ABSTRACT.
Relationship of soil physical quality parameters and maize yield in a Brazilian Oxisol

Anderson C. Bergamin1*, Antonio C.T. Vitorino2, Fábio R. Souza1, Luciano R. Venturoso3, Luara P.P. Bergamin4, and Milton C.C. Campos5
 
In Brazilian agriculture, maize (Zea mays L.) is prominent because of its magnitude of grain production. However, soil compaction changes negatively the soil physical attributes, limiting the crop growth. This study aimed to evaluate physical attributes of a clayey Oxisol (Rhodic Hapludox) under no-tillage, and the relationships between these attributes with maize yield in the Midwest region of Brazil. Besides this, indicators of soil physical quality when subjected to levels of compaction were determined. A randomized complete block design was applied with five replicates. Treatments were induced levels of compaction: a reference condition that reflects 8 yr of no-tillage (NT); no-tillage with additional compaction by tractor traffic in one (NT-1), two (NT-2), four (NT-4), and six passes (NT-6). There was significant correlation (P < 0.01) between all physical attributes of the studied soil. Maize yield was positively correlated to macroporosity (r = 0.41*), and negatively to penetration resistance (r = -0.42*), geometric mean diameter (r = -0.51*), and mean weighted diameter (r = -0.53*). The index of emergence speed, stem diameter, plant height, grain mass, and grain yield decreased as soil compaction increased. The physical attributes evaluated, especially the resistance to penetration and soil macroporosity, reveal the level of soil compaction and can be used as soil physical quality indicators.
Keywords: Correlation, no-tillage, physical attributes, tractor traffic, Zea mays.
1Universidade Federal de Rondônia (UNIR), Departmento de Agronomia, Av. Norte/Sul 7300, Rolim de Moura, RO, Brasil. *Corresponding author (anderson.bergamin@unir.br).
2Universidade Federal da Grande Dourados (UFGD), Faculdade de Ciências Agrárias, Rodovia Dourados-Itahum, km 12, Cidade Universitaria, Dourados, MS, Brasil.
3Instituto Federal de Rondônia (IFRO), Rodovia RO 257, km 13, Sentido Machadinho do Oeste, Zona Rural Ariquemes, RO, Brasil.
4Centro Universitário da Grande Dourados (UNIGRAN), Faculdade de Ciências Exatas e da Terra, Avenida Manaus 4283, Centro, Rolim de Moura, RO, Brasil.
5Universidade Federal do Amazonas (UFAM), Instituto de Educação, Agricultura