Universidade Federal de Viçosa

About: Universidade Federal de Viçosa is a education organization based out in Viçosa, Brazil. It is known for research contribution in the topics: Population & Biology. The organization has 16012 authors who have published 26711 publications receiving 353416 citations.

Efeito residual da adubação com composto orgânico sobre o crescimento e produção de alface

Abstract: This paper aimed to evaluate the residual effect of organic compost fertilization on lettuce growth and yield Seedlings of 'Baba' lettuce were fertilized with five doses of organic compost (00, 228, 456, 684 and 912 ton/ha of dry matter), in the presence and in the absence of mineral fertilizer (643 kg/ha of 4-14-8 plus two side dressings of 30 kg/ha of N) The residual effect was evaluated by carrying out a second cultivation on the same plots with no fertilizer addition after the first cultivation Fertilization with organic compost increased the second cultivation yield up to 27,367 kg/ha of fresh weight at the highest dose, in plants grown between 80 and 110 days after organic compost application The mineral fertilization showed no residual effect The residual effect also resulted in increases in soil exchangeable bases, P, and effective soil cation exchange capacity (CEC) reaching values of 1077 cmolc/dm3, 461 mg/dm3 and 1108 cmolc/dm3, respectively

Historical land use change and associated carbon emissions in Brazil from 1940 to 1995

Abstract: [1] The evaluation of impacts of land use change is in general limited by the knowledge of past land use conditions. Most publications on the field present only a vague description of the earlier patterns of land use, which is usually insufficient for more comprehensive studies. Here we present the first spatially explicit reconstruction of historical land use patterns in Brazil, including both croplands and pasturelands, for the period between 1940 and 1995. This reconstruction was obtained by merging satellite imagery with census data, and provides a 5′ × 5′ yearly data set of land use for three different categories (cropland, natural pastureland and planted pastureland) for Brazil. The results show that important land use changes occurred in Brazil. Natural pasture dominated in the 1950s and 1960s, but since the beginning of 1970s it has been gradually replaced by planted pasture, especially in southeast and center west of Brazil. The croplands began its expansion in the 1960s reaching extensive areas in almost all states in 1980. Carbon emissions from historical land use changes were calculated by superimposing a composite biomass map on grids of a weighted average of the fractions of the vegetation types and the replacement land uses. Net emissions from land use changes between 1940 and 1995 totaled 17.2 ± 9.0 Pg-C (90% confidence range), averaging 0.31 ± 0.16 Pg-C yr−1, but reaching up to 0.47 ± 0.25 Pg-C yr−1 during the 1960s and through 1986–1995. Despite international concerns about Amazon deforestation emissions, 72% of Brazil's carbon emissions during the period actually came from deforestation in the Atlantic Forest and Cerrado biomes. Brazil's carbon emissions from land use change are about 11 times larger than its emissions from fossil fuel burning, although only about 18.1% of the native biomass has been lost due to agricultural expansion, which is similar to the global mean (17.7%).