July 1998
Most farmers today are happy with the early spring we had this year. May was warm and dry and we were are able to plant the cereal grains ahead of schedule and watch them grow quickly. I read reports of a good wheat harvest in some parts of south-western Ontario. Let us hope that the recent rains will hold off to allow for a good crop and a timely harvest at home.
Our short season does not permit a second cash crop. So do we just plow the field and leave it there till next spring while we get ready for the bean and corn harvests? Of course not! A good ecological farmer knows that a bare field is like asking for trouble and it would forego an excellent investment opportunity - an investment in soil fertility. An ecological farmer will take every opportunity to plant a cover crop or a winter crop.
First of all, if we leave a field bare then Mother Nature will cover it for us - usually with a good crop of weeds - and it does not take long. Tillage will disturb the seeds that a weed may have set this summer. A cover crop will compete with and suppress weeds until the frost. Winter crops will continue to suppress weeds next spring either until harvest or until the crop is tilled as green manure. Therefore cover crops are an excellent weed control method; they are cost effective versus herbicides, are much safer for the farm family, and present less risks for the environment.
Winter crops also have the advantage of offering an interesting cash crop. After having served their function of good weed control, a decision may be made in the spring. Our harsh winters are sometimes rough on winter crops; they either suffer from the frost or they stand in too much water on our flat lands. Winter crops fare best on well drained fields and rolling hills. If the crop is strong in the spring, then leave it for harvest; otherwise, till it for green manure which is still a valuable investment. And surprise! It is great to start the spring with the planting already done in a few fields thanks to a winter crop.
Our soils are in dire need of organic matter. Ideal soil contains about 5% organic matter, but over the last decades, we have sold our straw, mono-cropped light plants like soybeans, killed the micro-organisms with sprays, sold our livestock and lost the manure to the point where the average organic matter in North American soils now stands around 2%. It is no wonder that we need all that expensive fertilizer! Organic matter creates good tilth which improves drainage during wet seasons, improves water retention for the dry days, lightens the soil and thus reduces the horsepower required for tillage and, very importantly, provides nutrients for the next crop. An ecological farmer craves for the fall season when he/she can invest in organic matter with a good cover crop.
Another important issue is erosion. You wonder where the field nutrients went when you see the rivers turn brown in the spring. Cover crops hold the soil down during the rains in the fall and spring. Cover crops also provide a break in the pest and weed cycles that typically align themselves with preferred crops. The break is important to decrease their reproduction capacity and interrupt their preferred feeding habits.
Cover and winter crops suit some situations and not others. The most obvious opportunity is following a cereal harvest in July or August. There are also old pasture and hay fields which are due for a crop rotation and they become available in August. There is land which is being reclaimed from overgrowth or bush plus the fields that have been tile drained this summer. There is the idle farm that you just purchased or rented in view of next year’s crop.
It is obviously difficult, but not impossible to use cover crops with corn and soybeans. An organic farmer likes to plant soybeans in wide rows in order to cultivate weeds. You can also drive through to broadcast clover in the soybeans in late summer or early fall; as the leaves fall, they create a seed cover, cause germination and you get a good legume cover in the fall and spring for nitrogen fixation and organic matter in order to plant corn, wheat or barley.
There are several cover crops and winter crops to choose from:
As you can see, cover crops and winter crops are very important allies for the organic farmer, either in the field or at home in the garden. He/she would consider herbicides and fertilizers as an unnecessary expense, but cover and winter crops as a critical low-cost investment in a sustainable farm. They play many roles and repay their worth several times. So don’t leave those fields idle this fall, make them work for you.
A contribution by Tom Manley
President of Homestead Organics