Sustainability & Energy Crops

1. Sustainability & Energy Crops Peter Scharf University of Missouri Plant Sciences

2. SOIL EROSION SOIL EROSION SOIL EROSION Importing half of their food Argolis, Greece • 7000 B.C.—Simple agriculture begins • 4000 B.C.—Agriculture intensifies • 3000 B.C.—Major civilization • 2500 B.C.—Civilization collapses • 1500 B.C.—New civilization • 200 B.C.—Civilization collapses • 900 A.D.—New civilization • 1200 A.D.—Civilization collapses

3. Argolis, Greece • Q: How do they know that erosion occurred? • A: Find topsoil deposits ‘downstream’ • Q: How do they know it caused civilizations to fail? • A: Erosion peaks = civilization peaks • Q: How do they know it was caused by agriculture? • A: Written records: Plow 3 times/year • Q: How do they know it wasn’t caused by weather? • A: Within-region differences in erosion/collapse schedules

4. What is ‘sustainability’? • Can continue the same practices for a long period of time • Outputs stable • Inputs stable • Off-site effects acceptable

5. Closer to home

6. Piedmont, Virginia Tell me what you see

8. Diverse ag Tobacco Cotton Closer to home • Used to be a major ag region • “Soil erosion was rampant from early times” • “Most old agricultural fields are now in pine forests”

9. Erosion: a familiar face in Missouri

10. Biofuels: potential impact on erosion • Pressure to: • Put more land into crops (marginal) • Increase cropping intensity • More continuous corn • Reduced erosion? • Corn stover removal? (cellulosic ethanol) • Continuous soybean? (biodiesel) • Grass for cellulosic ethanol—thumbs up!

11. Biofuels: potential impact on erosion • Pressure to: • Put more land into crops (marginal) • Increase cropping intensity • More continuous corn • Reduced erosion? • Corn stover removal? (cellulosic ethanol) • Continuous soybean? (biodiesel)

12. Corn Stalk Ethanol 7-15X Higher Erosion and C

13. What is ‘sustainability’? • Can continue the same practices for a long period of time • Outputs stable? • Maintain topsoil • Maintain nutrients • Inputs stable? • Continued availability of energy inputs? • Off-site effects acceptable? • N, P, sediment, atrazine in water

14. Energy inputs & balance • Nitrogen fertilizer is by far the biggest single energy input • Efficient N use will be crucial to a positive energy balance • In-season N application timing • Diagnose correct rate (varies across the field) • Avoid streaky applications (equipment problems)

15. Energy budget for corn production Data from Shapouri et al. 2002, nine state average

16. Energy inputs & balance • Nitrogen fertilizer is by far the biggest single energy input • Efficient N use will be crucial to a positive energy balance • In-season N application timing • Diagnose correct rate (varies across the field) • Avoid streaky applications (equipment problems)

17. Nitrogen timing in 2009:in-season N kicks butt again + 68 bu/acre 153 N sidedress V7.5 180 N at planting

18. Crop N need is variable within fields What happens if you apply 150 lb N/acre to this field?

19. Diagnosing where to put more N

20. Controller runs ball valve to change fertilizer rate Computer in cab reads sensors, calculates N rate, directs controller sensors Crop sensors for N rate diagnosis

21. 55 on-farm sensor N demonstrations 2004-2008

22. Sensor-N impact on energy balance of ethanol

23. Streaky N applications are very inefficient

24. SUMMARY: Sustainability & Energy Crops • Soil erosion is the biggest threat to sustainability • Only major historical reason for agricultural failure and collapse • Missouri is an erodibility champion • Grass fine, corn stalks maybe not • Energy input is another major obstacle • Efficient N use is crucial (HIGH energy input) • Transport of low-density crops (hay)?

25. SUMMARY: Sustainability & Energy Crops • Off-site effects and sustainability • Judgement call • N, P, sediment, atrazine • Much more of an issue with corn grain and stover than with grass and wood