It’s no secret good crop yields begin with healthy plants, and healthy plants grow from vigorous roots. There are hundreds of products on the market guaranteeing stronger plants and, by extension, better production. At the V-Town Ag-Explore 2017, H. Grant Troop, CPAg/CCA offered some science-based advice to help farmers determine what their plants do — and don’t — need.
Plants “need to get resources from the soil,” so building a high-fertility soil is key, Troop noted. Regular soil tests which report on pH, phosphorous, and potassium are essential. Some growers may believe their soil chemistry is adequate because their crops appear healthy and produce an acceptable yield. However, crops can have nutrient levels below the level for optimal performance without showing visible signs of deficiency. Many symptoms only appear after crops become stressed due to heat, drought, and the like. By then, the yield is already irreparably diminished.
When it comes to soil amendments, Troop said, “Spend your first dollar on getting the pH up with lime.” Until the pH is at the proper level, plants will struggle to access nutrients from the soil, even if they are present in adequate levels.
He also recommended testing micronutrients at least every other soil test. Micronutrients are often overlooked, but they should not be. They affect plants’ biochemistry at every developmental stage and are involved in the production and transportation of enzymes. Even small differences in the levels of micronutrients can have major impacts on crop yields.
An excess of one micronutrient can limit a plant’s ability to access other nutrients. While a visual deficiency symptom or tissue analysis may indicate which nutrient the plant lacks, it does not necessarily follow adding that particular nutrient (either through the soil or through foliar applications) will solve the problem.
Calcium, for example, helps build strong plants by contributing to cell division and cell structure. Unfortunately, foliar applications of calcium are generally of little use. Troop notes: “You have to have calcium in the ground.” An analysis of the soil’s chemical profile prior to planting provides the opportunity to correct potential problems before they develop.
Once a grower has adjusted the soil pH and added the appropriate nutrients via compost, manure, and/or other amendments, the goal is to keep those nutrients in the root zone for as long as possible and to foster the plant’s ability to utilize the materials. There are materials on the market which can help.
In the case of nitrogen, stabilizers have been effective in reducing volatilization, leaching, and denitrification by bacteria. The crops benefit by having longer access to the nitrogen. The environment benefits through decreased pollution potential. The farmer benefits by getting more value out of his investment.
Phosphorus is another nutrient which can be difficult to manage. Because phosphorus binds quickly with minerals in the soil, it can quickly accumulate to unsafe levels without being readily available to the crops. By mid-season, much of the phosphorus applied in the spring has become unavailable to crops, and yield can suffer. Materials which help phosphorus stay in a more soluble form throughout the season can have significant benefits for crops.
Humic acids are created as microbes break down organic matter. These acids do not easily degrade further, so they are important influences on soil fertility and water-holding capacity. Their presence aids in stabilizing soil productivity.
Growth stimulants promote plant growth on a cellular level. Where they are used, plants show increased size and enhanced drought resistance.
Another way of maximizing plant growth is by enhancing the root system. Roots only take up nutrients at the tips, so the majority of the root system is just a conduit, not an access point. There is a way to make the entire root system a nutrient receptor, however: mycorrhizae. These fungi attach along the length of plant roots, absorb water and nutrients from the soil, and pass them to their host plants. Increased food and water translates into increased plant growth and production.
While there are some opportunities to improve plant health during the growing season, Troop’s message to farmers is to prevent problems before they occur by preparing the soil with the nutrients and biologics necessary for optimal crop yields.