The effects of various land use types, wetland (RW), upland field (CL), paddy field (RP), and forest land (PF), on soil carbon sequestration in the Naolihe National Nature Reserve have been studied. The results indicated that PF demonstrated significantly higher levels of soil organic carbon (SOC) and total nitrogen (TN), underscoring its superior capacity for maintaining soil fertility. Dissolved organic carbon (DOC) was the most prevalent carbon fraction in CL, while labile carbon was less plentiful. Conversely, labile organic carbon (LOC) and microbial biomass carbon (MBC) showed considerable variability among different land-use types. Land use was determined to affect the composition of the soil bacterial community, with Pseudomonadota being the predominant phylum. RP demonstrated a markedly elevated abundance of the microbial carbon-fixing gene (cbbL; (1.65 ± 1.35) × 105 copies/g), indicating an enhanced capacity for microbial-mediated carbon fixation. These findings underscore the crucial role of land use in governing soil carbon dynamics and provide a quantitative theoretical basis for wetland restoration and sustainable land management.

Mining soils often suffer from low biodiversity, poor organic matter, and environmental disturbances, which hinder seed germination and plant growth. This study utilized composting and phytocapping approaches to reclaim Fe tailing soil at field scale through addition of different organic residues and Sesbania sesban plant. The improvement of soil quality parameters including pH, soil organic matter (SOM), electrical conductivity (EC), cation exchange capacity (CEC), total N, total P, total microbial count, organically bound Fe, total Fe in soil, and in different parts of the plant were analyzed for 90 days. Organically bound iron was analyzed through Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) and microbial community dynamics through 16S rRNA genome sequencing. All treatments showed highly significant difference (p < 0.05) in the pH values compared to C, while within treatments negligible changes in the pH was observed. In case of SOM, organically and plant treated samples showed significant increase as compared to C sample, similarly N, P content, EC, CEC and microbial count, total Fe and organically bound Fe were also significantly increased. The shift of microbial community from lithotrophs to organotrophs was observed compared to control which showed higher abundance of chemolithotrophs. It is concluded that the addition of organic matter enhanced the iron tailing properties along with iron mineralization, while S. sesban has further improved this process and uptake iron efficiently. These findings suggest treatment strategies applicable not only to iron mining sites but also to other extraction sites, including Cu and Pb.

Agricultural irrigation accounts for approximately 90% of global freshwater consumption. As water scarcity intensifies, the reuse of treated wastewater (TWW) emerges as a viable and sustainable solution. While the reuse of wastewater can enhance soil properties, it also poses risks, such as increased soil salinization and heavy metal contamination. This study compared the effects of irrigation using TWW and groundwater (GW) on soil physicochemical properties in Algeria. The analysis is based on laboratory assessments of pH, electrical conductivity (EC), TDS, salinity, and calcium carbonate contents, along with soil quality index (SQI) in both irrigated and non-irrigated (control) soils. Statistical analyses revealed significant variations among treatments. TWW-irrigated soils exhibited higher pH (7.48 ± 0.04) but lower EC1 : 5 (262.5 ± 12.58 μS/cm) and salinity (0.127 ± 0.005 g/kg) compared to GW-irrigated soils. GW samples showed elevated salinity levels, suggesting the need for salt-tolerant crops, while TWW and control samples indicated optimal EC1 : 5 values. Soil samples were neutral to slightly alkaline, suitable for a wide range of crops, and exhibited high limestone content, indicating potential for cultivating calcicole species. Findings suggest that TWW reuse is preferable to GW, as it does not adversely affect soil properties and supports the sustainability of the water-soil-plant ecosystem. SQI results indicated TWW-irrigated soil had moderate quality similar to control, while 67.7% of GW-irrigated soils had poor quality. The implementation of agroforestry systems is recommended to mitigate salinity risks associated with high lime of Calcisols. Extensive monitoring of soil properties and inclusion of further indicators such as heavy metals, biochemical, and microbial traits are advisable.

Soil, being a natural body which, on the one hand, obeys the internal laws of self-development (in particular, the erasure of lithomemory and the development of pedomemory during one stage of evolution) and, on the other, is exposed to various (including anthropogenic) factors. The soil shows, theoretically, all types of nonlinear dynamic behavior. The most common are multistability and amplitude shrinkage. The realization that processes occurring in soils are nonlinear in time, whether in daily, annual (seasonal), or long-term cycles of development (self-development) of these soils, allows us to bring soil closer to other biotic, bio-abiotic, and inert natural and natural-anthropogenic “nonlinear” objects. The study of such a “class of nonlinear objects” is essential to be able to create sustainable management systems for territories.

All factors of soil formation can be divided into random ones, which the researcher cannot control when studying soils and ground cover, and non-random ones, which can be studied in detail assessing their contribution to the formation of soil of a particular taxonomic rank. The random soil-forming factors include cryogenic, fluvial, anthropogenic, migratory, denudation, erosion, and solifluction, while the non-random factors comprise climatogenic, biogenic (mainly phytogenic), lithogenic, and chronogenic ones. It is shown that an essential element of randomness is found in the course of erosion processes. However, the established significant methodology for predicting the magnitude of soil erosion and assessing the likelihood of expected damage from soil erosion makes it possible to minimize this random factor.

The possibility of developing algorithms for creating various soil classification systems based on the ideas of soil as a function of the properties of soil horizons (or their morphological elements, morphons), the construction of a soil profile as a given set of horizons (or morphons), and its belonging to a certain group of soil profiles is considered. The fundamental importance of creating a basic classification of soils—the Mendeleev’s soil table—is noted. This classification should be based on a genetic approach and should serve as construction material for any other soil classification. When developing a classification of soil resources, various criteria can be used to identify their groups (classification units): land categories; types of land use; qualitative conditions, ecological state, and administrative belonging of land; subjects of land relations; legal regime of land plots; the degree of contrast in the soil cover; dominant soils and their areas; etc.