Table 1.

Particle size distribution, Corg C/N ratio, and the total number of T-RFs in the Ultuna long-term experiment sampled in 1998a

Particle size (μm)TreatmentbParticle size distribution (g kg of soil−1)Corgconcn (g of Corg kg of bulk soil−1)C/N ratiocNo. of T-RFs
200–63Fallow170 c0.3 a15.37
NoN169 c0.35 a15.810
Ca(NO3)2 166 abc0.48 a9.48
GM165 bc0.75 b15.215
AM157 ab0.77 b5.09
SS156 a1.70 b20.110
Peat165 bc2.07 d37.57
63–2Fallow499 a5.65 a11.314
NoN500 ab6.75 ab11.110
Ca(NO3)2 518 ab8.44 ab11.919
GM516 ab10.49 bc13.718
AM519 b12.76 c10.016
SS562 c18.86 d10.415
Peat54 c21.77 d24.019
2–0.1Fallow251 bc3.88 a7.823
NoN254 c4.19 a7.622
Ca(NO3)2 247 bc4.75 b7.822
GM251 bc5.40 c8.024
AM248 bc6.16 d8.225
SS223 a5.90 d8.220
Peat234 b6.26 d10.017
  • a Means within one column that are not significantly different from each other at P = 0.05 are followed by the same letters.

  • b The pH of bulk soil samples was 6.6 in 1956 and decreased distinctly in the peat- and SS-treated plots. The pH values measured were 6.3, 6.5, 6.9, 6.3, 6.7, 5.8, and 5.8 for fallow, NoN, Ca(NO3)2, GM, AM, SS, and peat, respectively. This effect has already been discussed by Kirchmann et al. (36).

  • c C/N values are from G. Haberhauer, M. H. Gerzabek, and H. Kirchmann, personal communication.