THE INFLUENCE OF TILLAGE METHODS ON SOIL PHYSICAL-PROPERTIES AND WATER-BALANCE FOR A TYPICAL CROP-ROTATION IN SW SPAIN

In the present work the effect of several tillage methods on the physical properties of a sandy clay loam (Haploxeralf) from Seville province (SW Spain) has been studied in order to establish the optimum management for water intake and conservation in the soil. The following tillage methods were considered during the period 1984-1987: disc ploughing; mouldboard ploughing; cultivator application; disc harrowing; no-tillage. Two crops were used in rotation, wheat and sunflower. In each treatment, soil susceptibility to compaction and systematic measurements of resistance to penetration, bulk density, hydraulic conductivity and infiltration rate in the top layer were carried out. Changes in water profiles through the experimental period were also followed. The results presented in this paper correspond to the period autumn 1986-July 1987, the third year of rotation. They show important differences in soil physical properties as well as in the rate of replenishment and depletion of soil water storage as a result of treatments. Differences in crop response have also been observed. © 1990.