Soil Testing Procedures for Biologically Based Systems

1. Soil Testing Procedures for Biologically Based Systems Raymond C. Ward Ward Laboratories, Inc Kearney, Nebraska www.wardlab.com

3. Soil Testing for No Till Farmers • I have been interested in developing soil tests that could be analyzed quickly and at low cost that could let the farmer know how well his operation was improving yield and soil health. • Researchers at the National Tilth Lab at Ames Iowa are developing a soil quality index that may give the right parameters to analyze.

4. Total Organic C Potential Mineralizable N Soil pH Soil Extractable P Sodium Adsorption Ratio Electrical Conductivity Microbial Biomass C Microbial Quotient qCO2 Macroaggregate Stability Available Water Capacity Bulk Density Soil Quality Index

5. Carbon Cycle

6. Total Organic Carbon • Soil Organic Matter test • Loss on Ignition (LOI) • Carbon Analyzer • Soil Organic Matter is 58 % C • Food for Microbes

7. Microbial Biomass • Biological Activity • Active Soil Carbon • Increases with Cropping Intensity • Measurement involves Incubation for 3 days or more

8. Particulate Organic Matter • Decomposed Residue • Slow Turnover Pool of OM • Soils with the Most Intensive Cropping System Contains the Highest POM • Major Substrate used by Microbes

9. Mineral Associated Organic Carbon • This Organic Carbon is Not Influenced by Cropping Intensity • It is the Largest Supply of Organic Carbon • Takes Years to Increase • Stabilized (that part we could not destroy by tillage)

11. Nitrogen Cycle

12. Nitrogen Cycle • Plant and Animal Residue/Organic Soil N/Air N • Microorganisms • Ammonification (NH4) – Plant Uptake – Soil Complex • Nitrification (NO3) – Plant Uptake – Leaching - Denitrification • Immobilization (Soil Organic N)

13. Sulfur Cycle

14. Sulfur Cycle • Plant and Animal Residues/Organic Soil S • Microbial Breakdown • Oxidation/Reduction • Sulfates/Sulfides and from Fertilizers, etc • Sulfate • Plant uptake • Leaching • Soil Minerals

15. No-Till Sulfur Deficiency • Most of the Sulfur in the soil is held in the organic matter portion of the soil • The idea is to build organic matter to improve the health of the soil and increase productivity • C : N : S ratio • 100C : 8N : 1S

16. Soil Sample Depth • Evaluating No-Till • 0-2 inches most active • 2-6 inches • 6-12 inches • Evaluating Fertility • 0-8 inches for all nutrients • 8-36 inches for Nitrate, Chloride, Sulfate

17. Nutrient Uptake and Root Structure

19. Granular Structure

20. Microbe Tests

22. Soil pH • Important for Crop Growth • Important for Microbe Growth • Tendency to Decrease over Time • Some Herbicides Less Affective at Low pH • Broadleaf Crops Contain more Calcium and Magnesium

23. Optimum Soil pH Crop Mid Point Range (+/-) Wheat 6.3 .75 Corn 6.3 2.0 Soybean 6.3 1.2 Sunflower 6.6 2.1 Field Peas 6.5 1.0

24. Nitrate Soil Test Consider nitrate in your root zone Total Lbs/A are available Subtract total Lbs/A from N requirement N recommendation based on nitrate in the root zone

25. Phosphorus Soil Test Soil test ppm P Rating % Sufficiency 0-5 Very Low 25-50 6-12 Low 45-80 13-25 Medium 70-95 26-50 High 90-100 51+ Very High 100

26. Phosphorus deficiency

27. Potassium Soil Test Soil Test ppm K Rating % Sufficiency 0-40 Very Low 20-50 41-80 Low 45-80 81-120 Medium 70-95 121-200 High 90-100 201+ Very High 100

28. Sulfur Soil Test Soil Test ppm S Rating 0-3 Very Low 4-6 Low 8-12 Medium 13-20 High 20+ Very High

29. Sulfur in Wheat

30. Sulfur Deficiency

31. Zinc Soil Test Soil Test ppm Zn Rating 0-.25 Very Low .26-.50 Low .51-1.00 Medium 1.01+ High

32. Zinc Deficiency Wheat

33. Zinc deficiency

34. Zinc Deficiency Wheat

35. Copper Soil Test • 0-.20 Low • .20-.60 Medium • >.60 High

36. Copper Deficiency Wheat

37. Copper Deficiency Wheat