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The degraded areas in Southern Brazil are undergoing rapid conversion from abandoned fields into agroforestry system. Our focus was to investigate the impact of land use and soil properties on soil fauna and quality in an agroforestry system and a natural ecosystem. The agroforestry system had the presence of Cicadidae (0.1 ind trap−1), Diplura (0.01 ind trap−1), Gryllidae (0.2 ind trap−1), Gyrinidae (0.07 ind trap−1), and Larvae (0.3 ind trap−1), and it presents lower SOC (less 44.3%) and higher total N (more 29.8%) and P contents (more 68.8%) when compared with the natural ecosystem. Richness and diversity declined (less than 16.3 and 31.8%, respectively) with increasing soil pH. Natural ecosystem showed the greatest diversity (H' = 2.44) of soil fauna. A negative correlation was observed between diversity and soil pH (−0.91), and positive correlations among diversity and SOC (0.97), richness (0.88), and dominance (0.93). In conclusion, fauna abundance, precipitation, and soil pH played essential roles in soil quality through ecosystem services, habitat, and energy provision, which in turn promoted the entire soil food web. Thus, the findings in the agroforestry system and natural ecosystem help us to understand how land uses impact soil fauna, and soil quality. [ABSTRACT FROM AUTHOR]

Oil palm agroforestry systems associated with conservation management practices have been proposed as a more sustainable alternative to monoculture. We examined whether oil palm agroforestry systems (less and more diversified) under conservation management contribute to improving soil fertility (an indicator of soil sustainability), using a secondary forest fragment as a reference. We analyzed the effects of the agroforestry systems and the secondary forest on the following variables in the arable layer (0–20 cm) and in the layers along the soil profile (0–5, 5–10, 10–20, and 20–30 cm): active acidity (pH), calcium (Ca), magnesium (Mg), potassium (K), phosphorus (P), aluminum (Al), organic matter, potential acidity (H + Al), potential cation-exchange capacity (CEC), effective cation-exchange capacity (ECEC), Al saturation (AS), and base saturation (BS). Overall, soil acidity was lower in the agroforestry systems than in the forest, in all layers. In the arable layer, the pH, Ca, Mg, K, P, and BS values were higher in the agroforestry systems than in the forest. Liming, inorganic and organic fertilization, and the maintenance of organic matter on the soil may have contributed to improving soil fertility in the oil palm agroforestry systems. Our results suggest that, in the eastern Amazon, oil palm growing in agroforestry systems associated with conservation practices can contribute to the maintenance of soil fertility at adequate levels for the species cultivated in these systems. [ABSTRACT FROM AUTHOR]

Tree cultivation spacing can influence productivity and wood quality, with silvicultural, technological and economic implications. This study aimed to estimate the production and provide an economic analysis of Eucalyptus urophylla × Eucalyptus grandis stands as a function of planting spacing in a small rural property. The study was carried out in the Zona da Mata of Minas Gerais state, with the hybrid clone (GG100) established in 2 × 1 m, 2 × 2 m, 3 × 2 m and 3 × 3 m spacing. Inventories were carried out at 14, 54 and 84 months in four plots from each spacing, with 24 plants. Diameter at breast height (DBH), total height and survival rate were evaluated. The study evaluated the logistic model of growth and yield for the different spacings and analysed production costs, characterising the expenditure elements related to inputs and labour. For the economic analysis, we considered a discount rate of 8% p.a. and the valuation methods of net present value (NPV), annual equivalent value (AEV), average production cost (APC), and cost–benefit ratio (CBR). Spacing influenced diameter distribution, tree height and productivity. The optimal harvest age showed a tendency to decrease in smaller spacing. The increase in plant density (smaller spacing) did not promote a proportional increase in volumetric production. Our results indicated economic viability from 60 months onwards for all spacing, except for 2 × 1 m. [ABSTRACT FROM AUTHOR]

The stock of biomass and nutrients has been the basis of many studies in the forest area, mainly those that evaluate the nutritional sustainability of the system. The objective of the present work was to evaluate the biomass and nutrients for the hybrid Eucalyptus urograndis and Acacia mearnsii in monospecific and mixed-species stands at the age of 9 years. For this, the study was carried out in an experimental area in South of Brazil, with three treatments: 100% E. urograndis; 100% A. mearnsii; 50% E. urograndis + 50% A. mearnsii. The hybrid E. urograndis showed lower stemwood in mixed-species planting (105.8 Mg ha−1) when compared to monospecific planting (145.5 Mg ha−1), however A. mearnsii, which increased stemwood at planting (213.9 Mg ha−1) relating to its pure planting (143.6 Mg ha−1). The nitrogen concentration in the leaves and stembark (25 and 5 g kg−1, respectively) of A. mearnsii was significantly higher than that found in the respective hybrid E. urograndis components (18 and 3 g kg−1 for leaves and stembark, respectively). A. mearnsii had higher accumulation of biomass and nutrient accumulation in the mixed-species plantation when compared to its monoculture, and the inverse was observed for the hybrid E. urograndis, thus showing that mixed-species planting exerted a competition effect on eucalyptus. [ABSTRACT FROM AUTHOR]