An interesting discovery is helping in Baltic Sea conservation efforts in Finland. It involves the use a gypsum, which is a chemical substance known to most of us.
The environmental challenge we are talking about is that phosphorus, an essential plant nutrient, is transported from the farming fields through runoff into the rivers and sea. In the sea water, elevated levels of phosphorus cause eutrophication.
Yara, a chemical company, has together with a few Finnish partners developed a gypsum-based technique to stabilize soil particles in the farming fields. The method reduces soil (and nutrient) erosion caused by surface runoff.
The results achieved indicate that a high percentage of the phosphorus stays in the soil when the new technique is used. Consequently, harmful nutrient inputs into the waterways and sea are highly reduced. The new method also helps the farmer as more phosphorus is available for the agricultural plants. Furthermore, there is less need for costly, additional phosphorus fertilizers.
In spite of not being visible in this image, eutrophication caused by excessive nutrients is a problem on the Baltic coast of Finland. Photo (c) 2010 Erkki Siirila.
The method involves spreading of a gypsum-based product on the farming field after harvest or before planting. The product, which is basically gypsum (calcium sulphate), infiltrates with water into soil. According Yara, this well-known chemical compound in its slightly developed form improves “particle aggregation and dissolved phosphorus retention”. In addition, “better soil structure means that the earth resists rain and melting snow better and therefore prevents erosion and phosphorus leakage”.
Gypsum is useful to the farmer also because it improves the plants’ ability to utilise the phosphorus reserves of the soil. In addition, farmers can continue their agricultural activities as before. For the gypsum treatment to be effective, it would need to be repeated once in three to four years.
Gypsum treatment of the soil could be important news for many countries. Soil,sediment and nutrient runoff is degrading forestry and agricultural areas around the world. This runoff is also killing shallow marine ecosystems. Could gypsum help save the world’s endangered coral reefs?
A brochure on the gypsum-based method to control agricultural runoff into the sea can be found here:
