Terra Preta in Agriculture
The approx. 35,000 t of green waste that accrues annually in the Hameln-Pyrmont district is to be processed into 24,000 t of Terra Preta. Woody and soft material are separated.
The woody is pyrolyzed, then ground and mixed with the shredded soft material. The addition of lactic acid bacteria ensures climate-friendly fermentation when the air is largely excluded (loss of mass due to the escape of gases is only approx. 2% compared to up to 50% with composting). If after a certain period of time (depending on the outside temperature) the substrate smells nutty, mushroom-like, like forest soil, it is ready for use in the field and garden.
Since the material is "pre-digested" in a certain way by fermentation, it needs a living soil with many microorganisms, which this material serves as food, it is metabolized and contributes to the formation of humus, the imperishable biochar stabilizes the formation of humus. The application of chemical fertilizers and pesticides would seriously damage soil life and is not advisable.
In the medium and long term, fertility can be increased and maintained through the increasing humus content; with appropriate crop rotations and careful tillage, the farmer can achieve good yields and is no longer dependent on the use of chemicals and pesticides. To achieve appropriate prices, it may be advisable to switch to organic farming.
In addition to promoting biodiversity in the soil, the aim is to create a network of biotopes.
Since the subsidies for biogas plants will expire in the next few years, it could make sense to replace biogas plants with pyrolysis plants, existing local heating networks could be preserved, continued operation with fossil fuels could be avoided, at best this could be a temporary solution. If the cultivation of maize is discontinued, the material for operating the pyrolysis plants could be made from wood chips, grown in short rotation plantations. Rows of trees along the contour lines, so-called keylines, hold back the water, protect against wind erosion and provide shade in hot summers. Flower strips, small ponds and biotope networked trees can serve to build up biodiversity, create a balanced biological equilibrium and thus keep undesired animals and plants in check.
