Organic matter is an important aspect for every type of soil with regard to its fertility. Organic matter has an effect on:
- Chemical bonding of minerals: because of its bonding capacity, organic matter is able to bond positively charged parts. This ability lessens washing away of potash, magnesium and calcium for example.
- Water balance: soils that contain a lot of organic matter are better able to retain water and are therefore less susceptible to drought during dry periods.
- Air balance: it is proven that with high levels of organic matter there is a better balance between air, solid parts and water.
- Soil biology: organic matter is needed for soil ecology. Especially soil fungi and soil bacteria do well when there is enough organic matter available.
Supply of organic matter through compost is one of the most effective ways. A year after application, 90% of organic matter is still present in the soil, while this is much less with other soil improvers. The organic matter remains stable due to the composting process.
On clay soils the soil structure is dependent on the calcium deposits. Clay particles can also bind positive elements, similar to organic matter. When insufficient calcium is bonded to the clay particles, the structure of the soil will be negatively affected. Scattering gypsum is proven to improve the level of calcium deposits in clay soils. This has a positive effect on the soil structure, bringing more air, improving manageability and decreasing soakage.