Accessing Spreader Performance for Variable Rate Fertiliser Application

A spreading test program was developed to evaluate the ability of obtaining an accurate spread from a groundspread machine under different testing protocols operated throughout the world. The test program involved laying out an array of 1400 0.5 x 0.5m trays edge to edge which allowed a full measurement of the spread pattern occurring from a single spreader to be measured. Results showed that measured certifiable bout width differed by 14.8m at 15% Coefficient of Variation and 2.3m at 25% Coefficient of Variation. The ability of a spreader to be adapted to perform variable rate application was also investigated. A Nitrogen application map was created based on pasture growth and soil information. Test data collected from the spreader was used to simulate the ability to perform variable rate application using a geographical information system. It was concluded that overlap spread pattern was a major limiting factor of accurately applying fertilizer in the correct application zone. The investigation gave the ability to observe firstly, what the adequate requirements are for a spreader testing program, and secondly, how the collected information can be used to assess potential for variable rate application.