THE DYNAMICS OF THE SUBSTRATE RECOVERY OF WASTE DUMPS IN CALCARY MINING UNDER NATURAL REGENERATION

<div><p>ABSTRACT This study aimed to evaluate the dynamics of the physical and chemical recovery of the substrates of waste dumps of different ages undergoing natural regeneration, in a calcary mining in Salto de Pirapora - SP, Brazil. Characterization of the vegetation, vegetation and physical and chemical cover of the substrates of the abandoned waste dumps since 1994 and 2013 and the soil of a native forest fragment adjacent to the mining was carried out. Twelve plots of 10x10m were allocated in each environment. It was verified that the soil cover rate with herbaceous, grassy, regenerating and litter of the sterile stacks are similar to the native forest fragment. The same was observed for the physical characterization of soil resistance to penetration, soil moisture content and relative light index. For the chemical characteristics, in all areas sampled there is aluminum deficiency which, consequently, presented low potential acidity and alkaline pH. The CEC of the substrates of the waste dumps presented values similar to the CEC of the native forest fragment, with abundance in some essential nutrients, indicating the possibility of vegetation development in the sterile stacks and the contribution of the natural regeneration to the substrates. Thus, the plant-soil relationship via natural regeneration in the sterile piles contributed to the improvement of the edaphic quality of the substrates over time, being a potential form of recovery in calcary mining. Thereby, the Fabaceae predominated on the waste dumps, especially Leucaena leucocephala, which, despite being an exotic species, is relevant for the current recovery stage of the substrates.</p></div

SURFACE RUNOFF OF RAINFALL IN AN EXPERIMENTAL PLANTATION OF MACAÚBA PALM (Acrocomia aculeata) UNDER DIFFERENT FORMS OF MANAGEMENT

<div><p>ABSTRACT Several studies have been conducted aiming to explore the commercial potential of the macaúba palm. However, research on the hydrological processes of this crop are scarce. Thus, we aimed to quantify the surface runoff in a macaúba plantation subjected to different crop management techniques, from September 2012 toAugust 2013. We established 10 plots for surface runoff quantification; each plot had a 63-m² area, was delimited by metallic foils and had a gallon to collect runoff water at its outlet. Plots consisted of three treatments and three repetitions, plus one control plot, each having four macaúba plants. Treatments were as follows: treatment one (T1) - with no soil conservation technique being implemented; treatment two (T2) - with a narrow-base terrace 40 cm wide and 30 cm deep; treatment three (T3) - with bean being planted during the rainy months, forming vegetation strips; and control treatment (T0) - with no macaúba plants, with spontaneous vegetation growing throughout the entire plot and with no soil conservation technique being implemented. Surface runoff differed among treatments. T2 was the treatment with lowest runoff and also the one that demanded the highest precipitation volume for surface runoff to occur. Our results indicate that both the cover and the use of soil conservation techniques are closely related to surface runoff, which in turn affects the occurrence of erosion and infiltration.</p></div