Form Submission: Participation Entry

Roots are a significant source of carbon input into the soil, yet little is known about root growth response to altered nutrient availability. Unknown changes in water and nitrogen availability are expected in the next century as a result of shifting climate regimes and the effects are particularly relevant in dryland ecosystems where water and nitrogen are the most frequent limiting factors of net primary productivity. Previous studies have found that elevated resource availability increases aboveground NPP, but what about belowground NPP? My objective was to evaluate belowground NPP by measuring root growth response to water and nitrogen additions within three semi-arid ecosystems. The experimental treatments consisted of three replicates of manipulations: a control, water, nitrogen, and water plus nitrogen. Root growth was measured with ingrowth cores and monitored at six-week intervals for eighteen weeks. We tested the hypothesis that an increase in both water and nitrogen would have the greatest influence on belowground NPP because water and nitrogen are the two most frequently limiting resources.