Soil stoichiometric characteristics and influencing factors in karst forests at microtopography and microhabitat scales

Abstract. To quantitatively assess soil stoichiometric characteristics in karst forests under complex microenvironments, this study systematically investigated the distribution patterns of soil nutrients and influencing factors across different microtopography and microhabitat scales in the Maolan karst forest. The results indicated that: (1) Soil nutrient contents exhibited strong spatial heterogeneity across the study area. (2) Microhabitat factors (stone gully, stone surface, soil surface) significantly influenced nutrient accumulation, although the response patterns varied among different nutrient elements. (3) Microtopographic factors (slope degree, slope aspect, slope position) were not only significantly correlated with soil nutrient patterns but also governed the spatial distribution gradients of certain nutrient elements. (4) Different response mechanisms of nutrients to microtopographic and microhabitat factors, combined with the different nutrient regulation and absorption strategies of various plant life forms (evergreen trees, deciduous trees, shrubs, herbs), collectively shaped the complex stoichiometric characteristics. The factors of microhabitat, microtopography, and plant life form exhibited synergistic effects on the soil stoichiometric characteristics in karst forests, with microhabitat and microtopographic factors playing a dominant role at this scale. Although biotic factors like plant life forms showed relatively weaker direct influences, their regulatory effects were closely interrelated with microhabitat and microtopographic factors. This multidimensional feedback mechanism reflects the complexity of nutrient cycling in karst soils.