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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Dairy Forage Research » Research » Research Project #440816

Research Project: Kentucky Alfalfa Nutrient Survey: Understanding the Role of Soil Fertility

Location: Dairy Forage Research

Project Number: 5090-21500-002-006-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Sep 15, 2021
End Date: Sep 14, 2026

1) Conduct a detailed survey of the nutrient status of alfalfa production fields in Kentucky and use this information to direct future soil fertility research. 2) Summarize existing Kentucky alfalfa response data to phosphorus, potassium, and lime application and contribute to the Fertilizer Recommendation Support Tool (FRST). 3) Establish a demonstration trial that will compare two levels of management intensity and provide an educational platform for intensifying the management of alfalfa in mid-South.

Alfalfa will be sampled from multiple fields in Kentucky and surrounding states as feasible. All management operations will be recorded to aid in data interpretation. Tissue samples will be collected and analyzed for nutrient concentrations (N, P, K, Ca, Mg, S, Fe, Mn, Zn, Cu, B, and Mo) via digestion/spectroscopic analysis, and nutritive value (crude protein and digestibility) via Near Infrared Spectroscopy (NIRS). Soil samples will be collected in the same field areas as tissue samples to help give more meaning to plant tissue results. Additionally, forage biomass samples will be collected as able to provide a yield estimate. Tissue, soil, and biomass samples will be collected a select set of fields at each harvest to provide an understanding of how/if tissue samples can be used to guide nutrient applications for future harvests. Where able, we will work with selected producers to apply nutrient strips in an individual field and then collect yield and nutrient data that will provide more consequential information than a single forage sample for a field with only one nutrition management scheme. The Fertilizer Recommendation Support Tool (FRST) will be expanded to include alfalfa. Existing data that has led to current fertilizer rate recommendations will be compiled for individual states for future use in. the calibration aspect of FRST. The last part of this project will evaluate the current yield plateau in alfalfa production and develop a demonstration project. This demonstration will also be used as platform for in-service trainings for extension agents and agricultural professionals, and focused workshops and field days for alfalfa producers in Kentucky and surrounding states.