Straw Strip Return Increases Soil Organic Carbon Sequestration by Optimizing Organic and Humus Carbon in Aggregates of Mollisols in Northeast China

In agroecosystems, effective straw return modes are one of the key practices for increasing soil fertility and carbon (C) availability. Although they improve quality, there is currently little information available regarding influence distinct with respect to potential organic (SOC) sequestration. this study, we established a five-year (2015–2019) field experiment in Mollisols Northeast China, which included four modes, plow tillage as control (PTS), rotary (RTS), strip (RSS), (PSS), investigate impact on physicochemical properties, aggregates, C The results reveal that RSS effectively improved properties. Such responses increased contents SOC, fulvic acid (FAC), humin (HMC) all layers (0–30 cm). proportion macroaggregates was higher RSS, whereas silt/clay lowest at depths 0–20 cm; consequently, mean weight diameter (MWD) geometric (GMD) were cm due physical structure. 0–10 20–30 layers, highest humic (HAC) concentrations associated aggregate sizes found contrast 10–20 cm, had HMC. Structural equation modeling (SEM) revealed transformation mainly mediated through silt/clay-associated FAC, HMC, ultimately determining HAC (81%) HMC (85%) primary humus fractions SOC Therefore, study shows suitable mode improving stability, sequestration China.