Background: Soil aggregate and particulate organic matter (POM) C and N provide valuable insight into C cycling and storage, and are sensitive to management, but effect of these pools on corn yield is unknown. Methods: Corn yield, N uptake, and aggregate and POM C and N at 0–5, 5–25 and 25–50 cm were measured and correlated in continuous corn (Zea mays L.) (CC), strip-till corn/soybean [Glycine max (L.) Merr.] (CS), and organically managed corn/soybean/wheat (Triticum aestivum L.) with green manure (CSW). Results: The POM differed only at 0–5 cm, where greater POM mass was found in CS than CC and CSW. Lower POM-C and POM-N was found in CSW than CC and CS. Overall, CSW had fewer macroaggregates (>250 μm) and associated C and N than CC and CS, but free silt and clay (<53 μm) and microaggregates (53–250 μm) were enriched in C and N in CSW. Yield and macroaggregate-occluded C and N were negatively correlated. Yield and 5–25 cm free silt and clay C were positively correlated. Conclusions: While organic matter in aggregate-occluded fractions is beneficial for soil C storage, it was correlated with lower grain yields, highlighting a potential tradeoff between yield and long-term C sequestration.
Bibliographical noteFunding Information:
Thanks to D.S. Duncan, A. von Haden, R.D. Jacskon, and K. Nicolakakis for helpful comments on the manuscript, to Dr. Lawrence G. Oates for C and N analysis, and to Dr. Gregg R. Sanford, Janet Hedtcke and the late Dr. J.L. Posner for maintaining the WICST trial and associated data. Generous internal support for the WICST trial was provided by the University of Wisconsin Arlington Agricultural Research Station. Funding was provided by USDA-NIFA Hatch Project 229696, the Wisconsin Fertilizer Research Council and USDA-NIFA-AFRI-004715.
© 2017, Springer International Publishing Switzerland.
- Carbon storage
- Cropping systems
- Soil organic matter dynamics