Integração lavoura pecuária: efeitos no solo, na forragem, modelagem e simulação econômica
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2010-07-30
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Universidade Federal de Goiás
Resumo
When approaching the crop-livestock integration (CLI) theme, the present thesis
had as one of its main objectives to evaluate the alterations in the soil-plantanimal-
environment components exercised by the crop and pasture rotation
dynamics in crop and livestock integration system. Two adjacent areas, one
representing the natural environment (original cerrado vegetation) and other the
degraded pastures served as reference ( control ) to the inferences performed.
The experiment was performed at a 92 ha area, divided into six paddocks of
approximately 15 ha, where the annual crops and pastures rotation was made.
The soil samplings were collected at the 0-10, 10-20, 20-30, 30-40 and 40-50 cm
layers. There was an increase in the carbon contents of the microbial biomass, in
the microbial quotient and in the organic matter on the soil and reduction in the
metabolic quotient at the pastures chronological sequence environments, at the
crop-livestock integration system, in comparison with the degraded pasture. The
different pastures stages within the crop-livestock integration system stocked the
average of 17,67 Mg ha-1 carbon more than the degraded pasture up to a 50 cm
depth. The Cerrado contained the most carbon stock and the degraded pasture
the least among all the environments studied. There was a significant decrease in
the phosphor and potassium contents in relation to the pasture age increase and
an increase in the calcium and magnesium contents. Micronutrients contents
among the treatments evaluated presented values above the demand for capim-
Marandu. The capim-Marandu samplings were performed in five different seasons
of the year (winter, beginning and end of spring, summer and autumn).
Quantitative and qualitative alterations at the forage were observed during the
experimental period. Changes on the structural components green leaf, green
stem and dead material, as well as on DM (Dry Matter), GP (Gross Protein), TDN
(Total Digestive Nutrients) and FND (Fiber in Neutral Detergent) contents, among
others, characterized the forage on the different periods. The qualitative variations
among the forages are of high magnitude, being outlined the significant drop on
GP (Gross Protein) and TDN (Total Digestive Nutrients) contents according to the
pasture maturity development. All pastures chronological sequence treatments,
after 2,5 years of crop, resulted in favorable evaluations, having P1 treatment as
the best investment option with NPV (Net Present Value) equals to R$144,34
followed by P2 treatment with R$112,61 and P3 with R$58,54, indicating to be a
favorable Project. There is indication on the present work that the biggest loss in
relation to the obtained economic advantages happens already from the second
year after the pastures establishment. Such results may constitute important
implications at CLI systems planning. Carbon bonus at pasture based animal
production system may be a financial incentive for the producer to join the
pastures rotation with annual crops. Nevertheless it is necessary that studies are
performed to quantify emissions of gases responsible for greenhouse in order to
verify whether the result represents a bonus or an environmental onus to the
producer.
Descrição
Palavras-chave
fertilidade do solo , biologia do solo , idade da pastagem , estoque de carbono no solo , modelagem de sistema de produção , soil fertility , soil biology , pasture age , carbon stock on soil , production
system modeling , 1. Fertilidade do solo 2. Biologia do solo 3. Idade da
pastagem 4. Estoque de carbono no solo 5. Sistema de
produção - modelagem
Citação
MUNIZ, Luciano Cavalcante. Crop - livestock: effects on soil,
fodder, economic modeling and simulation. 2010. 217 f. Tese (Doutorado em Ciências Agrárias) - Universidade Federal de Goiás, Goiânia, 2010.