Soil cultivation: By horse or by tractor?
In an eight-year long-term study by the university of Kiel (professor Rainer Horn) the effects of soil cultivation on the physical properties of the soil have been examined. The comparison has been drawn between a light weight tractor and a pair of heavy horses performing an array of agricultural activities with equal tools, on comparable paddocks and with equal weather conditions. Even though the total weight of the horses was higher than the tractor a 40% higher pore volume had been measured in the horse powered paddock after 3 years. Which means there is a much lower soil compaction and therefore increased water retention capacity. The plants were so happy that they reacted with a 15% higher production rate.
In this study an unusually light tractor had been chosen but a damaging effect seems to occur already through the vibration and the slipping of the powered wheels! Normal tractors achieve their success through a high weight which compacts the ground on deep levels.
In addition, a horse is fueled with grass, straw and oats which it converts to subsistence, manure and work force. Contrary to popular opinion tractors have a very low efficiency rate where a maximum of only 25% (but usually less) of the petrol energy input is converted to traction power (not to mention the missing subsistence and manure production).
See for further information:
Projekt Humussphäre on the web-site of SoLaWi Hof Hollergraben (in german)
youtube: Symposion Aufbauende Landwirtschaft/Vortrag Klaus Strüber (in german)
Horses have a different footprint and we have the advantage to roam our fields with Shetland ponies . . .
Of course it takes a lot more time, but living soil cannot be substituted.