Corn tissue nutrient response related to soil health and fertility
Abstract
Nutrient uptake in corn (Zea mays L.) is influenced by many different factors which include properties of soil health. The push for increasing soil health has raised the question of how soil health and fertility measurements could be combined to improve nutrient management decisions. Attention to nutrient management decisions is critical for high-yielding corn production. While soil sampling for fertility testing is the generally accepted standard for making these decisions, this alone may poorly represent plant nutrient availability. Another tool used for managing plant nutrient health is tissue sampling and analysis. This tool is routinely used for some crops (e.g., especially specialty crops) for diagnosing plant nutrient needs and direct fertilizer decisions. End of season yield response to fertilizer may be improved by using both of these two diagnostic tools. Research conducted in 2019 and 2020 on 91 producer corn fields in Missouri encompassed many soil types, management practices, and landscape positions, resulting in 433 different experimental plots. Accuracy when predicting a corn tissue response to added fertilizer using established critical values were only 61 percent, 53 percent, and 55 percent for K, P, and S respectively. Adding soil health metrics to fertility results using random forest models improved prediction of a positive tissue response to K fertilization, but did not improve predictions for P or S. along with soil-test K, two soil health measurements emerged as important, soil respiration and beta-glucosidase. Multiple linear regression results when predicting yield response as a function of soil test and tissue test K produced mixed results. Yield response were best predicted using soil-test K, tissue-test K (p < 0.1). Phosphorus soil-test or tissue concentration alone or in any combination did not explain yield response. Sulfur yield responses were best explained with just tissue concentration alone as the only significant predictor variable. This research suggests that current tools for diagnosing K, P, and S nutrient needs in corn and making fertilizer decisions need to be improved, but current soil health measurements lack ability to do so.
Degree
M.S.