Density and Stoichiometric Characteristics of Carbon, Nitrogen, and Phosphorus in Surface Soil of Alpine Grassland in Sanjiangyuan

Abstract

The balance and stoichiometry of carbon (C), nitrogen (N), and phosphorus (P) can reflect the quality and content of organic matter and is very important for understanding ecological processes and ecosystem response to climate change and disturbance. To explore the spatial distribution characteristics of C, N, P, and their stoichiometry of topsoil in Sanjiangyuan (SJY), we sampled 0-20 cm soil of alpine grassland in SJY, measured soil C, N, and P, and analyzed their correlation with latitude, longitude, altitude, and vegetation characteristics (diversity, height, coverage, biomass, etc.). The results showed that the average densities of soil organic C (SOC), total N (TN), total P (TP), and soil inorganic C (SIC) in SJY were 7.56 kg•m -2 , 0.71 kg•m -2 , 151.57 g•m -2 , and 1.77 kg•m -2 , respectively. The spatial distribution of SOC, TN, and TP in SJY showed a pattern of high in the east and low in the west, while SIC showed the opposite pattern. The heterogeneity of soil TP in the SJY region was small, which indicated that there may be little difference in soil parent materials in the whole region. The soil nutrients were mainly affected by longitude, soil water content, pH, and vegetation height and coverage. The C: N: P ratio of the 0-20 cm soil in the study area was approximately 48:5:1, and the C: N, C: P, and N: P ratios were significantly affected by soil water content and vegetation height. Soil C: N ratio (10.45) and N:P ratio (4.51) were lower than the national level, which indicated that the soil N mineralization capacity of SJY was higher than that of other regions in China, and the degree of soil N limit was small.

Effects of Utilization Methods on C, N, P Rate and Enzyme Activity of Artificial Grassland in Karst Desertification Area

“…The most important utilization of artificial grasslands is grazing and mowing, and differences in use patterns may alter the nutrient relationships of soil enzymes and key nutrients that have evolved over time [23], with far-reaching effects on ecosystem diversity and function [24]. Although a lot of basic research has been done on the relationship between key nutrient factors and soil enzyme activity in grassland soils [25][26][27][28][29], there is a lack of systematic studies on the rate of carbon, nitrogen and phosphorus and enzyme activity of grassland soils in karst desertification areas, especially for artificial grasslands, which are still at the stage of sporadic exploration. Since 1999, a large-scale special project in the karst areas of southern China has been implemented, which involves returning farmland to forest and grass and the vegetation restoration of rocky desertification management.…”

Improvements in Forest Segmentation Accuracy Using a New Deep Learning Architecture and Data Augmentation Technique

“…The region's climate type is plateau continental, with extensive wetlands and dense marshes, and has abundant water resources. Sanjiangyuan is called the "Chinese Water Tower" and is the birthplace of the Yangtze River, the Yellow River, and the Lancang River, which is an important source of fresh water in China [38][39][40]. Therefore, monitoring changes in the plateau forest cover of this region is important for water conservation, the global carbon cycle, climate change analysis, and combating global warming.…”