Soil nutrient supply and herbivory influence grass root longevity

摘要

The effects of soil improvement on root dynamics were examined at two grassland field sites. Application of insecticide (I) reduced all insect larvae. Through the use of in-situ root analysis methods, cohorts of roots were followed from initiation to death, and root longevity was assessed. Root density, appearance and disappearance were all reduced with I, reflecting a reduced root replacement when larval numbers were reduced. The removal of root herbivory also led to an increase in root longevity. Root appearance was increased with nitrogen and lime (NL) addition, and root longevity was reduced. At the second site, where the influence of nitrogen alone was examined, root density and turnover increased. Season and time of season were also shown to significantly influence root dynamics. The influence of management as an external driver of root dynamics was examined in a survivorship model.