1. Soil Management and Crop Biomass Removal Impacts on Soil Organic Matter Content Krisztina Eleki, Richard M. Cruse, László Fodor, Lajos Szabó, and Sándor Holló

2. ????????????????????????? Can we remove crop biomass and conserve soil organic matter content (humus)?

3. Why is this an important question? The U.S. government “Vision for Bioenergy and Bio-based Products in the United States” – from biomass by 2030 5% of power, 20% of transportation fuels and 25% of chemicals

4. Why is this an important question? Much of biomass will come from agricultural land

5. What do we understand? Soil Organic Matter very important Sustainability Soil quality Crop production Soil and water conservation

6. What do we understand? Soil organic matter if organic matter added* Soil organic matter if biomass removed* * For simple cropping systems – one or two crop, one or two fertilizer management treatments

7. We do not understand interactions! Crop type Crop rotations Fertilizer management – root mass and microbial activity Manure applications – organic matter additions Tillage – microbial activity Root morphology (form) effects

8. Key – seeking evidence Can we harvest crop biomass? IF YES How much can we harvest? What is best management?

9. Objective Determine the effect of management practices on Soil Organic Matter (SOM) change with time Crop rotation Fertilizer management Manure application Crop biomass removal

10. Methods Location – Kompolt, Hungary, Rudolf Fleischmann Research Station - 47°45' N and 20°15' E Multifactor experiment – four replications Crop rotations (main plots) - 3 Fertilizer rate (splits of main plots) - 12 Fertilizer management (second split) - 3

11. Methods (cont.) Fertilizer rates – 12 Commercial fertilizer rates Manure application Biomass removal vs. no removal

12. Methods (cont.) Experiment 1961 – 2001 SOM measured: 0 – 30 cm depth Analysis of Variance

13. Results

14. Fertilizer P < 0.0008 1961 SOM = 2.58%

15. Results Cont. Corn Four Crop Rotation P = 0.08 1961 SOM = 2.58%

16. Results 4 YR Corn, 4 Alfalfa Yearly Application 4 YR app., 4 YR none P < 0.0001

17. Results No Manure Biomass Removal Manure – 35.2 Mg/ha Biomass Removal No Manure Biomass Incorp. P < 0.0008

18. Conclusions Rotations ???? Fertilizer management Manure applications Biomass removal

19. Next Step Test 2 soil carbon models against this data Use best model to estimate SOM change across landscape in Iowa With different management With biomass removal