Blocks should represent management units - as explained in the article "Blocks Overview"; as included in that article:
When dividing a farm into blocks, each block should:
- Grow the same pasture/fruit or crop
- Support similar animals
- Have similar climate
- Have similar topography (for pastoral blocks)
- Have similar fertiliser applied
- Have the same drainage system
In some cases we see very small blocks being created, for example "I’ve just received an analysis of a 96ha total farm modelled as 116 separate blocks – 4 soil types total on farm. Yes it has crops, and irrigation but a good 70% of the blocks would be under 0.3 of a ha"
Creating so many small blocks increases the risks of making mistakes in the data entry, in producing model errors and making reports hard for farmers, other consultants and others to understand.
One of the key issues with very small blocks is when they have animals allocated to them. If, for example, small areas of dryland around the irrigation pivot are blocked separately, rather than simply as part of a larger block with a pivot in there; all of the animals allocated to that block will "rotate through it". This can produce some quite perverse results eg. 1000 dairy cows rotating through a 0.3ha pasture block and quite often can generate model errors.
When the simplify tool is run over such analyses, such blocks tend to be merged with little to no overall effect on the analysis results.
The "illusion" of more precision can be counter productive and should be avoided.