EFFECT OF PLOUGHING DEPTH AND SPEED ON TRACTOR FUEL CONSUMPTION IN A SANDY-LOAM SOIL OF OYO STATE-NIGERIA

Abstract

Farm Tractor acquisition in Oyo State-Nigeria is fast growing despite its huge initial capital outlay. These
tractors are primarily utilized for ploughing operations which represents the most costly single item in the
budget of an arable farmer. Tractor fuel consumption constitutes a significant parameter that affects
tractors performances for ploughing operations. The effect of ploughing speed and depth on tractors fuel
consumption was therefore examined in a bid to establish their optimum operating conditions.
The soil characteristics of the study site were determined using laboratory tests. Ploughing operations,
using ASABE standard D497.5 were carried out on 100 x 500 m research farmland 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 to statistical analysis using ANOVA and multiple regression analysis (p<0.05).
The soil type in the study site is predominantly sandy-loam. Mean fuel consumption for Fiat, MF and
Steyr models were 23.35, 23.58 and 24.55 l/ha while average of 16.78, 22.02 and 32.67 l/ha of diesel
were used to plough 20, 25 and 30cm depths respectively. Fuel consumption values increases with
ploughing dept significantly, there is 31% increase from 20 to 25cm and 48% increase from 25 to 30cm
depths. Mean fuel consumption at 5.5, 6.5 and 7.5 km/h ploughing speeds were 20.0, 24.25 and 27.23 l/ha
respectively. Fuel consumption increased by 4.25 liters (21%) when speed is increased from 5.5 to 6.5
km/h and 2.98 liters (12%) when speed increases from 6.5 to 7.5 km/h. Mean fuel consumption (23.35,
23.58, 24.55) l/ha for MF, Fiat and Steyr tractors respectively were significantly different at the various speeds and ploughing depths (0.87 less than or equal to r²  less than or equal to 0.99).

The most appropriate combination of ploughing operating parameters in terms of tractor fuel economy is
achieved using Fiat tractors at 6.5 km/h ploughing speed and 25cm ploughing depth. Tractors’
performance for ploughing operation depends significantly on ploughing speed, ploughing depth and
tractor type. However, the depth of crop roots should determine the appropriate ploughing depth in order
to minimize expenses on fuel.