Biomechanics of sprint running: a methodological contribution

Abstract

The long-term effects of two different tillage systems, conventional(CT) and no tillage (NT), were studied in an olive orchard in Santaella(Southern Spain) for 15 years. In both tillage systems, two distinctzones developed in the orchard in relation to soil physical properties;one underneath the tree canopy, and the other in the rows between trees.Surface soil organic matter content, bulk density, cone index,macroscopic capillary length and hydraulic conductivity showedsignificant differences between tillage systems and positions. After 15years, the NT treatment achieved greater bulk density and cone indexvalues than CT. This compaction reduced the infiltration rate of NT soilwith respect to CT, particularly in the rows between trees. Despite thatreduction, the NT soil retained a moderate infiltration potential. Thatmay be explained by the high infiltration rates and macroporosity of thezone beneath the tree, the temporary effects of tillage on infiltrationand probably by the self-repair of soil structure in the Vertisolstudied. Yield was not affected by tillage except in one year with verylow precipitation, where NT significantly yielded more than CT. Thereduction in infiltration in NT must have been compensated by unknownfactors that improve the tree water supply in drought years. (C) 1999Elsevier Science B.V. All rights reserved.