Measuring the quality of work and power requirement in grain maize stubble
The quality of work that is provided by the shredder is assessed by conducting field tests in line with the pertinent DLG test framework. The measurements are taken while the machine is shredding at usual groundspeeds in harvested maize fields that meet the testing requirements.
To document the conditions for the present test, the test engineers logged the crop variety and maturity stage, the type of soil and soil value number, the profile of the terrain, weather data, the tractor and com-bine harvester used as well as the header model, the stubble height and the amount of trash left in the field, the moisture level of the trash plus the weather on the day of the test.
The shredder was then set up according to the prevailing field conditions. This was done during extra runs before the actual test runs started.
The pto input was measured on a pto hub dynamo of the DLG Test Center. Forward speed and test course were measured with a Correvit L400 from KISTLER MESSTECHNIK. The fuel consumption was measured using DLG’s mobile fuel meter.
The height of the stubble left in the field after shredding was measured immediately after the test runs. These measurements were taken at a number of sample spots and involved measuring the height of that stubble that had been rolled over before shredding as well as stubble that had not been rolled over before the shredding pass.
After each of the three test passes some of the mulched material was sampled from a 1 m2 area and then exposed to gentle air drying. After that, it was fractioned by a drum sieve (Photo 5). The quality of work was assessed by a number of experienced farmers. These assessed the quality of work according to a four-stepped grading system: ‘very good’ /
‘good’ / ‘satisfactory’ / ‘not satisfactory’.
The moisture of the material was measured gravimetrically at the lab after individual samples were taken during the shredding passes.
Measuring service time
The service work that was carried out by experienced and expert operators are listed below. While they were servicing the machine the time was measured with a stopwatch.
Greasing all grease points incl. the nipples on the drive shaft
The grease gun was next to the machine and readily at hand when clocking started. Each nipple received three shots of grease. After all grease points were attended, the operator replaced the grease gun on the ground next to the machine. This stopped the time taking.
Checking the oil level in the main gearbox.
The necessary tool was readily at hand and placed next to the machine. The tester opened the oil plug and checked the filling level. Then he replaced the plug. Time taking was stopped when the operator had placed all necessary tools on the ground next to the machine.
Checking the belt tension
Again, all tools necessary to check the belt tension were readily at hand next to the machine. After the operator checked the belt tension, he placed all tools back on the ground next to the machine. This stopped the time taking.
Tensioning the belts
Again, the necessary tool was readily at hand next to the machine. After the operator tensioned the belt, he replaced the tool on the ground next to the machine. This stopped the time taking. As mentioned above, each check was repeated a number of times and by several persons. Then the individual measurements were averaged. All tools used for the tests are listed in the report.
Field testing the machine on user farms
The test machine was operated on a number of farms. After each operation, the operators had to fill in a questionnaire which comprised several questions on handling and quality of work. The operators answered the questions by check marking ‘very good’ / ‘good’ / ‘satisfactory’ / ‘not satisfactory’.