These days most regional councils are putting rules in place around what can and can't be done on the land and what level of nutrient run-off is allowable.
To make sound environmental policy requires councils and farmers knowing what's happening with the soils; do they leach nutrients easily, do they hold water, how naturally fertile are they?
This information is contained in a soil map but surprisingly few farmers have one, and even councils like Waikato Regional Council, which is funding the production of new digital soil maps - an S Map - won't have the whole region surveyed for another seven years.