Litter often decomposes more rapidly in its native habitat (“home”) than in non-native habitats (“away”), a phenomenon called the “home-field advantage”. To explore the driving mechanism of home-field advantage of litter decomposition is important to predict the process of plant nutrient return and ecosystem carbon budget. This study reviewed the research progress on the home-field advantage of litter decomposition in recent years by discussing the quantification of home-field advantage, the controlling factors, and related driving mechanisms. There are four common metrics to describe home-field advantage in litter decomposition, and the use of linear model analysis to calculate home-field advantage is more appropriate. Litter quality (chemical composition, etc.) and soil microbial community structure are the main factors influencing the home-field advantage of litter decomposition, and soil fauna, climatic conditions, decomposition time, plant life form and growth form can also influence the intensity of the home-field advantage. Greater differences in litter quality usually generate stronger home-field advantage. Microbial taxa in the soil drive the home-field advantage of litter decomposition, but the role of soil microbes is often mediated by animal and climatic disturbances. In addition, the existence of phyllosphere microbes makes the home-field advantage of litter decomposition stronger. The litter chemical convergence hypothesis, decomposer control hypothesis and substrate quality-matrix quality interaction hypothesis are major hypotheses explaining the home-field advantage in litter decomposition, but they are not impeccable. We believe that the association between litter and soil microbial community is the driving force behind home-field advantage. The current researches on the factors and relative contribution of home-field advantage are not deep enough and usually focusing on a single ecosystem. Future investigations should explore deeper on the factors and their relative contributions of home-field advantage, and focus on more ecosystem types to improve the understandings of the mechanism of home-field advantage.

Aims Phenols are organic components that are resistant to be decomposed during litter decomposition, and their initial content greatly affects the subsequent decomposition process. However, patterns of their initial content in plant litter at the global scale are unclear. In this paper, the content of total phenol and soluble phenol in litter and their response to climate, mycorrhizal association, life forms and soil properties were assessed at the global scale.
Methods Data were collected from published scientific articles before November 5, 2021, the content and influencing factors of total and soluble phenol in plant litter were discussed at the global scale. Among them, 98 articles had total phenol content, covering 350 observations, and 18 articles had soluble phenol content, covering 70 observations. The linear mixed model was used to compare the differences of total phenol and soluble phenol content in root and leaf litter of different functional traits. The linear mixed model was also used to evaluate the effects of different environmental factors on total phenol and soluble phenol content in root and leaf litter. The linear mixed effect model selection method was used to further evaluate the relative importance of influencing variables on the initial total phenol and soluble phenol content in litter.
Important findings Results showed that (1) The average initial total phenolic and soluble phenolic content of the global litter was 65 and 88 mg·g^-1, respectively. (2) Mycorrhizal association had a significant effect on the total phenolic content in root litter and the soluble phenolic content in leaf litter. The total phenolic content in root litter of plants with both arbuscular mycorrhiza and ectomycorrhiza was significantly lower than that in litter of plants with ectomycorrhiza, while the soluble phenolic content in leaf litter of plants associated with both arbuscular mycorrhiza and ectomycorrhiza was significantly higher than that in litter from plants associated with arbuscular mycorrhiza. (3) Phylogenetic types (gymnosperm, angiosperm) and leaf morphology (needleleaf, broadleaf) had significant effects on the total phenolic content in leaf litter, and the total phenolic content in litter of broadleaf and angiosperm plants was significantly higher than that in litter of needleleaf and gymnosperm plants. (4) Average temperature diurnal range, precipitation in the driest month, and precipitation in the driest quarter were significantly positively correlated with the total phenolic content in leaf litter. (5) Precipitation in the warmest quarter and soil moisture were significantly negatively correlated with the content of soluble phenol in leaf litter. (6) Leaf morphology had the most significant effect on total phenolic content in leaf litter. Overall, these results will be useful for understanding the relationships between litter functional traits and phenols and for predicting the decomposition of plant litter under future climate change scenario.

Aims In order to simulate the actual situation to the greatest extent, the decomposition dynamics of litter in subtropical natural broadleaf forests were explored using a litter “sandwichs” method.
Methods A three-year field in-situ experiment of undisturbed litter layer decomposition was carried out in a natural subtropical broadleaf forest. Eleven layers of litter with different decomposition degrees were isolated accurately by laying nylon nets (60 mesh, 1.2 m × 1.95 m) every three months, and the dynamic of labile and recalcitrant carbon (C) and nitrogen (N) contents were analyzed.
Important findings The results showed that: 1) During the whole decomposition process, the labile and recalcitrant C participated in the decomposition at different times. Water-soluble organic C began to decompose first and sustained release time up to 295 d, while the recalcitrant C began to decompose behind for many days (at 4th layer, 422 d), and the change in acid-hydrolyzed organic C fluctuated greatly due to the fates of the labile and recalcitrant C. 2) Compared with that of C, the dynamics of N in the whole decomposition stage were more complex, to some extent, with obvious periodicity, that is, N retention (1st to 3rd layers, 90-295 d), release (4th to 6th layers, 422-670 d), and retention again (7th to 11th layers, 802-1 200 d). 3) The undisturbed decomposition of litterfall layer was beneficial to the N storage. On the one hand, at the early stage of decomposition, the labile substances from the upper litterfall were accumulated in the lower layer due to the leaching, which reduced the risk of their leaching loss. On the other hand, recalcitrant C and N was prone to accumulate in the bottom layers, which was beneficial to C and N retention. It can be concluded that the natural decomposition state of forest litter layer is conducive to the return of litter recalcitrant C and N into soil. Therefore, more attention should be paid to the protection of litter layer in forest management, which could ensure litter decomposing in its natural state to improve the stabilization and enrichment of C and N.

Aims The purpose of this study is to examine the responses of litter decomposition to nitrogen (N) deposition and aboveground litter manipulation.
Methods A two-factor experiment of N addition and litterfall manipulation was performed in a N saturation evergreen broadleaf forest on the western edge of the Sichuan Basin in China from June 2014 to June 2019. We conducted three levels of N addition, including an N control (CK, ambient N input), low N (LN, 50 kg·hm^-2·a^-1) and high N (HN, 150 kg·hm^-2·a^-1), and three levels of litterfall manipulation, including intact litter input (L0, no litter alteration), litter reduction (L-, reduced by 50%) and litter addition (L+, increased by 50%).
Important findings We found six-year N addition did not significantly alter the aboveground litter input in the studied forest ecosystem. N addition significantly inhibited leaf litter decomposition, with the leaf litter decomposition significantly decreased in high N treatment. N addition significantly reduced the remaining rate of manganese (Mn) in the late stage and promoted the release of Mn. Litter manipulation did not significantly alter the rate of leaf litter decomposition, but increased the remaining rate of Mn in the litter and slowed down the release of Mn. There was no significant interactive effect between N addition and litter manipulation. This study showed that N addition affected litter decomposition in subtropical N-saturated evergreen broadleaf forests by directly affecting litter decomposition, while litter manipulation mainly affected the content of Mn during litter decomposition. Therefore, the content of Mn of litter may play a key role in the process of litter decomposition in response to N input.

Aims Ombrotrophic peatlands, dominated by Sphagnum, are important carbon sinks in terrestrial ecosystems. The dynamics of growth and decomposition of dominant plants usually determine the carbon sink potential of ombrotrophic peatland. However, it is still controversial how nitrogen deposition impact on the growth and decomposition of mosses in ombrotrophic peatland. Moreover, the effects of nitrogen deposition on the growth and decomposition of dominant mosses are rarely reported in subtropical ombrotrophic peatlands.
Methods We selected an ombrotrophic peatland in southwestern Hubei Province as the study area. Different concentrations of NH₄Cl solution were sprayed in situ. Here biomass harvesting and decomposition bag methods were adopted to estimate growth and litter decomposition of S. palustre and Polytrichum commune.
Important findings (1) Nitrogen deposition had obvious effects on the height and biomass of the two mosses. Moreover, there was a threshold value of nitrogen deposition at the level of about 3 g·m^-2·a^-1. (2) The effects of nitrogen deposition on the growth of the two mosses were different, and the response sensitivity of S. palustre to nitrogen deposition was greater than that of P. commune. (3) High nitrogen deposition levels (i.e., 6 and 12 g·m^-2·a^-1) inhibited the decomposition of S. palustre, while the effect of low nitrogen deposition (i.e., 3 g·m^-2·a^-1) on the decomposition of S. palustre depends on time. All the concentrations of nitrogen deposition inhibited the decomposition of P. commune litter. (4) After one year of decomposition, the average final mass residual percentage of S. palustre was 105.99%, and 70.79% for P. commune. The decomposition rate of P. commune was much higher than that of S. palustre. (5) Nitrogen deposition significantly affected the chemical element content and stoichiometric ratio of the two moss litters, and was closely related to decomposition time.

Aims As key components in plant litters, the total phenols and condensed tannins greatly regulate decomposition process of forest litter, which can be directly or indirectly affected by forest gaps. The aim of this study was to determine how the forest gaps would affect the losses of total phenols and condensed tannins of foliar litter during decomposition in subalpine forest.
Methods We conducted a three-year in situ litter decomposition experiment on different forest gaps (i.e. gap center, canopy gap, expanded gap, closed canopy) in a subalpine forest of western Sichuan, and six foliar litters including Juniperus saltuaria, Abies fargesii var. faxoniana, Larix mastersiana, Betula albosinensis, Salix paraplesia and Rhododendron lapponicum were selected. The measurements were conducted to examine the losses of litter total phenols and condensed tannins during winter and growing season.
Important findings Litter total phenols and condensed tannins showed higher loss rates in the first decomposition year, with the levels of 10.76 mg·d^-1 and 8.5 mg·d^-1, respectively. The effects of forest gaps on the degradation of phenolic components gradually were getting weak with the litter decomposition proceeding, and exhibited obvious seasonal differences. The total phenols content of six litters all decreased rapidly in the growing seasons, while litters with higher initial condensed tannins with faster loss rate were found in the first winter, suggesting that both litter quality and seasons would significantly alter litter phenolic components losses during long-term decomposition under forest gaps. These results are helpful for deeper understanding of the litter decomposition process and nutrients cycling in forest ecosystems, which provide scientific data to improve the development of management policies in subalpine forests.

Aims Changes in the depth and duration of seasonal snowpack induced by climate change may affect litter decomposition, particularly the release of labile carbon during the early decomposition periods in alpine forests. Our objective of this study was to assess the effect of snow removal on labile carbon fractions in litter (i.e., dissolved organic carbon (DOC), hot-water extractable carbon (HWEC) and non-structural carbon (NSC)) during early stage of litter decomposition in an alpine forest on the eastern Qingzang Plateau.
Methods An in situ litter input microcosm experiment was conducted in an alpine forest dominated by 120 to 150-year-old fir (Abies fargesii var. faxoniana) from October 2018 to October 2019. Air-dried fir needle litter was incubated at control and snow removal plots and the concentrations of total organic carbon (TOC), DOC, HWEC, NSC, soluble sugars and starch in decomposing fir litter were determined during winter (snow formation period, snow coverage period and snow melt period) and growing season (early, middle and late growing season).
Important findings Results showed that litter mass remained by 76.4% and 86.2% at control and snow removal plots, respectively, over one year of decomposition. After decomposition for one year, 60.5% and 74.8% of organic carbon remained in decomposing litter at control and snow removal plots, respectively. After decomposition for a winter, the release of HWEC and soluble sugars from decomposing litter were lower, while TOC, DOC, NSC and starch in fir needle litter were higher in snow removal plots than that in control plot. After decomposition for a growing season, the release of TOC, HWEC, DOC, NSC, soluble sugars and starch were reduced by 36.3%, 0.8%, 43.7%, 28.3%, 21.7% and 33.7%, respectively, in the snow removal plots compared to those in the control plots. The results from partial least square model indicated that labile carbon release was strongly controlled by soil freezing-thawing cycle, urease activity, soil temperature and DOC concentration. These results suggest that the presence of snow cover accelerated the release of labile carbon from decomposing litter during winter and growing seasons, highlighting the importance of seasonal snow cover in controlling litter decomposition in high-latitude and high-altitude ecosystems. Moreover, the significant influence of snow cover on labile carbon release during winter could have a legacy effect on litter decomposition during the subsequent growing season, suggesting that snow cover is of great significance for soil biogeochemical cycles in this alpine forest.

Aims As the first colonizer of leaf litters, the phyllospheric microbes may directly participate in the decomposition of litters.
Methods To test this hypothesis, the diversity of phyllospheric microbes and their effects in needle litter decomposition of Pinus massoniana were investigated by employing high-throughput amplicon sequencing techniques and indoor decomposition experiments.
Important findings (1) There are abundant and diverse microbial communities in the phyllospheric microbes of P. massoniana, and the microbial communities changed rapidly along with needle senescence. A large number of shared operational taxonomic units were detected among samples of mature needles, litter needles, and decomposing needles. (2) The decomposition process of P. massoniana needles can be divided into two stages: the rapid decomposition period (the first 8 months) and the slow decomposition period (after 8 months). Phyllospheric microbes of the senesced needles (fallen but not in contact with the soil) could decompose needle litters, and the decomposition rates exhibited the trend of phyllospheric microbes + soil microbes treatment > phyllospheric microbes treatment > soil microorganism treatment. There are synergistic effects between phyllospheric microbes and soil microbes during the decomposition of P. massoniana needles. (3) The decomposition rate of needle litters was significantly positively correlated with those of lignin and cellulose, while not correlated with the activity of lignin or cellulose decomposing enzymes. For ligninolytic enzymes, the activity of polyphenol oxidase had a significantly negative correlation with peroxidase activity. Meanwhile, activity of ligninolytic enzyme β-glucosidase had a significantly positive correlation with cellobiohydrolase activity. In conclusion, the present results indicate that the phyllospheric microbes can directly participate in the decomposition of needle litters, and its effect on the decomposition rate of needle litters of P. massoniana is superior to that of the soil microbes. These results have advanced the litter decomposition theory and provided theoretical foundation for further investigation into the core microbiome participating in litter decomposition.

Aims This study aimed to explore the response of ammonia oxidizing bacteria (AOB) to litter decomposition and nitrogen application in the topsoil of desert steppe, and the main environmental factors influencing the AOB were also analyzed. Thus, this study will contribute to better understanding of the mechanism of nitrogen cycle function gene abundance in response to nitrogen deposition in arid and semi-arid desert steppe regions.
Methods We conducted the nitrogen fertilization experiment in the desert steppe in Yanchi, Ningxia. The four plant litters, including Sophora alopecuroides, Artemisia scoparia, Stipa breviflora and Agropyron mongolicum were selected as plant litter input treatments. The nitrogen fertilization treatments, including control (0 g·m^-2·a^-1) and nitrogen application (9.2 g·m^-2·a^-1), were applied to explore the response of AOB to nitrogen deposition and different litter inputs in top soil (0-5 cm) of desert steppe by fluorescent quantitative PCR and high-throughput sequencing.
Important findings Our results showed that there were 3 phyla, 4 classes, 6 orders, 7 families, 8 genera and 17 species of AOB in the topsoil of desert steppe under nitrogen application and litter decomposition. The AOB communities were mainly derived from Nitrosomonas and Nitrosospira, which were from beta-Proteobacteria, and Nitrosospira was the dominant species. Compared with the control, the gene copy number of AOB was significantly decreased under nitrogen application, indicating that nitrogen application inhibited nitrification in the topsoil of the desert steppe. Whereas, the response of AOB-ammonia monooxy genase subsuit A (amoA) gene abundance varied under different plant litter decomposition. Litter input could alleviate the inhibition of nitrogen enrichment on soil AOB-amoA gene abundance to a certain extent, but did not change the trend of soil AOB-amoA gene abundance. A redundancy analysis confirmed that soil organic carbon, total phosphorus, ammonium nitrogen and nitrate nitrogen contents were the key environmental factors affecting niche separation of AOB-amoA gene abundance in desert steppe soil. The results showed that nitrogen addition could significantly reduce the gene abundance of AOB-amoA, thereby affecting the nitrification and the direction of soil nitrogen transformation in the topsoil of desert steppe.

Aims In studies on the relationship between plant species richness and productivity, species richness is regarded primarily as an independent variable and productivity as a response variable, whereas other factors that may affect community productivity at the same species richness levels, such as species combination and composition, are largely ignored. The objectives of this research have been determined: (1) the effect of community structure on community productivity, including species combination, composition, and functional groups to which the species belongs, and (2) the relationship between species richness and community productivity in subalpine meadow communities.
Methods In the pot experiment, seeds of four plant species (Festuca sinensis, Elymus nutans, Medicago sativa and Dactylis glomerata) were sown to pots in terms of given species combination and composition at varying levels of species richness (1, 2, 3, 4). In both monocultures and mixtures, the overall planting density of the community was 100. Seeds were sown in equal numbers to pots in communities of diverse species combinations at various levels of species richness. The species composition of four-species mixed-seeding communities was designed as 10%, 20%, 30%, and 40% density proportions, respectively. Each treatment had five replicates, and weeds were manually removed on a regular basis. The above-ground biomass in each pot had been harvested, dried, and measured by species at the end of September.
Important findings Community productivity increased with increasing species richness at lower species richness, but not substantially at higher species richness, The combination and composition of community species had a significant effect on community productivity, with the mixed-seeding community containing Elymus nutans and communities with a high proportion of Elymus nutans having higher productivity. Among the functional groups to which the species belonged, legumes either promoted or inhibited the production of other species. Elymus nutans enhanced community productivity, whereas Festuca sinensis and Dactylis glomerata had no discernible effect. As a result, it could be inferred that there is an apparent relationship between species richness and productivity, and plant community productivity is more dependent on species combination and composition than on species richness.

Ams Nitrogen (N), phosphorus (P), and potassium (K) are key elements for plant growth and development. Exploring the ecological stoichiometry characteristics of N, P and K in different phenological stages is of great significance for understanding the physio-ecological processes such as nutrient limitation, resource absorption and utilization, and biomass allocation of plants.
Methods Here, we collected root, stem, leaf and spike samples of Chenopodium quinoa in different phenological stages, and measured the concentrations of N, P and K. We compared the differences of N, P, K contents and their ratios among roots, stems, leaves and spikes and among phenological stages, and analyzed their relationships with the biomass allocations.
Important findings (1) The mean N contents was 9.28, 12.22, 33.68, 31.28 mg·g^-1 in the roots, stems, leaves and spikes, respectively. The breakdowns was 2.64, 3.71, 4.98, 5.68 mg·g^-1 for P contents, and 25.63, 43.80, 74.08, 56.73 mg·g^-1 for K contents, respectively. These resulted in mean N:P of 4.66, 4.20, 7.37, 5.70, N:K of 0.39, 0.31, 0.46, 0.62, and K:P of 13.77, 14.31, 16.82, 9.79 in the roots, stems, leaves and spikes, respectively. (2) The root, stem, and spike N, P and K and the leaf N and P contents decreased significantly with the phenological subsequences, reflecting the obvious dilution effect of biomass. On the contrary, the leaf K contents increased significantly with phenological subsequences, indicating an extremely strong drought resistance mechanism of C. quinoa under drought stress. The allocation ratios of N, P, K and biomass in the roots and stems kept stable, those in the leaves decreased, while those in the spikes increased with the phenological subsequences, indicating that the key resource allocation regulation of leaves and spikes occurred during the flowering stage. As the biomass increased in the filling stage, the nutrient elements gradually transferred to the spikes. (3) The variation source analysis revealed a greater contribution of organs to the variance of N, K contents and N:P, while a less one to the variance of P contents, than the phenological stages. (4) The allocation ratios of N, P, K and biomass were coupled among various organs. Specifically, the allocation ratios of root and leaf biomass showed a positive correlation with those of the root and leaf N, P and K, while a negative correlation with those of the spike N, P and K. The biomass allocation ratio of spike was positively correlated with spike N, P and K allocation ratios, while negatively correlated with root and leaf N, P and K allocation ratios. These results provided theoretical reference for further understanding of crop phenological character and guiding practical production in alpine regions.

Aims Leaf temperature is one of the important microenvironmental parameters for energy exchange and physiological processes of plants. Leaf thermal traits can regulate leaf temperature so as to relieve heat damage to some extent. However, systematic studies on leaf thermal traits are rare.
Methods In the present study, 43 dominant canopy species of four typical vegetation types with varying temperature and precipitation from tropical to temperate zones in Yunnan Province were selected: savanna vegetation, tropical rain forest, subtropical evergreen broadleaf forest, and temperate mixed forest. We selected 23 thermal traits that might have influence on leaf temperature, including leaf morphological, optical, material property, anatomical and physiological traits.
Important findings The results showed that plants in savanna vegetation mainly relied on transpiration for cooling. Savanna species have thin leaves and short life span. They are mainly “quick investment-return” species. Tropical rain forest plants developed large leaves, with low transpiration rates, which have no advantage of leaf cooling. Thick leaves and high water content can alleviate high temperature to some extent. They adopted “slow investment-return” strategy. Subtropical evergreen broadleaf forest was rarely exposed to extreme temperatures. The species had thick leaves, long leaf life span, and adopted “slow investment-return” strategy. They did not show obvious thermal adaptation traits. Temperate mixed forest had small and thick leaves, growing in clusters which provides benefits for thermal insulation. Photosynthetic rate of canopy evergreen plants in this forest was low, adopting “slow investment-return” strategy, while photosynthetic rate of deciduous plants was high, presenting “quick investment-return” characteristics. This study systematically investigated the variation of leaf thermal traits and plant adaptation strategies along temperature and precipitation gradients, providing a theoretical basis for further understanding of plant adaptation to the environment.