River Transport of Phosphorus as Controlled by Large Scale Land Use Changes

Publisher Website
Google Scholar
Abstract
Land use, within the area studied, displayed two large-scale changes over a period of 100 years. One was the transition from ley cultivation to grain production. The other change was the decrease in the number of livestock. The phosphorus balance for the area, accompanying these changes, showed that the early net export of about 1 kg per hectare and year at the end of the last century became a net import during the 1940s. Agricultural practices have changed, decreasing the share of land exposed to surface erosion, but the change is insignificant compared to the transport change found in the watercourse. The decreasing use of organic manure and the transition to the use of inorganic fertilizers coincided with the changes of phosphorus transports observed. It is also evident that the acid/base effects of fertilizers, the amounts of lime (CaO) used, the increasing areas of soils with a declining pH and the transport decrease in the water all occur during the same period of time. To conclude, the most important factors of large-scale land use changes coinciding with the transport drop in the late 1960s, seemed to be related to changes in transport mechanisms, rather than to large-scale pool changes.