Soil Health and Deep Plowing Under The Tuscan Sun

Italy to many, is the birthplace of farming with a soil nomenclature system dating from 500 AD. In the mere distance of Maine to North Carolina they have all four major soil temperature groups – frigid, mesic, thermic and hyperthermic and 4-times the soil unit diversity of the USA. Match all this to the cultural and Epicurean richness, throw in Lombardy cedars, olives and pasta, plus true prairie soils (Mediterranean steppes) and you have a nearly ideal setting for a soil biology tour. More recently, Italian scientists have developed their own soil health tool, the index of biological fertility (IBF) with 5 categories. It turns out most soils surveyed so far,- despite 2,000 years of plowing-, fall into the high fertility class leaning on indicators like basal CO2 respiration, metabolic carbon, organic matter and mineralization potential – right in line with what the Solvita team is working on for a standardized, practical soil  biology test system for soil labs worldwide.

(top-left to bottom-right) Brinton examines clods of deep-plowed soil in Montebuono “Good Mountain”, Italy; Hilly plowed wheat fields in Tuscany; 2-Bottom deep-plow; deep-plowing tractor, Trattoria Casa Maria; Vertic Cambisol soil profile, Tuscany.

Get up early on a mid summer morning in Tuscany and you’ll discern the metallic squeech of Lamborghini caterpillar tractors slowly pulling immense 2-bottom deep-plows across the hilly Landscape, in preparation for fall grain sowing. How does that work? Conditioned to American reduced-tillage views one is shocked automatically. Yet they’ve been doing some form of this for centuries (the Etruscan plough dates to 500 BC). We ran our own soil health tests: in the intense mid summer heat (100F), basal respiration is nearly dormant (as is soil moisture) with virtually no detectable nitrate. Once re-wetted in the lab the soils exhibited a lively Solvita CO2 burst,- exactly what we expect to happen in the fall when rains return as durum grains are planted. Aggregate stability was excellent as well as OM. These soils appear to have survived well a management regime which in another time and place would be destructive. Still, change is coming and the mapping of IBF across the provinces, with a focus on practices putting some Italian soils in danger, is progressing slowly. One thing is certain, they’ve kept these soils well for millennia and no wonder: the culture depends on it. For more info on the IBF system and our soil health test results for Italian soils, please contact solvita@woodsend.com.