There has been an increase in the area of secondary tropical forests in recent years due to forest restoration in degraded areas. Recent analyses suggest that the success of passive forest restoration is highly uncertain and needs to be better understood. This study aimed to investigate the behavior of saturated hydraulic conductivity (Ks) and some hydrophysical soil attributes between agricultural land uses, restored forests, and a degraded forest fragment. The areas evaluated are located in the municipality of Rio Claro, São Paulo, Brazil, under different types of land use: (i) two areas in the process of passive forest restoration: one of 18 and another of 42 years (NR18 and NR42); (ii) a degraded forest fragment (FFD); (iii) pasture (P), and (iv) sugarcane (SC). The hydraulic soil conductivity characterization was performed using the Beerkan method. Dry soil bulk density (BD), total porosity (Pt), macroporosity (Mac), microporosity (Mic), penetration resistance (PR), mean aggregate diameter (MWD), and soil organic carbon (OC) were also determined. The comparative analysis of the hydrophysical attributes of the soil superficial horizon in agricultural land uses (P and SC), restored forests (NR18 and NR42), and a degraded forest (DFF) confirms that the recovery of soil hydrological functioning in ongoing forest restoration processes can be a relatively slow process. In addition, the intensity of previous land use leaves footprints that can affect passive restoration areas for decades after agriculture abandonment, increasing the time for the recovery of Ks and soil hydrophysical attributes.

The conservation of ecosystems has benefited from planted forests which provide reforested wood reducing the pressure on deforestation of natural forests. Soil physical attributes determine soil water storage capacity; therefore, they play an important role on plant roots’ development which may compromise plant’s survival. The study tested the influence of soil physical and water attributes on the survival of Eucalyptus spp. clones under dry tropical climate. Two areas were selected, including one with living plants and a second with non-living plants of Eucalyptus spp. clones. Moreover, five soil profiles were studied in each area and the parameters estimated were soil bulk density, total porosity, saturated hydraulic conductivity, soil water retention curve, pores size distribution, available water capacity, and S index. Soil physical and hydric attributes did not differ between the area with living plants and the one with non-living plants. The saturated hydraulic conductivity in the area surface layer was high for both the living plants and non-living palnts; 331 mm h-1 and 294 mm h-1, respectively. The S index (to give the value) indicated that the structure was suitable for the development of Eucalyptus trees. Furthermore, it was possible to affirm that soil physical and water attributes of the studied areas were promising for the cultivation of Eucalyptus spp. in the dry tropical climate.

Using the right spatial arrangement is a sustainable way to prevent or at least delay the emergence of weeds in the crop production. This study evaluated the influence of row spacing and plant density of maize on weed control based on the phytosociological survey. It was conducted on an Oxisol textured medium in a 400 m 2 area under semiarid conditions. The hybrid maize 30F53YH was managed under a no-till cropping system with three types of row spacing ( , and 8.0 plants m -2 ). The experimental design was randomized complete blocks with four replications in a factorial arrangement 3 × 3. The phytosociological survey of the weeds was randomly performed four times in each subplot, using the inventory square (0.5 m × 0.5 m). The collected data were analyzed using the R statistical program. Among the specimen's families identified on the field, three of them need to be highlighted due to its high values of density, frequency, and dominance. These families were Fabaceae, Poaceae, and Amaranthaceae. Also, it was identified that the Leucaena leucocephala species may be classified as a weed, as it acted as an invasive species on maize. The weed control was greatly influenced by the interaction of both parameters rather than only row spacing or the plant density factor. The results showed that the reduced spacing and high crop population decreased the presence of weeds in the maize crop.

A restauração florestal por meio da regeneração natural e a evolução do funcionamento físico-hídrico do solo Nayana Alves Pereira Tese apresentada para obtenção do título de Doutora em Ciências. Área de concentração: Solos e Nutrição de Plantas Piracicaba 2020 Nayana Alves Pereira Engenheira Agrônoma A restauração florestal por meio da regeneração natural e a evolução do funcionamento físico-hídrico do solo versão revisada de acordo com a resolução CoPGr 6018 de 2011