View Full Table | Close Full ViewTable 1.

The influence region on the number of surveys collected, no-tillage adoption, ksoc values, and Bulk density.

 
2004–2007
2008–2010
Region Bulk density Surveys Planted corn No-till adoption ksoc Surveys Planted corn No-tillage adoption ksoc
g cm−3 no. ha*1000 % g soc/(g × yr) no. ha*1000 % g soc/(g×year)
North-central 1.35 934 338 97 0.0117 796 346 69 0.0135
Central 1.31 2035 251 68 0.0135 941 229 57 0.0142
Northeast 1.29 3289 276 20 0.0165 2353 308 11 0.0171
East-central 1.24 6777 436 11 0.0171 12,479 447 5 0.0175
Southeast 1.25 3289 434 29 0.0160 1811 405 33 0.0157



View Full Table | Close Full ViewTable 2.

Selected characteristics of the two field experiments conducted in 2009 that were used to define harvest indexes, root/shoot ratios, and cob/dry ear ratios.

 
Characteristics Aurora Wessington-1
Location 96°40´ W, 44°18´ N 98°34´ W, 44°40´ N
Previous crop corn soybean
Planting date 15 May 2009 12 May 2009
Root sampling data (silking) 19 Aug. 2009 5 Aug. 2009
Planting population (seed/ha) 86, 500 74,000
Rainfall (cm) 18.52 39.83
GDD °C 1134 1315
Tillage system tilled no-tilled
Soil series Brandt silty clay loam Houdek loam
fine-silty, mixed, superactive, frigid Calcic Haplodolls fine-loamy, mixed, mesic Typic Argiustolls



View Full Table | Close Full ViewTable 3.

The influence of NASS region and year on yield, no-tillage adoption rate, nonharvested C returned to soil (NHC), SOC mineralization rate, the SOC benchmark, and calculated sequestered SOC. The standard deviations are shown in parenthesis.

 
Yield
NHC
Sequest.
SOC
Region 2004–2007 2008– 2010 2004–2007 2008–2010 SOC benchmark 2004–2007 2008–2010
Mg/ha kg/(ha yr)
NC 6.17 8.45 3.46 4.73 39.5(8.96) 229 412
C 5.45 8.95 3.06 4.36 40.2(9.76) 69 329
NE 8.27 7.76 4.64 5.02 45.2(9.51) 182 231
EC 7.98 9.33 4.46 5.24 44.8(9.60) 125 264
SE 7.2 9.51 4.04 5.34 39.1(8.50) 266 454



View Full Table | Close Full ViewTable 4.

The influence of sampling region and the short-term sequestered C rates on partial C footprints for the 2004 to 2007 and 2008 and 2010 time periods.

 
2004–2007
2008–2010
Region Sequestered C Partial C footprint Sequestered C Partial C footprint
kg SOC/(ha × yr) g CO2eq/MJ kg SOC/(ha × yr) g CO2eq/MJ
North-central 229 –14.9 412 –19.6
Central 69 –5.10 329 –14.8
Northeast 182 –8.86 231 –12.0
East-central 125 –6.31 264 –11.4
Southeast 266 –14.9 454 –19.2