Will foliar feeding seedling cotton increase yield?

Work in this area indicates that foliar feeding seedling cotton, even stressed cotton, will not generally result in increased yields. The appearance of the cotton may be helped, but it is very rare that a yield response will occur from such a treatment.

Stress from being too wet or too cool is generally the problem, not necessarily a nutrient deficiency. The argument heard is that the plant can't take up nutrients, so foliar feeding will keep it going and "kick if off." If the plant is under so much stress that it cannot take up nutrients from the soil, what can it do with nutrients applied to its leaves?

If you are leaning toward foliar feeding seedling cotton, here are several things to consider.

A small seeding covers only a small area. The products sold for this purpose are low analysis to start with and are recommended at rates in the 1 quart per acre range. For example, consider a product that is about 9 percent nitrogen and weighs 12 pounds per gallon. If the recommendation is to apply 1 quart per acre broadcast, that comes to 0.99 pounds of nitrogen per gallon, or 0.2475 pounds per quart. You are putting out 0.2475 pounds of nitrogen per acre. Leaf area covers perhaps 1 percent or less of the surface acre. How much of the applied material contacts the plant? How much of the applied material gets into the plant?

If the plant is under stress, uptake of the material that actually gets on the leaf surface is greatly reduced. As you can see, not much of the product gets into the plant to do anything at all. If some nutrients do get into the leaf, and if the plant is under stress, what will it do with them? At that point, nutrient deficiency is not the problem. Fertilizer corrects nutrient deficiency, not other problems.

A noted physiologist and graduate student, in a nearby cotton state, did a study on foliar-feeding, stressed seedling cotton. Several treatments were involved, but none had any real positive effect. In fact, the best looking treatment, visually, was 10 gallons total volume per acre of water.