1. Figure 1. Residue removal effects on corn yields as affected by N rate in 2009 and 2010 for poorly and well-drained soils. Asterisk indicates significant difference between residue removal within each N rate at p=0.05.

2. Figure 2. Residue removal effects on corn yields as affected by tillage in 2010 for poorly and well-drained soils. Different letters indicate significant difference between residue removal and tillage at p=0.05.

3. Figure 3. Total soil carbon as affected by two years of residue removal for poorly and well-drained soils. Different letters indicate significant difference between residue removal at p=0.05.

4. Figure 4. Potential changes to net soil organic carbon from carbon input from above- and below-ground biomass minus losses from microbial respiration to a depth of 15 cm. Carbon budget was conducted in 2010 in a well-drained soil and poorly-drained soil under different tillage and N fertilization regimes.

5. Figure 5. Soil bulk density as affected by two years of residue removal and tillage systems for poorly and well-drained soils. Different letters indicate significant difference between residue removal and tillage at p=0.05.

6. Figure 6. Aggregate mean weight diameter as affected by two years of residue removal, tillage and nitrogen rate systems for a poorly-drained soil site. Different letters indicate significant difference between residue removal, tillage and nitrogen rate at p=0.05.

7. Figure 7. Steady water infiltration rates as affected by residue removal and tillage for poorly and well-drained soil sites. Different letters indicate significant difference between residue removal and tillage at p=0.05.

8. Figure 8. Potential sink or source for Atmospheric CO 2 -C. 1.Include above ground biomass, grain, and root biomass for ANPP 2.(ANPP + BNPP) – Rh 3.Positive values indicate a sink for atmospheric CO 2

9. Figure 9. Seasonal CO 2 emissions under different residue removal and tillage management in 2009 and 2010 for the poorly drained soil site in Ames.

10. Figure 10. Seasonal N 2 O emissions under different tillage management in 2009 and 2010 for the poorly drained soil site in Ames.

11. Figure 11. Mean annual N 2 O emissions under different corn residue removal management in 2009 and 2010 for the poorly drained soil site in Ames.

12. Table 1. Effect of N fertilizer Rate on Corn Biomass N and C Content at Plant Maturity Across Sites, 2009-2010 (John Sawyer and Jose Pantoja). N Rate Veg.CobGrainTotal Veg. Cob GrainTotal lb N/acre- - - - - - - - - -lb N/acre - - - - - - - - - -- - - - - - - - - - - -lb C/acre - - - - - - - - - - - - - - 028 (43%)3 (4.6%)34 (52%)651,770 (50%)230 (5.5%)1,555 (44%)3,550 15059 (38%)6 (4.0%)89 (58%)1543,140 (43%)510 (7%)3,670 (50%)7,320 25073 (40%)7 (3.8%)103 (56%)183 3,375 (42%)555 (7%)4,080 (51%)8,010 Only the main effect of N rate was statistically significant for N and C (p<0.001). Veg., vegetative material.