Spatial variation and driving mechanism of soil organic carbon components in the alluvial/sedimentary zone of the Yellow River

Abstract

Alluviation and sedimentation of the Yellow River are important factors influencing the surface soil structure and organic carbon content in its lower reaches. Selecting Kaifeng and Zhoukou as typical cases of the Yellow River flooding area, the field survey, soil sample collection, laboratory experiment and Geographic Information System (GIS) spatial analysis methods were applied to study the spatial distribution characteristics and change mechanism of organic carbon components at different soil depths. The results revealed that the soil total organic carbon (TOC), active organic carbon (AOC) and nonactive organic carbon (NOC) contents ranged from 0.05-30.03 g/kg, 0.01-8.86 g/kg and 0.02-23.36 g/kg, respectively. The TOC, AOC and NOC contents in the surface soil layer were obviously higher than those in the lower soil layer, and the sequence of the content and change range within a single layer was TOC>NOC>AOC. Geostatistical analysis indicated that the TOC, AOC and NOC contents were commonly influenced by structural and random factors, and the influence magnitudes of these two factors were similar. The overall spatial trends of TOC, AOC and NOC remained relatively consistent from the 0-20 cm layer to the 20-100 cm layer, and the transition between high-and low-value areas was obvious, while the spatial variance was high. The AOC and NOC contents and spatial distribution better reflected TOC spatial variation and carbon accumulation areas. The distribution and depth of the sediment, agricultural land-use type, cropping system, fertilization method, tillage process and cultivation history were the main factors impacting the spatial variation in the soil organic carbon (SOC) components. Therefore, increasing the organic matter content, straw return, applying organic manure, adding exogenous particulate matter and conservation tillage are effective measures to improve the soil quality and attain sustainable agricultural development in the alluvial/sedimentary zone of the Yellow River.

Study on the Effects of Reducing Nitrogen Fertilizer: Stabilizing Yield and Carbon Sequestration by Synergistic Utilization of Chinese Milk Vetch and Rice Straw in Double-Cropping Rice Area

“…The application of MV and RS also affected labile organic C, which was readily available to microorganisms to provide available nutrients for crop growth [9] and could be transformed to new C as sequestrated and stabilized in soil by microorganisms [10]. Non-labile organic C could provide abundant nutrients for an extended period due to a slow rate of turnover; this represented the soil's potential for soil C accumulation and storage [11]. When fresh organic matter was input, microorganisms quickly decomposed it into labile organic carbon, with only a small fraction being stabilized or sequestered [12].…”

Spatio-temporal evolution of land use and carbon sink effect of forest ecosystem in Dabie Mountains

“…Since the late 1990s, land use types have been constantly changing, and the loss of carbon storage has exceeded 32.97 Tg. The transfer of construction land and grassland degradation are the main factors for the decline of carbon storage [3][4] . The forest ecosystem is the largest organic carbon pool in terrestrial ecosystems and plays an important role in the global carbon cycle [5] .…”

Effective soil particle size distributions and critical size of enrichment/depletion in splash erosion for loessial soil

“…Splash erosion is a process in which soil particles are detached and transported due to the impact of raindrops, and splash erosion is the initial step in the water erosion process (Quansah, 1981;Van Dijk et al, 2002;Kinnell, 2005;Angulo-Martínezet et al, 2012). Splash erosion provides loose sediments for the later erosion process (Zhang et al, 2020;Li et al, 2021). Therefore, the study of splash amount and particle size sorting characteristics can help reveal the characteristics of splash and understand the soil erosion process deeply.…”