ABSTRACT.- Soybean (Glycine max (L.) Merr.), an economically relevant crop, establishes a symbiotic association with rhizobia to obtain nitrogen (N2) from the air by biological nitrogen fixation with important benefits. In Uruguay inoculants formulated with two strains, Bradyrhizobium elkanii U1301 and U1302, are recommended since 1984. Besides that, the study of native-naturalized rhizobia populations is relevant because these strains could compete with applied inoculants and may present a better symbiotic efficiency.

ABSTRACT.- The production of ethanol from biomass pursuant to the EU Renewable Energy Directive (2009/28/EC) requires an estimation of the levels of greenhouse gas (GHG) emissions from biofuels to assess the emissions savings in comparison to fossil fuels. Within this framework, the carbon footprint was estimated for four bioethanol cropping systems:a maize-wheat-sorghum rotation without the harvest of crop residues (MWS), a maize-wheat-sorghum rotation with harvested crop residues (MWS-R), switchgrass (Sw), and continuous sweet sorghum (Ss).

Carbon net emission is a critical aspect of the environmental footprint in agricultural systems. However, the alternatives to describe soil organic carbon (SOC) changes associated with different agricultural management practices/land uses are limited. Here we provide an overview of carbon (C) stocks of non-forested areas of Uruguay to estimate SOC changes for different soil units affected by accumulated effects of crop and livestock production systems in the last decades.

ABSTRACT.- Aim: The intensification of livestock systems generates structural and functional changes in native grassland, which alter their capacity to respond to disturbances. Our objective was to evaluate the resilience to an extraordinary consecutive-droughts event, across an intensification gradient of livestock systems. Our prediction was that sites with more intensive management (less diverse) will have lower resilience (as resistance and/or recovery) to drought. Location: South-central region of Uruguay.

ABSTRACT.- Aim:The intensification of livestock systems generates structural and functional changes in native grassland, which alter their capacity to respond to disturbances. Our objective was to evaluate the resilience to an extraordinary consecutive-droughts event, across an intensification gradient of livestock systems. Our prediction was that sites with more intensive management (less diverse) will have lower resilience (as resistance and/or recovery) to drought. Location:South-central region of Uruguay.

ABSTRACT.- Plants grow associated with complex communities of organisms, and their development depends largely on management practices, available nutrients in the soil, environmental conditions, and the balanced equilibrium established among all these factors. In unbalanced environments, diseases, insects, and weeds can decrease agricultural productivity or even destroy crops.

ABSTRACT.- Plants grow associated with complex communities of organisms, and their development depends largely on management practices, available nutrients in the soil, environmental conditions, and the balanced equilibrium established among all these factors. In unbalanced environments, diseases, insects, and weeds can decrease agricultural productivity or even destroy crops.

RESUMEN.- La teoría de Estados Alternativos de Biomas (EAB) contribuye a explicar la presencia de biomas abiertos (pastizales, arbustales) en ambientes suficientemente cálidos y húmedos para el desarrollo de biomas de bosque. En estos ambientes se pueden encontrar áreas dominadas por biomas abiertos que, según esta teoría, responden principalmente al fuego y a la herbivoría.

RESUMEN.- Los incendios son fenómenos catastróficos, devastadores, peligrosos y costosos para una región. A pesar de su relevancia, se conoce poco sobre su dinámica espacial y temporal en la provincia de La Pampa. El objetivo general de este trabajo fue identificar y caracterizar los incendios -en particular, los más extensos- ocurridos en la provincia de La Pampa durante el período julio 2001-junio 2017 (16 campañas) empleando información provista por sensores remotos. Para ello se utilizó información de focos de calor de MODIS Rapid Response distribuidos por el sistema web FIRMS.

RESUMEN.- Los incendios son fenómenos catastróficos, devastadores, peligrosos y costosos para una región. A pesar de su relevancia, se conoce poco sobre su dinámica espacial y temporal en la provincia de La Pampa. El objetivo general de este trabajo fue identificar y caracterizar los incendios -en particular, los más extensos- ocurridos en la provincia de La Pampa durante el período julio 2001-junio 2017 (16 campañas) empleando información provista por sensores remotos. Para ello se utilizó información de focos de calor de MODIS Rapid Response distribuidos por el sistema web FIRMS.