TABLE 1.

Soil pH, total organic carbon, and nitrogen for the different treatments in the Ultuna Long-Term Soil Organic Matter Experimenta

Treatment designationFertilizer regimenMean ± SD
pH1% of dry soil
Total organic CTotal N
AUnfertilized (bare fallow)5.47 ± 0.161.01 ± 0.030.09 ± 0
BUnfertilized5.63 ± 0.051.22 ± 0.100.11 ± 0.01
CCalcium nitrate Ca(NO3)26.26 ± 0.041.43 ± 0.030.13 ± 0
DAmmonium sulfate (NH4)2SO43.97 ± 0.141.29 ± 0.010.20 ± 0.01
JSolid cattle manure6.02 ± 0.092.20 ± 0.050.20 ± 0.01
OSewage sludge4.68 ± 0.032.76 ± 0.080.27 ± 0.01
  • a When the experimental site was established in 1956, the soil pH was 6.5 and the total organic C and total N were 1.5% and 0.17% of the dry solids, respectively.