02649naa a2200241 a 450000100080000000500110000800800410001902400350006010000160009524501560011126000090026752018880027665000220216465000240218665000240221065000220223465000210225665000180227765000090229570000170230470000160232177300700233718713962017-08-03       2011    bl uuuu     u00u1 u    #d7 a10.1007/s11104-010-0559-z2DOI1 aKASCHUK, G.  aQuantifying effects of different agricultural land uses on soil microbial biomass and activity in Brazilian biomesbinferences to improve soil quality.  c2011  aMaintenance of soil quality is a key component of agriculture sustainability and a main goal of most farmers, environmentalists and government policymakers. However, as there are no parameters or methods to evaluate soil quality directly, some attributes of relevant soil functions are taken as indicators; lately, an increase in the use of soil microbial parameters has occurred, and their viability as indicators of proper land use has been highlighted. In this study we performed a meta-analysis of the response ratios of several microbial and chemical parameters to soil disturbance by different land uses in the Brazilian biomes. The studies included native forests, pastures and perennial and annual cropping systems. The introduction of agricultural practices in all biomes covered previously with natural vegetation profoundly affected microbial biomass-C (MB-C)?with an overall decrease of 31%. Annual crops most severely reduced microbial biomass and soil organic C, with an average decrease of 53% in the MB-C. In addition, the MB-C/TSOC (total soil organic carbon) ratio was significantly decreased with the transformation of forests to perennial plantation (25%), pastures (26%), and annual cropping (20%). However, each biome reacted differently to soil disturbance, i.e., decreases in MB-C followed the order of Cerrado&gtAmazon&gtCaatinga&gtAtlantic Forest. In addition, the Cerrado appeared to have the most fragile soil ecosystem because of lower MB-C/TSOC and higher qCO2. Unfortunately, the Cerrado and the Amazon, demonstrated by our study as the most fragile biomes, have been subjected to the highest agronomic pressure. The results reported here may help to infer the best land-use strategies to improve soil quality and achieve agriculture sustainability. The approach can also be very useful to monitor soil quality in other tropical and subtropical biomes.  aMicrobial biomass  aSoil microorganisms  aSoil organic matter  aComposto organico  aMateria organica  aMicrobiologia  aSolo1 aALBERTON, O.1 aHUNGRIA, M.  tPlant and Soil, The Haguegv. 338, n. 1-2, p. 467-481, Jan. 2011.