Response of selected physical properties of Fluvisols to tillage implements and frequencies at Haramaya, Eastern Ethiopia

The study was conducted to evaluate the effects of tillage implements and frequencies on selected physical properties of Fluvisols at Haramaya University, Eastern Ethiopia, during the 2013 cropping season. Soil bulk and particle density, total porosity, texture, and soil water retention were analyzed immediately (within 72 hours) and one month after tillage for samples collected from 0-20 and 20-40 cm depths. The experiment was laid out in a split-plot design with treatment combinations consisting of three levels of tillage frequencies (0, 2 and 4) and two tillage implements, oxen-drawn traditional Maresha and disc plows, with three replications. Results indicated that the mean bulk density values were significantly different (P < 0.05) at plow layers (0-20 cm). It ranged from 1.68 g cm-3 for disc plows at two passes to 1.72 g cm-3 for zero tillage and disc plows at four passes one month after tillage at a depth of 21-40 cm. Tillage with a disc plow at increased frequencies decreased total porosity, while oxen-drawn Maresha increased total porosity. Insignificant differences (P < 0.05) in mean values of particle size distribution were observed except for percent clay content immediately after tillage with disc plows at two passes, which showed significant highest mean value (26.30%). Tillage by traditional Maresha resulted in more water holding capacity at increased tillage frequencies. Tillage practice using disc plows at two passes significantly affected the bulk density, total porosity, and soil water retention characteristics. In conclusion, tillage implements and frequencies have shown a negative effect on the physical properties of Fluvisols by disrupting the structure of the soil at surface and subsurface depths, resulting in varying levels of impact on soil bulk density, total porosity, and soil water retention characteristics. Therefore, it is recommended to use the tillage implements at reduced frequencies for less disruption of soil properties while performing soil tilth for agricultural production.