Planting Under Trees Kill Yields

Can you afford to farm tree-lined field borders?

Published on: Sep 18, 2007

If you've been following our Corn Illustrated plots in the magazine or on our Website, results are in for how well, or how poorly, the outside 12 rows near a mature, tree-lined fence row performed this year. These 12 rows were not part of our plot, but were harvested separately to gauge the effect of the trees, then compared to the same hybrid at the same nitrogen rate from six rows in the middle of the field.

Have you ever seen a combine yield monitor register 5 bushels per acre? It did on the first six rows next to the tree line. There was virtually no corn in most of those six rows. Some plants never got taller than a foot. The outer rows of the six did, but many stalks were barren. Averaged together, the entire 12 rows made roughly 20 bushels per acre. Final adjustments for moisture have not been made yet.

The entire field was severely damaged by drought. It consists of three feet of loam soil over gravel. Last year yields on that type of soil in south-central Indiana ran 150-180 bushels per acre. This year, 65 to 120 bushels per acre catches most fields. The comparison strip to check against the rows near the fence line made 90 bushels per acre.

It doesn't take a math expert to figure out that planting those first 12 rows didn't pay this year. Yield was less than one-fourth of the rest of the field. At 20 bushels per acre and $3.50 per bushel corn, that's only $70 per acre revenue, which does little more than cover costs of sidedress and starter nitrogen.

"The first 12 rows would normally do better than that, but the first six rows right against the tree line are hardly ever very good, even in good years," says Jim Facemire, Edinburgh, cooperator for the Corn Illustrated plot.

This example makes a strong case for considering whether it's worth planting those rows nearest a tree-lined fence row or woods. It might be worth investigating what wildlife program incentives are available from either the Farm Service Agency or the Indiana Department of Natural Resources. Those agencies were pushing such programs last spring, knowing it would be tough to compete against $4 corn. But it may not be as tough to compete against $3.50 corn, if the ground going into the practice is so marginal that it may or may not return enough revenue to cover variable expenses, let alone any left over for labor, management, machinery and land.

Bob Eddleman, former Indiana State conservationist, recalls a study in northern Indiana where a windbreak actually improved yields. However, that was typically in very sandy soils, and yields were improved on the opposite side of the windbreak from where the 12 rows were planted in Facemire's field. Eddleman is researching the topic, and will report his findings soon.

Meanwhile, push your pencil hard when you're negotiating on land rent on tree-lined fields, or figuring input purchases on your own land. You may be losing more on land yield than you think. In this case, 12 rows across this field equaled three-fourths of an acre. That's lots of dollars spent on inputs that generated precious little revenue, and a negative return on investment.