Ecological Indicators (Oct 2023)
Correlations between plant and soil for their C, N, P contents and stoichiometry on the steep gully slopes
Abstract
Steep gully slope is the primary geomorphic composition on the Loess Plateau with serious soil erosion. The impact of plant (leaf, litter and root) on soil nutrients and their stoichiometric characteristics, and the correlations between them are not yet fully understood on steep gully slopes. This study was conducted to identify the correlations of carbon (C), nitrogen (N), phosphorus (P) contents and their stoichiometry between soil, and leaf, litter and root under typical plant communities on Chinese Loess Plateau's steep gully slopes. Total six communities (two shrubs and four grasses) and one farmland planted with Zea mays (control) were tested. Within the selected quadrat (shrub of 2 m × 2 m, grass of 1 m × 1 m), the fresh and mature leaves were firstly taken in different positions of the plant, and then all the surface litters were gathered. Root and soil were taken from the 0–120 cm depth, which was divided into seven soil layers (0–10, 10–20, 20–30, 30–40, 40–60, 60–80 and 80–120 cm). Our results revealed that significant differences were detected in C, N, P contents and stoichiometry of plant (leaf, litter and root) and soil among most of plant communities. For various plant communities, shrub communities had higher contents of C, N and P in leaves, litter and roots. Soil organic carbon and total nitrogen contents declined with soil depth by 61% to 87% and 45% to 77%, respectively. Total contents of soil P and root C, N, P varied irregularly along with soil. It was proved that shrub communities were relatively P-deficient, while farmland and grass communities were N-limited. Besides, partial N and P nutrients were released to soil from litter on steep gully slopes. Significant correlations between soil C, N, P contents and that of the root and litter were examined. Furthermore, the correlations became more significant when C, N and P nutrients of root and litter were quantified by their storages. This study offers a deep understanding of the interactions between soil and plant nutrients, which is conducive to future ecological environment management and improvement in the semi-arid region.
