Farm Scale Study: Results from 2009 field season
Part of the reason for blogging about our farm scale study is my belief that data should be openly accessible. I wanted to post results as we collected the information, to make the study available for continuous review by anybody interested in the project.
My idealism has fallen prey to time constraints. Instead of posting each new chunk of data as the growing season progressed, I am finally posting a season summary now that the 2009 harvest is stored and snow is on the ground.
As in 2008, we grew corn, soybean, sweet potato, and sweet sorghum organically at three different farming scales:
- Biointensive plots were managed according to methods recommended by John Jeavons, in his book How to Grow More Vegetables…, using only human labor and hand tools. Each biointensive plot covered 20 m2 (215 sq. ft.).
- Market garden plots were managed with hand tools and walk-behind tractors. Each market garden plot covered 126 m2 (1356 sq. ft.).
- Small farm plots were managed primarily with conventional 4-wheeled tractors, supplemented with hand tools and walk-behind tractors for tasks that weren’t suited to the larger machines. Each small farm plot covered 836 m2 (9000 sq. ft.)
Conducting the study took less time and energy in 2009 than in 2008. The combined research plots cover almost 4,000 m2 (~1 acre). In 2009 we used 166 hours of labor and 61 L (16 gal) of fuel to conduct the study. That compares with 311 hours and 72 L (19 gal) to conduct the same study in 2008. Perhaps we learned something between years.
In 2009 the biointensive and market garden scale plots out-yielded the small farm plots. Most of this difference was due to sweet sorghum, which did much better in the smaller scale systems in 2009. Sweetpotato yields were lower in 2009 than in 2008 at all scales. Other crops had similar yields between years at the small farm scale, but superior yields in 2009 at the biointensive and market garden scales. The 2009 trend toward higher yields at smaller scales was the opposite of the trend observed in 2008.
As in 2008, the biointensive plots required more labor per unit area than the market garden or small farm plots. Small farm plots used the most energy per unit area.
Metabolic (food) energy accounted for all of the energy consumed at the biointensive scale. Fossil fuel energy accounted for most of the energy consumed at the market garden and small farm scales.
Although differences between land use efficiency and energy use efficiency at the three scales were modest, differences between labor use efficiency were pronounced. Biointensive plots made the most efficient use of energy and small farm plots made the most efficient use of labor. Market garden plots were intermediate in terms of yield, labor efficiency, and energy efficiency.
The gallery below shows photos taken in the research plots since I last posted about the study in mid-July. Click on an image to expand it and see a more detailed caption.
All data presented here are preliminary, and were collected during the second year of a four-year study. Thanks to Tony Silvernail, Brian Geier, John Rodgers, Moises Hernandez and the KSU farm crew for making this study possible.