Hidrologia em domínio colinoso associado à Argissolo Vermelho Distrófico Abrupto na Estação Experimental de Pesquisa de Erosão / Assentamento Fazenda Engenho Novo (EEPE/AFEN) – município de São Gonçalo/RJ

Abstract

The physical characteristics of Argisols naturally promote hydraulic discontinuity along the profile, making it susceptible to water erosion and the occurrence of lateralized flows. In this sense, the use of vegetation cover for soil and water conservation is relevant, especially in agricultural areas, as it contributes to the protection of the soil against the direct impact of raindrops and for greater stability of aggregates. In addition, the action of root systems contributes to the formation of biopores, increasing water infiltration rates and contributing to the reduction of erosion losses and surface runoff. This research was carried out at the Experimental Station for Research on Erosion/Establishment Fazenda Engenho (EEPE/AFEN), a region that can be considered a pole of family farming in the city of São Gonçalo/RJ. This work had as general goal to analyze the hydrological behavior in an area of Abrupt Dystrophic RED ARGISOL located in a hilly domain submitted to different managements and uses. The monitoring of matrix potentials was carried out using tensiometers with a mercury manometer installed at depths of 20, 30 and 100cm in three erosion plots: a) T0 – bare soil; b) T1 – soil covered with cassava (Manihot esculenta Crantz) and tropical cudzu (Pueraria phaseoloides); c) T2 – soil covered with cassava, tropical kudzu and pigeon pea (Cajanus cajan). The precipitation monitoring was carried out daily using the Ville de Paris pluviometer. The results of the chemical analyzes were compared with data obtained in the same area in 2014 and revealed that the bare soil had the worst results in practically all the analyzed parameters (pH, organic carbon, phosphorus, potassium, calcium + magnesium, aluminum, V value and m value, as well as the most significant losses over five years), indicating a process of soil degradation in the treatment without vegetation cover. On the other hand, in the installments where vegetation cover was used, the results indicate a process of system regeneration. As for the hydrological behavior, it was evidenced that in the T0 plot at all depths the variations of the matrix potentials were always smaller, when compared to T1 and T2. At a depth of 20 cm, the best drainage conditions were observed in all treatments, especially in T1 and T2. At a depth of 30 cm, greater drainage difficulties were observed. Anyway, the best results were obtained in T1 and T2. At a depth of 100 cm, the values of matrix potentials in the three plots remained close to the saturated condition throughout practically the entire period. The total load data showed that the T0 plot presented equal total loads over several days, indicating the occurrence of lateral flow for a longer period, while in T1 and T2 the same behavior was not observed.