Effects of slope aspect on altitudinal pattern of soil C:N:P stoichiometry in alpine forest of Tibet

Knowledge of altitudinal patterns in soil C, N and P distribution is important for understanding biogeochemical processes in mountainous forests, yet the influence of slope aspects on soil stoichiometry has been largely neglected in previous studies. In this paper, a total number of 150 topsoil samples at four altitudes (3700, 3900, 4100, 4380 m a.s.l.) on sunny and shady slopes of Sygera mountains in the Southeastern Tibet were collected. Soil C, N and P contents, and pH, were measured. Soil temperature, moisture and richness of plant species were investigated at each sampling site. The results showed that: 1) in sunny slope, soil C, N and P concentrations increased with the increase in altitude, whereas soil C:N, C:P, and N:P decreased along the altitudinal gradient on s. Soil moisture was the main regulator of soil nutrition and stoichiometric ratios. 2) In shady slope, soil C and N contents had no significant difference along the altitudinal gradient except the higher values at low altitude, whereas soil P increased first and then decreased. Soil C:N increased with the increase in altitude, whereas C:P and N:P decreased first and then increased. Soil temperature and species richness were the main factors influencing soil nutrition and stoichiometric ratios. 3) Decoupling of soil C:N:P stoichiometry was observed in shady slope owing to changes in soil pH and temperature. 4) The rich contents of soil C and P were observed at two slopes along the altitudinal gradient, and high capacity of N supply existed at the topsoil in shady slope. These results suggested that slope aspect plays an important role in shaping the altitudinal pattern of soil C:N:P stoichiometry in mountainous forests.

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Changes in Soil C, N, and P Concentrations and Stoichiometry in Karst Trough Valley Area under Ecological Restoration: The Role of Slope Aspect, Land Use, and Soil Depth

Forests ◽

10.3390/f12020144 ◽

2021 ◽

Vol 12 (2) ◽

pp. 144

Author(s):

Tianyang Li ◽

Jiangmin Zeng ◽

Binghui He ◽

Zhanpeng Chen

Keyword(s):

Land Use ◽

Ecological Restoration ◽

Soil Depth ◽

Interactive Effects ◽

Slope Aspect ◽

Soil C ◽

Soil P ◽

Soil C And N ◽

C And N ◽

Valley Area

This study aims to investigate the roles of slope aspect, land use and soil depth in altering the soil organic carbon (C), total nitrogen (N), and total phosphorus (P) traits in the karst trough valley area experiencing extensive ecological restoration. A total of 54 soil samples were collected at 0–10, 10–20, and 20–30 cm soil depths from secondary forest, plantation forest, and grassland on the relatively more shaded east-facing slope and the contrasting west-facing slope, respectively. The independent and interactive effects of slope aspect, land use, and soil depth on soil C, N, and P concentrations and stoichiometry were determined. The results show that soil C and N concentrations were markedly higher on the east-facing slope than on the west-facing slope, and soil P concentrations showed an opposite trend, leading to significant differences in soil C:P and N:P but not in C:N ratios between the two aspects. Soil C and N concentrations were not affected by land use, and soil P concentration was significantly higher in plantation forest than in secondary forest and grassland. Soil C and N concentrations significantly decreased with increasing soil depth, but soil P concentration presented no significant changes with soil depth. Both the land use and soil depth did not differ in terms of their elemental stoichiometry. There were no significant interactive effects of slope aspect, land use and soil depth on soil C, N, and P traits. Our results indicate that soil C, N, and P changes are more sensitive to slope aspect rather than land use and soil depth in the karst trough valley area under ecological restoration.

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Effects of Grazing Intensity on Plant-Soil C: N: P Stoichiometry with Precipitation Changes During the Growing Season in Desert Grassland

10.21203/rs.3.rs-911986/v1 ◽

2021 ◽

Author(s):

Wei Yan ◽

Fengling Shi ◽

Tao Wan

Keyword(s):

Species Diversity ◽

Plant Growth ◽

Grazing Intensity ◽

Desert Grassland ◽

C:N:P Stoichiometry ◽

Soil C ◽

Plant Soil ◽

Heavy Grazing ◽

Significant Difference ◽

The Impact

Abstract Background and aimsHigh-intensity grazing in the Mongolian grassland has led to the general deterioration of biodiversity and ecosystem functioning. Although abundant evidence shows that grazing affects the structure and function of grassland ecosystems, research on the impact of precipitation, especially under drought and overgrazing. MethodsWe examined the effects of heavy grazing, moderate grazing and no grazing on plant communities; plant and soil C, N and P contents; and plant and soil C:N:P stoichiometry in the desert grassland in different years with different amounts of precipitation. ResultsThere was no significant difference in the species diversity between the grazing and no grazing treatment, while the no grazing treatment was significantly higher than the heavy grazing treatment. Compared with the amounts in the no grazing and moderate grazing treatments, the N and P contents of the plants in the heavy grazing treatment were the highest, and the N content of the soil increased. There was a positive correlation between precipitation and the N and P contents of plants and the C and N contents of the soil at 0-10 cm and 10-20 cm. ConclusionsOur study suggest that a large amount of precipitation of plant growth will drive changes in the community species diversity. Grazing promoted the flow of N between plants and the soil, especially under heavy grazing. Under grazing stress, plants maintain the potential of compensatory growth, and precipitation in the peak season of plant growth induces rapid growth, suggesting that precipitation is an important factor driving grazing ecosystems.

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TIME-INTEGRATED COLLECTION OF CO2 FOR 14C ANALYSIS FROM SOILS

Radiocarbon ◽

10.1017/rdc.2021.42 ◽

2021 ◽

pp. 1-17

Author(s):

Shawn Pedron ◽

X Xu ◽

J C Walker ◽

J C Ferguson ◽

R G Jespersen ◽

...

Keyword(s):

Soil Temperature ◽

Molecular Sieve ◽

Emission Sources ◽

Soil C ◽

Silicone Tubing ◽

2Nd Generation ◽

C Cycle ◽

Uptake Rates ◽

Two Generations ◽

Cleaning Procedures

ABSTRACT We developed a passive sampler for time-integrated collection and radiocarbon (14C) analysis of soil respiration, a major flux in the global C cycle. It consists of a permanent access well that controls the CO2 uptake rate and an exchangeable molecular sieve CO2 trap. We tested how access well dimensions and environmental conditions affect collected CO2, and optimized cleaning procedures to minimize 14CO2 memory. We also deployed two generations of the sampler in Arctic tundra for up to two years, collecting CO2 over periods of 3 days–2 months, while monitoring soil temperature, volumetric water content, and CO2 concentration. The sampler collects CO2 at a rate proportional to the length of a silicone tubing inlet (7–26 µg CO2-C day-1·m Si-1). With constant sampler dimensions in the field, CO2 recovery is best explained by soil temperature. We retrieved 0.1–5.3 mg C from the 1st and 0.6–13 mg C from the 2nd generation samplers, equivalent to uptake rates of 2–215 (n=17) and 10–247 µg CO2-C day-1 (n=20), respectively. The method blank is 8 ± 6 µg C (mean ± sd, n=8), with a radiocarbon content (fraction modern) ranging from 0.5875–0.6013 (n=2). The sampler enables more continuous investigations of soil C emission sources and is suitable for Arctic environments.

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How Elemental Stoichiometric Ratios in Microorganisms Respond to Thinning Management in Larix principis-rupprechtti Mayr. Plantations of the Warm Temperate Zone in China

Forests ◽

10.3390/f12060684 ◽

2021 ◽

Vol 12 (6) ◽

pp. 684

Author(s):

Mengke Cai ◽

Shiping Xing ◽

Xiaoqing Cheng ◽

Li Liu ◽

Xinhao Peng ◽

...

Keyword(s):

Microbial Biomass ◽

Soil Temperature ◽

Microbial Communities ◽

Microbial Biomass Carbon ◽

Gram Negative Bacteria ◽

Medium Density ◽

Biomass Carbon ◽

Gram Negative ◽

Gram Positive Bacteria ◽

Stoichiometric Ratios

The stoichiometric ratios of elements in microorganisms play an important role in biogeochemical cycling and evaluating the nutritional limits of microbial growth, but the effects of thinning treatment on the stoichiometric ratio of carbon, nitrogen, and phosphorus in microorganisms remain unclear. We conducted research in a Larix principis-rupprechtti Mayr. plantation to determine the main factors driving microbial carbon (C): nitrogen (N): phosphorus (P) stoichiometry following thinning and the underlying mechanisms of these effects. The plantation study varied in thinning intensity from 0% tree removal (control), 15% tree reduction (high density plantation, HDP), 35% tree reduction (medium density plantation, MDP), and 50% tree reduction (low density plantation, LDP). Our results indicated that medium density plantation significantly increased litter layer biomass, soil temperature, and other soil properties (e.g., soil moisture and nutrient contents). Understory vegetation diversity (i.e., shrub layer and herb layer) was highest in the medium density plantation. Meanwhile, thinning had a great influence on the biomass of microbial communities. For example, the concentration of phospholipid fatty acids (PLFA) for bacteria and fungi in the medium density plantation (MDP) was significantly higher than in other thinning treatments. Combining Pearson correlation analysis, regression modeling, and stepwise regression demonstrated that the alteration of the microbial biomass carbon: nitrogen was primarily related to gram-positive bacteria, gram-negative bacteria, soil temperature, and soil available phosphorus. Variation in bacteria, actinomycetes, gram-positive bacteria, gram–negative bacteria, and soil total phosphorus was primarily associated with shifts in microbial biomass carbon: phosphorus. Moreover, changes in microbial biomass nitrogen: phosphorus were regulated by actinomycetes, gram-negative bacteria, and soil temperature. In conclusion, our research indicates that the stoichiometric ratios of elements in microorganisms could be influenced by thinning management, and emphasizes the importance of soil factors and microbial communities in driving soil microbial stoichiometry.

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Soil respiration on an aging managed heathland: identifying an appropriate empirical model for predictive purposes

Biogeosciences ◽

10.5194/bg-10-3007-2013 ◽

2013 ◽

Vol 10 (5) ◽

pp. 3007-3038 ◽

Cited By ~ 8

Author(s):

G. R. Kopittke ◽

E. E. van Loon ◽

A. Tietema ◽

D. Asscheman

Keyword(s):

Soil Respiration ◽

Soil Temperature ◽

Cultural Landscapes ◽

Plant Biomass ◽

Model Fit ◽

Selection Procedures ◽

Soil C ◽

Experimental Planning ◽

Improve Model ◽

Level Model

Abstract. Heathlands are cultural landscapes which are managed through cyclical cutting, burning or grazing practices. Understanding the carbon (C) fluxes from these ecosystems provides information on the optimal management cycle time to maximise C uptake and minimise C output. The interpretation of field data into annual C loss values requires the use of soil respiration models. These generally include model variables related to the underlying drivers of soil respiration, such as soil temperature, soil moisture and plant activity. Very few studies have used selection procedures in which structurally different models are calibrated, then validated on separate observation datasets and the outcomes critically compared. We present thorough model selection procedures to determine soil heterotrophic (microbial) and autotrophic (root) respiration for a heathland chronosequence and show that soil respiration models are required to correct the effect of experimental design on soil temperature. Measures of photosynthesis, plant biomass, photosynthetically active radiation, root biomass, and microbial biomass did not significantly improve model fit when included with soil temperature. This contradicts many current studies in which these plant variables are used (but not often tested for parameter significance). We critically discuss a number of alternative ecosystem variables associated with soil respiration processes in order to inform future experimental planning and model variable selection at other heathland field sites. The best predictive model used a generalized linear multi-level model with soil temperature as the only variable. Total annual soil C loss from the young, middle and old communities was calculated to be 650, 462 and 435 g C m−2 yr−1, respectively.

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Soil respiration and N2O emission in croplands under different ploughing practices: a case study in south-east China

Soil Research ◽

10.1071/sr07225 ◽

2009 ◽

Vol 47 (2) ◽

pp. 198 ◽

Cited By ~ 8

Author(s):

Shutao Chen ◽

Yao Huang

Keyword(s):

Soil Respiration ◽

Soil Temperature ◽

Agricultural Soils ◽

Field Measurements ◽

Triticum Aestivum L ◽

N2o Emission ◽

Cropping Season ◽

Significant Difference

Studies on the CO2 and N2O emission patterns of agricultural soils under different ploughing practices may provide an insight into the potential and magnitude of CO2 and N2O mitigation in highly managed farmland soils. In this study, field measurements of soil respiration and N2O flux with different ploughing depths were performed in the 2003–04 wheat (Triticum aestivum L.), 2004 maize (Zea mays L.), and 2004–05 wheat seasons. Soil temperature and moisture were simultaneously measured. Results showed that, in each cropping season, the seasonal variation in soil respiration developed with a similar pattern for different treatments, which was primarily regulated by soil temperature. This work demonstrates that ploughing depth can influence long-term loss of carbon from soil, but this was contingent on preceding cropping types. Given the same preceding cropping practice, no significant difference in N2O emission was found among different ploughing depths in each cropping season.

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Depth-Dependent C-N-P Stocks and Stoichiometry in Ultisols Resulting from Conversion of Secondary Forests to Plantations and Driving Forces

Forests ◽

10.3390/f12101300 ◽

2021 ◽

Vol 12 (10) ◽

pp. 1300

Author(s):

Xiaogang Ding ◽

Xiaochuan Li ◽

Ye Qi ◽

Zhengyong Zhao ◽

Dongxiao Sun ◽

...

Keyword(s):

Soil Depth ◽

Soil Layer ◽

Pinus Elliottii ◽

Slash Pine ◽

Pine Plantations ◽

Secondary Forests ◽

Masson Pine ◽

Soil Layers ◽

Soil C ◽

Significant Difference

Stocks and stoichiometry of carbon (C), nitrogen (N), and phosphorus (P) in ultisols are not well documented for converted forests. In this study, Ultisols were sampled in 175 plots from one type of secondary forest and four plantations of Masson pine (Pinus massoniana Lamb.), Slash pine (Pinus elliottii Engelm.), Eucalypt (Eucalyptus obliqua L’Hér.), and Litchi (Litchi chinensis Sonn., 1782) in Yunfu, Guangdong province, South China. Five layers of soil were sampled with a distance of 20 cm between two adjacent layers up to a depth of 100 cm. We did not find interactive effects between forest type and soil layer depth on soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) concentrations and storages. Storage of SOC was not different between secondary forests and Eucalypt plantations, but SOC of these two forest types were lower than that in Litchi, Masson pine, and Slash pine plantations. Soil C:P was higher in Slash pine plantations than in secondary forests. Soil CNP showed a decreasing trend with the increase of soil depth. Soil TP did not show any significant difference among soil layers. Soil bulk density had a negative contribution to soil C and P stocks, and longitude and elevation were positive drivers for soil C, N, and P stocks. Overall, Litchi plantations are the only type of plantation that obtained enhanced C storage in 0–100 cm soils and diverse N concentrations among soil layers during the conversion from secondary forests to plantations over ultisols.

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Waste Plastic as soil bearing Capacity Enhancer

UIC Research Journal ◽

10.17158/516 ◽

2016 ◽

Vol 19 (2) ◽

Author(s):

Ruben M. Ruiz ◽

Renan P. Limjuco ◽

Ebony Joseph B. Dolino ◽

Michelle T. Llaban ◽

Jeric N. Maratas ◽

...

Keyword(s):

Bearing Capacity ◽

Primary Objective ◽

California Bearing Ratio ◽

Engineering Properties ◽

P Value ◽

Waste Plastic ◽

Soil P ◽

Significant Difference ◽

Engineering Soil ◽

Recycled Waste

The necessity of improving the engineering properties of soil has been recognized; therefore, it is very important to find ways to enhance the weak soil, and using plastic waste is one promising way of doing it. The primary objective of this study is to compare the bearing capacity of the two types of soil (Clay and Item-201) in different concentrations of plastics, namely, at 0%, 0.5%, and 1%. Primarily, this investigation aimed to compare the California bearing ratio (CBR) of the two types of soil each with three concentrations of plastic. This study made use of the experimental design, specifically posttest design only to determine the effectiveness of using recycled waste plastic as soil bearing capacity enhancer. Findings revealed that in terms of the type of soil, there is a significant difference in California bearing ratio between clay and Item 201 (p-value < 0.05). On the other hand, the California bearing ratio of the soil samples in various concentrations are not the same. As with the interaction between the type of soil and the waste plastic, a two-way ANOVA reveals that there is significant interaction between them that might have influenced California bearing ratio in the soil (p-value < 0.05). Keywords: Engineering, soil, waste plastic, soil bearing capacity enhancer, California bearing ratio, experimental, ANOVA, Davao City, Philippines.

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Soil contents and stoichiometry of carbon, nitrogen, and phosphorus in Finnish farmland and feedbacks on management patterns

10.5194/egusphere-egu21-12350 ◽

2021 ◽

Author(s):

Sichu Wang ◽

Oona Uhlgren ◽

Anna-Reetta Salonen ◽

Jussi Heinonsalo

Keyword(s):

Organic Matter ◽

Management Practice ◽

Combustion Method ◽

Agricultural Management ◽

Soil Columns ◽

Nitrogen And Phosphorus ◽

Deep Soil ◽

C:N:P Stoichiometry ◽

Soil Layers ◽

Soil C

The coupled cycles and interactions of soil carbon (C), nitrogen (N), and phosphorus (P) are fundamental for soil quality and soil organic matter (SOM) formation. Low C:N ratios through nitrogenous fertilizer addition may accelerate SOM cycling and promote C mineralization in soil, whereas P limitations may decline C storage by reducing plant and microbial biomass production. Deeper soil layers&#8217; C-N-P stoichiometry has an important role in regulating SOM formation in subsoils. However, there is little information on soil C:N:P stoichiometry in deep soil layers of farmland. In this study, soil columns up to one meter were collected from 32 farms distributing across Finland with different soil texture and agricultural management history. The one-meter soil columns were cut into 10 cm deep slices and analyzed for the total organic carbon (TOC), total nitrogen (TN) by dry combustion method and total phosphorus (TP) contents by aqua regia digestion and ICP-OES method. Overall, the TOC, TN and TP contents all dropped sharply in 30-40 cm soil layers, but TP contents rose again in deep soil. The role of agricultural management practice (including crop rotation, crop cover, crop diversity and fertilization) on soil C:N:P stoichiometry as well as organic matter accumulation in the deep soil layers were explored. The preliminary results will be presented in the poster. The data deepens our understanding of soil C, N and P coupling and interaction related to soil C sequestration.

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Phosphorus forms and their distribution under long-term no tillage systems

Plant Soil and Environment ◽

10.17221/270/2018-pse ◽

2019 ◽

Vol 65 (No. 1) ◽

pp. 35-40

Author(s):

Kai Wei ◽

Zhenhua Chen ◽

Xiaoping Zhang ◽

Lijun Chen

Keyword(s):

Management Practice ◽

Crop Growth ◽

No Tillage ◽

Soil P ◽

P Loss ◽

Phosphorus Forms ◽

Significant Difference ◽

Mouldboard Plough ◽

P Fertilizers

Phosphorus (P) stratification in no-tillage (NT) systems has important implications for crop growth and potential P loss, but little is known about P forms and their distribution when mineral P fertilizers are placed to the depth of 5 cm in NT soil. A 10-year field experiment was used to study the effect of NT and mouldboard plough (MP) on soil P forms at three depths (0–5, 5–10 and 10–20 cm) and their relationship with Fe and Al oxides. The results indicated that stratification of organic P forms occurred under NT treatment, and Fe oxides may have a stronger capacity for adsorbing the P forms. When mineral P fertilizers were placed to the depth of 5 cm under NT treatment, there was no significant difference in P forms or crop yield between NT and MP treatment, and orthophosphate did not show any significant difference under NT treatment between 0–5 cm and 5–10 cm depth. Overall, the agricultural management practice that mineral P fertilizers are placed to the depth of 5 cm under NT treatment could result in stratification of P forms, while the changes in the distribution of P forms in soil profiles might help reduce potential P loss in surface runoff and do not make any difference to crop growth.

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