Wednesday, November 15, 2006
286-23
Cluster Analysis as a Tool for Identification of Fertility Regimes that Enhance Long-Term Productivity of Alfalfa.
Sofia Lissbrant, Sylvie Brouder, Brad Joern, Suzanne Cunnigham, and Jeffrey Volenec. Dept of Agronomy, Purdue Univ, 915 W State St, West Lafayette, IN 47907-2054
Recommendations regarding P and K fertilization as well as critical soil and tissue concentrations for optimal growth of alfalfa (Medicago sativa L.) differ throughout the literature. The objectives of this study were to investigate how long-term P and K fertilization affect soil test P and K levels, tissue P and K levels and alfalfa growth and how this information can be used to predict alfalfa agronomic performance. A factorial combination of four P treatments (0, 25, 50, and 75 kg P per ha per year) and five K treatments (0, 100, 200, 300, and 400 kg K per ha per year) were replicated four times. Beginning in 1998, herbage samples were obtained after each forage harvest in May, June, July, and September. Soil samples were collected in April as well as after each harvest. Samples were analyzed for P and K concentrations. Cluster and variance reduction analysis applied to mass per shoot and shoots per square meter measured in each treatment plot identified 6 clusters with large differences in yield, yield components, and persistence. Ongoing work will identify cluster attributes such as fertility treatment, herbage P and K, and soil test values that impact performance, both positively and negatively. This information will assist us in optimizing P and K fertilization strategies for long-term productivity of alfalfa.
Handout (.pdf format, 4550.0 kb)