Effects of Three Tillage Systems on Physical Properties of a Sandy Loam Soil

To evaluate the impact of tillage systems on soil environment, it is necessary to quantify the modifications to the soil structure.Three different techniques were compared: minimum tillage with discs harrow, medium tillage with discs plow and conventional deep tillage with mouldboard plowing.Tests were carried out over a sandy loam soil in the Higher Institute of Agronomy of ChottMeriem (Tunisia).Tillage was followed by a first resumption 10 days after and a second one 20 days after.The studied parameters were measured at initial state and after tillage over time.Soil structure was characterized by its resistance to penetration and bulk density.Crumbling index was also evaluated by the method of clods sieving.In soil tilled by conventional system, soil resistance and bulk density increased for a depth of 30 cm.In contrast, tillage with discs plow showed lower values of these parameters in both the surface layer (10 cm) and the plowing depth (20 cm).Minimum tillage system, showed the best values of soil resistance and bulk density than the other systems and a better improvement in soil crumbling index.