One way to increase crop production and productivity is to properly feed crop plants, which
results in increased production per unit area. Chemical fertilizers and compost alone cannot
provide for plants' needs. Therefore, mixing these two types of fertilizers in a specific ratio is
necessary. The main problem with mixing compost and chemical fertilizers is controlling their
mix ratio. In this study, a twin-shaft paddle mixer was designed, fabricated, and evaluated to
solve the problem of adequately mixing compost and fertilizer urea. The constructed device
includes a 1.5 kW electromotor, chassis, paddle, and chain-sprocket mechanism. Experiments
at three levels of the axis rotational speed of 20, 40, and 60 rpm and three levels of mixing
path length of 72, 108, and 144 cm, and two levels of paddle angle of 45 and 60-degree with a
rotating axis in three replications under factorial test based on completely randomized block
design. The analysis of variance of a distance effect on the measured urea-compost ratio
showed that the rotational speed of the axes, the paddles angle, and mixing length of 1 and 5
% level were significant. Also, the results of the comparison of mean effects of treatments
showed that the paddle angle of 45 degrees, the rotational speed of 40 rpm, and the mixing
length of 108 cm had the best performance.