Key Points
The information collected in the study last year, 2001/02, is preliminary data that needs further verification. It can be used as a guide to develop draft sampling and testing procedures but, after a further season’s research, the Code of Practice may differ slightly from the points discussed below:
- The dry matter percentage of maize forage will vary markedly within paddocks, between paddocks and hybrids and in relation to agronomic practices. Thus sampling and testing practices are needed to account for this variability.
- The sampling of a harvested maize forage (silage) crop to determine the dry matter can be most accurately determined by taking auger corer samples immediately after the stack has been compacted, down the length of a finished stack. This method of sampling should be used whenever possible.
- Generally twice as many samples will need to be taken by hand to get the same accuracy as can be achieved with the auger. To achieve a ±0.5% dry matter 95% of the time,14 corer samples need to be taken.
- It is very difficult to get an accurate dry matter value by sampling from trucks.
- At least four samples per truck and at least 65% of the total number of trucks need to be sampled to be 95% confident of being within 1.5% dry matter of the true dry matter.
- Samples must be placed in a moisture-proof sealed plastic bag and delivered to a laboratory for testing as soon as possible. If delivery within 24 hours is not possible, samples should be immediately frozen to avoid change due to the ensilation process.
- To comply with the Weights and Measures Act certified weighing equipment needs to be used for any forage that is weighed.
- All laboratories using the agreed protocol of 500gm dried for 48hrs achieved good agreement with, a standard deviation of ±0.4%.
Further research is needed to confirm last season’s findings and to investigate how combining samples and sub-sampling impacts on the accuracy of the result.