|SKINNER, HOWARD - RETIRED ARS EMPLOYEE|
|Polumsky, Robert - Wayne|
Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/27/2017
Publication Date: 1/5/2018
Citation: Dell, C.J., Gollany, H.T., Adler, P.R., Skinner, H., Polumsky, R.W. 2018. Implications of observed and simulated soil carbon sequestration for management options in corn-based rotations. Journal of Environmental Quality. 47:617-624. https://doi.org/10.2134/jeq2017.07.0298.
Interpretive Summary: Increasing the storage of carbon in soils, in the form of soil organic matter, can increase plant available water capacity and drainage of soils, helping crops adapt to extreme weather conditions. Soil carbon levels were measured from an eight-year study evaluating switchgrass, reed canarygrass, and a corn-soybean-alfalfa rotation grown for biofuel production; measured values were compared to soil carbon levels predicted by the CQESTER model; and the model was then used to predict soil carbon accumulations in two common crop rotations (diary forage and corn/soybean) with several management options. Measurements showed that each of the bioenergy crops could increase the amount of soil carbon, and measured values corresponded well with carbon accumulation predicted by the model. CQESTER predicted that soil carbon accumulation would be much greater for a dairy forage rotation than a corn/soybean rotation, due to little soil disturbance during the four year period of perennial alfalfa. No-till planting further increased soil carbon in both a diary forage rotation and a corn/soybean rotation, but applying manure and planting winter cover crops between corn crops had little impact on predicted soil carbon storage. The simulations support the value of dairy forage rotations and other land uses, which include perennial plants, for increasing soil organic matter.
Technical Abstract: Managing cropping systems to sequester soil organic carbon (SOC) improves soil health and a system’s resiliency to impacts of changing climate. Our objectives were to 1) monitor SOC from a bio-energy cropping study in central Pennsylvania that included a corn-soybean-alfalfa rotation, switchgrass, and reed canarygrass; 2) use CQESTR, a process-based soil C model, to predict SOC sequestration in the bioenergy crops (with and without projected changes in climate); 3) use CQESTR to simulate influence of tillage, manure application, cover cropping, and corn stover removal in typical diary forage (silage corn-alfalfa) or grain corn/soybean rotations. Over eight years, measured SOC increased 0.4, 1.1, and 0.8 Mg C/ha/yr in the bioenergy rotation, reed canarygrass, and switchgrass, respectively. Simulated and measured data were significantly correlated at all depths. Predicted sequestration (8-14 Mg C/ha over 40 yr) in dairy forage rotations was much larger than with corn/soybean rotations (-4 to 0.6 M Mg C/ha over 40 yr), due to multiple years of perennial alfalfa. No-till management increased sequestration in the simulated dairy forage rotation and prevented the net loss of C from tillage in corn/soybean rotations. Simulations indicated limited impact of cover crops and manure on long-term SOC sequestration. The low solids content of liquid dairy manure is the likely reason for less than expected impact of manure. Overall, simulations suggest that inclusion of the perennial alfalfa provides the greatest potential for SOC sequestration on a typical Pennsylvania crop rotation.