Resumoas rochas basálticas possuem composição rica em elementos químicos considerados nutrientes às plantas, o que a torna apta para o uso agrícola, melhorando a fertilidade dos solos. Objetivou-se com esse trabalho avaliar o efeito de doses de basalto moído nos teores de alguns nutrientes no solo. Foi utilizado um Latossolo amarelo ácido e de baixa CTC, formação geológica Boa Vista, estado de Roraima. a rocha basáltica da formação apoteri foi coletada na pedreira da serra de Nova Olinda, Boa Vista. Os tratamentos consistiram da incorporação e incubação de oito doses do pó da rocha (0; 0,85; 1,70; 3,35; 5,03; 10,05; 20 Levels of finely ground basalt rock in the chemical properties of a yellow latosol of the savannah of Roraima abstRaCtBasaltic rocks have chemical and mineralogical composition that allows its agricultural application due to its capability of improving soil fertility. The aim in this work was to evaluate the effect of levels of finely crushed basalt rock in soil chemical conditioning. a dystrophic Yellow Latosol from pre-weathered Boa Vista Formation was used. The rock of the apoteri formation was collected in the mine of Nova Olinda near Boa Vista. The treatments consisted of the incorporation and incubation of eight rock powder levels (0; 0.85; 1.70; 3.35; 5.03; 10.05; 20.40 and 40.80 g kg -1 ). The experimental design was entirely randomly with eight treatments and three replicates. after the incorporation of the rushed rock powder for a period 180 days of soil incubation, the soil was analyzed and determined the values of Ca 2+ , Mg 2+ , ph in h 2 O, ph in KCl, al 3+ , h+ al, Zn, Fe, Cu and Mn. The level of 20.40 g kg -1 of basalt provided the maxim reduction of the active acidity, varying from 4.8 to 5.5. Concentrations of exchangeable Ca 2+ and Mg 2+ increased, but their increments in the soil solution was small. Basalt levels presented high efficiency for neutralization of the potential acidity. amendments with crushed rock increased extractable amounts of Zn, Fe and Cu in soil, after incubation.

Levantamento de plantas daninhas em área rotacionada com as culturas da soja, milho e arroz irrigado no cerrado de Roraima). As famílias com maior ocorrência foram as Amaranthaceae, Euphorbiaceae e Poaceae. Dentre as espécies, 82,60% pertencem à classe botânica das dicotiledôneas. Palavras-chave -Composição Florística. Matocompetição. Plantas invasoras.Abstract -This study had as its objective to identify and to quantify the levels of population density of the weeds species in crops rotated with soybean, rice, and corn in the savannah of The State of Roraima. Through the inventory square method, the identifi cation and count of the species was realized, with 30 sampling of 1m² in an area of 120 ha. Although some weeds have also been observed in other surveys in Brazil, some species were in insignifi cant levels of population in this survey, but were not considered as relevant, because the damage caused by weeds were infl uenced by both the density and the survivability of each species. The knowledge of the diversity and number of weeds in the crop is the fi rst step towards the realization of effective control. Therefore, it avoids unnecessary spending with inappropriate products and decreases the risks of environmental pollution arising from the misuse and abuse of herbicides. Twenty three species were identifi ed from 15 botanical families. The species with larger populations were Lindernia crustacea (288.667 plants ha ), and Physalis angulata (125.000 plantas ha -1 ). Families with higher prevalence were the Amaranthaceae, Euphorbiaceae and Poaceae. Within the species, 82.60% belong to the botanical class of dicots.