Northern Utah Alfalfa Nutrient Survey 2008
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J. Barnhill*, G. Cardon, M. Pace, C. Israelsen, C Miner, L. Greenhalgh, S. Banks, M. Shao, D. Rothlisberger, and S. Olsen Utah State University Extension
![Northern Utah Alfalfa Nutrient Survey 2008 J. Barnhill*, G. Cardon, M. Pace, C. Israelsen, C Miner, L. Greenhalgh, S. Banks, M. Shao, D. Rothlisberger, and S. Olsen Utah State University Extension Producers frequently ask Extension Agents which nutrients they should have an analysis completed for and whether a soil or a tissue analysis would be best. Agents haven’t had data on the frequency of minor nutrient deficiencies, so it was difficult to make an informed determination of which, if any, of them should be included in the analysis. This survey of 38 established alfalfa fields in ten northern Utah counties was completed to determine if there were significant secondary and micro-nutrient deficiencies occurring. Soil and tissue samples were analyzed for 11 essential plant nutrients. The tissue analysis identified deficiencies for three nutrients which the soil test had failed to identify. Ten percent or more of the fields were deficient in P, K, Zn, Cu, Mn, S, and B according to either the soil or tissue analyses. The study suggests that these nutrients should be tested for more frequently and that a tissue analysis be used for that evaluation. ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Abstract Results Conclusions Map 2. Boron Method Utah State University alfalfa tissue adequacy values are primarily derived from the ‘Plant Analysis Handbook’ by James, Wolf & Mills, 1991 Fig. 1 Percent of Fields Deficient Extension Agents in ten northern Utah counties collected soil and tissue samples from 38 established alfalfa fields. The samples were taken as close to harvest as possible. The number of fields evaluated in each county was determined by that counties number of irrigated crop acres. The samples were analyzed for P, K, Ca, Zn, Fe, Cu, Mn, Ni, S, B, and Mg. Tissue Sample Adequacy Levels The question of how well the soil and tissue tests correlate with each other is important in determining which test to use. For many of the nutrients there was a large variation between the fields identified as deficient with a soil analysis and those that were identified deficient using a tissue analysis. This variability was most obvious for sulfur and boron. A ‘P’ test to determine the degree of correlation revealed that the soil and tissue test for sulfur were not correlated, but they were for boron. The ‘P value’ for sulfur and boron were 0.3505 and 0.018 respectively. The ‘P value’ needs to be less than 0.05 for the correlation to be considered strong. Adequacy levels for the Ni tissue test and the Ca & Mg soil test were not available . Map 1. Sulfur On maps 1 and 2 each sampling site is represented by a colored circle. Yellow circles indicate a deficient reading from the tissue test, while small circles indicate a deficient reading from the soil test. If the two tests are correlated most of the yellow circles will be small. The yellow circles are not predominantly small on the sulfur map, but they are on the boron map, thus the two tests are not correlated for sulfur, but are correlated for boron. Tissue analyses are generally considered to be more accurate than soil analyses for the secondary and micro-nutrients. Soil Sample Adequacy Levels USU ALFALFA TISSUE ADEQUACY LEVELS P % K % Ca % Zn ppm Fe ppm Cu ppm 0.26 2.0 1.3 21 30 5 Mn ppm S % B ppm Mg % Mo ppm N % 25 0.26 30 .25 1.0 4.5 USU ALFALFA SOIL ADEQUACY LEVELS (mg/kg) P K Zn Fe Cu 15 150 1.0 5 0.2 Mn Ni SO 4 - S B hot water 1.0 0.5 8 0.5](https://image.slidesharecdn.com/jamesbarnhill-091217154042-phpapp02/85/Northern-Utah-Alfalfa-Nutrient-Survey-2008-1-320.jpg)
J. Barnhill*, G. Cardon, M. Pace, C. Israelsen, C Miner, L. Greenhalgh, S. Banks, M. Shao, D. Rothlisberger, and S. Olsen Utah State University Extension
