Divergent Drivers of Various Topsoil Phosphorus Fractions Across Tibetan Alpine Grasslands. Issue 4 (25th April 2022)

• Record Type: Journal Article
• Authors: Li, Ziliang; Zhang, Dianye; Peng, Yunfeng; Qin, Shuqi; Wang, Lu; Hou, Enqing; Yang, Yuanhe
• Is Part Of: Journal of geophysical research. Volume 127:Issue 4(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-04-25
• Subjects: alpine ecosystem -- phosphorus availability -- phosphorus cycle -- phosphorus fraction -- phosphorus pools; Geobiology -- Periodicals; Biogeochemistry -- Periodicals; Biotic communities -- Periodicals; Geophysics -- Periodicals; 577.14
• DOI: 10.1029/2022JG006795
• Languages: English
• ISSNs: 2169-8953

Abstract

Abstract: The storage and dynamics of various soil phosphorus (P) fractions could determine soil P availability, and thus regulate terrestrial carbon cycle and its feedback to climate warming. However, little evidence is available about patterns and drivers of soil P fractions in alpine ecosystems which could play a crucial role in terrestrial carbon cycle. Here we evaluated various topsoil P fractions and their determinants in Tibetan alpine grasslands using systematic measurements along a 3, 000 km transect. Our results showed that topsoil P concentrations in Tibetan alpine grasslands were higher or equivalent than those in temperate and tropical‐subtropical ecosystems. Our results also revealed distinct drivers among various soil P fractions: microbial properties and soil pH were dominant drivers of labile P and secondary mineral P fractions, respectively. Mineral properties were key determinants of occluded P and organic P fractions, whereas primary mineral P fraction was largely predicted by precipitation and mineral properties. The large‐scale evidence obtained in this study offers new insights for better predicting the trajectory of soil P availability and its interactions with ecosystem carbon cycle in alpine ecosystems under changing environment. Plain Language Summary: Over the 21st century, soil P availability is expected to play a vital role in regulating vegetation productivity and thus exerts a strong control on the responses of terrestrial carbon cycle to global change. However, our understanding about the size and drivers of various soil P fractions in alpine ecosystems is very limited. Based on extensive field investigation along a 3, 000 km grassland transect, we explored regional patterns and dominant drivers of various topsoil P fractions across Tibetan alpine grasslands. We observed that topsoil P concentrations in Tibetan alpine grasslands were higher or equivalent than in temperate and tropical‐subtropical ecosystems. We also found that biological properties were dominant drivers of labile P fraction and geochemical factors were key determinants of secondary mineral P, occluded P and organic P fractions. By contrast, primary mineral P fraction was mainly predicted by precipitation and mineral properties. Our findings provide basis for better understanding the dynamics of soil P availability in alpine ecosystems under changing environment. Key Points: Topsoil phosphorus concentrations in Tibetan alpine grasslands were higher or equivalent than temperate and tropical‐subtropical ecosystems Microbial properties and soil pH were dominant determinants of labile and secondary mineral phosphorus fractions, respectively Mineral properties were key drivers of occluded and organic phosphorus, but primary mineral phosphorus was predicted by precipitation and mineral properties