Biocrusts control the nitrogen dynamics and microbial functional diversity of semi-arid soils in response to nutrient additions

TitleBiocrusts control the nitrogen dynamics and microbial functional diversity of semi-arid soils in response to nutrient additions
Publication TypeJournal Article
Year of Publication2013
AuthorsDelgado-Baquerizo M., Morillas L., Maestre F.T, Gallardo A.
JournalPlant and SoilPlant and Soil
Volume372
Pagination643-654
Date PublishedNov
ISBN Number0032-079x
Accession NumberWOS:000326093300046
Keywordsavailability, biodiversity, biogeochemical cycles, carbon, crusts modulate, dissolved organic n, dissolved organic nitrogen, ecosystem, fungal communities, global desertification, mediterranean grassland, mineralization, phosphorus, shannon-weaver diversity index
Abstract

Human activities are causing imbalances in the nutrient cycles in natural ecosystems. However, we have limited knowledge of how these changes will affect the soil microbial functional diversity and the nitrogen (N) cycle in drylands, the biggest biome on Earth. Communities dominated by lichens, mosses and cyanobacteria (biocrusts) influence multiple processes from the N cycle such as N fixation and mineralization rates. We evaluated how biocrusts modulate the effects of different N, carbon (C) and phosphorus (P) additions on theN availability, the dominance of different available N forms and the microbial functional diversity in dryland soils.Soil samples from bare ground (BG) and biocrust-dominated areas were gathered from the center of Spain and incubated during seven or 21 days under different combinations of N, C and P additions (N, C, P, N + C, N + P, P + C, and C + N + P).The relative dominance of dissolved organic N (DON) and the microbial functional diversity were higher in biocrust than in BG microsites when C or P were added. Changes in the C to N ratio, more than N availability, seem to modulate N transformation processes in the soils studied. In general, biocrusts increased the resilience to N impacts (N, C + N, N + P, C + N + P) of the total available N, ammonium, nitrate and DON when C was present.Our results suggest that biocrusts may buffer the effects of changes in nutrient ratios on microbial functional diversity and DON dominance in dryland soils. Thus, these organisms may have an important role in increasing the resilience of the N cycle to imbalances in C, N and P derived from human activities.

Short TitlePlant Soil
Alternate JournalPlant Soil<br/>Plant Soil