Intense soil preparation and disturbance in crops, over time, reduces the quantity and quality of soil organic matter. Given this context, this work aimed to determine soil carbon stocks and labile fractions under agroforestry system (AFS) and toposequences in an altitude marsh, Taquaritinga do Norte, Pernambuco, Brazil. The study was carried out at the Yaguara farm, and the areas studied were native forest with 4.57 ha and coffee plantation in shade with native forest with 25.59 ha. Soil samples were collected in four trenches measuring 1.5 x 1.5 x 0.60 m, with a distance of 50 meters. Soils were collected at depths of 0–20, 20–40 and 40-60 cm, followed by chemical, physical and density analyzes to determine soil carbon stocks and labile fractions. The area with shaded coffee showed higher values ​​of soil carbon stocks at depths of 0-20 cm and 20-40 cm. At a depth of 40-60 cm, the AFS top toposequence showed the highest carbon stock with 11.73 Mg ha-1, followed by the area with native vegetation with 10.6 Mg ha-1, slope with 9.23 Mg ha-1 and pediment with 7.00 Mg ha-1. It was found that the top toposequence with shaded coffee exhibited a greater stock of labile carbon at depth 0-20 cm with a value of 1.06 Mg ha-1, followed by the bedding areas (SAF) with 0.88 Mg ha-1, native forest with 0.79 Mg ha-1 and slope with 0.67 g kg-1. However, the area of native vegetation showed the highest value of labile carbon at a depth of 40-60 cm. It was concluded that the area with shaded coffee in the top toposequence showed great capacity to increase total carbon stocks and labile carbon stocks of soil organic matter.

The present work aimed to quantify the concentrations and biomass stock of fine andthick roots, in three areas in the municipality of Capitão Poço-PA, Brazil. The areas used were degraded area, recovery area and native forest. For soil sampling, 24 trenches were opened, measuring 70 x 70 x 100 cm. In these trenches, soil samples were taken at depths 0-10, 10-20, 20-30, 30-40, 40-50, 50-60, 60-80 and 80-100 cm and sieving was carried out.All roots and other underground plant structures that remained in the sieve were collected by manual collection. The roots were separated into two diameter classes: fine roots ≤ 5 mm and thick roots > 5 mm, kiln dried and weighed.In the analysis, higherconcentrationsofthickand fine roots were observed in an area of native forest at depths of 0-10 and 10-20 cm. In the areas analyzed in this study, the root density in the topsoil of 0-10 cm was mainly composed of fine roots.In the three areas analyzed in this study, it was observed that from a depth of 10-20 cm there were decreases in theconcentrationsofthick roots. The area under recovery approached the area of native forest in the concentration of fine roots, demonstrating possible improvements in soil quality and recovery is probably actually taking place.

Through sustainable agriculture it is possible to explore the coffee culture in consortium with native forests in more rugged reliefs, as coffee is a permanent crop in addition to the climatic conditions offered by the swamps that favor its development. Given the above, the present work proposes, based on the acidity results, to quantify  the need for correctives in the soil to obtain a better nutritional use offered by agroforestry cultivation of organic coffee in the shade with favorable results to increase productivity and, consequently, the farmer's profit. The research was carried out at the Várzea da Onça farm, in the Yaguara Ecological Complex, located in the municipality of Taquaritinga do Norte, Borborema plateau, in the Agreste Pernambuco mesoregion. Altitude, it is necessary to adopt appropriate management techniques that guarantee production, soil conservation and biodiversity, proposing soil correction to guarantee the ideal nutritional conditions for coffee growth. For this purpose, soil samples were collected in the Top (T), Hillside (E) and Pedimento (P) ranges at depths of 0-20, 20-40 and 40-60 cm when planting shaded coffee and soil samples from Native Forest (MN) preserved and legally protected from the Brejo de Taquaritinga. Active, exchangeable and potential acidity were analyzed, as well as the sum of bases, the potential and effective cation exchange capacity, base saturation and aluminum saturation. The results obtained were subjected to analysis of variance and the means were tested at 5% by the Tukey test. A potential of the system was found with low to very low natural fertility, with a strongly acidic reaction. Thus, adequate soil management and correction techniques are necessary for the crop to absorb all the nutrients made available by the organic matter present on the surface, concluding that all slopes require liming, the slope of Hillside and Mata Nativa they also need plastering for the culture to develop properly.