We like to think that the bio-extensive approach to market gardening minimizes the risk of overloading the soil with nutrients because the fallow lands make it possible to grow lots of cover crops to maintain soil structure and organic matter rather than relying on large quantities of manure and compost. However, we are now seeing the consequences of ignoring our own farm philosophy when we resorted to off-farm inputs to correct a phosphate deficiency.
The essential requirements of a soil upon which to grow onions profitably are a high state of fertility, good mechanical condition, properties – that is, if it contains sufficient sand and humus to be easily worked, is retentive of moisture and fertilizers, and is capable of drainage – all other requirements can be met.
In the last few years I have noticed a lot of buzzwords being used around the grazing industry and in my readings, like sequestration of carbon, living soils, microbes, mycorrhizal fungi, biochar, regenerative agriculture, micro-biome and cover cropping. These all are in reference to techniques and terminology associated with awareness of soil biology. If any of you are like me, I sometimes will not ask a simple question because I don’t want to sound uninformed, so today I will start out with a simple explanation as to what the natural cycle of plant photosynthesis is and how a plant goes about getting the nutrients it needs to grow.
By proper methods of tillage, crop rotation, or green manuring, and even by the application of fertilizers, the interaction between prevailing soil conditions and biological phenomena may be modified so as to promote the activity of desirable micro-organisms and retard the development of the undesirable ones.
Some 2000 years ago a handful of Roman writers, themselves skillful farmers, championed the soil as the foundation of a farm’s success. This insight remains true today and has guided my own approach to the soil. From the outset I have followed the Roman precepts of working with nature, not against it. This insight cannot be more urgent than today, when all of us are struggling with finite resources.