Soil Structure and Moisture Constants Changed by Tobacco Waste Application in a Clay Textured Field

In this study, effect of tobacco waste (TW) application on soil structural parameters and water holding capacity were determined in a clay field. Tobacco waste was applied into a clay soil surface (0 - 15 cm) with 4 different rates (0, 2, 4 and 6%) and three replications in a randomized plot design. After eight months, changes in soil organic carbon content, bulk density (BD), total porosity (F), gravimetric (W) and volumetric ( θ ) water content, air filled porosity (Fa) and relative saturation (RS) values were determined in clay soil for each treatment. TW application rates significantly increased organic C contents and F values while they significantly decreased bulk density values of the clay soil. Although the W values significantly increased over the control, the θ and RS values decreased with increasing the F values by the application of TW. The high application rates of TW (4 and 6%) increased moisture content at permanent wilting point (PWP) more than at field capacity (FC). Thus, AWC values in higher rates of TW were lower than the AWC values in 2% rate of TW and control treatments. Increasing Fa is important for plant root respiration and microbial activity especially in the clay soils. The high rates of TW increased F values but decreased the AWC of clay soil over the control treatment.