Soil Bulk Density and Potato Tuber Yield as Influenced by Tillage Systems and Working Depths

To evaluate the effects of tillage systems on soil bulk density, yield and quality of potato crop (Solanum tuberosum L.), three different tillage techniques were studied: reduced tillage using discs harrow (RT), medium tillage depth using discs plow (MT) and conventional deep tillage using moldboard plowing (CT) with three working depths of 10, 20 and 30 cm respectively. Tillage was followed by a first resumption after 10 days and a second one after 20 days. Soil structure was characterized by its bulk density and potato quality by tubers size and yield. Samples were collected from tilled plots at different dates spaced of 20 days. The obtained data were tabulated and analysed using IBM SPSS 17.0 version and Tukey test. Compared to MT and RT, CT decreased bulk density to 1.16 g cm-3 against 1.23 and 1.4 g cm-3 60 days after tillage respectively for the two previous tillage systems and increased tubers size and consequently the potato yield to an average of 11 Mg ha-1 compared to 9 and 7 Mg ha-1 respectively for MT and RT. The statistical analyses of the data showed significant effects of the treatments and the measurement date on soil bulk density.