On the Noise of Farm Machinery and its Effects on Human Performance

Abstract

The noise is one of the largest environmental stress in mechanized farming. Noise of some field and barn machinery was investigated by a portable noise-level-meter, a stereotype taperecorder and an octave-band-analyser.
Table 2 shows noise loudness from representative sources. Noises of a speed sprayer and a wheel cutter not only showed the highest loudness, but also contained more abundant components of relatively high octave bands as shown in Fig. 1. Noises of higher frequency seemed to originate chiefly from a blower and a cutting wheel.
Seventeen normal-hearing students were exposured to each of recorded noises of a 27PS tractor, a forage harvester and a wheel cutter for 7.5hr including a noon recess of 60min and twice rests of 15min. Heart rate, critical flicker fusion frequency and output of adding integers of one figure were not influenced significantly by being exposured to noises. Only hearing acuity at octave band level centered at 4, 000c/s showed a significant loss after the first 75min exposure to the noise of a forage harvester (Fig. 2).