Comparative Performance Evaluation of Tractor-Drawn Mouldboard and Disc Plows under Varying Soil Conditions in Rwanda

This study was conducted at Gishari College Demonstration Farm to investigate the performance evaluation of tractor-drawn mouldboard and disc plows, the spatial variability of soil properties, and the economic efficiency of tillage operations. The research aimed to optimize tillage practices by providing insights into how different plows perform under varying soil conditions and their associated operational costs. To achieve these objectives, a Completely Randomized Design (CRD) was employed over a 3,600 m2 area Treatments combined two types of plows (Mouldboard and Disc) with three plowing depths (10 cm, 15 cm, and 20 cm), resulting in six treatment combinations replicated across the farm. Data on fuel consumption, soil resistance, weed count, cutting width, field capacity, field efficiency, and wheel slippage were collected and analyzed using descriptive statistics. The study revealed that the soil texture across the farm was predominantly sandy loam, characterized by an average sand content of 62.13%, silt at 28.75%, and clay at 9.12%. Bulk density was found to increase with soil depth, from 1.015 g/cm3 at 0 - 10 cm to 1.338 g/cm3 at 0 - 20 cm, while moisture content also increased from 21.01% to 26.09% within the same depth range. Spatial analysis identified distinct zones of compaction and moisture retention, highlighting the importance of targeted soil management practices to enhance soil health and productivity. The performance evaluation showed that the mouldboard plow achieved superior results in terms of cutting width, effective field capacity, and soil inversion. Specifically, it recorded a cutting width of 0.654 m and an effective field capacity of 0.334 ha/hr at 0 - 10 cm depth. However, it also exhibited higher wheel slippage, reaching 22.35% at 0 - 20 cm depth, and required more operational time compared to the disc plow. The disc plow, although having a narrower cutting width and lower field capacity, demonstrated higher field efficiency (up to 93.684%) and lower wheel slippage (16.60% at 0 - 10 cm), making it more suitable for shallow tillage and harder soils. Both plows showed comparable soil inversion capabilities, with no significant differences in weed burial effectiveness. Therefore, the disc plow presents a preferable option for operations where cost sensitivity and fuel efficiency are critical, whereas the mouldboard plow remains essential for tasks requiring thorough soil inversion and deeper plowing. The mouldboard plow is recommended for deep tillage and effective soil turnover, particularly in fields with high weed pressure, while the disc plow is better suited for routine, cost-efficient operations in fields where traction and operational speed are prioritized. The findings advocate for a balanced approach to tillage selection, considering both soil management and economic sustainability to optimize agricultural productivity under varying field conditions.