Biological soil crusts (****) greatly change surface soil structure and nutrient enrichment processes in arid and semiarid regions. However, their impacts on solute transport characteristics and nutrient loss are still not clear. In this study, the solute (Cl- and Ca2+) transport experiments were conducted on soils covered by moss-dominated **** and uncrusted soil on sandy and loessal soils on the Loess Plateau, respectively. We analyzed the solute transport characteristics of the **** covered soil and uncrusted soil in different soil depths (0-5 cm and 5-10 cm). The **** mulching generated delay effects on the solute breakthrough process of 0-5 cm soils. https://www.selleckchem.com/products/ap-3-a4-enoblock.html The breakthrough time of Cl- in the **** covered soil was 3.83 (sandy soil) and 2.09 times (loessal soil) longer than that in the uncrusted soil. The breakthrough time of Ca2+ in the **** covered soil was 2.50 and 2.73 times longer than that in the uncrusted soil. Due to the strong influence of **** mulching, the pore volume number of the complete solute brech is of great significance for the improvement of soil fertility and vegetation restoration on degraded land in arid and semiarid regions.We analyzed composition and spatial distribution of main species in the surrounding grassland of Baiyinhua mining area in Inner Mongolia. The results showed that there were 55 plant species in the grassland, with dominant species being Stipa grandis, Carex korshinskyi, and Cleistogenes squarrosa, and common species being Leymus chinensis, Agropyron cristatum, and Anemarrhena asphodeloides. The accumulative relative importance value of those six species was 79.6%, with their densities being 26.6, 204.7, 105.4, 107.1, 68.2 and 55.1 individuals·m-2, respectively. The population density of those six species was modeled by the semi-variance function. The population distribution was in accordance with the exponential model, exponential model, exponential model, spherical model, linear model and Gaussian model, respectively. Through analyzing the spatial distribution pattern, structure ratios were 59.2%, 97.2%, 89.1%, 94.5%, 62.6% and 72.1%, respectively. The spatial autocorrelation of C. korshinskyi, C. squarrosa and L. chinensis populations was mainly affected by structural factors, whereas S. grandis, A. cristatum and A. asphodeloides were mainly affected by random factors. According to results from the fractal dimension analysis, population distribution patterns of S. grandis, C. korshinskyi, C. squarrosa and A. cristatum were simple, and the spatial dependence was strong. Both L. chinensis and A. asphodeloides showed contrasting patterns with those four species. From 2D and 3D images, S. grandis and A. asphodeloides showed gradient diffusion, while C. korshinskyi, C. squarrosa, L. chinensis and A. cristatum showed patch distribution. The results showed that the spatial distribution of the main species in this grassland community did not correlate with mining.Investigating ecological stoichiometry of leaves and fine roots of forest swamps in the Greater Hinggan Mountains will improve our understanding of plant nutrient use and material cycling in ecosystems at high latitudes with high sensitivity to climate change. In this study, we collected leaf and fine root samples from 19 dominant and subordinate vascular plant species and measured their C, N and P concentrations in three typical forest swamps (Larix gmelinii-Carex schmidtii, L. gmelinii-Vaccinium uliginosum-moss and L. gmelinii-Ledum palustre-Sphagnum) of the Greater Hinggan Mountains, China. We compared CNP stoichiometry in leaves and fine roots among different forest swamp types, plant growth forms, and mycorrhizal types. Standardized major axis regression was performed to examine the relationships between leaf and fine root stoichiometry. The results showed that interspecific variation accounted for the largest proportion of total variation in CNP stoichiometry of leaves (42.5%-84.6%). NP had the highest, CN had the intermediate, and CP had the lowest interspecific variation in both leaves and fine roots. L. gmelinii-C. schmidtii forest swamps, which had higher soil nutrient and water availability, had lower CN and CP in leaves and fine roots. NP of all three forest swamps were lower than 10, indicating N limitation in this ecosystem. Herbaceous plants had significantly lower leaf CP, fine root CN, and fine root CP than woody species. Both ectomycorrhizal and ericoid mycorrhizal plants had higher leaf and fine root CN and CP than arbuscular mycorrhizal and non-mycorrhizal species, while the CP of ericoid mycorrhizal plants was significantly higher than that of ectomycorrhizal species. Forest swamp type, plant growth form, and mycorrhizal type all had greater influences on leaf and fine root CN and CP rather than NP. Leaf and fine root CN, CP, and NP were positively correlated, indicating strong coordination between plant above- and below-ground CNP stoichiometry.Quantifying the response of tree transpiration (T) to the variation of soil water supply capability and atmospheric evaporative demand is beneficial for a better prediction of water use and hydrological cycles in forests and deepen the understanding of the relationship between forest and water. Larix principis-rupprechtii in the Xiangshuihe watershed at the south side of Liupan Mountains was used as the research object. We simultaneously monitored sap flow density by thermal diffusion probe and the environmental factors. The response of the T to the soil volumetric water content (VWC) and potential evapotranspiration (PET) was analyzed. The results showed the response curve of T to VWC was quite similar under any different PET levels. With increasing VWC, T increased rapidly and then slowly, and began to be stable when VWC reached a threshold. This process could be well fitted by the saturated exponential function. However, the VWC threshold was different, and its value increased with rising PET. The relationship of daily T to PET was a quadra-tic equation, and PET also had a threshold effect. A stand transpiration model considering the effect of soil water supply capacity and atmospheric evaporative potential was founded which coupled the response relationship of T to PET and VWC in the rapid growth season. This model could well estimate the diurnal variation of transpiration, and provide guidance for the management of plantation water control.
Biological soil crusts (BSCs) greatly change surface soil structure and nutrient enrichment processes in arid and semiarid regions. However, their impacts on solute transport characteristics and nutrient loss are still not clear. In this study, the solute (Cl- and Ca2+) transport experiments were conducted on soils covered by moss-dominated BSCs and uncrusted soil on sandy and loessal soils on the Loess Plateau, respectively. We analyzed the solute transport characteristics of the BSCs covered soil and uncrusted soil in different soil depths (0-5 cm and 5-10 cm). The BSCs mulching generated delay effects on the solute breakthrough process of 0-5 cm soils. https://www.selleckchem.com/products/ap-3-a4-enoblock.html The breakthrough time of Cl- in the BSCs covered soil was 3.83 (sandy soil) and 2.09 times (loessal soil) longer than that in the uncrusted soil. The breakthrough time of Ca2+ in the BSCs covered soil was 2.50 and 2.73 times longer than that in the uncrusted soil. Due to the strong influence of BSCs mulching, the pore volume number of the complete solute brech is of great significance for the improvement of soil fertility and vegetation restoration on degraded land in arid and semiarid regions.We analyzed composition and spatial distribution of main species in the surrounding grassland of Baiyinhua mining area in Inner Mongolia. The results showed that there were 55 plant species in the grassland, with dominant species being Stipa grandis, Carex korshinskyi, and Cleistogenes squarrosa, and common species being Leymus chinensis, Agropyron cristatum, and Anemarrhena asphodeloides. The accumulative relative importance value of those six species was 79.6%, with their densities being 26.6, 204.7, 105.4, 107.1, 68.2 and 55.1 individuals·m-2, respectively. The population density of those six species was modeled by the semi-variance function. The population distribution was in accordance with the exponential model, exponential model, exponential model, spherical model, linear model and Gaussian model, respectively. Through analyzing the spatial distribution pattern, structure ratios were 59.2%, 97.2%, 89.1%, 94.5%, 62.6% and 72.1%, respectively. The spatial autocorrelation of C. korshinskyi, C. squarrosa and L. chinensis populations was mainly affected by structural factors, whereas S. grandis, A. cristatum and A. asphodeloides were mainly affected by random factors. According to results from the fractal dimension analysis, population distribution patterns of S. grandis, C. korshinskyi, C. squarrosa and A. cristatum were simple, and the spatial dependence was strong. Both L. chinensis and A. asphodeloides showed contrasting patterns with those four species. From 2D and 3D images, S. grandis and A. asphodeloides showed gradient diffusion, while C. korshinskyi, C. squarrosa, L. chinensis and A. cristatum showed patch distribution. The results showed that the spatial distribution of the main species in this grassland community did not correlate with mining.Investigating ecological stoichiometry of leaves and fine roots of forest swamps in the Greater Hinggan Mountains will improve our understanding of plant nutrient use and material cycling in ecosystems at high latitudes with high sensitivity to climate change. In this study, we collected leaf and fine root samples from 19 dominant and subordinate vascular plant species and measured their C, N and P concentrations in three typical forest swamps (Larix gmelinii-Carex schmidtii, L. gmelinii-Vaccinium uliginosum-moss and L. gmelinii-Ledum palustre-Sphagnum) of the Greater Hinggan Mountains, China. We compared CNP stoichiometry in leaves and fine roots among different forest swamp types, plant growth forms, and mycorrhizal types. Standardized major axis regression was performed to examine the relationships between leaf and fine root stoichiometry. The results showed that interspecific variation accounted for the largest proportion of total variation in CNP stoichiometry of leaves (42.5%-84.6%). NP had the highest, CN had the intermediate, and CP had the lowest interspecific variation in both leaves and fine roots. L. gmelinii-C. schmidtii forest swamps, which had higher soil nutrient and water availability, had lower CN and CP in leaves and fine roots. NP of all three forest swamps were lower than 10, indicating N limitation in this ecosystem. Herbaceous plants had significantly lower leaf CP, fine root CN, and fine root CP than woody species. Both ectomycorrhizal and ericoid mycorrhizal plants had higher leaf and fine root CN and CP than arbuscular mycorrhizal and non-mycorrhizal species, while the CP of ericoid mycorrhizal plants was significantly higher than that of ectomycorrhizal species. Forest swamp type, plant growth form, and mycorrhizal type all had greater influences on leaf and fine root CN and CP rather than NP. Leaf and fine root CN, CP, and NP were positively correlated, indicating strong coordination between plant above- and below-ground CNP stoichiometry.Quantifying the response of tree transpiration (T) to the variation of soil water supply capability and atmospheric evaporative demand is beneficial for a better prediction of water use and hydrological cycles in forests and deepen the understanding of the relationship between forest and water. Larix principis-rupprechtii in the Xiangshuihe watershed at the south side of Liupan Mountains was used as the research object. We simultaneously monitored sap flow density by thermal diffusion probe and the environmental factors. The response of the T to the soil volumetric water content (VWC) and potential evapotranspiration (PET) was analyzed. The results showed the response curve of T to VWC was quite similar under any different PET levels. With increasing VWC, T increased rapidly and then slowly, and began to be stable when VWC reached a threshold. This process could be well fitted by the saturated exponential function. However, the VWC threshold was different, and its value increased with rising PET. The relationship of daily T to PET was a quadra-tic equation, and PET also had a threshold effect. A stand transpiration model considering the effect of soil water supply capacity and atmospheric evaporative potential was founded which coupled the response relationship of T to PET and VWC in the rapid growth season. This model could well estimate the diurnal variation of transpiration, and provide guidance for the management of plantation water control.
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