Micromammal taphonomy and site formation process of Nutria Mansa 1 archaeological site (Buenos Aires, Argentina)

This paper presents the results of the taphonomic analysis of the micromammal bone remains recovered from Nutria Mansa 1 (NM1), an archaeological site located in the Pampean plains, Argentina. This campsite was occupied by hunter-gatherers that processed and consumed Lama guanicoe during the Late Holocene. In NM1, there are taxa from different environments: mammals from arid and semiarid environments (Patagonic Phytogeographic Province) and humid and temperate environments (Pampean Phytogeographic Province). The main objective of the present study was to evaluate how the recorded small mammal species were incorporated into the archaeological site and which of them were exploited by humans. The micromammal assemblage shows traces of post mortem agents such as weathering, chemical action of sediments, and probably some evidence of predation. The micromammal bones in the archaeological record offer no clear evidence of human modification, and their presence can be the result of predation or other postdepositional agents such as the action of water on the flood plain.Fil: Gómez, Gustavo Norberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano. Universidad Nacional del Centro de la Provincia de Buenos Aires. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano; ArgentinaFil: Bonomo, Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Arqueología; Argentin

Ação do imazapic+imazapyr sobre a tiririca (Cyperus rotundus) e os desnitrificadores em milho Action of imazapic+imazapyr on purple nutsedge (Cyperus rotundus) and denitrifying bacteria in corn

Os objetivos do experimento foram avaliar a eficácia do imazapic+imazapyr sobre a tiririca e a influência desta planta daninha sobre a população de desnitrificadores em solo cultivado com milho. O experimento foi realizado em caixas de 0,70 x 0,30 x 0,30 m, onde foram semeados o milho tolerante às imidazolinonas (C-901CL) e plantados 50 bulbos de tiririca. O delineamento experimental foi o inteiramente casualizado, com seis repetições. Os tratamentos foram constituídos por: 1. milho sem tiririca; 2. milho com tiririca; 3. milho com tiririca capinada; 4. milho com tiririca e imazapic+imazapyr (63+21g ha-1 de i.a.) em pós-emergência; e 5. milho com tiririca e imazapic+imazapyr (63+21g ha-1 de i.a.) em pré-emergência. O herbicida foi eficiente em pós-emergência, diminuindo as manifestações epígeas da tiririca em 41% e proporcionando controle visual de 88% aos 21 dias após a aplicação. Os desnitrificadores do solo aumentaram em seis e dez vezes aos 24 e 54 dias após a semeadura do milho, respectivamente, com a presença de tiririca. A aplicação do herbicida em pós-emergência reduziu a população de desnitrificadores para 1,91x10(5) NMP (número mais provável), 89% menor que a testemunha capinada (16,78x10(5) NMP).<br>The objective of this work was to evaluate the efficacy of imazapic+imazapyr in controling purple nutsedge and its effect on the population of denitrifying bacteria in soil cultivated with corn. The trial was set up in 0.70 x 0.30 x 0.30 m boxes where imidazolinone tolerant corn (C901CL) was seeded together with 50 purple nutsedge bulbs. The experimental design was randomized with six replications. The treatments were: 1) corn without nutsedge; 2) corn with nutsedge; 3) corn with cut nutsedge; 4) corn with nutsedge treated with imazapic+imazapyr (63+21 g ha-1 i.a) applied in post-emergence and 5) corn with nutsedge treated with imazapic+imazapyr (63+21 g ha-1 i.a), applied in pre-emergence. The herbicide was efficient when applied in post-emergence, reducing in 41% the setting of aerial parts of the nutsedge with visual control effect of 88%, twenty-one days after spraying. The soil denitrifying bacteria increased six and ten-fold, 24 and 54 days after corn seeding, respectively, in the presence of purple nutsedge. The application in post-emergence reduced the denitrifying population to 1.91x10(5) MPN (most probable number) , 89% less than the non-weeded check (16.78x10(5) MPN)