Search Results (2)

The present study investigated the effects of different soil substrates (mixtures, based on a mica schist-derived soil), on the plant growth, soil chemical properties, nutritional status and photosynthetic parameters of chestnut (Castanea sativa) seedlings. The aim was to produce robust seedlings, suitable for plantations or reforestation of forest ecosystems, while also provide the necessary nutrient input during the early stages of development. A pot experiment was conducted comprising four treatments: (i) CONTROL, consisting of soil derived from mica schist weathering (MS), (ii) MS with inorganic fertilization (MS-FER), (iii) MS amended with forest floor, derived from evergreen broad-leaved trees (MS-EFF); and (iv) MS amended with forest floor, derived from chestnut trees (MS-CFF). Regarding seedlings’ growth, both types of forest floor exerted a positive effect similar to that observed after inorganic fertilization (MS-FER), while all treatments maintained a satisfactory and stable photosynthetic performance; however, an enhancement in leaf chlorophyll content (CCI) was specifically observed under inorganic fertilization. Except Olsen P and exchangeable Mg, which were significantly higher in the MS-FER treatment, all the other soil nutrients were higher either in the MS-EFF, or in the MS-CFF treatments. Overall, both types of forest floor proved effective as organic amendments, suggesting that they could serve as an alternative or complement to inorganic fertilization, potentially reducing fertilizer inputs in chestnut seedling production. Full article

Mica schist weathered soil possesses a number of poor engineering characteristics, which make it difficult to use as a subgrade material for resource utilization. Therefore, in this study, a new type of curing agent, CFSD (cement–fly ash–slag–desulfurized gypsum), is proposed for this soil. The effects of different curing agent dosages, age of preservation, and confining pressure on the stress–strain curves were analyzed via the uniaxial compression test and triaxial compression test, while the micromorphological characteristics of cured soil were analyzed via X-ray diffraction analysis and the SEM test combined with Image J software. In this paper, we also establish a microscopic mechanism model to determine how curing agents increase the strength of mica schists. The results reveal that the compressive strength of solidified soil increases rapidly within 28 days; the CFSD dosage of 4% at 7 d increased by 103.23% by 28 d. After 28 d, the trend of compressive strength growth was flat. The CFSD dosage of 4% at 7 d increased by 128.34% by 90 d; with the increase in the dosage, the curve transformed from flat to steep. These results suggest that the CFSD dosage is positively correlated with the damage strain and damage bias stress of solidified soil. The curves for the strain softening type with a 4% dosage as the initial effective confining pressure increased from 50 kPa to 300 kPa; the failure stress and failure strain increased by 202.09% and 90.85%, respectively. With the increase in curing agent dosage and maintenance age, the pore size of 2~5 μm, >5 μm interval decreased from 56.46% to 27.92%, the porosity decreased from 12.51% to 4.6%, and the hydrate produced by the curing agent cemented and filled up the pore space between the loose particles of the soil body. Thus, the large pore space became microporous, and the pore structure densification was greatly improved. Full article