Organic and inorganic carbon storage in Dutch agricultural systems

Soil carbon is critical for food production, mitigating climate change and supporting soil biodiversity, yet agricultural intensification is leading to significant losses. Despite the need to stop agricultural soil carbon depletion, uncertainties persist regarding agricultural practices that can promote soil carbon storage across different pedological conditions.

Although soil carbon encompasses both inorganic and organic components, most research has focused on the effect of agricultural management on organic carbon (OC) due to its sensitivity to soil disturbances and role in soil functioning. However, there is growing evidence showing that agricultural activities can cause irrevocable losses of inorganic carbon (IC), which may be detrimental for soil health and contribute to climate change. It is therefore crucial to study the response of both inorganic and organic carbon to agricultural management.

In the SoilProS project we investigate how soil agricultural management influences soil carbon storage across diverse pedological conditions. For this purpose, an unprecedented total of 956 grasslands and cropland soil samples were collected from a wide range of agricultural management and pedological conditions in the Netherlands. Detailed information on agricultural management was gathered using questionnaires. We used random forest analysis to untangle the key drivers of soil OC and IC.

Our preliminary results indicate that soil properties together with management practices such as nitrogen fertilization and physical soil disturbance in arable fields, and mowing and grazing in grasslands, contribute to explain the variation of both soil OC and IC in the Netherlands. These findings are essential for developing more tailored, sustainable management practices.