The term “yield enhancement” is a term that is meant to describe the combination of practices that are used to increase yields and quality of crops. In the past this term has been used almost exclusively in soybeans, but I feel that it can be applied appropriately to other crops as well.
I have mentioned the idea of positive and negative inputs a few times through the years, but I feel this concept can be put to good use with regard to yield enhancement. This concept divides practices and inputs into two categories with one being the standard methods such as soil fertility, weed control, pest management, drainage and others as “negative” items.
These things are not really negative, but they are not optional. They must be done regardless of the cost in order to protect the crop from yield loss. The grower essentially decides to do these things when the crop is established.
There are items that are not considered by growers as necessary for the crop, but which offer opportunities for increasing profits. This second group which I consider as “positive” items include irrigation, the application of yield boosting products such as fungicides, plant growth regulators, foliar fertilizers, biological stimulants, etc. This set of methods and materials are sometimes controversial but some have crossed the line from unproven to proven in recent years. The use of fungicides in soybeans and plant growth regulators in cotton are examples of this.
Today there are many fungicide products and combinations that are used in soybeans and to lesser degree in corn. Only a few areas have worked with fungicides in cotton, but this activity will likely increase as a way to improve quality and to reduce foliar diseases and boll rot. The use of these “positives” will likely increase as growers push the yield envelope higher each year.
Another class of products, the biologicals, is gaining more interest in recent years. Some of these have been shown effective in suppressing diseases and nematodes, reducing insect activity, and modifying plant physiological processes so as to allow plants to resist stress. One of these is chitosan, which has been found capable of reducing nematodes, boosting chlorophyll index, and reducing transpiration during drought.
I have seen some good yield response to this material, especially in cotton, but also in soybeans. It promotes earliness and ease of defoliation in cotton, especially in situations where nematode numbers are high. It has other benefits in stand establishment and reduction of insect pests through suppression of chitin formation.
The formation of chitin, the substance from which most insect and microbial structures are composed, is suppressed by chitosan. This capability has unique possibilities in the management of pests that are not well controlled by “conventional” pesticides such as aphids that are adept at developing tolerance to other materials. The amazing thing is that this idea is not new at all, having been known for well over a century and used widely in other parts of the world.
There are other natural substances such as neem, insecticidal soap, and synthetic products like diflubenzuron (Dimilin) and novaluron (Diamond) which have shown similar effects on chitin formation. Both chitosan and neem reduced nematode numbers in tests I have done in actual farm situations. Materials like neem and chitosan are not new, but are usually overlooked in favor of more conventional products. The great thing about these lesser known materials is that they are very safe, easy to apply, and are less expensive than many conventional products.
Those who know me are used to my deviation from the norm with regard to methods for dealing with production problems, especially pests. I also look for safer ways to deal with problems whenever possible. If it works and it’s safe I will try it. Call me crazy if you want, but I call it “thinking outside the box”.