Effect of Variable-Depth Tillage System on Energy Requirements for Tillage Operation and Productivity of Desert Soil

Abstract

Tillage systems classified into two groups: conventional (CT) and conservation (CVT) tillage. The first group (CT), soil inverted and crop residues buried. (CT) has some disadvantages. Firstly, disturbing the soil unnecessarily in areas where the soil structure and condition is not required is wasteful of time and fuel. Secondly, incorrect tillage depth can cause damage to the soil structure, which can lead to the formation of a compaction layer. The second group, (CVT) defined as no-tillage with leaving at least 30% of the crop residue on the field. (CVT) improves the efficient usage of the natural resources of water and soil. However, (CVT) has some drawbacks such as not recommended if the soil has compaction problems. Recently a third group emerged, namely variable-depth tillage (VDT), or precision tillage technology optimizes soil physical properties only where the tillage needed by applying tillage at the required depth. (VDT) has been shown to reduce costs, labor, fuel consumption and energy requirements. To implement (VDT) system, it is necessary to determine and map soil penetration resistance, spatially and with depth through the soil profile. Therefore, an experiment conducted in a field to evaluate a technology to determine the tillage depth based on soil penetration resistant at different depths of soil. The field experiment area divided into five plots (no-tillage - uniform-depth tillage at 25cm tillage depth - uniform-depth tillage at 35cm tillage depth - uniform-depth tillage at 45cm tillage depth - variable-depth tillage) where, no-tillage indicated to (CVT), uniform-depth tillage indicated to (CT) and (VDT) indicated to precision tillage. The study measurements were fuel consumption rate (FCR), actual field capacity (AFC), power requirements (PR), specific energy (SE), operating costs (OC), soil penetration resistance (SPR) and sorghum yield (SY). The results showed that compaction layer occurred between the soil depths of 25cm and 35cm. Therefore, the (VDT) system was used at a tillage depth of 35cm. The average ratio from total field area that needed to till was about 47%. The results showed that (VDT) system caused a decreasing in the (FCR), (PR) and (OC) about 35%, 35% and 23%, respectively, compared to uniform-depth tillage system (UDT), while the (AFC) for VDT system increased about 21% compared to (UDT). The (SY) for (VDT) system increased about 53% compared to (UDT) at 25cm tillage depth, while the (SY) for VDT system decreased about 8% and 11% compared to (UDT) at 35cm and 45cm tillage depth, respectively.