Berry's Picks

Bermudagrass Decline

I have had lots of questions and looked at a good many fields where the bermudagrass has thinned or is completely gone.

While the quick response to questions about bermudagrass decline is to blame it all on last year’s drought and drought stress, the broad term we call bermudagrass decline can encompass many ailments and is usually associated with more than one problem. Certainly, the drought brought on many problems and is the key contributor to many of the issues that are still causing problems in our bermudagrass fields.

However, we have no control of the weather, so I am going to focus on some primary factors that we can change to help our fields.

Many of the fields with thinning stands (actually almost every field), I have looked at this year have low potassium (K) fertility. With the unprecedented higher cost of fertilizer, the last few years, many folks have understandably been only adding nitrate and skimping on potassium. For heavy producing fields, potassium needs to be added at the same rate as nitrogen for maximum production and healthy stands.

This much potassium is not cheap but is required for heavy bermudagrass production. Potassium deficiencies will result in poor stress tolerance, poor disease resistance, and lower rhizome or stolon production. Fields with low K levels may have issues with fungus and other diseases, but the disease is probably only a symptom of low K levels.

Low soil pH is another soil nutrient issue that we can correct. Low soil pH can reduce the availability of other nutrients like phosphorus, potash, calcium, and magnesium. This can cause the plants to starve due to their inability to utilize nutrients. In some instances, a low pH can lead to toxic levels of Aluminum (AL). This will result in damaged root systems and little to no root growth.

These two issues can be determined with a simple $12.00 soil test. The test will tell you if you are low in any of the major nutrients as well as your soil pH. The soil test will make nutrient recommendations based on what nutrients are currently available in your soil. If you are deficient in K, you can add it at any time and expect some results after some good rainfall. If your soil is acidic, planning lime application in the fall can make a big difference in next year’s stand.

Nutrient deficiencies and the drought are the primary reason for bermudagrass decline. But there are some secondary factors that can also play a major role in decreasing bermudagrass stands. Due to the weak stands of bermudagrass, weed competition was really bad this last year. For every pound of weed you have in your field, you are losing a pound of grass. So, being ready to get on top of any weed issues in your fields next year can really help allow your bermudagrass to be able to utilize all the nutrients you are applying as well as any available moisture. It does not pay to feed weeds.

Soil compaction can affect the ability of your soil to absorb nutrients and water. Haying operations and even cattle traffic on your fields can eventually compact your soil to the point that most nutrients and water just run off rather than soaking into the soil. There has been much debate about the effectiveness of aerating land; there are certainly pros and cons. My biggest concern with aerating would be if your plants were already weak, aerating may further weaken the roots. For this reason, I really only recommend aerating healthy stands, preferably early spring before green-up. These are certainly not the only reasons we have lost bermudagrass this last year, but these are a few of the issues I have noticed in the last few months that have really helped to thin some bermudagrass stands.