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Management systems that include trees tend to provide higher amounts of plant biomass to the soil, contributing to the increase in carbon (C) and nitrogen (N) stocks. This study simulated C and N stocks and their compartments in a crop-livestock-forest integration system in the edafoclimatic conditions of the Maranhão Cerrado using the Century 4.5 model. The evaluated areas were native Cerrado vegetation (NV) and crop-livestock-forest integration (CLFI). The calibration process gradually modified the model parameters to better fit the simulated and observed soil C and N stocks. The best fit between the data was obtained after changes in the main parameters (DEC3(2), DEC4, and DEC5) that controlled the rate of decomposition of soil organic matter. C and N stocks increased by 14% and 15%, respectively, over 14 years after replacing NV with CLFI. The slow compartment of C presented greater sensitivity to changes in management, with an increase of 47% compared with that of NV. The active compartment increased by 31% and the passive compartment remained constant for over 14 years. Future scenarios, where pasture was maintained between the eucalyptus trees and the scenario that allowed the soybean, corn, and Brachiaria rotation between the trees, were more effective, accumulating approximately 37 Mg C ha-1. The continuous contribution of residues from the trees and pasture increased C and N stocks in the long-term in the slow fraction, where the total organic carbon increased from 32 to 36 Mg ha-1 when NV was replaced with CLFI. The model predicted the C and N stocks with accuracies ranging from 1 to 11% of the observed values. [ABSTRACT FROM AUTHOR]

The soil fauna is one of the bioindicators of soil quality that has greater sensitivity, being easily altered by changes that occur in natural and agricultural ecosystems. The objective of this work was to evaluate the density and diversity of the soil macrofauna and the functional groups of the epigeal macrofauna that are most representative in no-tillage, pasture, eucalyptus cultivation and native savanna systems in Uruçuí, Piauí, Brazil. Five soil management systems were used: pasture (PAS); no tillage soybean in corn straw (NT1); no tillage of corn under straw of mombaça grass (NT2); eucalyptus (EUC), in addition to a savanna area used as a reference (FA). Fauna collection was performed using pitfall traps containing 4% formaldehyde. The fauna was evaluated by the number of individuals per trap per day, wealth, average wealth, Shannon's diversity index and Pielou's uniformity index. The data was subjected to analysis of variance, and when significant, was subjected to the Friedman test. The pasture system had the least impact on edaphic fauna when compared to native savanna forest and when compared to management systems and the collembola, orthoptera and diptera groups were the most abundant in the studied management systems. [ABSTRACT FROM AUTHOR]

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The implementation of integrated agricultural production systems is considered a promising strategy for sustainable agricultural intensification in Brazil. This study aimed to evaluate the effects of different monoculture and integrated production systems on the microbiological attributes and organic carbon of soil from the Cerrado region in Piauí, Brazil. Soil samples were collected from the 0.0-0.10-m layer in the following systems: no-tillage (PD), pasture (PAS), exclusive eucalyptus cultivation (CEE), integrated livestock-forest system (IPF) and a native Cerrado (CN) area, which was used as reference. Total organic carbon (TOC) and nitrogen (NT) contents, microbial biomass carbon (CMIC), microbial respiration (MR), microbial quotient (qMIC), metabolic quotient (qCO2), as well as the activities of the hydrolysis of fluorescein diacetate (FDA), acid phosphatase, β-glucosidase and urease enzymes were evaluated. High TOC contents were found in the CEE, IPF and PAS systems, and high CMIC and qMIC values were found in the CN and CEE systems. The variables MR, qCO2 and enzymatic activity varied as a function of the management systems. The IPF and CEE systems caused improvements in the soil attributes, with increases in organic carbon and microbial biomass. The IPF integrated production system promoted improvements in the microbiological indicators of soil quality and was considered an environmentally sustainable agricultural production system. The transition from CN to agricultural areas caused changes in the soil microbiological indicators, which were perceived several years after anthropogenic intervention, indicating that even with the adoption of conservation systems, it was not possible to reestablish the soil microbial biomass. [ABSTRACT FROM AUTHOR]