Soil testing
- 1. Soil Testing
- 2. Why test soils? to determine fertilizer needs increased yields faster growth = money to grower
- 3. How much fertilizer is enough? Underfertilized growth, yield reduced increased susceptibility to disease, insects
- 4. How much fertilizer is enough? Overfertilized ties up micronutrients leaches into groundwater – nitrate pollution expensive
- 5. How much fertilizer is enough? Best approach: Frequent soil tests followed by low level applications of fertilizer at regular intervals
- 6. Plant Nutrient Levels Level 1: Deficient growth, productivity slowed
- 7. Plant Nutrient Levels Level 2: Sufficient plant needs satisfied adding more fertilizer only increases growth slightly - not worth cost
- 8. Plant Nutrient Levels Level 3: High high nutrient levels maximum growth can easily become too much - toxicity, pollution, nutrient tie-ups.
- 9. Plant Nutrient Levels Level 4: Toxic yields decline plant damage
- 10. Three methods for finding nutrient deficiencies in plants:
- 11. 1 Visual inspection deficiency signs yield reductions slow growth ureliable damage already done
- 12. 2 Soil test measure nutrient levels of soil most common method determine lime, fertilizer needs soil conditions not identified
- 13. 3 Tissue testing measures nutrient levels in plant itself bypasses soil to determine if nutrient was taken up by plant measures nutrient levels in the plant itself most complete and accurate
- 14. Testing basis chemical reactions that produce color changes depending on amount of minerals in soil not always reliable - human error, results vary
- 15. Home test kits More common among greenhouse and nursery growers Results may vary and not compare w/ lab tests
- 17. Projessional Lab Laboratory testing with instruments Extraction - filter water through soil sample spectrophotometer - p asses light through solution, measures amount of light absorbed
- 18. Professional Lab use charts to interpret measurements based on validated tests on similar soils results may vary from lab to lab
- 19. Professional lab Standard laboratory series soil test includes: texture organic matter content pH nutrients – NPK high, medium and low rating
- 20. Results Based on needs of area Standard/Optional depending on lab Soluble salts CEC Ca S Mg Trace elements
- 21. Results Nitrogen difficult to test because soluble Test for organic matter storage - what crop took out
- 22. Soil Testing University of Wisconsin Extension and private labs perform soil tests http://soiltest.cfans.umn.edu/ http://www.soilperfect.com/
- 23. How to use test kit