Soil degradation and the decline in soil available nitrogen and phosphorus in the main forest types in the Qinling Mountains of China. Despite many advances in the understanding of C, N and P cycling in forest soils, many questions remain.
Tropical Tree Species Effects on Soil pH and Biotic Factors and the Consequences for
Macroaggregate Dynamics
- Introduction
- Materials and Methods
- Results
- Discussion
- Conclusions
The flux of Al in litterfall was significantly correlated with the dry mass macroaggregate fraction in the smallest size classes (0.25–0.5 mm) (Table 2). The effect of vegetation on soil pH affected macroaggregate fractions in the smallest size classes (Table 3; Table A2).
Joint Control of Net Primary Productivity by Climate and Soil Nitrogen in the Forests of Eastern China
Materials and Methods 1. Study Area
Stepwise regression was used to analyze the linear regression in forest NPP with climate and soil N. Next, we performed a stepwise multiple regression to identify the effects of climate factors and soil N on forest NPP.
Discussion 1. Carbon Budget
To confirm the effects of climate and soil on NPP, partial GLM was performed, and the results showed that the overall model including MAT, MAP and Nre, could account for 84.8% of the spatial variation in NPP (Figure 5). Spatially, climate and soil were both significantly linearly correlated with NPP, and the combined effect of MAT, MAP and NV accounted for 84.8% of the spatial variation of NPP.
Charcoal Increases Microbial Activity in Eastern Sierra Nevada Forest Soils
Materials and Methods 1. Field Site
Potential nitrification rates were determined for unamended JP and LP soils, JP soils amended with JP-derived charcoal, and LP soils amended with LP-derived charcoal. However, potential nitrification rates at the end of the incubation were higher in LP than in JP soils (Figure 5; Table 4) indicating a higher capacity of LP soils to support nitrifying microorganisms.
Soil Organic Matter Accumulation and Carbon Fractions along a Moisture Gradient of Forest Soils
The lowest soil moisture content was recorded in the soil of the WT80-100 variety (Table 4). A statistically higher carbon content in the surface horizons was noted in the soil of the WT80-100 variety.
Interstorm Variability in the Biolability of
Tree-Derived Dissolved Organic Matter (Tree-DOM) in Throughfall and Stemflow
Materials and Methods 1. Study Site Description
Ten individual cedar trees were selected for stem flow sampling, five each with bare and epiphyte-covered canopies (individual tree characteristics listed in Table S1). As flow-through and stock flow at this site contain 104–106 bacteria mL−1[24], the inoculum was prepared for each storm. Stem volume from the sampled bare cedars was 2-5 times greater than observed under the epiphyte-covered cedars (Table 1).
DOC concentrations in rainwater (<7 mg-C L−1) were always significantly lower than in runoff and stem flow (full data set provided in Table S2).
Discussion 1. Hydrometeorology
The range of tree BDOM percentages in cedar and stem declines matches values observed in broadleaf wood declines, ~60% [7]. This precludes the use of discrete storm data to estimate the annual yield of tree BDOM from fall and stem flow. Little information has been reported on the proportion, rate and yield of tree BDOM at fall and thickness.
Molecular and optical properties of wood-derived dissolved organic matter in flow-through and stem flow from live oak and eastern red cedar. Front.
Enrichment Planting and Soil Amendments Enhance Carbon Sequestration and Reduce Greenhouse Gas
Methods of Literature Collection
By searching using Google Scholar and ISI Web of Science, a wide range of published literature was collected with a Boolean value determined by logical strings containing “and/or” with the keywords “agroforestry”, “environmental service”, “enrichment planting", "greenhouse gas" emission". More than 200 publications, both refereed and non-peer-reviewed, were found; they were further classified according to the criteria "carbon sequestration and agro-forestry" and "greenhouse gas emissions and agro-forestry".
Role of Agroforestry in C Sequestration and Reducing Greenhouse Gas Emissions
In Mediterranean regions, the total rate of C sequestration in vegetation and soils of different agroforestry systems can be up to 1.3 Mg C ha−1y−1[35]. In the subtropics, agroforestry systems combining intercropped trees and shrubs store more C in vegetation and soil compared to systems with only trees or trees grown with legumes or cereals as intercropping systems [38,39]. A study in central Alberta, Canada showed that silvopastoral systems had higher SOC and lower GHG emissions compared to agroforestry systems containing either hedgerows or shelterbelts combined with annual cropland [32,34].
Despite their potential to mitigate GHG emissions, agroforestry systems can be a significant sink or source of GHGs, depending on management practices.
Management Intervention to Enhance C Sequestration and Reduce GHG Emissions 1. Impacts of Enrichment Planting on C Sequestration and GHG Emissions
The impact of biochar on greenhouse gas emissions in modified soils depends on both biochar and soil properties [20]. The impact of biochar on greenhouse gas emissions has produced mixed results depending on soil type, feedstock type and season of application [58,59]. The effects of manure from different types of livestock and compost also vary in terms of greenhouse gas emissions from the soil.
Silvopastoral systems were found to be superior in terms of both C sequestration and GHG emissions reduction compared to agroforestry systems involving annual cropland.
Effects of Near Natural Forest Management on Soil Greenhouse Gas Flux in Pinus massoniana (Lamb.)
Hook. Plantations
Regression models were used to analyze the correlation between soil greenhouse gas flux and soil temperature and soil moisture in the four plantations. Results of multiple linear regression analysis of biogeochemical parameters and annual average soil greenhouse gas flux in the four plantations. Therefore, the differences in soil N2O emissions between near natural plantations and control plantations were mainly due to differences in the C:N ratio of leaf litter and the N content available in the soil.
The variation in the CH4 uptake rate can only be attributed to the C:N ratio of leaf litter.
Seasonal Effects on Microbial Community Structure and Nitrogen Dynamics in Temperate Forest Soil
The seasonal trend was similar to MB-C (and slightly similar to MB-N) only in layer S. In particular, seasonal changes in gross specific potential NH4+-N and net inorganic N production were strongly related to Sat/ mono (Figure S6). Seasonal changes in MCS, particularly in the relative dominance of fungi and bacteria, may be associated with C:N-stoichiometry and N dynamics.
These findings can be interpreted as indicating similar seasonal changes in soil microbial element limitation.
Discriminating between Seasonal and Chemical Variation in Extracellular Enzyme Activities within
Multilevel Models
Materials and Methods 1. Site Description
N Forest has an average temperature of 6.0◦C, with an average of 11.0◦C between April and September and 0.7◦C the rest of the year. The average temperature in S Forest is 13.7◦C between April and September, and 3.7◦C the rest of the year, with an overall average temperature of 8.7◦C. Figure 1 shows the temperature and precipitation trends in the two forests over the year.
Sampling points were marked in the field in order to repeat sampling at the same points and avoid introducing bias into the analyses.
Results 1. Leaf Litter
Plots for conditional random effects models in soil, including prediction intervals, can be seen in Figure 5. Compared to litter, a large amount of variance was derived from the fixed part of the model. There was no difference between forests and little difference between layers, except in the deeper part of the soil in the S forest.
The random part of the model expressed a large amount of variance (R2m= 0.718) with a clear seasonal effect (ICCseason=0.561) with sharp differences in autumn compared to spring and summer.
Discussion 1. Leaf Litter
Response of extracellular enzyme activities in a hardwood forest to soil temperature and seasonality and potential effects of climate change. Soil Biol. Lignin and cellulose degradation and nitrogen dynamics during decomposition of three types of leaf litter in a Mediterranean ecosystem. Soil Biol. Nitrogen content in Oa layers of forest soils affects carbon pathways and nitrogen mineralization. Soil Biol.
Microbial enzyme activities in leaf litter, humus and mineral soil layers of European forests. Soil Biol.
Changes in Soil Enzyme Activities and Microbial Biomass after Revegetation in the Three Gorges
Such changes in nutrient availability in the riparian soil environment will cause significant variation in soil enzyme activities and microbial biomass in the WLFZ of the TGDR. The soil and water erosion is serious in the less vegetated riparian zone of the Ruxi River. In the riparian zone of TGDR, although the P (TP and AP) content showed no significant difference between the three treatments, the uptake of P by soil microbes was increased in bare cypress soils, which is most likely due to the greater mass of SOC ( Table 2) that existed in bare cypress soil through overcompensation for the lower SMP [31].
Carbon and phosphorus cycling in microbial biomass depending on phosphorus availability.Soil Biol.
Distribution Changes of Phosphorus in Soil–Plant Systems of Larch Plantations across
The highest concentration of soil-labile P was observed in a 10-year-old stand, namely 40%. Changes in the concentration of labile P in the soil (sum of Resin-P, NaHCO3-Pi and NaHCO3-Po) with stand age in a larch plantation. A possible explanation for the decrease in soil labile P in the 25-year-old stand is a scenario of improper harvesting.
Changes in labile P in the soil during the 25- and 50-year stand may be due to increased PRE.
Soil Nitrogen Responses to Soil Core Transplanting Along an Altitudinal Gradient in an Eastern
Tibetan Forest
The dramatic temperature fluctuations lead to seasonal variations in the abundance and structure of AOA and AOB communities in alpine areas [4,23,24]. In both soil layers, A2 had the highest ammonium and nitrate concentrations during the early growing season, but a lower ammonium concentration was found in the organic soil during the onset of the freeze period and the thaw period (Figure 3c). In this study, we found that the samples on A2 had greater abundance of AOA and AOB than A1 at most sampling times, except for early growing season AOA and freeze period AOB in organic and mineral soils, respectively.
Increased temperature at A3 resulted in a lower abundance of AOA and a greater abundance of AOB in the organic soil.
Characterization of Phosphorus in a Toposequence of Subtropical Perhumid Forest Soils Facing a
Materials and Methods 1. Study Sites
The Feo, Fed, Aloand Aldcontents peaked in the prime location Bt2 horizon and in the Bw2. Organic P was the dominant P fraction in the montane forest soils of the three sites (Table 3). Due to the low total Pi concentrations at the three study sites, the different chemically extractable Pi contents increased downhill, but not significantly.
Distribution of radionuclide137Cs in soils of a moist mountain forest in Taiwan.Appl.
Regional Scale Determinants of Nutrient Content of Soil in a Cold-Temperate Forest
Methods 1. Site Description
The forest of the Daxing'an Mountains is one of the most important areas in China: the lush natural forest is widely distributed. The study was conducted in the eastern forest zones of Daxing'an Mountain Range NE), Heilongjiang Province and Inner Mongolia Autonomous Region. The forested area of the Daxing'an Mountains was systematically divided into 30 km × 30 km grids using ArcGIS 10.0 (Esri, Redlands, CA, USA) as the meshing tool.
The slopes of the regression lines were used to indicate the different responses of forest types to climate changes.
