An important part of the plan is to use the seaweed as a building block for humus, as indicated in the introduction.

Humus are organic acids, complex molecules, which arise after the breakdown of dead plant parts and which are digested by soil organisms. Thanks to the chemical structure of humic acids, they not only retain water but also nutrients such as calcium, magnesium, potassium, ammonia, phosphorus, sulphur, iron, manganese, zinc, copper, etc. In humus-poor soils, on the other hand, rain or irrigation water and the dissolved nutrients simply move to deeper aquifers, out of reach of plant roots. Thanks to these properties, humus-rich black soils can bridge a dry season.

In addition to the humus content, the Chernozem also has a very good structure, that is, plant roots have no trouble branching out in the soil and there is enough oxygen so that soil organisms, abundantly present to great depths, can breathe. The soil also contains a lot of calcium, so it does not become acidic quickly. All these properties ensure that a Chernozem does not need extra fertilizers or soil improvers and that it produces good yields, provided it is managed sustainably.

What makes Ukraine so fertile is the soil type Chernozum, which stands for a layer of humus more than 25 centimeters thick. In combination with the right climate, this is the most fertile soil on the earth.

A disadvantage is that the carbon can be converted back into CO2 if managed incorrectly, for example by plowing a lot or using pesticides that kill soil life, education is essential here.

Option 1 regarding time/interest of audience: Examples of places to deposit this humus are:

• countries at risk of desertification, with some available freshwater supplies and relatively little surface salt on which water retention and cooling measures are planned, such as planting trees

• Farmlands that are well managed, no tillage such as plowing while keeping the soil well aerated, erosion prevention, ability to water crops in case of drought

• Sell commercially as compost, but co2 retention is less controllable

Option 2 with regard to time/interest audience: My hope is to reverse the process whereby an area the size of 3 x Belgium can now be turned into desert every year by planting trees in the compost and humus which will form a better microclimate. At scale, this could contribute very significantly to the absorption of CO2, in addition to having local cooling and food benefits.