Crop Diversity Effects on Near-Surface Soil Condition under Dryland Agriculture

Table 3

Crop diversity effects on soil carbon, nitrogen, C : N ratio, particulate organic matter (POM) C, and microbial biomass C at 0–10 cm for long-term crop and pasture treatments near Mandan, ND.

Soil property	Small grain-fallow	3 yr fixed rotation	5 yr fixed rotation	Dynamic rotation	Grazed pasture^†
Soil organic C; (Mg C ha^−1)	19.9 (1.0) b^‡	22.7 (0.9) b	26.9 (0.4) a	25.7 (0.7) a	31.0 (0.7)
Total N; (Mg N ha^−1)	2.0 (0.1) c	2.2 (0.1) b	2.5 (0.1) a	2.4 (0.1) a	2.6 (0.1)
C : N ratio	10.23 (0.26) bc	10.20 (0.11) c	10.73 (0.10) a	10.67 (0.12) ab	12.02 (0.11)
POM-C; (kg C ha^−1)	1172 (144) c	2834 (151) ab	3078 (162) a	2486 (144) b	4690 (262)
Microbial biomass C; (kg C ha^−1)	549 (48)	748 (89)	657 (42)	671 (32)	992 (116)

†Soil property values for grazed native vegetation with the same soil type are shown for comparison but were not included in statistical analyses.
^‡Values in parentheses represent mean standard error. Mean values in a row followed by a different letter are significantly different at 𝑃≤0.05.