Planting corn into sod comes with some general opportunities and challenges. Corn could generate a gross return of $500-700/acre, or more, depending on yield and marketing. That is a large enough opportunity to consider taking old pasture or hay fields and converting them to corn for 2011.
While some producers have plenty of experience with corn, others are more experienced with tobacco, hay or pastures. The general comments below are targeted to both types of producers.
1. Nitrogen benefit. Land that has been in a grass and/or legume sod for four years will reduce the fertilizer nitrogen (N) requirement by about 25 lbs. N/acre. If that soil has been in sod for five years or more, then fertilizer N can be reduced by 50 lbs. N/acre.
2. The vast majority of hay and pasture fields are potassium (K) deficient. Hay removes a lot of K2O from the soil, while pasture fields tend to remove a little less. Without even conducting a soil test, odds are very good that the sod will need about 60 lbs. K2O/acre. Of course, a soil sample provides a much more accurate estimate of what is needed in the field.
3. Soil test now, or as soon as the soil allows. Fertilizer prices are rising along with corn commodity prices. A soil test spans 20 acres and will cost about $5-10/sample. The fertilizer bill will be well over $1,500 for those same 20 acres. A soil test identifies the nutrient deficiencies in the soil and allows you to apply only what fertilizer is needed. Pull about 10-20 cores, each 4 in. deep, for a 20-acre area. Mix all of the cores together and from that mix, send in a sample for testing.
4. Apply K, phosphorus and zinc fertilizer according to the soil test recommendations. These applications can be made anytime before planting.
5. It’s too late for lime this year. If your soil pH comes back low, you can apply agriculture lime, but it will not help much until the 2012 growing season. If you could have applied lime last fall, that would have been ideal. Pelletized lime is marketed as reacting faster with the soil, but it will not react fast enough to help with this season. Save your money and stay with commercial agriculture lime. If your pH is really low (5.5 or less), lower your expectations for yield. Unless you receive an inch of rain every week during the growing season, yields will be reduced.
6. Control the weeds early and stay aggressive. If at all possible, burndown the sod before you plant corn. Ideally, corn would be planted into “brown” remnants of weeds. Either Gramoxone or glyphosate are good options. Gramoxone tends to work a little better than glyphosate at cooler temperatures.
7. Keep sod waterways. Examine the sod fields and identify low areas where water flows. Many producers spend a lot of money establishing sod waterways. Here is one opportunity to leave them established before you start row-cropping.