Cover crop mixtures

When choosing a mixture, it is essential to consider the practicalities, such as the management of variable seed sizes, potential rotational conflicts with similar species, and cost.

It is also important to consider how the components will complement each other:

Growth: Is one component likely to out-compete another?

Destruction: Are the life cycles and breakdown characteristics suitably matched?

Objectives: Do the functional traits help to achieve your overall goal?

Other crops: Are any of the components going to give problems in the following crops?

Common mixes

The most common mix is grass and legume, such as:

• Winter rye and hairy vetch
• Oats and red clover
• Field peas and small grain species

Other mixtures include a legume or small grain with forage radish or just different small grains mixed.

Mixtures usually do a better job of suppressing weeds than a single species.

Growing legumes with grasses help compensate for the decreases in nitrogen availability for the following crop.

Winter rye-hairy vetch mixtures provide another advantage for managing nitrogen. When a lot of nitrate is in the soil at the end of the season, the rye is stimulated (reducing leaching losses). When little nitrogen is available, the vetch competes better with the rye, fixing more nitrogen for the next crop.

A crop that grows erect, such as winter rye, may support hairy vetch and help it grow better.

Mowing close to the ground kills vetch supported by rye more easily than vetch alone. This may allow mowing, instead of herbicide use, in no-till production systems .