The study of the effects of soil tillage systems on some physical and chemical properties of a Typic Paleudal and on cassava yield (Manihot esculenta, Crantz) was carried out in the northwest of the state of Paraná, Brazil in 1994/95 and 1996/97. Three soil tillage systems were used: (a) no-tillage; (b) minimum tillage (field cultivator and disc harrowing); and, (c) conventional tillage (mouldplowing and disc harrowing). A randomized complete block experimental design with six replications was used. Higher macroporosity values in the 0.10 m soil layer were obtained in the minimum tillage and conventional cultivation systems. No tillage had the highest soil density and the lowest macroporosity values. Minimum tillage resulted in the greatest concentration of available phosphorus, K+ and Ca2+, and the lowest concentration of Mg2+ in the 0-0,05 m soil layer. Soil organic matter content was not influenced by the preparation systems. Minimum tillage and conventional tillage systems resulted in the tallest plants and highest tuberous root yields in the two years of assessment. When compared to the other tillage systems, no-tillage presented smaller plants and lower yield.
soil physical properties; soil fertility; soil tillage; no till; soil porosity