Reducing nutrient loss in intensive agriculture – preliminary pot research

The maintenance of appropriate soil structure is critical for preventing soil degradation and mitigating nutrient losses that cause eutrophication of water bodies. An important challenge to combat eutrophication in the Baltic Sea is reducing phosphorus losses from agricultural land. Gypsum (CaSO4∙2H2O) has been identified as a promising soil amendment that improves soil structure and reduces phosphorus leaching. However, it has not been widely used in Poland. The article explains the importance of gypsum during the formation of a lumpy soil structure and in reducing phosphorus losses. A total of 18 samples were prepared, including three replicate samples without and with gypsum. Gypsum was added to each of the three pots based on the bulk density of the soil to correspond 4 Mg of gypsum per ha. The soil samples were analysed for total phosphorus, phosphates, available phosphorus, pH in water, KCl, and organic carbon. The study presents findings of a laboratory pot test conducted on three soil samples from Southern Poland. The pot experiment indicated a decrease in turbidity of leachates from the soil samples treated with gypsum. Gypsum application did not significantly affect soil pH and total phosphorus content. Analysis of the soil samples before and after the watering showed that the total phosphorus concentration did not change. This was due to the low share of phosphorus released relative to the total phosphorus content in the soil.