The Effect of Ploughing Depth and Speed on the Fuel Consumption of some Commonly Used Farm Tractors in Selected States of South-Western Nigeria.

摘要

Ploughing operation represents the most costly single item in the budget of an arable farmer. The rate of acquisition of farm tractors in South-Western Nigeria is fast growing despite its huge initial capital outlay. A substantial portion of these tractors are utilized essentially for ploughing operations among other uses. Tractor fuel consumption constitutes a significant parameter that affects the overall performance of tractors for ploughing operations. The effect of ploughing speed and depth on ploughing operation performance were therefore examined in a bid to minimize operating costs and maximize farm profit margins. The soil characteristics of the selected states were determined using laboratory tests. Ploughing operations, using ASABE standard D497.5 were carried out on 500 x 500 m research farmlands in each of the selected states using Massey Ferguson (MF 435, 100hp), Fiat(F130D, 100hp) and Steyr(CVT170, 100hp) tractors that were purchased in 2009. Field experiments were conducted at 5.5,6.5 and 7.5 km/h ploughing speeds for ploughing depths of 20, 25 and 30cm. The fuel consumption was measure by estimating the quantity of diesel that fills the tractor fuel tank to capacity after each runs of the experiment. The results were subjected tostatistical analysis using AN OVA and multiple regression analysis (p<0.05). Soil types in Ondo, Ogun and Oyo States are predominantly clay-loam, sandy-clay and sandy-loam respectively. Mean tractor fuel consumption in Ondo, Ogun and Oyo states were 29.72, 28.23 and 27.25 l/ha while average of 25.88, 27.83 and 31.10 l/ha of diesel were used to plough 20, 25 and 30cm depths respectively. Fuel consumption values increases with ploughing depth, there is 7.5% increase from 20 to 25cm and 11.7% increase from 25 to 30cm depths. Increasing the ploughing depth increases the tractor's fuel consumption significantly. Mean fuel consumption at 5.5, 6.5 and 7.5 km/h ploughing speeds were 27.04, 28.50 and 29.26 l/ha respectively. Fuel consumption increased by 1.46liters (5.4%) when speed is increased from 5.5 to 6.5 km/h and 0.76 liters (2.6%) when speed increases from 6.5 to 7.5 km/h. Mean fuel consumption (27.60, 28.31, 29.29) l/ha for MF, Fiat and Steyr tractors respectively were significantly different in theselected states (0.87 < r~2 < 0.99). The most appropriate combination of ploughing operating parameters in terms of tractor fuel economy is achieved at Oyo State using Steyr tractors at 6.5 km/h ploughing speed and 25cm ploughing depth. Tractors' performance for ploughing operation depends significantly on ploughing speed, soil type, ploughing depth and tractor type. Seed placement less than 25mm into the soil is recommended for crops that are directly seeded. However, the depth of crop roots should determine ploughing depth in order to minimize expenses on fuel.