Chinese hickory (Carya cathayensis Sarg.) is a woody nut and oil tree from China. Intensive management including heavy application of chemical fertiliser and long-term application of herbicides has resulted in serious soil loss and degradation. This study aimed to test the hypothesis that intercropping in the soil under Chinese hickory stands may improve soil fertility and microbial community functional diversity. A field experiment consisting of four treatments (clean tillage; intercropping rape (Brassica rapa L.), ryegrass (Lolium perenne L.) or Chinese milk vetch (Astragalus sinicus L.) was conducted to study the effects of intercropping on soil organic carbon (SOC) structure and microbial community functional diversity under C. cathayensis stand, by means of 13C-nuclear magnetic resonance (NMR), and EcoPlates incubated at 25°C. After 4 years of treatment, intercropping increased available nitrogen (N), phosphorus and potassium in the soil by 25.1–54.2, 4.2–6.0 and 0–22.5 mg kg–1, respectively, relative to the clean tillage treatment; intercropping rape, ryegrass and Chinese milk vetch increased SOC, microbial biomass C (MBC), and water-soluble organic C (WOC) by 23.1–24.7, 138.6–159.7 and 56.2–69.5% (P < 0.05), respectively. The structure of SOC was also greatly changed by intercropping treatments. Intercropping increased carbonyl C by 29.9–36.9% (P < 0.05) and decreased alkyl C, O-alkyl C and aromatic C by 10.0–16.4, 18.9–20.9 and 10.5–16.6% (P < 0.05), respectively. Intercropping markedly improved microbial community functional diversity, which is characterised by increases in average well-colour development (AWCD), Shannon index and evenness index. Correlation analysis showed significant positive correlations among microbial biomass N, water-soluble organic N, SOC, WOC, MBC and AWCD (P < 0.05 or P < 0.01). The results demonstrate that sod cultivation is an effective soil management practice that improves soil quality and eliminates detrimental effects of clean tillage in Chinese hickory production.

Microorganism is directly exposed to the plant toxin environment and play a crucial third party in herbivores gut. Although previous studies have proved the existence of gut bacteria that help CWs degrade TS, the specific core flora and its function have not been explored.

To assess the effects of long-term intensive management on soil carbon cycle and microbial functional diversity, we sampled soil in Chinese hickory (Carya cathayensis Sarg.) stands managed intensively for 5, 10, 15, and 20 years, and in reference Chinese hickory–broad-leaved mixed forest (NMF) stands. We analyzed soil total organic carbon (TOC), microbial biomass carbon (MBC), and water-soluble organic carbon (WSOC) contents, applied ¹³C-nuclear magnetic resonance analysis for structural analysis, and determined microbial carbon source usage. TOC, MBC, and WSOC contents and the MBC to TOC ratios were lower in the intensively managed stands than in the NMF stands. The organic carbon pool in the stands managed intensively for twenty years was more stable, indicating that the easily degraded compounds had been decomposed. Diversity and evenness in carbon source usage by the microbial communities were lower in the stands managed intensively for 15 and 20 years. Based on carbon source usage, the longer the management time, the less similar the samples from the monospecific Chinese hickory stands were with the NMF samples, indicating that the microbial community compositions became more different with increased management time. The results call for changes in the management of the hickory stands to increase the soil carbon content and restore microbial diversity.

Exponential fertilization has been regarded as an important technique for improving seedling quality at the initial plant-growth stage. In our study, containerized one-year-old Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) rooted cuttings were reared at four nitrogen (N) fertilizer levels (0, 0.5, 1.0, 2.0 g cutting⁻¹ season⁻¹) under two topdressing methods (conventional and exponential) for a 210-day greenhouse rotation to evaluate growth and nutrient loading capacity of seedlings. N fertilizer was applied 20 times at an interval of 10 days during the study period. The results indicated that the schedule and rate of fertilization significantly affected the height, ground diameter, and biomass of Chinese fir rooted cuttings. The nitrogen concentration of different plant organs followed the order of leaves > root > stem. Compared to the CK, the N concentrations in root, stem, and leaves increased by 39.6%, 16.6%, and 41.1% in the conventional fertilizer treatment, and by 22.6% to 81.4%, 27.3% to 152.6%, and 73.6% to 135.5% in exponential fertilization treatments, respectively. The N concentrations of root, stem, and leaves of Chinese fir rooted cuttings under EF2 (1.0 N g cutting⁻¹) were significantly higher than that of conventional fertilization (p < 0.05). However, there was no significant difference of phosphorus and potassium concentrations among different plant organs. Steady-state nutrition and superior growth performance were achieved by rooted cuttings fertilized exponentially at the rate of 1.0 g cutting⁻¹ yielding (EF2).

Taxus media Rehder is a high-value tree species and can be used for landscape afforestation and medicinal purposes considering its beautiful shape and secondary metabolite paclitaxel. In May 2019, ...

Predicting the spatial distribution of species in relation to suitable areas under global climate change could provide some references for conservation and long-term management strategies for the species. In this study, the MaxEnt was optimized by adjusting the feature combination and regulation magnification parameters with the ENMeval data package. Based on 127 Cremastra appendiculata spatial distribution locations and 14 environmental factors, the potential distribution areas of C. appendiculata under the present and future climate conditions (2050s, 2070s) were simulated, and the dominant environmental factors influencing the spatial distribution of C. appendiculata were analyzed. The feature combination (FC) and the regularization multiplier (RM) were selected as per the Akaike information criterion (AIC). The model showed complexity and degree of over-fitting (delta AICc = 0, omission rate = 0.106, the difference in the curve values between the training and testing areas was 0.021) after establishing the optimal model (FC = LQH and RM = 2.5), and the results indicated that the optimal model performed well in simulating the potential spatial distribution of C. appendiculata (the area under the receiver operating characteristic curve = 0.933). The results showed that the suitable habitat of C. appendiculata currently in China is 187.60 × 10⁴ km², while the highly suitable habitat is 118.47 × 10⁴ km², the moderately suitable habitat is 53.25 × 10 ⁴ km², and the poorly suitable habitat is 15.88 × 10⁴ km². There is an increasing trend in the suitable habitat of C. appendiculata under six climate scenarios, including SSP1-2.6, SSP2-4.5, and SSP5-8.5 in the 2050s and the 2070s, and that habitat will extend to the northwest as a whole. The highly suitable habitat of C. appendiculata in nature reserves is 0.47 × 104 km²; consequently, there is a large gap in the protection of C. appendiculata. The distribution of C. appendiculata was influenced by the temperature, precipitation, and normalized vegetation index.