Footprints of a Grass Farmer
Draining the Land

Tom Frantzen, Alta Vista

1974 was my first year of farming. I rented my dad’s 240 acres with high hopes. What I remember best about that year and the next one was the stark contrast between the crops on ground that had drainage tile as compared to the near total failure of cropping undrained land. I raised a lot of hogs in 1975 and hit a good market for them. Living at home, single and with few living expenses, I had money to invest. Dad had installed 5-inch clay tile on about 30% of the farm. I bought enough clay tile to drain another 60% of the farm. The only place where we did not tile was the Saude and Lawler soils. These soils have gravel subsoil and are naturally well drained. All of this tile were laid out on 80- to 90-foot line spacing. The 80-foot patterns were used on the Clyde soil areas. When this task was finished I thought that drainage was taken care of. It is interesting to note that in 1980 I had 4,000 feet of plastic 4-inch tile plowed in between some of the clay lines that were 90 feet apart.

I am very satisfied with the five-year organic rotation that we use. There are significant differences in the texture of my organic soils when compared to the last of my chemically treated soil. I thought that this rotation would improve the infiltration and general drainage of the soil. I am sure that it does, but I am observing large differences on the crops and soil conditions in between the tile lines. Could crops be even more sensitive to drainage in organic systems than in conventional ones? I think that they are.

Timing of field operations is critical to organic row crop weed control. Rotary hoeing, harrowing and cultivation all have narrow timing windows. All of these tools are sensitive to soil conditions. Lumpy, crusted soil with poor tilth from standing water makes cultivation difficult. Soil in poor condition cannot flow uniformly around the base of the crop to cover small weeds. Flame weeding is an exception here. The compounding factor is that an organic farm cannot fall back and use herbicides for weed control if these mechanical weed control practices fail. One of the reasons for the higher value for organic crops is this inherent risk involved in growing them. Would the value of these crops justify additional investments in more subsurface drainage? How can a value be placed on the likelihood of better weed control? What about the long-term consequences of increasing weed pressure? These are tough but demanding questions. I am going to put an economic value to this factor when I calculate the return per dollar invested.

Maintaining enough available soil nitrogen to grow a good corn crop is another difficulty organic farmers face. Wet years with significant periods of standing water provide the conditions for denitrification. This causes some problems for chemical farmers, who can rely on available and cheap nitrogen. But we organic operators face a really tough situation. We lose available nitrogen too, and any organically approved replacements are very expensive. Again, as with weed control, the value of the crop is higher and the risk of failure is also elevated. Here drainage is even more important. Research work in Minnesota looking at the losses of available nitrogen in the soil profile concluded that close spaced tile lines (40 feet) and shallow placed lines three feet deep significantly reduced denitrification. This is not a big influence in crop yields every year. The years when we have really wet May and June weather, the stage is set for yield loss in the poorly drained soils. As I write this I am observing the differences in the color of my organic corn. One spot in the field has 60-ft spaced tile. The corn looks really good. In another area the lines are spaced at 90 ft, and the corn in between these lines is stunted and has that poor yellow color. In an organic situation what choices do I have to replace the nitrogen lost by these wet conditions? What other than tile prevented the other corn from showing lack of available nitrogen?

The five-year rotation provides a good diversity of crops. I enjoy this because it is a lot easier to get 40 acres of corn cultivated on time than it is to do 165 (half of the farm). The pressure in the spring now comes from the need to get the oats in as soon as possible. Any delay in planting this crop usually results in low yields and poor quality. Tile greatly improves the odds of early planting. What would I do if I were prevented from planting them because of wet conditions? The planting date window here is smaller than either corn or soybeans.