The deal with soybeans
Not long after I started farming in 1968, my area experienced four years of drought in the middle 1970's.
When this drought began, most farmers used a rotation heavily weighed toward corn. It was unusual for a farmer to plant more than 100 acres of soybeans. The drought in 1974 when dryland corn was a complete failure and soybeans made 30-35 bushels per acre resulted in soybeans being tagged the "miracle crop". For some of us who were financially thin, soybeans kept us in farming until the weather got better.
Over the years the 50/50 rotation of corn and soybeans became the standard through much of the Midwest because of agronomic advantages of switching every year. In the last few years farmers have taken a different attitude about the rotation. Comments on Ag Online and from other sources have been that corn yield increases have been enough greater than soybean yield increases to tip the scale in favor of more acres of corn and fewer of soybeans.
This switch has surprised me. In the area where I farm, yield increases for soybeans have paralleled those for corn. Even with the prices at planting time this year, I know of only one field in my community where corn was planted on 2006 corn ground. I do not know how the yield was, but the field looked bad all summer.
This situation leaves me pondering why soybeans continue to be so popular in Nebraska while they have lost favor in other states. Soybean yields have kept pace here while in other locations they have not. What factors could be different here than in other places where soybeans and corn are raised? This year Nebraska will have the highest per acre yield of soybeans in the United States. Some think that this is due to irrigation. However, in any given year roughly 60% of soybean acres in Nebraska are not irrigated. Many of the dryland acres would be considered marginal by farmers in the Central Corn Belt.
This year soybeans were again the miracle crop where I farm. June was the driest in history and July rainfall was not much more. Even under those conditions my soybean averaged 55 bushels per acre. That is only one bushel under record year of 1994. Surprising to me, corn averaged 147, well above my average but 25 bushels below the record of 2004. In four of the last five years the soybean yield has been over 50 bushels per acre.
Studying comparable yields of corn and soybean over the years shows almost a perfect parallel between yields and rainfall patterns. In years when rain came early in the summer, like 2004, corn yields were better. In years where rainfall was late in the season, like 2007, soybean yields were better.
One commentator I read this week compared dryland yields in Ontario. The numbers he used were 40 bushel soybeans and 220 bushel corn. His conclusions were obviously different than a farmer in Nebraska who raised 55 bushel soybeans and 147 bushel corn.