A big part of the land in the Baltic Sea region is used to produce food, i.e.as agricultural area. These activities affect the Baltic Sea, since much of what leaves the fields, especially by waterflows but also by the air, eventually ends up in the sea. The main impacts on the Baltic from agriculture are loss of nutrients from farmlands, i.e. phosphorus and nitrogen, and of hazardous substances, i.e. biocides.
Looking at the net pollution load from human activities on water, 40 %  of the phosphorus and nitrogen pollution comes from agriculture. (Concerning both nitrogen and phosphorus, 40 % of the net pollution load from human activities comes from agriculture.)
However, it is important to remember that agriculture also can contribute to the ecosystem. The animals provide manure that can be used both as fertilizers and for producing biogas, the fields provide us with food, and the crops use nutrients (e.g. from manure or extracted from sea water) and carbon dioxide for their growth.
In this section we have included:
Alternatives to hazardous substances, biogas from manure, extraction of nutrients in situ from sea water, improved use of fertilisers, removal of nutrients from agricultural wastewater and constructed wetlands.
 Jordbruksverket (2009), Jordbruksstatistisk årsbok 2009, Jönköping, Sverige