Some common errors made during May planting

Sunday, April 3, 2011

Planting depth, crusting and weed control can all present challenges at this time of year. Some tips on dealing with them

by PAT LYNCH

There is so much going on with crops in May, it is easy to forget some things. I have gone back through my May notes for the past couple of years to come up with some common problems that arise in May.

The most common error in May is planting depth. Check planting depth of every row in as many fields as practical. The same depth setting will drop seed at different depths in different fields.   

Many producers use a cultivator before planting corn. Improper cultivator setting is the biggest fault in secondary tillage. Many cultivators are level side to side, but few are level from front to back. If they are not level front to back, you normally set it to the shallowest row. This results in the deepest row working too deep. This brings up wet soil. If you plant into this wet soil, you have uneven emergence.

Crusting is a concern in many years. If you are worrying about a crust, think ahead. If there is a lot of rain followed by a high-pressure weather system with sunny days and wind, your field will crust. Do not wait to see if a crust will form. Use a rotary hoe before it forms. If a crust has already formed, a rotary hoe may not work. The best piece of equipment is a cultivator with the last row of sweeps working the ground about one inch and the rolling basket and tine harrows moving the crust.

Do not worry about killing corn. Many producers have tried to reduce corn populations that were too high by using a cultivator. These efforts were unsuccessful. It is very hard to kill corn that has not emerged with a cultivator.

If you are concerned about a low corn population, research by Greg Stewart, Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) corn specialist, suggests that there is no cost benefit in replanting fields with 21,000-22,000 corn plants.

Soybeans respond to early planting. According to Horst Bohner, OMAFRA soybean specialist, the one thing that consistently increases soybean yield is planting early. From my experience, tillage before planting soys also improves yield. In Horst's plots, he gets about one bushel for tillage before planting soys. The growers I talk to say it is more like five to 10 bushels per acre. If soys are following corn, tillage to break down some corn stalks and warm the soil lets you plant earlier.

If you are concerned about weeds in soys – and if you are not, you should be – consider a residual herbicide in Roundup Ready soys. Growers use a residual herbicide in Roundup Ready corn and have seen the benefit. The same strategy should apply to Roundup Ready soys.

I feel Ontario growers are collectively losing yield because of the glyphosate mentality of not spraying until the weeds are up. When we used to spray Lasso and Lorox or Sencor and Dual, we controlled weeds from the start. We need that mentality with Roundup Ready soys. You do not have to use the full rate of a pre-emerge herbicide. The idea of a set-up rate works in corn and soys. You can mix your set-up herbicide with glyphosate if you are no-till. Wheat weed control is always challenging. If you have underseeded red clover, you may be reluctant to spray too early in case you damage the red clover. Trials by OMAFRA weed specialist Mike Cowbrough have shown that you can spray red clover underseeding any time without affecting it. This presumes normal spraying with normal weather.

Research and on-farm trials by Dr David Hooker, corn and soybean agronomist, University of Guelph, Ridgetown Campus and OMAFRA cereals specialist Peter Johnston have shown the advantage of using a fungicide at weed control time. In fact, in some fields, you will get a bigger yield increase by using a fungicide than by controlling weeds. There is very little research to show a yield advantage to from controlling weeds in wheat. Spraying weeds in wheat will help harvesting, keep any killed out spots clean and reduce the weed seed bank. BF

Consulting agronomist Pat Lynch, CCA (ON) formerly worked with the Ontario agriculture ministry and with Cargill.