Crops: The Lynch File - What lay behind those 300-bushels-an-acre yields - and can we repeat them?

Sunday, January 4, 2009

To get consistently high yields, we must be able to irrigate. Till then, we will need hybrids with good root systems

By PAT LYNCH

"So, Doug, how is the corn harvest going?"

"Well, I have seen something I never saw before," Doug replied.

"The combine monitor hit 300 bushels per acre in spots in a couple of farms."

Doug was not the only one making those comments this fall. In 1991, we had growers who hit 200 bushels per acre in spots just like growers did in 2008. For years, many thought we would not see yields like those in 1991. Of course, in the last two years individual growers have indeed averaged 200 bushels an acre on their farms.

I asked Doug what he did to get those yields this year. He said, "Nothing really. It was quite a surprise to me to get those yields."

If we look back on this year, there were a lot of things that happened to make this possible. First was the excellent shape the soil was in. The year 2007 was dry and the fall was exceptional in terms of good growth. This meant that the soil was in good condition going into the winter.

Then we had a spring which allowed early planting. Of all the factors this year, the early planting across the province was the single biggest one leading to the season's record high yields. The early planting into good soil conditions allowed good and even emergence. From all our scout reports, there may never have been a year when we had such good emergence over a large area of Ontario.

The summer weather was also conducive to good corn yields. The fact that the crop did not run out of moisture was the second biggest explanation behind our record yields. There were farms this year who ran over 100 bushels an acre more than they did last year. The reason was water. If a plant is stressed because of compaction, poor root growth and even some diseases, timely water helps the plant to grow out of the stress.

This suggests that, if we are going to consistently get high yields in Ontario, we must be able to irrigate. Now, before you say that this is ridiculous, just hear me out. There could be a 100-bushels-an-acre extra yield to pay for this irrigation.

What's more, we have the water – not in the summer but in the spring. Each spring, you see all the water run off your fields. If you could hold that water on the farm, you could use it to irrigate in the summer. The days of being able to pull water from anywhere, any time, are over. But capturing this spring floodwater reduces the damage of spring run off and helps to grow crops.

You would need about a two-acre pond for every 100 acres and the pond would have to be lined with heavy clay. Many farms already have that heavy clay somewhere on the property. Then you would need to apply probably one inch per acre at two different times in the season.

But until we get more irrigation, we will need hybrids with good root systems. We have finally turned the corner in getting these hybrids with better roots. The newer generations of hybrids coming out will take us to the next yield plateau.

When I think back to the discussion with Doug and his 300-bushel-an-acre corn, his answer that he did nothing different was correct. He did not use a higher seeding rate. He did not use extra fertilizer. On the other hand, those big yields lowered his soil test levels.

So he will have to replace some of that P and K. So does that mean we can get 300 bushels per acre by only putting on enough nitrogen for 160 bushels an acre? Maybe, if you have the soil in good condition and enough moisture.

In 2008, we had record yields with regular management. When planning for 2009 crops, remember how you got those yields in 2008 and don't change too much. BF

Pat Lynch CCA (ON) is head agronomist for Cargill in Ontario.