Scrub, there are a lot of factors as to why farmers install drain tile, soil types, terrain, subsoil types, water table levels, field locations, yearly rainfall amounts, crops being grown, but the bottom line is, tile pays big dividends over time to farmers, especially at the cost per acre to grow any crop, the investment is so high on a per acre basis verse the profit per acre that tile lessens to risk to achieve a profit year in and year out is the nuts and bolts of the issue.
With combines today almost all equipped with both mapping and yield data, it makes it very easy for farmers to talk themselves into tiling land, they have all the data they need at a glance when harvesting crops, whereas decades ago, farmers went with averages after harvest to determine what needed tiling, today, they can narrow it down to even the spacing they want, what will profit them the most on a per field basis.
The narrower the margins are for profit, the higher the input costs, the more vital role tile plays in profitability, and that's how its viewed by most, farmers and bankers both want consistency and predictability, tile provides that to the equation on a lot of farm fields, history has shown this over and over again.
450 Bron, thanks for the information on Tait.