Soil net nitrogen mineralisation across global grasslands

ANITA RISCH; STEPHAN ZIMMERMANN; RAUL OCHOA-HUESO; MARTIN SCHÜTZ; BEAT FREY; JENNIFER FIRN; PHILIP FAY; FRANK HAGEDORN; ELIZABETH BORER; ERIC SEABLOOM; W HARPOLE; JOHANNES KNOPS; REBECCA MCCULLEY; ARTHUR BROADBENT; CARLY STEVENS; MARIA SILVEIRA; PETER ADLER; V BAEZ JACOME; LORI BIEDERMAN; JOHN BLAIR; CYNTHIA BROWN; MARIA CALDEIRA; SCOTT COLLINS; PEDRO DALEO; AGUSTINA DI VIRGILIO; ANNE EBELING; NICO EISENHAUER; ELLEN ESCH; ANU ESKELINEN; NICOLE HAGENAH; YANN HAUTIER; KEVIN KIRKMAN; ANDREW MACDOUGALL; JOSLIN MOORE; SALLY POWER; SUZANNE PROBER; CHRISTIANE ROSCHER; MAHESH SANKARAN; JULIA SIEBERT; KARINA SPEZIALE; PEDRO TOGNETTI; RISTO VIRTANEN; LAURA YAHDJIAN; BARBARA MOSER

NATURE COMMUNICATIONS

Nature Publishing Group

Año: 2019

2041-1723

Soil nitrogen (N) mineralisation (Nmin), the conversion of organic N into inorganic forms, is the main source of plant-available N in grasslands, and a critical driver of productivity and nutrient cycling. Soil net Nmin, the The balance between mineralisation and immobilisation, soil net Nmin, varies with soil properties and climate. However, because most global-scale assessments of net Nmin are laboratory-based, the global regulation of net Nmin in real-world field conditions and its implications for productivity and soil function, remain unclear. Here we (i) explore global spatial patterns , (ii) test key hypothesized drivers of field and lab soil net Nmin and (iii) evaluate the link between these two net N min measures across 30 grasslands worldwide. Primary drivers differed between field- and lab-based measures. By combing all key predictors and lab Nmin measures we were able to reveal the direct and indirect drivers of site-level field Nmin. Greater field soil net Nmin was directly driven by temperature of the wettest quarter, greater lab soil net Nmin and lower bulk density, indirectly by greater soil C content and greater abundance of bacterial ammonia oxidisers (AOB). Conversely, lab soil net Nmin was directly driven by climate, soil organic C and abundance of AOB. This work provides crucial insights into global Nmin dynamics in grasslands and can help to improve predictions of global change impacts on ecosystem productivity.