Earthworm assemblages in different intensity of agricultural uses and their relation to edaphic variables

The objective of this study was to relate earthworm assemblage structure with three different soil use intensities, and to indentify the physical, chemical, and microbiological soil variables that are associated to the observed differences. Three soil uses were evaluated: 1-Fifty year old naturalized grasslands, low use intensity; 2-Recent agricultural fields, intermediate use intensity, and 3-Fifty year old intensive agricultural fields, high use intensity. Three different sites for each soil use were evaluated from winter 2008 through summer 2011. Nine earthworm species were identified across all sampling sites. The sites shared five species: the native Microscolex dubius, and the introduced Aporrectodea caliginosa, A. rosea, Octalasion cyaneum, and O. lacteum, but they differed in relative abundance by soil use. The results show that the earthworm community structure is linked to and modulated by soil properties. Both species abundance and diversity showed significant differences depending on soil use intensity. A principal component analysis showed that species composition is closely related to the environmental variability. The ratio of native to exotic species was significantly lower in the intensive agricultural system when compared to the other two, lower disturbance systems. Microscolex dubius abundance was related to naturalized grasslands along with soil Ca, pH, mechanical resistance, and microbial respiration. Aporrectodea caliginosa abundance was related to high K levels, low enzymatic activity, slightly low pH, low Ca, and appeared related to the highly disturbed environment. Eukerria stagnalis and Aporrectodea rosea, commonly found in the recent agricultural system, were related to high soil moisture condition, low pH, low Ca and low enzymatic activity. These results show that earthworm assemblages can be good indicators of soil use intensities. In particular, Microscolex dubius, Aporrectodea caliginosa, and Aporrectodea rosea, showed different temporal patterns and species associations, due to the changes in soil properties attributable to soil use intensity, defined as the amount and type of agricultural operations

Microbiological activity and carbon mineralization in pampean soils with different agricultural use intensity

ABSTRACT 1 The processes involved in the flows of matter and energy of terrestrial ecosystems depends 2 heavily on soil biological activity, the current conventional agricultural managements could alter 3 the biological mechanisms involved in decomposition and nutrient cycling in agroecosystems. 4 The aim of this study was to compare the activity levels and soil microbial biomass between 5 different agricultural pampean soil uses and its relationship to carbon mineralization. 25 years of 6 agricultural use were compared with 25 years of ecological reserve naturalized where each 7 agroecosystem soil were collected at 61 -125 -183 -236 -302 -368 -431 -488 days for 8 measuring their moisture, organic matter, enzymatic activity, microbial biomass carbon, soil 9 respiration, metabolic quotient, microbial quotient and carbon mineralization rate. The distance 10 between agroecosystems is less than 800 m, thus assuming the same soil and climatic conditions. 11 The data were evaluated by Friedman test finding significant differences in moisture, organic 12 matter, enzymatic activity, soil respiration y microbial quotient (p< 0.01). Difference was also 13 found in the microbial mineralization rate of carbon (p< 0.1). 14 KEY WORDS 15 Microbiological activity; carbon mineralization; soil use. 16 PeerJ PrePrints | https://doi.org/10.7287/peerj.preprints.1608v1 | CC-BY 4.0 Open Access

Trend in rifampicin-, multidrug- and extensively drug-resistant tuberculosis in Italy, 2009\u20132016

Tuberculosis (TB) caused by strains of Mycobacterium tuberculosis that are rifampicin-resistant (RR), multidrug-resistant (MDR) (strains resistant to at least isoniazid and rifampicin) or extensively drug-resistant (XDR) (MDR strains resistant to any fluoroquinolone (FQ) and to at least one second-line injectable drug (SLID): kanamycin, capreomycin or amikacin) is a major threat to TB control globally. All three groups require treatment with second-line drugs (SLDs). We previously reported that MDR- and XDR-TB in Italy occurred mostly in foreign-born persons (FBPs) , but no major information on RR, MDR or XDR trends in FBPs and Italian-born persons (IBPs) were shown. Here, we documented these trends from 2009 to 201