Least limiting water range: A potential indicator of changes in near-surface soil physical quality after the conversion of Brazilian Savanna into pasture

• Autores: Leão, Tairone Paiva; Da Silva, Álvaro Pires Da; Macedo, Manuel Cláudio Motta; Imhoff, Silvia del Carmen; Euclides, Valẽria Pacheco Batista
• Año de publicación: 2006
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: CERRADO; CONTINUOUS GRAZING; CRITICAL BULK DENSITY; LEAST LIMITING WATER RANGE; SHORT-DURATION GRAZING; TROPICAL GRASS
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

The Brazilian savanna, or "Cerrado", is an ecosystem that originally covered more than 200 Mha in Brazil. It is estimated that about 49.5 Mha in the Cerrado are now covered with cultivated pastures, which are responsible for half of Brazilian beef production. However, soil and pasture degradation represent a threat to this productive system and to the Cerrado ecosystem itself. Thus, the objective of this research was to evaluate the least limiting water range (LLWR) as an index of near-surface soil physical quality after conversion of Brazilian savanna to continuous and short-duration grazing systems. Three sites were evaluated: native Cerrado (NC), continuous grazing (CG), and short-duration grazing (SG). Thirty soil cores (5 cm height, 5 cm diameter) were collected at each site, and used for soil bulk density, soil water retention curve, and soil penetration resistance curve determinations. The results were used for quantification of LLWR and critical bulk density (Dbc), in which LLWR equals zero. The near-surface soil physical quality, as evaluated by the LLWR, was most restrictive for potential root growth in SG. In CG, potential restriction was moderate; however, the entire soil bulk density range was below the Dbc. In NC, potential restriction was minimum. The soil structural degradation process was primarily related to the increase in stocking rates in the grazing systems. The LLWR proved to be a useful indicator of Cerrado soil physical quality, being sensitive to alterations in near-surface physical properties.
Fil: Leão, Tairone Paiva. University of Tennessee; Estados Unidos
Fil: Da Silva, Álvaro Pires Da. Universidade de Sao Paulo; Brasil
Fil: Macedo, Manuel Cláudio Motta. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; Brasil
Fil: Imhoff, Silvia del Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; Argentina
Fil: Euclides, Valẽria Pacheco Batista. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; Brasil