As we are focusing on using the soil microbiome to help store carbon I was really disappointed when I visited one of our mentor’s farms BoerinNatuur.nl and found out after 4 years of trees growing on his land the amount of fungi in the soil was still almost as low as in conventional soil. We only found 2 fungi in 30 frames, while the forest soil held almost 300 in 30 frames. This started a quest to figure out how to restore fungi in the soil quicker. We eventually found 4 scientifically backed methods, but no mention of which method would work better. 1 getting soil from a forest, 2 cooking potatoes and burying them in forest floor for a month, 3 high fungal compost and 4 digging out saplings from the forest with some soil and planting them into the target agroforestry system.

Seeing as each of these methods has very different cost structures and labor intensity it makes a huge difference to know which is quickest, cheapest and gives the best results. So we decided to try all 4 at BoerinNatuur. Each in their own tree row, between these 2 meter wide rows there is 20 meters of pasture.

1 – We got 2 kilos of forest soil and spread it out over the target tree row of about 100 meters in the afternoon so it wouldn’t get killed by the UV light from the sun.

2 – We cooked potatoes, put them in a container and dug them into the soil. A month later they were colonized by some fungi, and also eaten by mice. This experiment didn’t go as was described in the literature, but we applied it to a tree row of 100 meters as well

3 – We took 5 kilos of fungal rich compost and spread it out over the next 100 meters tree row

4 – We got 5 saplings with soil and planted them in their own 100 meter tree row.

We went back a month later and took soil samples in all 4 plots up to 30cm and in a control plot that hadn’t received any treatment. We didn’t think we would have results this quickly but wanted to check anyway.

Due to circumstances we only managed to analyze the samples about a week and a half later. We used a microscope to count the number of fungi in each sample. The control sample still had 2 fungi in 30 frames. The potato sample also had 2 fungi in 30 frames. The compost and forest soil had 8 fungi in 30 frames and the saplings gave us 12 fungi in 30 frames after just a month.

These results were great as this means we can increase the rate of CO2 capture in soil and symbioses much faster than previously assumed.

We will continue to research these and other methods further to improve carbon and nutrient capture in our soils.

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