SURVEYS, FIELD STUDIES, AND LABORATORY INCUBATION EXPERIMENTS TO IMPROVE ALFALFA PRODUCTION IN THE MID-SOUTH

The objective of the alfalfa survey was to determine the role of soil fertility in the alfalfa yield plateau. Soil samples at depths of 10, 15, and 30 cm and tissue samples were collected from 114 alfalfa stands across Kentucky and surrounding states. Results indicate that soil fertility is likely contributing but not driving the alfalfa yield plateau. The main objective of the polyhalite incubation study is to determine if POLY4 was soluble enough to support potassium (K) and sulfur (S) for plant growth. The design of the study included four fertilizer treatments, three soil types, and four incubation times. POLY4 released K and S in a manner that would support plant growth but release rates do vary among soil types. There was some evidence of slow-release S properties by POLY4. The objective of the polyhalite field study was to determine if POLY4 could promote comparable alfalfa yields and tissue K and S concentrations to other fertilizer sources. Trials were conducted in Lexington, KY and Princeton, KY. Results indicated no yield differences between treatments, including the control. POLY4 was able to increase tissue K and S over the control, and at concentrations comparable or greater than other fertilizers.