Avoid Bermuda grass decline Richmond County Daily Journal

Avoid Bermuda grass decline  Richmond County Daily Journal

Thinning of bermudagrass characterizes bermudagrass decline.  Photo courtesy of Anthony Grow

Thinning of bermudagrass characterizes bermudagrass decline. Photo courtesy of Anthony Grow

ROCKINGHAM – In the summer, bermudagrass is the backbone of our forage systems in the Sandhills.

Throughout the county, there are thousands of acres of this highly productive forage grass that feeds cattle, goats, sheep and even horses in the summer and winter months after it is harvested for hay. If you take a trip around the county between June and September, round “coastal” bermuda grass bales arranged in neat rows on field edges are a common sight.

Although bermudagrass is a highly productive forage, farmers must manage the grass intensively to produce a high-quality crop. Sometimes hay producers are disappointed with production, as they may see a thin stand or bare spots in the field. This is often referred to as “Bermudagrass decline.” Weather, usually lack of rain, is often the first culprit that causes low yields and poor grass condition.

However, there are also other factors that can cause Bermuda grass to decline, and there are some practices that can increase Bermuda grass resilience during dry periods.

Reasons for the decline:

1. Low potassium (K) fertility: Potassium or commonly known as “potash” contributes to winter hardiness, disease resistance and root/shoot production. When K is deficient, bermudagrass does not produce “runners” that keep the grass full and thick. To determine if a K deficiency is the cause of the problem, a soil analysis will be the first step toward solving the problem. Collect representative soil samples from affected areas. Soil sampling tells us what nutrients may be missing as well as the soil pH. For further questions regarding soil sampling, please contact the Richmond County Extension Office. Potassium deficiency may occur during periods of drought even if there are sufficient amounts in the soil. Since potash is absorbed by the roots and is water-soluble, a lack of moisture may lead to symptoms of potash deficiency.

2. Low soil pH: There are several ways that improper soil pH causes problems with Bermuda grass. In our area of ​​North Carolina, toxic levels of soluble aluminum occur in soil where the soil pH is very low. Excess aluminum damages the roots and prevents any further root growth. Low soil pH also reduces the availability of other nutrients such as phosphorus, potash, magnesium, calcium, and others. Ultimately, low soil pH deprives the plant of water and nutrients. The recommended soil pH should be at least 5.5 for coastal bermudagrass, preferably 6.0. Overseeded forages such as clover and ryegrass need a pH of 6.0 or higher for optimal growth.

3. Leaf spot: Brown leaf spot is usually associated with bermudagrass decline. The leaves will have small brown circular lesions that affect the quality of the hay. Brown leaf spot typically attacks Bermuda plants where K levels are low.

4. Ryegrass and other cool-season grasses: The past two springs have been abundant with rainfall and annual ryegrass. Although ryegrass is a boon to some who need spring forage, it comes at a cost. In the spring, when ryegrass breaks dormancy, abundant ryegrass can outcompete ryegrass for water, nutrients and light. Heavy growth of ryegrass and its removal as straw can deplete large amounts of nutrients from the soil, effectively reducing the amount available to bermudagrass. To avoid this problem, be sure to avoid late applications of N (no later than March) on ryegrass stands and utilize as much of the ryegrass forage as possible by grazing it closely.

5. Drought: Bermuda grass is quite drought tolerant. However, if drought is combined with other stressors such as nutrient deficiency and pH stress, drought can be difficult for Bermuda plants to deal with. Remember to maintain soil fertility during good growing conditions (periods of rainfall) so if drought becomes a problem, Bermuda grass will be more resilient.

6. Nutrient mismanagement in hay production: Bermuda grass can be an excellent hay crop if managed properly. But what has been removed, we must replace. Applying high rates of nitrogen fertilizers, such as urea, can increase bermuda plant yields and quality, but producers must be aware of depletion of other plant nutrients, such as potash, which can lead to declines. Annual soil testing and special attention to K levels helps mitigate these problems.

Remember, bermudagrass can be a high-quality forage but comes with a level of intensive management. When used for hay, Bermuda grass removes significant amounts of nutrients from the soil, so it is important that producers replace what is removed using proper soil sampling and fertility plans.

If you have any questions about soil fertility or bermudagrass production, please contact the Richmond County Extension Office at (910) 997-8255.

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