Nitrogen dynamics in soils with different hydrocarbon contents planted to barley and field pea

Abstract

Nitrogen dynamics and cycling are important in plant-soil ecosystems, and they may differ between hydrocarbon-contaminated and uncontaminated soils. The objective of this experiment was to study the effects of petroleum hydrocarbons and remediation methods on nitrogen dynamics and cycling in plant-soil ecosystems. The experiment involved two plant species (barley and field pea) grown in soils at four different hydrocarbon levels (0, 5, 25 and 55 g kg-1). Hydrocarbon contamination significantly reduced N uptake by plants, but increased N accumulation in soil microbial biomass. It widened the C:N ratio in soil and led to more available N being immobilized by soil microorganisms, which reduced available N for plant uptake. Urease activity increased with hydrocarbon content in soil due to the increase of microbial biomass and activity.