How do Organic Farming Systems compare with Conventional when it comes to soil biology? Data shows the differences in % of biologically-managed farms compared to conventional, as defined by the study authors.
FIBL (Switzerland) and University Wageningen (Netherlands) have completed a worldwide scientific survey (meta-analysis) of more than 149 separate paired-soil analysis studies conducted in comparative farming published in a peer-reviewed journal has found that organic-based farming systems had 32% to 84% greater microbial biomass carbon, microbial biomass nitrogen, total phospholipid fatty-acids, and dehydrogenase, urease and protease activities than conventional systems. The study did not distinguish if conventional systems were No-Till or not.
The study revealed through categorical subgroup analysis that crop rotation, the inclusion of legumes in the crop rotation and organic inputs (manures and composts) were important farming practices affecting soil microbial community size and activity. Moderns farms without crop rotations or organic amendments displayed lowered biological qualities overall. It was not reported how cover crops fit in. Organic farming has long included “green manures” which are cover crops, but the conventional farming systems compared had none.
Speaking to an audience of 500 at the Asilomar Eco-Farming Symposium in Monterey, California, Will Brinton, Ph.D. asked the question: “What’s a Healthy Soil?” To answer it he presented a summary of new data, following a session with Ray Archuleta. The presentation is posted on line at: ASILOMAR. Brinton, who did his graduate studies in Europe before soil health was recognized in the USA, told the audience that “pioneers in this group and others long before created the concept and reality of soil health and the science metrics underlying it”. As an example, he showed slides of soil enzyme and respiration studies dating to the 1970’s when the German Ministry of Agriculture ( conservative and largely supportive of intense, chemical-oriented farming) decided to investigate if biological farming could result in improved farm performance. “It was then as it is now a competition between high yields with fertilizers or high soil quality and high-value crops for future generations”. The surveys showed organic farms after a half-century had slightly lower yields but significantly higher soil carbon, one hallmark of soil quality. The data, according to Brinton, support the thesis that by relying on traditional practices of crop rotations (some as long a 7 years) blended with mixed tillage practices, soil biological quality can be steadily improved. The real issue is, are you on erodible soils?”