Soil samples are sent to two different places, one is a standard lab which will provide you with a soil analysis and fertility recommendations and the other is WARD labs in Kearney Nebraska, which provides you with the same but, unlike the former, it shows you N content through a different method (thus concludes on fertility recommendations based on the N content measured from such method). This method is called Haney test, developed by Rick Haney of United States Department of Agriculture and Agricultural Research Service in Temple, Texas. Moreover, WARD labs gives you results for a phospholipid fatty acid test, which is used to profile different phylla of bacteria and fungi in the soil. Since both tests can recommend you how much N is required in the soil to seed the next crop for the upcoming season, it bears to ask the question, which one is better?
Over the last three years, canola, pea and wheat have been rotated in the same trial and treated under different fertilization rates. Fertilization treatments were set as follows. A) 0% (Control) – N recommendations from standard lab. 100% of the recommended N will be applied. B) N recommendations from the standard lab will be 30%. Then it will be topped up with that recommended by the WARD Haney analysis to equate the total recommended by Haney. C) N recommendations from WARD lab. 100% of the N recommended from the Haney soil test will be added.