LEWISTOWN – In the third and final installment of the cover crop series, we will look at the other benefits and disadvantages to cover crops.

Cover crops have many other benefits other than suppressing weeds for cash crops:

Erosion control

It has been discovered that fields that are covered are less susceptible to erosion for three reasons. The first, according to research from the US Department of Agriculture, is plant residues and leaves reduce the harsh impact of raindrops, which reduces the amount of soil rain could potentially loosen. Another reason is the plant stems reduce the amount of water flowing over the soil. Finally, roots of plants hold the soil and prevent it from washing away.

Organic matter

and soil tilth

To promote good soil structure, organic matter in the soil is important, according to the USDA, it helps to increase the drainage and aeration of the soil. Organic matter is also important for the soil to better hold in nutrients. Cover crops can be an excellent source of organic matter or can help maintain natural organic matter.

Nitrogen fixation

Legume cover crops are able to fix nitrogen found in the atmosphere through certain bacteria in the soil. This allows the nitrogen to be slowly released into cash crops when the cover crops begin to decay.

Nutrient trapping

or scavenging

Cover crops which are planted and growing during times when the soil would typically be bare can help to trap nutrients that could be lost if nothing is planted. Nutrients can either be lost through leaching or runoff from rainwater. These nutrients could help with the overall growth of cash crops or nearby water source water quality.

Beneficial organisms

Different cover crops may improve the soil environment for organisms that improve the soil quality or prey on harmful pests.

Feed and forage

Some cover crops, especially those in the grass family, can be used for livestock feed. This can be made into hay or used directly for grazing.

While these are some, not all of the advantages to cover crops, there are also disadvantages to using the same cash crop fields for cover crops. However some of these can have minimal effect if managed correctly.

Additional expenses, which could include the cost of seeds, labor and equipment for planting. This could also include the cost for alternative equipment because of greater amounts of residue from the cover crop.

Competition with cash crops, this could happen if the cover crop goes unmanaged. Incompletely managed cover crops can behave like weeds, if left unchecked, according to USDA research. They can compete for water, light and nutrients, sometimes leaving less water for the cash crop in dry seasons.

Pests, while the preventing of pests is a possible advantage, sometimes they can bring or keep around bad pests. Farmers can reduce this by planting cover crops that do not provide a ‘green bridge’ for pests. For example, clover root curculio is a common pest of red clover, which has been known to attack

alfalfa plants.