Soil Aggregation and Carbon Sequestration as a Result of Carbon Nanopolymers Application under an Alluvial Degraded Soil

Soliman, Enas; Abdullatif, Yasmin; El-Ghamry, Ayman; Mansour, Mostafa M.

doi:10.21608/ejss.2025.335402.1917

Soil Aggregation and Carbon Sequestration as a Result of Carbon Nanopolymers Application under an Alluvial Degraded Soil

Document Type : Original Article

Authors

Soils Department, Faculty of Agriculture, Mansoura University, Mansoura 35516, Egypt

10.21608/ejss.2025.335402.1917

Abstract

The soil's resistance to erosion and degradation, distribution of pore sizes, carbon sequestration and the microbial community are all directly dependent on soil aggregation, particularly macro- (0.25–2.00 mm) and micro- (0.053–0.25 mm) aggregates. Therefore, this study focused on monitoring the formation of macro and micro-aggregates to determine how soil macro-structure in clay loamy soil responds to the addition of carbon nanopolymers (CNPs) as a source of organic carbon (OC) during 30 days of incubation under a constant temperature (25 °C), and further, which soil properties are primarily responsible for the accomplishment of that aim. A short-term (4 weeks) incubation experiment was conducted in the laboratory of the Soils Department, Faculty of Agriculture, Mansoura University using three carrier materials such as chitosan (CS), pectin (PC), and acacia gum (AG) which were polymerized using methacrylic acid (MAA) and loaded with three concentrations (0, 50, and 75%) of NPKCa in addition to the control (100% NPKCa) at field moisture condition. The treatments were laid out in a completely randomized design with three replications. After 30 days of incubation, the obtained results showed the ability of nano-acacia gum (NAG) at both concentrations 50 and 75% to increase the total organic carbon (TOC) by 170.30, and 182.38% respectively. In addition, nano-pectin loaded with 75% NPKCa (NPC75%) recorded an increase in macro-aggregates (>0.25 mm) formation with 28.84% more than the control (71.46 mm). While nano-chitosan loaded with 50% NPKCa (NCS50%) treatment continued to provide dissolved organic carbon (DOC) in soil with an increase of 123.33% and encouraged the formation of micro-aggregates more than macro-aggregates (>0.25 mm) which has an important role in increasing the carbon sequestration in soil. Also, the soil's high TOC and Ca2+ have a greater negative clay zeta potential enhancing the formation of macro-aggregates, particularly NAG and NPC. Also, NAG can increase the mean pore diameter (MPD) with an average of 10.31 μm due to its effect on soil macro-aggregates. All suggested nanopolymers succeeded in increasing the TOC content and soil quality until the end of the study period. The loading with NPK can improve the stability of CNPs at the same time it is considered slow-release fertilizers. Macro-aggregates contain younger organic material, while micro-aggregates are confined to older OC. Long-term carbon sequestration in terrestrial systems originates from TOC confinement within micro-aggregates. Therefore, the study requires more time to monitor their decomposition in different soil textures.

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