Soil microbial relative resource limitation exhibited contrasting seasonal patterns along an elevational gradient in Yulong Snow Mountain

Abstract

Abstract Microbial relative resource limitations represented by enzyme stoichiometry reflect the relationship between microbial nutrient requirements and nutrient status in soil, but the issue on whether alterations in environments along elevational gradients affect the magnitude of microbial relative resource limitations remains unresolved. Here, we examined seasonal patterns in microbial relative carbon (C) and phosphorus (P) limitations indicated by vector lengths and angles using relative proportional enzymatic activities and key controlling factors along an elevational gradient in the Yulong Snow Mountain. We also analysed the relationships between microbial metabolic processes and microclimates (i.e. soil moisture and temperature), soil properties (i.e. pH and soil texture), and microbial attributes (i.e. microbial biomass and fungal: bacterial ratio). We found that soil microbial relative C limitation decreased with increasing elevations, with lower levels observed in the dry season than in the wet season. In contrast, soil microbial relative P limitation varied significantly with elevations, with linearly increasing trends in wet seasons but unimodal trends in dry seasons. Meanwhile, we found higher relative C limitation in the coniferous forest but higher relative P limitation in the broad‐leaved forest. Notably, soil microbial relative C limitation was primarily affected by the soil microenvironment (i.e. soil temperature) and substrate quantity (i.e. the ratio of soil dissolved organic C to available P), whereas soil microbial relative P limitation could be alleviated by increasing microbial relative C limitation combined with increasing soil pH. Additionally, the significant linear pattern of the C use efficacy with elevations was only observed in the wet seasons, which was directly influenced by soil microclimates and microbial relative C limitation. Overall, our results provided important information for better understanding the essential role of microbial processes in the regulation of C and P cycling in vulnerable subtropical mountain ecosystems. Read the free Plain Language Summary for this article on the Journal blog.