Effect of ridge tillage on the physical status of the soil and on the maize yield

Ridge tillage is a cultivation system in which the plant (generally maize, soya beans, sometimes sugar beer) is grown in ridges raised above the soil surface. This is a soil-protective technique with a long history in North A merica and many countries of Africa, but which has only been studied in exp eriments for the most part in Europe. Within the framework of cooperation between the Stent Istvan University (Go dollo University of Agricultural Sciences) and the Vienna University of Agr iculture, soil cultivation experiments were set up for the first time in Au stria in 1996 to study the ridge cultivation of maize. The experiment was s et up near Ilz in Steiermark with the following treatments: 1. Traditional cultivation with ploughing; 2. Direct drilling; 3. Ridge tillage. The maize was grown in a monoculture. Analyses were made of the soil physical status (soil resistance, moisture content, pore size, soil temperature) and the y ield. No chemicals were used in the ridge tillage system in order to determ ine how the technique could be applied in a biofarming system. In the first two years of the experiment there was no significant differenc e between the soil resistance values in the different treatments, all of wh ich had satisfactorily loose soil. Significant differences were observed, h owever, in the moisture content. In direct drilling and ridge tillage the m oisture content of the 0-10 cm layer in the interrows was 3.5-5.6 % greater than in the ploughed treatment and in other parts of the ridge (sides and top of the ridge). A similar but inverse trend was observed for the tempera ture. Within the total porosity a significant difference was only found for the macropores. There were no substantial differences in the yields in the first year, with over 11 t/ha in all treatments. The following year weed cover had the grea test influence on the yields: in the ridge tillage treatment mechanical wee d control (raising the level of the ridge) did not prove sufficient and the yield dropped by 4.0-5.1 t compared to direct drilling and traditional plo ughed cultivation, where chemical weed control was employed.