Cover Crops Can Provide Much Needed Forage

There is a lot of interest in double-cropping and growing cover crops this fall because of limited forage supplies and the success of these crops in 2012. In addition to providing much needed feed and pasture, there are several agronomic advantages to cover crops. These include erosion protection, nitrogen scavenging, nutrient cycling, building organic matter, improving soil structure and breaking pest cycles.

With the optimism in corn, soybeans and wheat and other cash crops, there is more pressure on each acre of land to produce. Hay and pasture acres have given way to corn, soybeans and wheat. Forage supplies are tight. Double cropping after a cereal crop using a cover crop such as oats is an opportunity to grow additional forage for your livestock. Research has shown that oats seeded after winter wheat harvest can yield 1 to 3.5 tonne per acre where manure was applied. Even in fields without manure, oats can yield 0.5 - 1.5 tonne per acre for forage. At current hay prices of $150 per tonne or more, cover crops can provide an excellent return.

Which Cover Crop Works Best?

Farmers have used a variety of species. Figure 1 shows the result of a 2005 Cover Crop Study comparing oats, oilseed radish, peas, red clover, annual ryegrass, and sudan grass planted after winter wheat harvest, with and without an application of manure. Cover crop yields were typically in the 0.5 - 1.0 tonne per acre range. Red clover (broadcast into the winter wheat in the spring), annual ryegrass with manure applied, and oats produced the most forage yield. Volunteer winter cereals left to grow yielded only 50 - 75% of the oat forage yield. At another site where the cover crops were planted after spring wheat, the volunteer spring wheat yielded about the same as many of the cover crops.

Figure 1. 2005 Cover crop as % of oat yield
Figure 1. 2005 Cover crop yield as % of oat yield

Establishment

Establishing a cover crop can be done using a no-till drill. An alternative is to broadcast the seed on the field, followed by a light tillage pass using a cultivator or rotary harrow to incorporate the seed. Plant the seed at 1.5 inch (3.75 mm) depth. Some tillage can reduce the disease pressure from the preceding cereal crop. Under dry conditions, following with a packer will firm the soil for better seed-to-soil contact and help retain moisture for better emergence. Manure can be applied immediately before planting. Incorporation of manure will capture more of the readily available nitrogen.

Figure 2. Barley seeded following winter wheat for fall grazing.
Figure 2. Barley seeded following winter wheat for fall grazing.


Harvest By Grazing

Harvesting the cover crop using strip grazing with cattle or sheep can be more efficient than cutting and baling. Cereal crops are usually ready to begin grazing about 45 days after planting (Figure 2). They should be grazed before the head-stage of the cereals, as forage quality begins to decline.

A question that often is asked is "does late fall and winter grazing compact the soil"? Research from Nebraska showed beef cattle winter grazing crop residues had no significant effect on the following year grain crop yield, and additional tillage was not required. However, spring grazing increased the soil bulk density and decreased water infiltration rate. Therefore cattle should not graze crop residues after the soil has thawed in the spring.

Figure 3. Strip grazing of kale, pea, barley and oat mixture.
Figure 3. Strip grazing of kale, pea, barley and oat mixture.

Agronomic Benefits

There are several agronomic benefits to using cover crops following a cereal crop. It provides soil protection from wind and heavy rains in the fall months before freeze up, builds soil organic matter, and the livestock improves nutrient cycling. With crops such as red clover, nitrogen can be fixed for the following crop. It also provide the livestock farmer a place to spread manure in the late summer and reduces the nitrogen that could be lost to the environment. The direct benefit to the livestock farmer is the extra feed produced, as he gets more from the land, rather than using more land!


For more information:
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