Compare effects of management practice to meta-analysis results

[dlebauer]

See https://github.com/orgs/ccmmf/discussions/14 and Table 6 from Conceptual Framework

A core component of the CCMMF project is a model that is sensitive to impact of management changes on GHG balance at State and County scales. Our expectation is that these responses will be consistent with previous findings (Table 6).

Practice Change	Soil C	N2O	CH4
+Cover Crops	↑↑	↓	↓
+Non-crop C	↑↑	↑	↑
↓Tillage	↑↑	↓	↔
↓N Fertilization	↔	↓↓	↔
↓Flooding	↔	↔	↓↓
Annual → Pere nnial	↑↑	↓	↔

Table 6: Expected directional effects based on prior syntheses. Direction of effect: increase (↑), decrease (↓), uncertain or variable (↔); two arrows indicate high confidence. Effects on CO2 flux are expected to be opposite of effects on Soil C stocks. Based on previous meta-analysis: (Robertson, Paul, and Harwood 2000; Bouwman, Boumans, and Batjes 2002; Six et al. 2004; Conrad 2007; Snyder et al. 2009; van Kessel et al. 2013; Basche et al. 2014; Poeplau and Don 2015; Liu et al. 2017)

Once validated, demonstrating agreement between the county-level results and larger-scale syntheses (e.g. meta-analyses, statewide cropland inventories, remotely sensed biomass/NEE products) will further increase our confidence in the system ...

References

Poeplau, Christopher, and Axel Don. "Carbon sequestration in agricultural soils via cultivation of
cover crops–A meta-analysis." Agriculture, Ecosystems & Environment 200 (2015): 33-41.

Van Kessel, Chris, et al. "Climate, duration, and N placement determine N2O emissions in
reduced tillage systems: a meta‐analysis." Global change biology 19.1 (2013): 33-44.

Six, Johan, et al. "The potential to mitigate global warming with no‐tillage management is only realized when practised in the long term." Global change biology 10.2 (2004): 155-160.

Basche, Andrea D., et al. "Do cover crops increase or decrease nitrous oxide emissions? A
meta-analysis." Journal of Soil and Water Conservation 69.6 (2014): 471-482.

Snyder, Clifford S., et al. "Review of greenhouse gas emissions from crop production systems
and fertilizer management effects." Agriculture, Ecosystems & Environment 133.3-4 (2009):
247-266.

Bouwman, A. F., L. J. M. Boumans, and N. H. Batjes. "Emissions of N2O and NO from fertilized
fields: Summary of available measurement data." Global biogeochemical cycles 16.4 (2002): 6-
1.

Conrad, Ralf. "Microbial ecology of methanogens and methanotrophs." Advances in agronomy
96 (2007): 1-63.

Robertson, G. Philip, Eldor A. Paul, and Richard R. Harwood. "Greenhouse gases in intensive
agriculture: contributions of individual gases to the radiative forcing of the atmosphere." Science 289.5486 (2000): 1922-1925.

Liu, Shuwei, et al. "A meta‐analysis of fertilizer‐induced soil NO and combined NO+ N2O
emissions." Global Change Biology 23.6 (2017): 2520-2532.