Reasons for Grain Lodging and Ways to Prevent It

By Dr. Michael D. Peel, NDSU Small Grains Extension Agronomist
mpeel@ndsuext.nodak.edu

Lodging in small grains was a major challenge to producers in eastern North Dakota and Western Minnesota this past growing season.  So the question is, how can we minimize this problem in the future?

The factors that affect lodging include: variety, soil type, fertility, moisture, seeding and crown depth, disease, and weather.  Varieties differ in height and straw strength, both of which impact the propensity of a variety to lodge. Taller varieties tend to lodge more than shorter varieties due to simple laws of physics, i.e. as the distance between the fulcrum and load increases the more likely the lever is to break.

Straw strength is important
Actual straw strength also is very important. Just because a variety is a semi-dwarf does not mean it won’t lodge. The combination of straw strength and plant height are the best indicators of lodging potential. A short strong strawed variety will be the least likely to lodge.

Soil type, nitrogen, and moisture all impact lodging. Wheat, or any small grain crop, responds to growing conditions. High nitrogen and high moisture favor lush rapid tall plant growth. You have probably noticed that crop growth tends to be better in low spots than on hill tops, and that lodging is more frequent in these areas. Why? Low spots tend to have heavier soil, collect moisture and tend to be higher in nitrogen, which favors increased plant growth. Not only are these plants taller, but they are also supporting more biomass and larger heads, compounding the effect of height.

Don’t apply more nitrogen than is necessary
Cutting nitrogen applications and praying for dry weather will certainly go a long way to solving lodging problems, but of course this would be at the expense of productivity and yield. The better strategy is to test the soil, find out how much nitrogen the crop needs to meet a reasonable yield goal, and don’t apply more than needed.

Producers often tell me, “Well, we fertilize for a 60-bushel yield even though we know 50 is more reasonable.” Don’t get caught in this trap; it’s a waste of money and will increase lodging problems, not to mention increased propensity for leaf disease.

The crown depth of wheat or barley, while difficult to quantify, is a factor in the plant’s ability to stand during conditions that favor lodging. A plant with a crown 1/4 to 1/2" deep will be more likely to lodge under wet windy conditions than one much deeper. Wheat and barley like to have their crown about one inch below the soil surface. If actual planting depth is less there is no way for the plant to have a deeper crown depth. Optimum planting depth for wheat and barley is 1.5" to 2" deep.

Use proper rotations and seed treatments to prevent root diseases
Root diseases can substantially weaken a wheat plant and increase lodging. Some root diseases like foot rot or eyespot can result in severely lodged wheat. While common root rot is common in the region, root diseases associated with severe lodging are not. The use of proper rotations and seed treatments are the best way to manage these and other soilborne diseases.

Weather is always a compounding effect when lodging is an issue. Heavy rain, combined with wind strong enough to knock down power lines and trees, will surely knock down even the most lodge-resistant variety, particularly when the soil is already wet. If this occurs while the crop is still growing it will generally recover and stand back up. When it occurs repeatedly, the ability of the crop to stand back up diminishes.

Take advantage of agronomic information
So what are the best recommendations to minimize lodging? Use the agronomic information provided in this issue to its fullest potential. The variety description tables (see pages 21-40) have extremely valuable information in them. Judiciously selecting varieties that contain the characteristics that you require, including lodging resistance, will pay dividends through harvest. Variety selection decisions should not be based on who runs the best commercials or on what your seed supplier has on hand, but on careful evaluation of unbiased information applicable to your growing area and conditions.