Marketable Cover Crops
by Klaus Karbaumer, photos by LeAnn Karbaumer, both of Platte City, MO
Our small horse-powered farm of about seventeen acres is divided up into roughly two acres of crop land, eight acres of permanent pasture, and five acres of hayfield. The rest of the land includes a pond, the farmstead and barnyard. We are actually over-stocked with four big Belgians and one Haflinger as our workforce, but since we also do hayrides two teams are just fine. Besides, we value the manure which we collect by stabling the horses for about ten hours a day. We keep up to 200 hens for our free-range egg production.
On our two acres of growing areas we raise about 50 different varieties of vegetables and herbs each year. Our records for 2009 indicate we sold a total of 9,600 pounds of our produce while still keeping enough for ourselves. Our produce serves an average of 70 to 80 CSA members, passersby who come in from the road, restaurants, and occasionally a farmers’ market.
We obviously have to work our land intensively for that kind of production. Since we strictly adhere to natural production methods without any pesticides and fertilizers whatsoever, we try to observe principles of crop rotation, succession, and companion planting very carefully. For many years I have admired the work of Anne and Eric Nordell with their intricate rotation and fallow patterns. Their method of weeding the soil, not the plant is very intriguing. Unfortunately, due to different climate and soil conditions, following their example is not feasible for us.
First, we do not have enough land suitable for vegetable production to use long periods of fallowing. Second, grass is our major weed challenge. Even relatively short fallow periods resulted in increased grass growth where I didn’t need it. Our summers here are very warm so occasional very heavy rain brought forth the grass quickly. The grass problem was aggravated by using large amounts of mulch, consisting of old hay, to rapidly improve the worn out soil during the first years on the farm. As a consequence, I prefer to keep crops in the ground all the time to shade out the grass.
Our cover crops have to provide the benefits of smothering weeds, improving soil structure, and replenishing organic matter. They also have to produce some income. For these purposes, we use turnips, mustard and lettuce within our plant successions. I broadcast these seeds thickly on areas where cover crops are necessary and let them do their work. Not all of the plants get harvested then, of course, as this would defeat the purpose. But enough will be taken for marketing so that money can be made while having the beneficial effect of the cover.
It is true that I use the brassica family vegetables quite often because they are so effective at suppressing weeds, fighting nematodes, and making the soil more friable. I try to let a year go by before I plant turnips, mustard, radishes, cabbage, etc… on the same spot. Sometimes the rotation is shorter and I have not experienced bad results. I think it is because of our rapid succession of different plants within one growing cycle.
For example, a plant succession might look like this: spring lettuce, summer tomatoes, fall turnips and overwintering spinach. Or it could be spring radishes followed by summer carrots sown alongside green beans, then Asian greens in the fall.
By the way, I have green beans pretty much on every plot (staggered timing, of course). They are a wonderful help of replenishing the soil with nitrogen, plus they suffocate weeds effectively since I plant the rows densely.
Also, lettuce lasts longer in the fall and even in cold weather stays tender for quite some time when grown tightly. Throughout the year, I plow shallowly and allow for the appropriate time interval before new crops are planted.
The results of these practices can be seen in our increased yields, the soil becoming more and more friable, as can be experienced that plowing and/or disking is easier for the horses, and that I have fewer and fewer problems with grasses, which are my biggest enemy. Also, due to increased tilth I find it easier and easier to grow good carrots which were a major problem when I started. I am convinced that marketable cover crops have merit and that other farmers might benefit from them, too. But by no means do I want to suggest that the system is perfect. I am learning from mistakes every year.