Application of a 3-D laser scanner for characterising centrifugal fertiliser spreaders

The suitability of using 3-D laser technology to assess the performance of a twin disc centrifugal fertiliser spreader was analysed. A static test with an Amazone ZA-M twin disc fertiliser spreader distributing di-ammonium sulphate was developed. The spreader was adjusted to spread the fertiliser at a distance of 12 m at three different rates. The test was conducted inside a building; 64 sample boxes were installed on the floor within a 2 m x 2 m frame. Considering the static test, for each spreading rate, five consecutive measurements were made using a Leica HDS6000 3D laser scanner. The information supplied by the laser scanner was correlated with the weight of the fertiliser collected in the boxes using linear regression equations. Each regression model was obtained for one particular and specific spreading configuration. This reduces the applicability of the method because for each spreader setting requires a new surface distribution to be measured to establish a new regression model. A field test was conducted to obtain a fertiliser distribution curve, with the machine set at 41.1 kg min(-1), while the tractor was progressing at 8 km h(-1). This information was used to validate the laser technology by comparing the real distribution curve with the simulated curve. The correlation coefficient (adjusted R-2) was 0.86. The information provided by the scanner also enabled the surface distribution of the product, the maximum spreading distance, the spreading symmetry on both sides of the machine and the trajectory of the grains of fertiliser to be analysed. (C) 2012 IAgrE. Published by Elsevier Ltd. All rights reserved.