Academic Level at Time of Presentation
Graduate
Major
Agriculture
List all Project Mentors & Advisor(s)
Dr. Alyx Shultz
Presentation Format
Poster Presentation
Abstract/Description
Soil testing is commonly used to guide nutrient management. However, plants may not use nutrients in the same way that soil tests predict. This can happen when nutrients interact and limit uptake. This study evaluated whether soil test results match plant nutrient status under different compost levels, with a focus on nutrient antagonism. Soils from three compost histories were used: no compost (T1), moderate compost (T2), and long-term high compost from repeated hog manure application (T3). Soils were mixed with ProMix and Perlite (1:1:1), and Chijimisai was grown under greenhouse conditions. Plant height and chlorophyll (SPAD) were measured weekly. Soil nutrients were analyzed using Mehlich III extraction. Leaf tissue samples were analyzed for nutrient concentrations. Soil test results showed adequate nutrient levels across treatments. However, leaf tissue results showed clear imbalances. Micronutrients increased with compost, including Zn (152, 472, 1280 ppm), Mn (128, 187, 224 ppm), and Cu (10, 15, 20 ppm) for T1–T3. Fe increased slightly from 122 ppm (T1) to 132 ppm (T2), but dropped to 80 ppm in T3, even though soil iron was adequate. This decline corresponded with reduced chlorophyll (SPAD: 83.8, 65.8, 69.2) and reduced plant height (17.7 cm in T2 vs 15.3 cm in T3). These results indicate that accumulation of micronutrients reduced iron uptake through antagonistic interactions, decoupling soil and plant nutrient status. These results show that soil tests alone can be misleading and should be combined with leaf tissue analysis for accurate nutrient diagnosis.
Spring Scholars Week 2026
Sigma Xi Poster Competition
Soil Nutrient Sufficiency Does Not Ensure Plant Nutrient Status
Soil testing is commonly used to guide nutrient management. However, plants may not use nutrients in the same way that soil tests predict. This can happen when nutrients interact and limit uptake. This study evaluated whether soil test results match plant nutrient status under different compost levels, with a focus on nutrient antagonism. Soils from three compost histories were used: no compost (T1), moderate compost (T2), and long-term high compost from repeated hog manure application (T3). Soils were mixed with ProMix and Perlite (1:1:1), and Chijimisai was grown under greenhouse conditions. Plant height and chlorophyll (SPAD) were measured weekly. Soil nutrients were analyzed using Mehlich III extraction. Leaf tissue samples were analyzed for nutrient concentrations. Soil test results showed adequate nutrient levels across treatments. However, leaf tissue results showed clear imbalances. Micronutrients increased with compost, including Zn (152, 472, 1280 ppm), Mn (128, 187, 224 ppm), and Cu (10, 15, 20 ppm) for T1–T3. Fe increased slightly from 122 ppm (T1) to 132 ppm (T2), but dropped to 80 ppm in T3, even though soil iron was adequate. This decline corresponded with reduced chlorophyll (SPAD: 83.8, 65.8, 69.2) and reduced plant height (17.7 cm in T2 vs 15.3 cm in T3). These results indicate that accumulation of micronutrients reduced iron uptake through antagonistic interactions, decoupling soil and plant nutrient status. These results show that soil tests alone can be misleading and should be combined with leaf tissue analysis for accurate nutrient diagnosis.