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.

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.

O preparado de raízes finas noduladas de feijão-caupi é uma alternativa de inoculação com estirpes que realizam a fixação biológica de nitrogênio de comunidade microbiana localmente adaptada às condições de clima e solos, bem como, às variedades locais. Esse trabalho avaliou o efeito da inoculação a partir de um preparado de raízes finas sobre o crescimento vegetativo do feijão-caupi, em comparação a inoculação comercial, adubação com ureia e suas combinações. O delineamento usado foi inteiramente ao acaso com quatro repetições e os seguintes tratamentos: T1- Testemunha (sem inoculação e adubação nitrogenada); T2- Inóculo com raízes; T3- Inóculo comercial; T4- Inóculo com raízes + adubação nitrogenada em cobertura; T5- Inóculo comercial + adubação nitrogenada em cobertura e T6- Adubação nitrogenada em cobertura. O tratamento inóculo com raízes + adubação nitrogenada em cobertura (T4) proporcionou maior comprimento radicular (57,25 cm) comparado ao tratamento com adubação nitrogenada em cobertura (T6) com42,00 cm. Para o número de nódulos aos 48 DAE, verificou-se que a inoculação com raízes (T2) foi superior a testemunha (T1) e a adubação nitrogenada em cobertura (T6). Os menores valores para o índice SPAD ocorreram na testemunha (40,25 g kg-1) e na adubação com ureia em cobertura (40,55 g kg-1). O tratamento com adubação nitrogenada em cobertura (20 kg ha-1 de ureia) implicou em menor crescimento da raiz e da parte aérea, número de nódulos, massa seca da parte da planta e índice SPAD. O uso da inoculação com raízes é uma alternativa viável para o agricultor familiar e produtores de base agroecológica, porém precisa ser avaliada em campo.

Integrated systems (crops, livestock, and forest) are tools to avoid increases in greenhouse gas (GHG) emissions, such as CO2, CH4, and N2O. The objective of this study was to evaluate the GHG emissions and soil biological and chemical characteristics in an integrated system. The experiment was carried out in an area with crop-livestock-forest integration systems (CLFI), in Pindaré-Mirim, state of Maranhão, Brazil. The treatments consisted of maize (Zea mays) intercropped with forage (Urochloa brizantha cv. Marandú) between eucalyptus trees (Eucalyptus urophylla × Eucalyptus tereticornis) (S1); maize intercropped with forage (Megathyrsus maximus cv. Massai) (S2); and degraded pasture areas with no soil or forage management for more than 14 years (S3), which was used as reference treatment. The experiment was conducted with four replications of four trenches for soil collection or four static chambers for gas flow assessments. The GHG emissions were collected by static chambers and analyzed by gas chromatography, and the soil quality was determined by chemical analysis. The interaction between GHG emissions and soil characteristics was assessed for each treatment, using multivariate analysis and PCA. The soil of the degraded pasture presented higher GHG emissions. The integrated systems presented negative methane fluxes, which denote their mitigating effect on GHG emissions. The CLFI system with eucalyptus and maize intercropped with U. brizantha cv. Marandú was the best option to improve the soil biological characteristics and mitigate GHG emissions. Crop-livestock-forest integration with Eucalyptus, maize, and U. brizantha cv. Marandú is indicated to improve soil biological characteristics and mitigate GHG emissions in the Amazonian region of the state of Maranhão, Brazil.