Time to plan your cover crops for 2013

Thursday, June 6, 2013

Red clover and oats are the favoured choices, but there are others, each with its unique characteristics. Try it. You'll like it

by PAT LYNCH

Cover crops are the newest crop in Ontario. They build organic matter, improve soil structure, reduce erosion and smother weeds. They have been grown on a few acres for years, but the forage shortage in 2012 added momentum to a great crop.

There are three months to grow crops from the time cereals and canola are harvested until cover crops are killed by frost. That is a full crop season for some crops.

Red clover is the number one cover crop in Ontario. After wheat harvest, consider mowing it to encourage growth and reduce weeds. This allows red clover the even start it needs. If there are spots where red clover did not survive, consider no-tilling oats into these areas. Where red clover is alive, the oats will not grow.

The second most planted cover crop is oats. They should be sown at 65-70 pounds per acre as soon as possible after the wheat harvest and are easier to establish if you have removed the wheat straw. I like some nitrogen to maximize growth.

If you are selling your oats cover crop for feed, use about 60 pounds of nitrogen per acre. If you are going to plow them down, consider 20-30 pounds per acre nitrogen. Manure is a good source of these nutrients. Try and plant oats that were harvested in 2012. Oats have a built-in dormancy. Oats harvested in 2013 will be at least two weeks later emerging.

In a year with lots of moisture (like 2013), the end result is the same from old and new oats. But in a dry year, later germination is a detriment. Adding peas to this mix can increase the yield and may increase feed quality.

If you are selling the oats cover crop, you will be removing phosphorus (P) and potassium (K). A two-tonne per-acre (dry matter basis) crop will remove about 40 pounds per acre of P and 80 pounds per acre of K. At spring 2013 prices, this is about $60 per acre.

If you are selling oats for forage, either harvest it as silage or wrap it. You want to try to cut and harvest in 24 hours.

A bigger issue is what tillage to use on your cover crop. Last year, there were a lot of acres of cover crops plowed. This defeated part of the value of cover crops. Mouldboard plowing a cover crop means extra secondary tillage in the spring. This extra tillage breaks down the soil structure that you were building with a cover crop. Each tillage pass also destroys organic matter and increases chance of erosion.

There are lots of vertical tillage tools that do a nice of turning under a cover crop, while leaving enough residue on top to meet the 30 per cent residue criteria. This year, one of the equipment demonstrations at Canada's Outdoor Farm Show is showcasing vertical tillage tools to handle cover crops. The idea of single pass seedbed preparation is to make only one pass to have a seedbed ready for planting.

There are other cover crops, each with its unique characteristics. You should try more than one. Eventually, every winter wheat acre in Ontario will have a cover crop. Try it. You'll like it. BF

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