One of the best tools to improve the bottom line, reduce future grief, and lower the risks of pests, disease and weeds is by using a diverse crop rotation.
“A good crop rotation is one where there is an adequate variety of crops grown so that any one type of crop is grown only once every three or four years,” says Harry Brook, crop specialist at the Alberta Ag-Info Centre. “A rotation like this can reduce pest costs, prolong the usefulness of pest control products, and improve the bottom line. Limiting or shortening the rotation may provide short-term financial benefits but in the long term, could severely limit future cropping options.”
One example that Brook uses is clubroot. “Once you have clubroot, it is there for the long haul. These soil-borne spores can remain viable in the soil for up to 20 years. If you have it, many counties will require the land be put on a four- or five-year canola-free crop rotation. However, resistance in a crop is not helped when the crop rotation is just wheat followed by canola.”
A variety of crop types can add to the health of the soil. “Pulses in a rotation improve soil health and reduce fertilizer costs,” adds Brook. “Peas, lentils and fababeans all capture nitrogen from the air and encourage beneficial bacteria and fungi that can benefit following crops.”
“Permanent forages in the crop rotation provide even more benefits,” Brook says. “They reduce the weed seeds present in the soil, increase organic matter, and are an excellent break for crop diseases and insect pests. Also, a varied crop rotation can help diversify a farm operation, reducing financial risk. It also spreads out machinery use, making them more efficient.”
Moisture use efficiency also improves with a varied crop rotation. Canola, wheat, and peas all root to different depths and extract moisture from different parts of the soil.
Permanent forages in rotation can also address soils problem such as soil salinity or acidity. Seeded in a field for three to five years, they are an excellent break from annual crops and add to the soil organic matter.
“A diverse crop rotation also naturally varies the pesticides used and reduces the chance of resistance developing to pest control products,” adds Brook. “Conversely, a tight rotation can quickly develop weed, insect or disease problems, requiring greater expense to control the issue.