Vision 2030

Since 2023, measures have been taken on approx. 20,000 hectares of agricultural land (that is almost 30% of the cultivated arable land in Weserbergland, Germany) that have resulted in a continuous annual build-up of humus. The establishment of a biological way of working with green mulch and mulch sowing was supported and stabilized by the introduction of biochar substrates made from green cuttings from the local district. More and more farmers are switching to the new system, away from chemical resources and towards organic, natural tillage. The formation of humus compensates 20% of the previous greenhouse gas emissions (CO2eq) in Weserbergland.

A large pyrolysis plant has been built, which produces biochar from the wooden parts of the green cuttings, residual forest wood and other untreated wood. This is mixed with the herbaceous parts of the green cuttings to form a biochar substrate (so-called terra preta). The districts of Weserbergland have understood their task of providing public service for their citizens and are delivering this material, produced in a communal cooperative, to regional farmers at low cost.

At the beginning, the farmers were a bit skeptical about whether they should participate. The new Nitrates Ordinance has only just threatened to lose income. The public image of agriculture was negatively influenced by many. And should terra preta help in a regenerative agriculture?

Then the test fields were convincing, on which larger yields were already generated in the first few years and thus the yield losses of the land use required by the “Way of Lower Saxony” were overcompensated. And not only in organic farming but also in conventional agriculture.

Today, a humus content of more than 10% has developed on the reformed areas, and the yields have increased significantly. Broad marginal strips of trees and bushes were created along the water to network the biotopes. Stripes of wood, along the contour lines, (keyline design) hold on to the precipitation.

When choosing the tree varieties, attention was paid to resistance to the increasing hot summers. Fruit trees and nut trees were planted, but also trees with valuable wood. With rows of trees adapted to the shape of the terrain, the precipitation is influenced in such a way that the water remains in the area. (see photo above, so-called Keyline design).

The agricultural areas, which were equipped with rows of trees according to the Keyline design, can cope better with the great summer heat, in the cold season they offer protection against wind and water erosion (www.baumfeldwirtschaft.de) and they promote biodiversity.

Especially interesting is the vitalization of the soil: the intensive humus build-up led to a healthy soil, the biochar provides living space for microorganisms and the mycorrhizal fungi, and stores water and nutrients. As a result, the nutrients reach the plants and are not largely washed out by rain, as was previously the case in chemical soil cultivation. The groundwater has also become clean again near the ground.

From the beginning, farmers took care to initially connect valuable biotopes with each other with the rows of trees (fruit trees, nut trees, wood use) as water edge strips and at the waysides, as proposed in the 2020 RROP environmental report. The other areas followed in the second step. Since both the yield and the quality of the crops grown have improved significantly, new brands have been created: Weserbergland potatoes and Weserbergland barley have a good reputation, and a separate Weserbergland label has been set up for better marketing.

The profitability of agriculture has increased again, so that adequate yields can be achieved even on small farms. Gradually the structures are changing from large, industrialized farms back to rural farms.

A close cooperation has developed with the Nature Park Weserbergland, and some new hiking routes along the verge trees have been added, connecting Deister, Süntel and Ith. The hotel and catering industry benefits from this. On the Süntelner Hohenstein you can enjoy an excellent view - a large explanatory board explains the composition of rows of trees along the water and the rows of trees, some of which are laid out in curved shapes along the contour lines - those who have become curious can find out more in the district's humus center with adjoining permaculture gardening and conference center.

The waste heat from the pyrolysis plant is used here to heat a large greenhouse with an attached green classroom. Next door is a small hotel that uses these rooms for meetings on weekends. School classes can garden  on raised beds with the Terra Preta, produced next door, and theoretically deepen the experience they have experienced in the adjoining classrooms. Outside there is a permaculture gardening area - the garden pioneers from Bec Hellouin were the model – only the biochar substrate element was added.

The combination of the two principles of permaculture and terra preta led to high and good quality yields by bringing the soil to life. A humus build-up of up to 20% was achieved. All expectations in terms of quality, quantity and biodiversity have been met, and in some cases have been exceeded.

In the winter half-year there are regular events at which farmers and professional gardeners exchange and train. In summer, the groups of visitors are shown around between the flower beds; the classrooms are also used for more intensive explanations.

In cooperation with the welfare associations, jobs for people with disabilities have been created in the nursery, with the help of master gardeners who plant and harvest here.

In the adjoining restaurant, visitors are spoiled with delicious dishes, with vegetables that are delivered directly from the nursery. If visitors need to relieve themselves, they go to the Terra Preta composting toilet, where solid and liquid are separated, collected and mixed with charcoal. In this way people experience the closing of cycles through lived practice.

A greengrocer's shop is connected, and visitors can buy products from the farm here, including vegetables, juices, jams and eggs. The best sellers are shapely shopping baskets made of wicker that also fit on bicycles. Several rows of willows have been planted on the wood strips along the water and are regularly cut as pollarded willows.

To the history:

In the beginning, several hundred tons of biochar substrate were transported to Weserbergland from a carbonation plant in northern Germany. Some conventional farmers and some organic farmers tried the material with the help of soil experts. The before-and-after comparison turned out positive and gradually more and more farmers were won over to Terra Preta. Perennial and flower nurseries have also joined.

The establishment of a communal terra preta cooperative contributed to the success. This enabled the biochar substrate to be issued to all members at particularly favorable terms. Many farmers and gardeners have joined, but also some garden and landscaping companies. It is important to locate as much biochar substrate as possible in the Weserbergland region itself. The investment costs of the carbonation plant were subsidized with funding from the federal government and the EU.

Today, a considerable portion of the finances comes from trading on the CO2 exchange in Leipzig, because 1 kg of biochar binds 3.6 kg of CO2 - including the build-up of humus and the avoided slip of methane, nitrous oxide and CO2, which was the case with the old method of the month Composting, will be offset here.

More and more agriculturally used areas are changing from CO2 emitters to CO2 sinks, companies can offset their CO2 emissions by purchasing certificates, i.e. payments to farmers who then reduce CO2 in a controlled process (soil samples on GPS-registered areas) by building up humus in their fields.

Rainer Sagawe,

Dr.-Ing. Stephan Martini,

Hameln, July 2021