COMPARATIVE ANALYSIS OF FIELD PERFORMANCES OF TWO DIFFERENT FARM TRACTORS

Abstract

A simplified comparative test procedure was developed and adopted to produce information to help farmers and other researchers in the selection and optimisation of tractors. Two different makes of farm tractors, MF 285 and New Holland TT 75 were compared in 96 field performance tests and 24 test conditions on the Indaloke series, sandy loam soil of the research fields of National Cereal Research Institute (NCRI), Badeggi, Niger State Nigeria. The criteria for the choice of the two test tractors were: traction system, age since purchased and put to use, Power Range (40 – 60 kW) and availability. The performance criteria used were fuel efficiency (kW.h/l) and power delivery efficiency (DBP/PTO ratio). Four categorical variables were used in the comparison, these were tractor make (MF 285 vs New Holland TT 75), soil condition (untilled vs tilled), working depth (7 cm, 10 cm and 15 cm), and no-load engine speed (rated vs reduced engine speed). Analysis of variance (ANOVA) was used to determine the statistical significance of the difference between the tractors operating in different settings and field conditions. Results indicate that NH TT 75 tractor exhibited higher field speeds in all test conditions when compared with the MF 285. With all test conditions combined, MF 285 tractor exhibited 21.3 % fuel advantage over NH TT 75 tractor. But when the two tractors were set at rated no-load engine speeds and operated at a working depth of 10 cm, NH TT 75 tractor demonstrated higher power delivery efficiency (0.297) as against MF 285 tractor (0.262).When the performances of the two tractors were combined, they indicated higher fuel efficiency (18.3 % difference) and power delivery efficiency (5.2 % difference) in tilled soil condition as compared to the untilled. MF 285 tractor indicated improvement in both fuel and power delivery efficiencies on a specific working condition when adjusted from rated no-load engine speed to the reduced no-load engine speed, while NH TT 75 tractor indicated no difference. Combining the working conditions, both tractors exhibited optimal performance when throttles are set at the reduced (1800 rpm) no-load engine speeds and operated at 15 cm working depth. Therefore, it was deduced that MF 285 tractor is best suitable to the study area from the standpoint of economy compared to the New Holland TT 75. However, when the timeliness of tillage operation is at stake, NH TT 75 tractor appeared to be the best choice owing to its higher field speed over MF 285.