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decreased in the 10-20 cm and 20-40 cm soil layers, and MBN increased firstly and then decreased in all three soil layers. As the soil depth increased, both MBC and MBN gradually decreased for all three forests. The MBC and MBN basically had the same seasonal variation in all three soil layers of all three forests, i.e., high in the summer and low in the winter. Correlation analysis showed that MBC was significantly positively correlated with soil organic matter, total nitrogen, and soil moisture, whereas MBN was significantly positively correlated with soil total nitrogen. It showed that soil moisture content was the main factor determining the variation of soil microbial biomass by Redundancy analysis. The results showed that the soil properties changed continuously as the young forest grew into the middle-aged forest, which increased soil microbial biomass and enriched the soil nutrients. However, the soil microbial biomass declined as the middle-age forest continued to grow, and the soil nutrients were reduced in the mature forest.

Leaf litter decomposition transfers elements from litter to soils that are essential for regulating nutrient cycles in plantation ecosystems, especially carbon and nitrogen. However, soil carbon and nitrogen dynamics in response to tree litter management remains insufficiently researched. We conducted a one‐year field experiment at a fast‐growing sweetgum tree plantation to evaluate the effects of leaf litter management on soil available nutrients, respiration rate and nitrogen mineralization rate. Three leaf litter treatments were applied, which were: (1) natural input (control); (2) double input and (3) non‐input. It was found that the double input treatment increased soil inorganic nitrogen and microbial biomass nitrogen, but had little effect on microbial biomass carbon, dissolved organic carbon or dissolved organic nitrogen compared with natural input. The non‐input treatment caused dissolved organic carbon to decrease compared with natural input. The respiration rate increased in the double input treatment, with a positive priming effect observed. Soil net ammonification, nitrification and mineralization rates also increased in the double input treatment in specific seasons. Meanwhile, positive linear relationships between respiration rate and all nitrogen transformation rates were observed for all treatments. Soil temperature was found to be an important prediction factor for predicting the respiration rate and mineralization as seasonal variations, but not for litter‐induced fluctuations. Soil water content and mineral nitrogen were the primary drivers of litter‐induced change to the respiration rate, whereas mineral nitrogen and microbial biomass were primary drivers of mineralization change. These results suggest that changes in soil nitrogen mineralization rate are strongly associated with the soil respiratory process, resulting in a potentially strong plant–soil feedback mechanism.

Solid−liquid phase-change materials (PCMs) offer exciting potential for energy conservation, but they suffer from a vital drawback of significant leakage. To overcome this issue, we develop a new strategy to obtain high-performance leakage-proof shape-stable phase-change materials (ss-PCMs) by the combination of an inner porous frame and outer superhydrophobic covers. Paraffin wax as PCM was first trapped into artificially cultured diatom frustule-derived porous ceramics, which was then encapsulated using diatom frustule-based superhydrophobic coatings. The prepared ss-PCMs exhibit a wax loading of 52.28 wt % with a melting enthalpy of 117.5 J•g −1 and a high stability even after 500 thermal cycles as well as a 72.7% increase in thermal conductivity. In addition, the prepared ss-PCMs show a compressive strength of as high as 13.0 MPa. The superhydrophobic coatings provide ss-PCMs with superior chemical resistance and excellent mechanical robustness under long-distance abrasion, cyclic tape-peeling, and water jet impact. This porous ceramicembedded, superhydrophobic coating-encapsulated strategy for obtaining high-performance ss-PCMs is expected to find potential applications in energy-efficient buildings, thermal management in electronic devices, self-cleaning materials, and so on.

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