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COMPARISON OF PUBLIC AND PRIVATE LAB FERTILIZER RECOMMENDATIONS IN FIELD CROPS

Applied Research

Mark Nelson
Extension Professor
UTAH STATE UNIVERSITY
BEAVER

Abstract

There are many sources that growers utilize to determine fertilizer needs for crops such as private and public labs. In many cases, these sources provide recommendations for a specific crop that will vary greatly, and the resulting fertilizer and application rates recommended can lead to large differences in costs for the grower. To correct or avoid macronutrient or micronutrient deficiencies in major crops, recommendations sometimes call for fertilizer rates that are excessive or not cost-efficient. Evaluating the effectiveness and economics of current fertilizer guidelines and recommendations will help growers to make better-informed decisions when it comes to choosing recommendation sources and fertilizer levels. An experiment was established in 2021 with 12 sites across the state of Utah in alfalfa, small grains, and corn to test and compare the fertilizer recommendations of five labs. The recommendations tested were from two public labs and three private labs located in the Western United States. A single, large composite soil sample to 12 inches from each site was dried, ground, split, and sent to each of the labs for analysis. The macronutrient and micronutrient rates recommended by each lab were then applied in four replications at each of the 12 sites. All fertilizer products were broadcast-applied in the early spring of 2021 as dry granular products. Results from 2021 indicate that there is little to no difference statistically in crop yield between the five recommendations and the control, where no fertilizer was applied at all. Across the four corn sites, there was no statistical difference in yield between treatments. Likewise, fertilizer recommendations had no effects on alfalfa yield in 14 total harvests at five sites. While very small differences in yield were observed, the cost per acre for each of the treatments from the labs varied greatly. Differences in the costs of recommendations among labs varied from $200 to $800/acre across the 12 sites. With the high fertilizer cost we are currently experiencing, these costs would be much higher this year.

 

Poster has NOT been presented at any previous NACAA AM/PIC

This poster is being submitted for judging. It will be displayed at the AM/PIC if not selected as a State winner. The abstract will be published in the proceedings.

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Authors: Mark Nelson, Megan Baker, Matt Yost, Earl Creech, Grant Cardon, Steven Price, Cody Zesiger, Reagan Wytsalucy, Randall Violett, Mike Pace, Jody Gale
  1. Nelson, M. Extension Professor, Utah State University, Utah, 84713
  2. Baker, M. Undergraduate Research Assistant, Utah State University, Utah, 84322
  3. Yost, M. Assistant Professor & Agroclimate Extension Specialist, Utah State University, Utah, 84322
  4. Creech, E. Professor and Extension Agronomist, Utah State University, Utah, 84322
  5. Cardon, G. Professor & Extension Soils Specialists, Utah State University, Utah, 84322
  6. Price, S. Associate Professor, Utah State University, Utah, 84501
  7. Zesiger, C. Associate Professor, Utah State University, Utah, 84404
  8. Wytsalucy, R. Associate Professor, Utah State University, Utah, 84535
  9. Violett, R. Associate Professor, Utah State University, Utah, 84720
  10. Pace, M. Extension Professor, Utah State University, Utah, 84302
  11. Gale, J. Associate Professor, Utah State University, Utah, 84701