Modelling of power and energy requirements for tillage implements operating in Serdang sandy clay loam, Malaysia

Information is required on power and energy requirements for tillage implements. Draught and energy requirement measurements were made with an instrumented tractor for mouldboard ploughing, disk ploughing, disk harrowing and rotary tilling in the Serdang sandy clay loam soil. The effects of travel speed and tillage depth or rotor speed upon the measured draught and power requirements were investigated. Four polynomial draught and power models from orthogonal regression analyses were formulated based on linear and quadratic functions of travel speed and tillage depth or rotary tiller bite length. The predictions by the draught models developed for the mouldboard plough and the disk harrow were within the ranges of draught recommended by ASAE Standards D497.3. A comparison of the draught model for the disk plough and power model for the rotary tiller with the ASAE Standards D497.3 could not be made simply because these guidelines are not listed therein. Four linear fuel consumption models from regression analyses were also formulated based on drawbar power or PTO power as well as equivalent PTO power. Fuel consumption rates predicted by ASAE Standards D497.3 were found to be 17-33% overestimates of the values predicted by the statistical models developed from measurements. However, fuel consumption rates reported by OECD Tractor Test were found to be 94-109% of the values predicted by the models developed. From 37 to 52% of the measured fuel consumption for the various ploughing operations was required to propel the tractor, and the remainder was used for the actual task of working the soil. Finally, average draught, fuel consumption, wheel slip, drawbar power, tractive efficiency and overall energy efficiency for draught implements as well as average PTO power, fuel consumption, wheel slip, wheel power and specific energy for powered implement are presented. The disk harrow was the most energy efficient implement in terms of fuel consumption and specific energy, followed by the rotary tiller, disk Plough and mouldboard plough. These obtained results will be helpful to develop comprehensive information on power and energy requirements of tillage implements for the formulation of Malaysian agricultural machinery management database. (C) 2004 Elsevier B.V. All rights reserved.