Wenceslau J. Goedert

Qualidade de um solo sob diferentes usos e sob Cerrado nativo

Sustainable soil use is becoming increasingly relevant given the increase of anthropic activities. In order to evaluate the soil quality, soil samples were collected from five areas: natural Cerrado (reference), native pasture, planted pasture, annual crops under conventional tillage and pine forest. The areas are located in the Federal District, Brazil, in a clayey Red Yellow Latosol (Acrustox). The following soil quality attributes were measured: bulk density, mechanical resistance to penetration, water infiltration rate, organic matter content, cation exchange capacity, carbon of microbial biomass and basal respiration. Based on the obtained data a comparative diagram was drawn and a soil quality index calculated for each type of use. The results showed a close inverse relationship between soil quality and intensity of use to which the areas were submitted. By analyzing these attributes and the establishment of a comparative model it was possible to evaluate the level of soil degradation caused by each type of use in each area.

Atributos físicos da qualidade de um solo sob sistema agroflorestal

Agroforestry systems seem to be a sustainable alternative for agricultural production. The objective of this work was to evaluate the quality of a soil used under an agroforestry system by the quantification of the following soil physical attributes: density, porosity, resistance to penetration and aggregate stability. The soil under agroforestry exhibited a superior quality compared to the same soil cultivated by a conventional system, reflected by smaller soil density, higher porosity, lesser resistance to penetration and higher aggregate stability.

Qualidade de solo submetido a sistemas de cultivo com preparo convencional e plantio direto

The objective of this study was to evaluate the quality of an Oxisol under tillage and no-tillage systems. Two experimental areas were studied, both located in Embrapa Cerrados, Planaltina, DF, Brazil, with eight and ten years of cropping. Soil samples were collected from different depth layers in the experimental plots and native cerrado vegetation area. The following soil atributes were evaluated: bulk density, soil porosity, available water capacity, degree of flocculation, soil resistance to penetration, organic matter content, cation exchange capacity, equilibrium phosphorus, microbial biomass carbon and basal respiration. The data obtained were compared with referential values related to soil quality. The soil quality under both systems is similar, considering the soil physical attributes. The values for organic matter and equilibrium phosphorus are also similar, but the cation exchange capacity is higher for soil under no-tillage. Concerning the biological attributes, the soil under no-tillage presents higher biological activity. The soil quality is similar, under both cropping systems.

Indicadores de qualidade de Latossolo Vermelho sob diferentes usos

The evaluation and monitoring of soil quality, in the micro-drainage basins which contribute directly to the Rio Descoberto reservoir, in the Rio Descoberto drainage b asin, Distrito Federal (DF), Brazil, are necessary, due to its disordered rural occupation. Thus, this study aimed at evaluating the quality indicators of Red Latosol (RL), in micro-drainage basins located in the northern Rio Descoberto drainage basin , under diversified uses and managements: Savannah (SA), reforestation (RF), native pasture (NP), cultivated pasture (CP), agriculture with covered soil (AC) and agriculture with partial soil covering (AP). Soil density (SD) presented the lowest value for SA and the highest one for AP. The CP area showed the highest values for soil resistance to penetration, reflecting the effect of animal trampling. The highest value for organic matter (OM) was 55.5 g kg -1 , in the CP, and the lowest one was observed in the AC (37.5 g kg -1 ), where decomposition processes are favored. The cation exchange capacity varied from 7.80 cmol c dm -3 (NP) to 9.75 cmol c dm -3 (RF), pointing out the liming effect . The values obtained for microbial biomass carbon and basal respiration showed positive effects of the grass root system in the development of microorganisms. Among t he soil quality attributes evaluated, the OM and SD stood out, confirming that a more intensive agricultural activity is directly related to the quality reduction of the RL evaluated.

Concentração de íons na solução de um Latossolo Vermelho sob diferentes sistemas de manejo

O objetivo deste trabalho foi avaliar as concentracoes de ions na solucao de um Latossolo Vermelho, em diferentes sistemas de manejo. Foram avaliados os sistemas de lavoura e pastagem continua, assim como os rotacionados em integracao lavoura-pecuaria. O experimento foi iniciado em 1991, e as coletas das solucoes foram realizadas em 2005 e 2006. Capsulas porosas foram instaladas as profundidades de 20 e 150 cm, e as solucoes foram extraidas em seis epocas de cada ano. As concentracoes de Cl-, SO42-, NO3-, H2PO4-, K+, Mg2+ e Ca2+ foram determinadas. Independentemente das profundidades e dos sistemas de manejo, a concentracao de ions nas solucoes, em ordem decrescente de grandeza, foi: NO3- >Cl- >SO42- >H2PO4- e Ca2+ >K+ >Mg2+. Entre os sistemas de cultivo, a concentracao dos ions na solucao decresceu e foi maior em lavoura continua sob preparo convencional, seguida de lavoura continua sob plantio direto e, finalmente, pelo sistema de integracao lavoura-pecuaria e pela pastagem continua. A profundidade de 150 cm, as concentracoes dos ions na solucao do solo sob pastagem continua e integracao lavoura-pecuaria foram sempre baixas, o que indica baixo risco de lixiviacao.

Uso das terras da parte norte da bacia do Rio Descoberto, Distrito Federal, Brasil

This work had the objective to evaluate the land use in the northern region of the Environmental Protection Area of Descoberto River, which encompasses the watersheds of the streams Barrocao, Bucanhao and Capao da Onca, accomplished with the support of geoprocessing techniques. A land use map of the area was produced through analysis and treatment of SPOT 4 satellite images, obtained in 2003, using the software ENVI 3.6. Then, the adequation of land use was checked using cross-tabulation between the maps of present and potential use for agriculture, with the software ArcView 8.3, allowing development of a map of land use suitability. The results showed that most of the area has been used under its agricultural potential, characterizing sustainability in the use of the natural resources, particularly of the soils.

Strategic planning in public R&D organizations for agribusiness: Brazil and the United States of America

There is increasing evidence that public organizations dedicated exclusively to research and development (R&D) in agribusiness need systematic management tools to incorporate the uncertainties and complexities of technological and nontechnological factors of external environments in its long-term strategic plans. The major issues are: “What will be the agribusiness science and technology (S&T) needs be in the future?” “How to prepare in order to meet these needs?” Both Empresa Brasileira de Pesquisa Agropecuaria (Brazilian Agricultural Research Corporation, Embrapa), attached to the Brazilian Ministry of Agriculture and the Agricultural Research Service (ARS) of the US Department of Agriculture (USDA) have developed a comprehensive strategic and operational planning process in order to answer these key questions in the 1990s. The main objective of this article is to present a comparative and preliminary analysis of concepts, methodologies, and processes utilized, and some results obtained by these public organizations.

CPAC: A Model for an R&D System for Tropical Agriculture

This chapter discusses the technical cooperation developed between Japan and Brazil to strengthen the Cerrado Agricultural Research Center’s (CPAC) research and development, and the EMBRAPA Cooperation System for the development of the Brazilian Cerrado. It addresses both changing demands and challenges for the Cerrado and those for the tropical savannahs of other countries. The discussion relates to the first two decades of activities by the CPAC, as defined in national projects and the program of the Brazilian Agricultural Research Corporation (EMBRAPA).1