Crops - The Lynch File: The pros and cons of weigh scales, small fields and other things that affect your yield

Thursday, January 31, 2008

Weigh scales help you plant cereals and beans accurately, while small fields yield less and cost more. These are among some points worth pondering this winter

by PAT LYNCH

Weigh scales and small fields - what does each have to do with the other? Absolutely nothing. But they are two of the things that made an impression this year.

Weigh scales are mounted on drills. They do an incredibly good job of helping you to plant cereals and beans accurately. You try to plant both beans and cereals by seed count. Seed bags tell you how many seeds per pound. These scales do an accurate job of allowing you to know how many pounds you have planted.

You have to know how many acres you plant. But that calculation is fairly simple if you know the width of your drill and the lengths of your fields, or the acreage of each field.

This year, small fields cost growers significant dollars. It first showed up with compacted areas from the 2006 harvest. Small fields have more acres of headlands. Compaction on headlands cuts yields. Small fields yield less. Then, when we got into spraying for aphids or any other spray, small fields again were submitted to more trampling.

What's more, small fields also limited the size of sprayer. If you can use a 90-foot sprayer instead of a 60-foot one, there is less trampling. If you go to a 120-foot sprayer, the tramp loss is less. The difference in tramp loss between a 60-foot and a 120-foot boom could be half a bushel per acre.

When you use custom sprayers, some will charge a start-up fee. That means they charge you to go to a field and then charge a fee per acre afterwards. With smaller fields, you can expect to pay more. Currently, growers with larger fields are subsidizing growers with smaller fields when a custom sprayer charges a flat per-acre fee.

On a completely unrelated topic, do you wonder why red clover is harder to establish in no-till wheat than conventional-till wheat? Ontario research shows that when you underseed red clover into no-till wheat you get about one-third less red clover than when wheat is conventionally tilled.

The reason, as a grower pointed out to me, is fairly simple. In no-till wheat, there is so much trash from both soybeans and the previous year's corn stalks that red clover has a more difficult time to establish itself than if the ground is worked and there is no trash.

By the way, that corn trash from two years ago is also a source of innoculum for Fusarium in wheat. Thus, fields with corn stover still showing pose a higher risk of Fusarium than fields without corn stover.

Another unrelated topic for winter discussion is insects in corn. In North America, about 50 per cent of the corn carries the Bt gene. There are researchers in the United States who suggest that, because of this high percentage, corn borer populations are dropping. So even if you are not using the Bt gene, you may be getting benefits from others using it.

In other crops, we are seeing more insects taking yield. In soybeans, the Bean Leaf beetle continues to increase in numbers. Each year it takes a bit more yield. There are seed treatments that can help control this pest. BF

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