ESRIG-EES colloquium: Zili Yuan, MSc EES student

---

Title: Agricultural Residues in the Netherlands and Their Role in the Soil Carbon Cycle – Are Residues Available for Bioenergy?

By: Zili Yuan, MSc EES student.

Summary:
The current food production system is important for the surviving and thriving of mankind. It currently feeds and supports the livelihood of around 200 million people on this planet. Because of that, it is one of the core interests of study of the Intergovernmental Panel on Climate Change (IPCC). Moreover, it will be increasingly affected by projected future climate change. Through increasing temperatures, changing of precipitation rates, land degradation and increasing frequency of extreme events, climate change is effecting on food security. It is essential to maintain the land/soil quality of our agricultural land in order to protect food security. Soil Organic Matter (SOM) is one of the most important soil content that has the most widely recognized impact on soil quality (Doran and Parkin, 1996). SOM is one of the most important preconditions for soil formation as well as an essential element for the preservation of the soil fertility (Körschens, 2010).

One of the major source of SOM in agricultural practice is returning the agricultural residues to the land. Therefore, although there have been talks about utilizing residues as a feedstock for second generation biofuel, it is essential, because of the reasons stated before, that these residues are going to be used to balance SOM. In this research, soil organic carbon (SOC) is used in stead of SOM, with a SOC;SOM ratio at about 1:2. The Netherlands and its agricultural system is used as a case study.

This research aim to determine:
1)What is the amount of residues available in the country, and their organic carbon composition, from different agricultural practices and farm types? and
2) How much of the residues will need to be returned to the land in order to satisfy the need for maintaining a stable soil organic carbon level without compromising food productivity of the land?
A SOC balance model was made to answer these questions.

This leads to concluded that almost all the residues in the Netherlands are needed for keeping the balance of SOM in the soil, and the system as it is now is more or less self-contained. There is little to no residue left available as second generation biofuel feedstock. Although the model in this study has its short comings, but it provides a clear indication that a cautious approach should be taken when accessing the residue availability., and for specific regions and areas, the issue should be analysed individually and thoroughly.