Lodging in Spring Cereals
Recent strong storms that brought heavy wind and rain have left sporadic lodging in many areas of the province, especially in barley fields. Lodging can have a significant impact on yield, and almost always has a negative impact on grain quality. In addition, lodging can create challenges when harvest time rolls around.
Lodging can be defined as when the stems of a crop have completely or partially fallen over from their normal vertical position. There are two types of lodging that occur in cereal crops:
1. Root Lodging
- Stems are straight and intact, but are leaning from the crown
- Most common form of lodging
- Tends to occur earlier in the growing season
- Involved disturbance of the root system
2. Stem Lodging/Breakage
- Bending/breaking of lower internodes
- Induced by storms (wind/rain/hail)
- Can occur from insect damage (eg. Wheat stem sawfly)
- Tends to occur when crop is drying down or ripe
For fields that lodge earlier in the season (prior to grain filling), it is possible for the plants to partially regain their upright position. This is done by the plant bending and enlarging one of its nodes into an “elbow” shape. The cells in the enlarged nodes will stretch on the shaded side of the stem in attempt to raise the plant. However, after the second time a stem lodges it will be unable to straighten again.
Lodging results from the combination of many factors but is usually induced by heavy winds. It is most observed in the grain filling stage, as most of the plant weight has shifted to the upper portion of the plant. The main factors that increase risk of lodging include:
- Tall varieties or varieties with poor straw strength. Taller varieties are prone to lodging as their center of gravity is higher compared to short varieties. However, within all crop types there is genetic variability or lodging resistance, and some varieties are just at higher risk for lodging than others.
- Wet soil conditions. High soil moisture levels can limit root development, and lead to root rot. Also, wet soils do not have to ability to anchor roots as well as dry soils.
- High seeding rates. If plant density is high, root space for individual plants is limited. As a result, root systems tend to be less extensive and poorly anchored.
- High N levels. Nitrogen fertilizer results in lush growth and heavy plant tissue, which can cause stems to become weak.
Yield loss resulting from lodging can vary, but research suggests that losses can be up to 40% if the lodging occurs within the 10 days after heading. Losses will be less if the grain filling stage has already passed, however, producers should be aware of kernel damage and sprouting in lodged fields that are wet.
Article written by Manitoba Crop Alliance’s Agronomy Extension Specialist (Cereal Crops), Mallorie Lewarne
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