COS 7-5
Soil biota as drivers of ecosystem sustainability and multifunctionality
Soil organisms play a key role in ecosystems by regulating nutrient uptake, plant productivity and by influencing plant diversity. The importance of soil biota for the sustainability of ecosystems is still unresolved. Moreover, it is unclear how multiple ecosystem functions are simultaneously affected by changes in soil biodiversity and community composition. We manipulated soil biodiversity in outdoor lysimeters filled with 230 kg soil and planted with an agricultural crop rotation. In addition to this we manipulated soil biodiversity and soil community composition in microcososm with experimental grassland. Subsequently we tested how changes in soil biodiversity and soil community composition influenced a number of ecosystem functions including nutrient leaching losses, greenhouse gas (N2O) production, plant productivity, nutrient uptake and plant diversity.
Results/Conclusions
Here we show that soil organisms and soil biodiversity can enhance the sustainability of natural and agricultural ecosystems by reducing nutrient leaching losses after rain and promoting nutrient uptake. Experiments performed in indoor microcosms and in outdoor lysimeters, showed that an increased abundance of mycorrhizal fungi and other soil biota, reduced leaching losses of nitrogen and phosphorus. The reduction of nitrogen leaching losses in outdoor lysimeters was substantial (a reduction of up to 80 kg N/ha/year) pointing to the key role of soil biota in nutrient cycling. Microcosm experiments with experimental grassland further revealed that nutrient losses depend on the composition of fungal communities and were reduced in microcosms with enhanced soil biodiversity. Mycorrhizal fungi were identified as a key driver of the observed effects. Our results indicate that changes in soil communities and the loss of particular groups of soil biota threatens ecosystem multifunctionality and sustainability.