[Physical properties of soil and maize production under two tillage systems in an alfisol of the State Guarico]
1995
Bravo, C.
Conventional tillage and no-tillage were compared on a Kandic Haplustalfs located in the state of Guarico, Venezuela during the last three years with the purpose of studying their effects on corn production and the physical properties of the soil. The results of each treatment were evaluated in terms of crop yield sand soil variables through a sampling of large plots of land at different times and depths during the development of the crop. The results of some physical analysis (particle size distribution, aggregate stability under the impact of rain drops, and the wetting of the soil) show certain tendencies toward surface and sub-surface compaction problems (sealing and crusting) as well as water erosion. In the surface layer the bulk density and the mechanical resistance were significantly greater in the no-tillage than in the conventional tillage while the rest of the depths generally showed inverse behaviors for every year. In relation to the porosity of the soil, significant differences were only present in the sampling of the planting within the first 10 cm, however, by the end of the cultivation such differences tended to disappear. The results of the bulk density, total porosity, and root concentration in the superficial horizon show that the area below the first 19 cm of depth presented the major restrictions, suggesting the presence of a problem of compaction. The corn yields were significantly higher for conventional tillage in 1991 and 1992. For the rest of the years, although significant differences were not registered, the no-tillage showed better results.
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