In the early 1800's Joseph Paxton wrote this about plant science. It is "one of the most attractive, most useful, and most extensive departments of human knowledge. It is, above every other, the science of beauty." Apparently Sir Paxton never had to make a field-call in which some difficult to explain abnormality had appeared on soybean plants.
Extension specialists in plant science attempt to find causes and remedies for numerous abnormalities in crops. To do so, we rely on not only the experiences of ourselves and our colleagues, but the accumulated knowledge from years of studying crop plant growth, development, and plant responses to management and stresses. Stresses can be biotic, such as plant pathogens or they can be abiotic such as temperature or drought. It is a stress, or more likely multiple stresses, that often cause of the signs and symptoms in the field.
During a field call, we try to diagnose the cause of the abnormality, determine the extent of damage to yield, decide if a remedy is warranted, and if warranted, should the remedy be deployed in-season or next season. This is often complicated because what we observe, including the results of diagnostic tests, are the result of a complicated set of interactions among a multitude of forces.
Plant pathologists use a triangle to illustrate these interactions for diseases. The three sides are labeled pathogen, genetics, and environment. On a broader scale and because the most frequent question relates to yield, I've borrowed the plant pathologist's triangle to explain soybean yield. The sides of my yield triangle are plant genetics (variety), crop management practices, and environment. Environment is several forces of nature and includes not only the field characteristics, but the stresses that may come and go as the growing season proceeds.
Of the three triangle sides, farmers have the least control of environment. They can select the variety they think has the highest yield and they can use the best management practices in an attempt to realize that yield potential. But, they are often nearly powerless to influence natural forces of weather, soil/landscape characteristics, and pests. I say nearly, because variety genetics and some management practices can moderate the effects of natural forces on soybean yield. But, they are only partly effective. This is why Missouri average soybean yield was 30 bushels/acre in 2012 and 49 bushels per acre in 2017. Because of natural forces, yield variation from place to place within a field may be larger than variation among years.
My yield triangle is depicted as equilateral triangles will all sides equal in length. But, we know that that is almost never the situation in a real field. If fact, the length of a side (indicating the importance of the factor) changes day to day, field to field and year to year. I can imagine an almost living triangle as we observe the contacting and lengthening of its sides as the growing season proceeds through each day and natural forces change in intensity. Susceptibility of yield to a natural force also changes within the growing season. All of this is to say that yield is complicated and the accumulated effects of all of the forces and interactions on plants are even more complicated. Science helps us understand these complications. It would be impossible to make diagnoses and recommendations without science.
When we are in the field or reviewing notes about the situation or studying diagnostic tests, we rely on science to make sense of what we observe. In many ways the process around a field-call is forensics. The steps commonly associated with forensics is information collection, examination, analysis, and reporting.
We rely on science at every step of that process. I don't know how else to describe the concept except that science is our friend. Like a friend, science sometimes frustrates us. Sometimes science tells us things we don't want to hear. Too often it mumbles, so that the message is unclear. But, science, if we listen, serves us well. It can keep us from making costly mistakes. It shows us the path forward including management strategies to deploy. Science is our best tool as we attempt to make sense of an abnormality and make conclusions and recommendations. And, science benefits all stakeholders from farm to industry to society.
There are other forces acting in a soybean field that are often outside of what we agronomists study, but we ignore them at our peril. Economic interests of the farmer, the input applicator, the input supplier, the owner of patents are all at work. Soybean management opinions come from bankers, government agencies, landlords and neighbors. Social interests including a sense of pride in the look and the yield of the field are also in play.
Just as forces of nature can work in contrary fashion, so do these extra-nature forces. For example, economic interests of the farmer and an input company are sometimes well aligned, sometimes opposed, or often somewhere along that continuum. A farmer's concern about yield loss, but also peer or public opinion, may result in the deployment of an unwarranted management practice.
When an agronomist is discussing the conclusions from a field-call with a farmer in may appear that the discussion involves just two people, the agronomist and the farmer. But, the discussion is actually multi-lateral and clearly involves several entities with much closer ties to the farmer than the agronomist. The late Senator Daniel Patrick Moynihan said "you are entitled to your opinion…you are not entitled to your own facts". We agronomists might believe we are the participant with most of the facts because we rely on science. But, other participants often present their side as facts, also. The conflicting statements among participants can be confusing for the one person that ultimately must make a decision, the farmer. The most harmful possible outcome of confusion is a distrust in public science.
The science used by agronomists is public science in the truest sense of the concept. All of our procedures, materials, results, and conclusions are public. The procedures and materials we use are selected to best answer a specific question. Skepticism is a healthy part of science. People can have honest disagreements about selected procedures or materials. That's why we make them public. We encourage debate and we learn much from that debate. Skepticism is healthy when the motivation for debate is to improve our knowledge about an issue so that we can make better recommendations and farmers can make better decisions. It becomes unhealthy when skepticism is aimed at science itself.
I wrote that science sometimes mumbles. It is our responsibility as agronomists to perform and interpret science to improve its clarity. Even when the message is clear, we or other interested persons can be uncomfortable because the message is not what someone wants to hear. This angst is most apparent when we agronomists make conclusions/recommendations related to the effects of natural forces on the soybean plants, but these conclusions/recommendations run counter to one or more of the extra-nature forces that I described.
Before, after and even during a field-call several parties with differing interests are communicating with the farmer. And that is exactly what should happen. To minimize confusion, it is incumbent upon all parties in the conversation to clearly state their interest and bias. Farmers need to hear all parts of the discussion, but all participants must be honest about their bias. Every interest has its legitimate place. So, no participant should denigrate the interest of any other participant. In particular, all participants should respect the science that informs conclusions/recommendations. We agronomists understand that our recommendations are not always followed and our conclusions are sometimes not believed. It is our responsibility to base our conclusions/recommendations on sound science. Farmer can then make an informed decision using all information provided. However, all parties in the discussion lose if our science is discounted. Some participants in the discussion may not like what science tells us. We can have useful discussions and even disagreements about interpretations from scientific studies. But, we cannot let anyone attempt to drive those discussions by disrespecting public science. Science has made US agriculture the envy of the rest of the world. We owe it to farmers, current and future, to apply appropriate scientific methods to their challenges.