Spreading gypsum to the fields effectively reduces the phosphorus runoffs from agriculture to the water bodies. Gypsum also reduces the leaching of the organic carbon and reduces the carbon dioxide emissions to the climate. The findings were done in the TraP-research project, implemented in years 2008 – 2012.
The research area of 100 hectares in Finnish Archipelago drainage basin showed that the gypsum treatment reduced the drift of phosphorus on average 50 %, and the dissolved phosphorus leaching was reduced by some 25 %. The effect of the gypsum lasts at least four years.
TraP -research projectwas conducted by Yara , the Finnish Environment Institute SYKE, the water protection association of river Vantaa and Helsinki area VHVSY, Luode Consulting Oy and TTS institute.
The gypsum meets to the protection goals of the Finnish Archipelago
Yara Suomi Oy has implemented their Baltic Sea Commitment by treating 100 hectares of field with gypsum in the sensitive areas of the Finnish Archipelago drainage basin. Also in these targets, the gypsum treatment was discovered to be an effective way to reduce phosphorus runoffs.
On the basis of regionalization models, made by SYKE, the reduction of the phosphorus load in the drainage basin in the Finnish Archipelago could at its best be 70 tons per year. This could be done if all the current clay fields in use would be treated with gypsum.
Finland has a goal to reduce the total phosphorus load by 120 tons per year. The productivity of the cultivation does not suffer for the treatment of gypsum. The gypsum method has now been approved to the draft of the new environmental compensation system.