Continuous Cropping Systems Reduce Near‐Surface Maximum Compaction in No‐Till Soils

Abstract

Because of increased concerns over compaction in no‐till (NT) soils, it is important to assess how continuous cropping systems influence risks of soil compaction across a range of soils and NT management systems. We quantified differences in maximum bulk density (BDmax) and critical water content (CWC) by the Proctor test, field bulk density (ρb), and their relationships with soil organic carbon (SOC) concentration across three (>11 yr) cropping systems on a silty clay loam, silt loam, and loam in the central Great Plains. On the silty clay loam, BDmax in sorghum [Sorghum bicolor (L.) Moench]–fallow (SF) and winter wheat [Triticum aestivum (L.)]–fallow (WF) was greater than in continuous wheat (WW) and continuous sorghum (SS) by 0.1 Mg m−3 in the 0‐ to 5‐cm soil depth. On the loam, BDmax in WF was greater than in W–corn (Zea mays L.)–millet (Panicum liliaceum L.) (WCM) by 0.24 Mg m−3 and perennial grass (GRASS) by 0.11 Mg m−3 On the silt loam, soil properties were unaffected by cropping systems. Elimination of fallowing increased the CWC by 10 to 25%. The ρb was greater in WF (1.52 Mg m−3) than in WW (1.16 Mg m−3) in the silty clay loam, while ρb under WF and WCF was greater than under WCM and GRASS in the loam for the 0‐ to 5‐cm depth. The BDmax and ρb decreased whereas CWC increased with an increase in SOC concentration in the 0‐ to 15‐cm depth. Overall, continuous cropping systems in NT reduced near‐surface maximum soil compaction primarily by increasing SOC concentration.