RESUMO

This study aimed to assess the effects of Eucalyptus and maize shading on characteristics related to water use by Brachiaria in agroforestry systems. Treatments were arranged in a split-split-plot design, with plots consisting of different spacing between Eucalyptus plants (12.0×2.0m and 12.0×4.0m), split-plots of different distances between Brachiaria and Eucalyptus (6.0, 4.0, and 2.0m), and split-split-plots of Brachiaria sowing sites (maize row and inter-row). One treatment with Brachiaria under full sunlight was included. Bread grass intercropping in maize inter-rows associated with the densest Eucalyptus spacing and bread grass proximity to Eucalyptus tree crowns adversely affected the stomatal conductance, internal carbon, and transpiration rate of bread grass. Water use efficiency of bread grass intercropped in maize rows decreased, regardless of the Eucalyptus plot design and distance between forages and trees.

O objetivo desta pesquisa foi avaliar os efeitos do sombreamento ocasionado por plantas de eucalipto e milho nas características relacionadas ao uso da água da braquiária em sistema agrossilvipastoril. O experimento foi realizado no delineamento em blocos casualizados, com quatro repetições. Os tratamentos foram arranjados em esquema de parcelas subsubdivididas, comas parcelas representadas constituídas pelos espaçamentos de plantio do eucalipto (12x2 e 12x4m), as sub-parcelas da distância da braquiaria e o eucalipto (6; 4 e 2m) e a subparcela do local de cultivo da braquiária (linha e entrelinha do milho). Além disso, foi adicionado um tratamento composto pela braquiária cultivada a pleno sol. O cultivo do capim-maradu na entrelinha do milho associado ao sombreamento intenso proporcionado pelo espaçamento mais adensado de eucalipto (12x2m) e a proximidade das plantas de capim-marandu às copas das árvores de eucalipto altera negativamente a condutância estomática, o carbo interno e a taxa transpiratória das plantas de capim-marandu. A eficiência no uso da água das plantas de capim - maradu é reduzida independente do arranjo espacial do eucalipto e da distância entre aforrageira e as árvores quando a forrageira é cultivada na linha do milho.

Assuntos

RESUMO

This study aimed to assess the effects of Eucalyptus and maize shading on characteristics related to water use by Brachiaria in agroforestry systems. Treatments were arranged in a split-split-plot design, with plots consisting of different spacing between Eucalyptus plants (12.0×2.0m and 12.0×4.0m), split-plots of different distances between Brachiaria and Eucalyptus (6.0, 4.0, and 2.0m), and split-split-plots of Brachiaria sowing sites (maize row and inter-row). One treatment with Brachiaria under full sunlight was included. Bread grass intercropping in maize inter-rows associated with the densest Eucalyptus spacing and bread grass proximity to Eucalyptus tree crowns adversely affected the stomatal conductance, internal carbon, and transpiration rate of bread grass. Water use efficiency of bread grass intercropped in maize rows decreased, regardless of the Eucalyptus plot design and distance between forages and trees.(AU)

O objetivo desta pesquisa foi avaliar os efeitos do sombreamento ocasionado por plantas de eucalipto e milho nas características relacionadas ao uso da água da braquiária em sistema agrossilvipastoril. O experimento foi realizado no delineamento em blocos casualizados, com quatro repetições. Os tratamentos foram arranjados em esquema de parcelas subsubdivididas, comas parcelas representadas constituídas pelos espaçamentos de plantio do eucalipto (12x2 e 12x4m), as sub-parcelas da distância da braquiaria e o eucalipto (6; 4 e 2m) e a subparcela do local de cultivo da braquiária (linha e entrelinha do milho). Além disso, foi adicionado um tratamento composto pela braquiária cultivada a pleno sol. O cultivo do capim-maradu na entrelinha do milho associado ao sombreamento intenso proporcionado pelo espaçamento mais adensado de eucalipto (12x2m) e a proximidade das plantas de capim-marandu às copas das árvores de eucalipto altera negativamente a condutância estomática, o carbo interno e a taxa transpiratória das plantas de capim-marandu. A eficiência no uso da água das plantas de capim - maradu é reduzida independente do arranjo espacial do eucalipto e da distância entre aforrageira e as árvores quando a forrageira é cultivada na linha do milho.(AU)

Assuntos

RESUMO

There are several forest operations involved in Eucalyptus timber harvesting. This study was carried out during brush-cutting; tree felling, bucking, delimbing, piling and manual extraction operations, with the following objectives: a) analyzing, ergonomically, two systems of brush-cutting: one manual and the other semi-mechanized, using two different machines; b) ergonomically evaluating three different brands of pruner machines used in delimbing felled trees. c) determining the feasible target of productivity as a function of ergonomic factors relevant to establish the time of resting pauses for workers in manual and semi-mechanized timber harvesting systems in mountainous terrain. Brush-cutting, either manual or semimechanized, is an activity carried out prior to timber harvesting. It is usually a hard work, with low productivity when compared with mechanized systems. Pruner machines have been used by forest companies, due to the great possibilities to improve productivity, quality and the health of workers. Ergonomics is a discipline that promotes the adequacy of work to the physical and mental characteristics of human beings, seeking to design production systems and products considering relevant aspects, including social, organizational and environmental factors. Companies should consider the ergonomic factor in the determination of daily worker production targets.

Assuntos

RESUMO

Worldwide, there are many pilot forestry projects that are under some stage of implementation, and much experience has been gained from them with respect to measuring, monitoring, and accounting for their carbon benefits. Forestry projects have been shown to be easier to quantify and monitor than national inventories, partly because not all pools need measuring: a selective accounting system can be used that must include all pools expected to decrease and a choice of pools expected to increase as a result of the project. Only pools that are based on field measurements should be incorporated into the calculation of carbon benefits. Such a system allows for trade-offs between expected carbon benefits, costs, and desired precision, while maintaining the integrity of the net carbon benefits. Techniques and methods for accurately and precisely measuring individual carbon pools in forestry projects exist, are based on peer reviewed principles of forest inventory, soil sampling, and ecological surveys, and have been well tested in many part of the world. Experience with several forestry projects in tropical countries has shown that with the use of these techniques carbon stocks can readily be estimated to be within less than +/-10% of the mean. To date, there is little experience with measuring the changes in carbon stocks over time but, using the correct design and sufficient numbers of permanent plots, it is expected that precision levels will be maintained at less than +/-10% of the mean. Internal verification can be accomplished through use of quality assurance/quality control plans. External or third-party verification is still in its infancy, and would greatly benefit from international agreements in relation to protocols used for all aspects of project design and implementation.

Assuntos