38 results

Quantification of tensile strength and friability of an oxisol (Acrudox) under no-tillage

Cássio Antonio Tormena, Marcelo Alessandro Araújo, Jonez Fidalski, Silvia Imhoff, Álvaro Pires da Silva

01/Jun/2008

The soil structural quality is important for plant emergence as well as for crop growth, development and yield. A wide range of soil tensile strength values indicates that soil structure conditions meet these requirements. The objective of this study was to evaluate the tensile strength and friability of an Oxisol (Acrudox) under no-tillage with crop rotation and crop succession. The soil management treatments consisted of: crop succession with wheat and soybean (SDS); crop rotation with corn-oats-soybean-oats-soybean-wheat (SDR) and SDR plus […]

Qualitative and quantitative changes in soil microbiota and biological nitrogen fixation under different soybean managements

Alan Alves Pereira, Mariangela Hungria, Julio Cezar Franchini, Glaciela Kaschuk, Lígia Maria de Oliveira Chueire, Rubens José Campo, [...]

01/Dec/2007

In this study, quantitative and qualitative microbiological parameters were evaluated to detect differences related to soil and crop management. The study was carried out in a field experiment installed 14 years ago on a Rhodic Eutrudox, in Londrina, PR, Brazil. Treatments were a combination of a crop sequence (S) (soybean/wheat) and a crop rotation (R) (lupin/maize/black oat/soybean/wheat/soybean/wheat/soybean), either under conventional tillage (CT) or no-tillage (NT). Evaluations were performed when all systems were under the soybean cropping season, at full flowering. […]

Temporal variation of the least limiting water range of an oxisol under no-tillage systems

Cássio Antonio Tormena, Marcelo Alessandro Araújo, Jonez Fidalski, Joaquim Mariano da Costa

01/Apr/2007

Despite the efficiency of no-tillage in improving soil and water conservation, the machinery traffic and absence of soil tillage can lead to surface compaction in clayey soils. The Least Limiting Water Range (LLWR) expresses the effects of management systems on the improvement or degradation of soil physical quality. The objective of this study was to quantify LLWR to discriminate the effects of management systems under no-tillage on soil physical quality. The treatments were crop succession under no-tillage, crop rotation under […]

Shoot and root growth of soybean and cover crops as affected by soil compaction

José Salvador Simoneti Foloni, Sergio Lázaro de Lima, Leonardo Theodoro Büll

01/Feb/2006

The cultivation of cover crops with vigorous root systems in crop rotation can improve the physical quality of compacted soils. The objective of this study was to evaluate shoot and root growth of soybean (Glycine max) and five species used as summer cover crops (Cajanus cajan, Cajanus cajan var. small, Mucuna aterrima, Dolichos lab lab and Crotalaria juncea) in a soil submitted to three different levels of subsurface compaction. Plants were grown in pots assembled with three PVC rings, 50 […]

Soil physical properties and organic carbon stratification rate in an oxisol after ten years under two different soil management systems

C. A. Tormena, R. Friedrich, J. C. Pintro, A. C. S. Costa, J. Fidalski

01/Dec/2004

In the clay and heavy clay soils, compaction of the surface layer represents one of the limitations under no-tillage. Under such conditions, periodic soil tillage has been adopted. Other techniques, such as crop rotation are indicated for the physical management of the soil due to a larger input of organic matter and bioporosity of the soil. The objective of this study was to quantify some soil physical properties in an eutroferric Red Latosol (rhodic Eutrudox), the organic carbon content and […]

Effects of grain production systems including pastures under no-tillage on soil physical properties and yield

S. T. Spera, H. P. Santos, R. S. Fontaneli, G. O. Tomm

01/Jun/2004

Ley forming modifier soil structure, which, in turn, effects soil physical characteristics in the upper layer. The objective of this study was to evaluate soil physical attributes and grain yield in a typical dystrophic Red Latosol (Typic Haplorthox) located in Passo Fundo county (RS), Brazil, after eight years of mixed production cultivation (1993 to 2000). The effects of production systems integrating grain production with winter annual and perennial pastures under no-tillage were assessed. Four mixed production systems were evaluated: system […]

Corn yield on no tillage crop-pasture rotation in presence and absence of white clover, grazing and nitrogen

T. S. Assmann, P. Ronzelli Júnior, A. Moraes, A. L. Assmann, H. S. Koehler, I. Sandini

01/Aug/2003

This field experiment was carried out at the Fundação Agrária de Pesquisa Agropecuária [Agrarian Foundation for Agricultural and Cattle Research] (FAPA), in Guarapuava, State of Paraná, Brazil, during the growing seasons of 1999 and 2000. The objective was to verify residual effects of nitrogen fertilization on maize crop under a no tillage system, in presence and absence of white clover and grazing animals. The experimental layout was a completely randomized block design with three replications. The treatments were arranged in […]

Water erosion caused by natural rainfall in a clayey Hapludox with different cropland tillage systems

J. F. Beutler, I. Bertol, M. Veiga, L. P. Wildner

01/Jun/2003

Rainfall and runoff together are the active agents of water erosion, furthermore influenced by soil cover and roughness, crop and soil tillage. Compared to conventional tillage, water erosion is reduced in soil conservation tillage because this method is less intensive, preserves the cover longer, and sometimes increases soil roughness. Erosion losses (soil and water) of a clayey Hapludox with a slope of 0.09 m m-1 were evaluated in Chapecó, Santa Catarina State, Brazil, from November 1994 to October 1999 under natural rainfall. […]

Effect of mixed crop production systems under no-tillage on soil fertility after eight years

H. P. Santos, R. S. Fontaneli, G. O. Tomm, S. T. Spera

01/Jun/2003

Soil fertility characteristics were evaluated on a typical dystrophic Red Latosol (Typic Haplorthox) located in Passo Fundo, State of Rio Grande do Sul, Brazil, after eight years of use under mixed production systems (1993 to 2000). The effects of production systems integrating grain production with winter annual and perennial pastures under no-tillage were assessed. Four production systems were evaluated: system I (wheat/soybean, white oat/soybean, and common vetch/corn); system II (wheat/soybean, white oat/soybean, and grazed black oat + grazed common vetch/corn); system III [perennial […]

Residual effect of potassium fertilization with ryegrass on subsequent rice under no-tillage

M. A. Simonete, L. C. Vahl, R. T. Fabres, J. R. R. Couto, R. Lunardi

01/Sep/2002

To evaluate residual effects of potassium fertilization throught ryegrass on subsequent rice, under no-tillage system, a field experiment was performed from May 1996 to April 1997 in the Agricultural Center (Centro Agropecuário) of Palma/UFPel, in the county of Capão do Leão, Rio Grande do Sul State, Brazil. The examined soil was a Planossolo (Albaqualf) belonging to the Pelotas mapping unit. Treatments consisted of three K levels applied on the ryegrass (0, 0.5 and 1 time the recommended dose of 70 […]

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