1. Title Simple Field Tests to Assess Soil Quality in Precision Agriculture Apurba Sutradhar BAE/Soil 4213 April 28, 2010 apurba@okstate.edu

2. Soil Quality  The capacity of specific kind of soil to function.  To evaluate the soil’s ability to perform basic function Maintaining productivityMaintaining productivity Filtering and buffering against pollutantsFiltering and buffering against pollutants Storing and cycling nutrients.Storing and cycling nutrients. Source: USDA Soil Quality Test Kit GuideSource: USDA Soil Quality Test Kit Guide

3. Soil Quality Varies Source: USDA Soil Quality Test Kit GuideSource: USDA Soil Quality Test Kit Guide  Differences in agricultural practices Till Vs No till Till Vs No till  Differences in crop growth areas Fast growth Vs Slow growth Fast growth Vs Slow growth  Differences in slope Plain land Vs Slope land Plain land Vs Slope land  Differences in wheel and non wheel areas Wheel Vs Non wheel Wheel Vs Non wheel  Differences in wet and dry areas Wet Vs Dry areas Wet Vs Dry areas

4. Soil Quality Varies Source: USDA Soil Quality Test Kit GuideSource: USDA Soil Quality Test Kit Guide Also Field Variability can be determined byAlso Field Variability can be determined by  Differences in soil type  Eroded and non-eroded areas  Row and inter -row areas

5. Assessing Soil Quality Source: USDA Soil Quality Test Kit GuideSource: USDA Soil Quality Test Kit Guide Two fundamental ways-Two fundamental ways-  Take measurements periodically over time to monitor changes or trends in soil quality.  Compare measured values to a standard or referenced soil condition.

6. Soil Quality Testing Kit Source: USDA Soil Quality Test Kit GuideSource: USDA Soil Quality Test Kit Guide Developed by John Doran and associates, Agricultural Research Service, Lincoln, NE.

7. Soil Quality Testing Kit Source: USDA Soil Quality Test Kit GuideSource: USDA Soil Quality Test Kit Guide Soil Properties Chemical pH Electrical Conductivity Nitrate level Physical Bulk Density Water content Infiltration Rate Aggregate Stability Biological Soil Respiration Earthworms

8. Soil Quality Testing Kit Source: USDA Soil Quality Test Kit GuideSource: USDA Soil Quality Test Kit Guide Advantages: Advantages:  On farm test  Provide immediate results  Can be monitored changes in soil quality over time  Can be diagnosed soil health problems due to land use and management.  Simple- can be conducted by landowner and extension worker

9. Soil Quality Testing Kit Source: USDA Soil Quality Test Kit GuideSource: USDA Soil Quality Test Kit Guide An example- Soil Respiration TestAn example- Soil Respiration Test Estimated time required : 40 minutesEstimated time required : 40 minutes

10. Soil Quality Testing Kit Source: USDA Soil Quality Test Kit GuideSource: USDA Soil Quality Test Kit Guide An example- Soil Respiration TestAn example- Soil Respiration TestCALCULATIONS: Soil Respiration (lb CO2-C/acre/day) = PF x TF x (%CO2 - 0.035) x 22.91 x H PF = pressure factor = 1 TF = temperature factor = (soil temperature in Celsius + 273) ÷ 273 H = inside height of ring = 5.08 cm (2 inches)

11. Planning-implementation-monitoring Courtesy: Dr. Kefyalew DestaCourtesy: Dr. Kefyalew Desta

12. Data Collection and Scoring Steps Courtesy: Dr. Kefyalew DestaCourtesy: Dr. Kefyalew Desta Data collection Apply scoring system Sum individual indicator values Sum component values General score and intervention Individual indicator intervention Scoring Standard values

13. Standard/Reference Values Courtesy: Dr. Kefyalew DestaCourtesy: Dr. Kefyalew Desta

14. Scoring

15. Applying the Scoring System Courtesy: Dr. Kefyalew DestaCourtesy: Dr. Kefyalew Desta IndicatorValue and (corresponding score) BestGoodPoor OM, %3.5-5 (25)2.5-3.5 (20) <2 (15) Physical properties Water stable aggregation, % >80 (6)60-80 (4)50-60 (2) Bulk density, g/cm 3 <1.1, <1.4, <1.6 (6) 1.1<BD<1.3,1.4<BD<1.6, 1.6<BD<1.7 (3) >1.4, >1.6, >1.7 (1) Depth, inch>40 (4)20-40 (3)<20 (2) Infiltration rate, in/hr0.4-2.0, 0.08-1.0, 0.01-0.1 (4) ± 0.2 of best value (3)± 0.4 of best value (2) Water holding capacity, cm/60 cm soil 6-9 (5)4-6, 9-10 (3) 10 (1)

16. Applying the Scoring System Courtesy: Dr. Kefyalew DestaCourtesy: Dr. Kefyalew Desta Chemical properties pH (6)5.8-7.3 (6)5.0-5.7, 7.3-8.0 (4) 8 (2) Fertility ( N, P and K), N-100% of yield goal P&K- 100% sufficient (5) N-80% of yield goal P&K- 80% sufficient (3) N-< 80% of yield goal P&K- < 80% sufficient (1) CEC, meq/100g soil 50-100 (5)16-50 (3)<16 (1) EC (dS/m @ 77 F)<0.98 (4)0.98 - 1.71 (3)>1.71 (1) IndicatorValue and corresponding score (in parenthesis) BestGoodPoor

17. Applying the Scoring System Courtesy: Dr. Kefyalew DestaCourtesy: Dr. Kefyalew Desta Soil Biological Properties Soil respiration lbs CO 2 -C/a/d 32-64 (10)16-32 (7) 64 (4) Microbial biomass mg C/kg soil 345-700 (8) 200-345 (5)<200 (3) Earth worm (#/ft 2 in holes) > 15 (7) 5-15 (4) <5 (2) IndicatorValue and corresponding score (in parenthesis) BestGoodPoor

18. Total Score and Intervention Courtesy: Dr. Kefyalew DestaCourtesy: Dr. Kefyalew Desta Total score Intervention typeDescription >90Minor new intervention; continue with maintenance to avoid degradation Look for the indicator with lowest score and intervene with appropriate remediation practices 80-90Moderate intervention Look for the indicator with lowest score for each component and intervene with appropriate remediation practices. <80Major and immediate intervention is required Investigate the score of indicators in each component and apply comprehensive best management practices. This level of soil quality warrants the need for raising soil organic matter level.

19. Online Soil Quality Assessment This SQA algorithm is under constructionThis SQA algorithm is under construction

20. References and Links United States Department of AgricultureUnited States Department of Agriculture http://usda.gov/wps/portal/usda/usdahome Free Soil Quality Test Kit Guide can be downloaded fromFree Soil Quality Test Kit Guide can be downloaded from http://soils.usda.gov/sqi/assessment/files/test_kit_complete.pdf Dr. Kefyalew DestaDr. Kefyalew Desta kefyalew.desta@okstate.edu

21. Comment Questions? Thanks!