Lodging in Oats and Wheat

Lodging results from low dry matter per unit length of culm. 2. Low dry matter per unit length of culm may result from a relatively low composition of lignin and various reserve materials, such as disaccharides and polysaccharides, or from the development of relatively small slender culms. 3. Culms, small in diameter but medium or high in composition of carbohydrates, may result from direct causes such as thick seeding or the planting of small seeds. Such culms, however, exhibit a low dry matter content per unit length of culm. 4. Culms low in composition of carbohydrates are due to the development within the plant of a low carbohydrate nitrogen relation. 5. A low carbohydrate nitrogen relation may result from hypernutrition, shading, or relatively high temperature. 6. Under field conditions lodging results from the interaction of all these environmental factors. Hypernutrition not only tends to induce a greater elongation of the culms, but through a stimulation of the tillering processes, it increases the thickness of stand and hence results in a greater degree of shading around the base of the plants. In warm rainy cloudy seasons, therefore, the conditions are most favorable for the development of lodging on rich soils.