In the face of the traditional model of succession of native environments in pastures or agricultural areas, followed by superpastejo and the concern with emissions of greenhouse gases in the Brazilian Amazon region, this work aims to determine the influence of different land uses on carbon sequestration and soil organic matter changes in the municipality of Pindaré-Mirim, in state of Maranhão. This study evaluated different uses of the soil: native forest; secondary vegetation (capoeira); degraded pasture and CLFI (Crop-Livestock-Forest Integration) system. The deformed and undisturbed samples were collected at depths: 0.00-0.10, 0.10-0.20, 0.20-0.30, 0.30-0.40, 0.40-0.60, 0.60-0.80 and 0.80-1.00 m. Soil densities were determined by the volumetric ring method, the carbon stocks by the carbon content in the soil evaluating the dry combustion, and the accumulated carbon stocks were calculated in 1.00 m. The physical fractions of the organic matter were determined by means of the granulometric method. At depth 0.0-0.10 m, the soil density in the native forest (1.17 g cm -3 ) was lower than the average of degraded pasture (1.40 g cm -3). There was no difference in the carbon content between all the land uses up to 0.40 m depth. The accumulated carbon stocks up to 1.00 m ranged from 49.52 Mg ha -1 to 64.41 Mg ha -1 and were higher in the native forest compared to capoeira and the ICLF system. In relation to the accumulated carbon stock, the native forest and degraded pasture were the ones that obtained the highest levels, followed by the capoeira and the CLFI system.

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The sustainability of ecosystems is closely linked with the assessment of soil properties that estimate their quality. This work proposes to evaluate soil chemical attributes as a function of the implantation of a crop-livestock-forest integration system (ICLF) in the region of Mata dos Cocais in the state of Maranhão, Northeast Brazil. The four different land uses evaluated were native vegetation with babassu, capoeira vegetation, degraded pasture and area under ICLF system (with marandu grass, maize and eucalyptus consortium). The samples were collected up to one meter deep, comprising seven layers: 0.00-0.10, 0.10-0.20, 0.20-0.30, 0.30-0.40, 0.40-0.60, 0.60-0.80 and 0.80-1.0 m. The chemical attributes evaluated were pH, Ca, Mg, Al, P, K and Na, potential acidity, base sum, base saturation and soil cation exchange capacity (CEC). The levels of P, in the 0.00-0.10 m layer, were higher in the ICLF system than those of the native forest with babassu. The levels of K in the ICLF system and degraded pasture were higher than the other land uses up to a depth of 0.40 m, ranging from 0.92 cmolc dm-3 to 0.62 cmolc dm-3 and 1.04 cmolc dm-3 and 0.67 cmolc dm-3, respectively. Base saturation was higher in soils under ICLF system and degraded pasture than those observed in native forest and capoeira vegetation. There was an effect in chemical attributes of the soil such as a function of land use and, in general, the highest values were found in areas with degraded pasture and ICLF.

The objective of this study is to estimate the production costs and profitability of corn cultivation in the setup phase of the crop-livestock-forest integration system for pasture recovery in the municipality of Pindaré-Mirim/MA, Brazil. The study was developed at the Technological Reference Unit (TRU) for the Integration of Crop-Livestock-Forest (ICLF) of Embrapa Cocais, located in the municipality of Pindaré-Mirim/MA, Brazil. Data collection occurred during the agricultural year 2015/2016. The management of the ICLF system was carried out following the molds of the "Santa Fé" technique. The cost of production was used to calculate the Total Operational Cost (TOC) and were extrapolated per hectare. For the economic analysis of corn production, three different prices were considered: (a) the price received by the producer; (b) the historical average of the last 30 months to the date of actual sale of the product; and (c) the minimum guarantee price of the federal government. The TOC was found to be US$ 1,672.72 per hectare. The economic efficiency indicators showed promising profit values, demonstrating that in this study with corn production in the 1st year, it would be possible to pay for the implementation of the ICLF system as an alternative for the recovery of degraded pasture.

The objective of this work was to evaluate the carbon content of the physical, chemical and oxidizable fractions of soil organic matter (SOM) and to calculate the carbon management index (CMI) in an area managed under an integrated crop-livestock system (ICLS) in the western region of Paraná - Brazil. The experiment was carried out at the experimental farm, belonging to the Universidade Estadual do Oeste do Paraná. Seventeen areas, which are managed in different ways, fifteen in ICLS and two areas of controls (Forest and Haymaking), using the design divided with two nested controls, with three replications were evaluated. Deformed and undisturbed soil samples were collected from all the areas to determine the total organic carbon (TOC), carbon stock, the physical, chemical and oxidizable fractions of SOM and the CMI in the layers of 0-0.05, 0.05-0.1 and 0.1-0.2 m. Little significant changes in the fractions were found for the management of the ICLS area in relation to the Forest and the area of Haymaking, although the Forest presented the best values for most of the studied fractions. It is recommended to adopt sustainable practices, such as ICLS, even though the average fractions tend to take time to match reference areas.

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Soil organic matter is degraded and easily altered by the type of management. The objective of this work is to determine the total organic carbon and humic substance fractions in the organic matter of the soil with different management types and depths in the western region of Paraná, Brazil. The work was carried out in the Experimental Farm "Professor Antônio Carlos dos Santos Pessoa", belonging to the State University of the West of Paraná. Five soil management systems were evaluated: one area with corn cultivation for silage (CS); other area with succession of crops, with soybean in summer and corn in winter (SC); the next area also with succession of crops, with soy in the summer and oat in the winter (SO); the following area with permanent pasture with Tifton (PP); and the last area with crop-livestock integration (ILC). For each management system, four plots were randomly selected, in each plot three simple samples were collected in a diagonal direction to form a composite sample for the depth of 0.00-0.05 m, 0.05-0.10 m and 0.10-0.15 m. Total organic carbon, fractionation of the humic substances and the AH/AF and EA/HUM ratios were calculated. For most of the analyzed variables, it was verified that there were significant differences (P < 0.05) between the systems evaluated in the studied depths. In the evaluated areas, the PP, SO and ILC systems presented the highest carbon content for all attributes analyzed.

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