, as well as risks of soil and water degradation. The objective of this work is to present assessments of near surface soil moisture spatial-temporal distribution, and to evaluate the impact of soil conservation techniques in reducing runoff, using small-scale experimental plots in a representative catchment of the Pernambuco State, Brazil. The study catchment is located in Alto Ipanema River Basin (AIRB) (with an area of 150 km2), which is located at the semiarid region of the São Francisco River (area of 641 000 km2). Soil and water monitoring was performed in experimental plots with different soil cover conditions (Bare soil plots; Plots with natural cover – Caatinga Biome vegetation; Plots with cactus Palma barriers; and Plots with mulch cover – Dry grass mulch at 4 t ha−1), where probes were installed for high resolution soil moisture assessment. In addition, regular soil moisture monitoring campaigns were conducted at 7 different locations, using a capacitance probe, with arboreal and shrub Caatinga vegetation, pasture and bare soil, predominantly Brachiaria decumbens. Mulch cover runs close to the Caatinga cover, but still with higher runoff generation, and presenting lower soil moisture temporal mean values. Caatinga was highly effective in terms of soil and water conservation at the small basin scale for both the dry and the wet season, resulting in a positive nexus between vegetation and water availability at the region.

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As técnicas conservacionistas são altamente relevantes para o uso sustentável do solo, especialmente em regiões do semiárido. O objetivo deste estudo foi investigar o impacto de técnicas conservacionistas na redução das perdas de sedimentos e no incremento da umidade do solo, utilizando parcelas sob chuva natural. O estudo foi realizado na Bacia do Rio Alto Ipanema, Brasil. O monitoramento experimental foi realizado em nove parcelas com diferentes condições de cobertura (solo descoberto; cobertura natural; cobertura morta; Palma Forrageira). A cobertura morta apresentou desempenho semelhante à cobertura vegetal arbórea natural, para controle de escoamento e perdas de sedimentos. A umidade do solo foi signifi cativamente maior nas parcelas com cobertura morta do que nas parcelas de solo descoberto. Adicionalmente, as linhas de Palma produziram resultados hidrológicos promissores. Experimentos complementares em laboratório, com chuvas simuladas, apresentaram resultados consistentes com as observações em campo, sob chuva natural.