Soil Dynamics


    Fertilizer Application


    Plant Physiology

Soil, Plant & Fertilizer

The performance of a particular plant or an entire crop is highly dependent on the fertility of the soil it is growing in. Soil fertility is a multi-faceted analysis of elemental concentrations and biological activity. To get a complete picture of soil fertility, concentrations of carbon, nitrogen, and sulfur, as well as the differentiation of carbon into total organic or total inorganic carbon (TOC or TIC) fractions, are all relevant parameters. Improving soil health by fertilization requires accurate measurements of a wide range of soils and fertilizers. Elementar’s wide range of multi- and single-element analyzers provide individualized solutions to even the most challenging problems.

Soil C:N ratio

The carbon and nitrogen content of soil is directly related to its ability to support healthy plant growth. The vario MAX cube is specially suited to soil analysis. Capable of measuring up to 5 g of soil means that sample inhomogeneity is not an issue. Automated ash removal reduces maintenance requirements and increases productivity. A unique purge-and-trap gas separation system means that even C:N ratios of 7000:1 are perfectly resolved. Additional options, such as using argon as the carrier gas and measuring sulfur or TOC, make the vario MAX cube a versatile, robust solution for soil elemental analysis.

Nitrogen in Fertilizer

The rapid MAX N exceed is ideal for determining the nitrogen content in fertilizer. With sample sizes up to 5 grams of inorganic or 1 gram of organic material, sample preparation in many cases is as easy as weighing the sample into the reusable steel crucibles.

Sulfur in Fertilizer

With the reduction of external sulfur sources, maintaining proper sulfur levels in soil by fertilization is becoming more important. The vario MACRO cube is the world’s only macro sample (up to 1 g) analyzer capable of measuring carbon, hydrogen, nitrogen, and sulfur all in one sample. The wide dynamic range of the thermal conductivity detector enables the accurate determination of sulfur from a fraction of a percent up to 100 % with just one calibration range. Whether interested in just sulfur or any combination of CHNS, the vario MACRO cube provides timely, reliable results with little maintenance, saving you time and money.

Carbon fractions

The total organic carbon (TOC) analysis provides essential information about microbiological activity and organic matter to characterize and evaluate soil and sediment. Soils can also contain a large amount of biologically inaccessible inorganic carbon (TIC), typically in the form of carbonates. Elemental carbon (ROC) is a further common source of carbon, which is also not bio-available. Separately measuring this third carbon fraction can give a much more accurate determination of bio-available, and thus environmentally relevant, TOC compared to acidification method. The revolutionary soli TOC cube measures these three carbon fractions in soils and other solids in a single sample without the need for corrosive acids, providing reliable results with minimal user input.

Soil & plant science publications using our instruments

Our customers use our instruments to do some amazing research in the soil & plant science application field. To show you how they perform their research and how they use our IRMS instruments, we have collected a range of peer-reviewed publications which cite our products. You can find the citations below and then follow the links to the publishing journal should you wish to download the publication.

If you would like to investigate our available citations in more detail, or email the citation list to yourself or your colleagues then take a look at our full citation database.

172 results:

Kinetic commitment in the catalysis of glutamine synthesis by GS1 from Arabidopsis using 14N/15N and solvent isotope effects
Plant Physiology and Biochemistry (2016)
Caroline Mauve, Nicolas Giraud, Edouard R.A. Boex-Fontvieille, Ingrid Antheaume, Illa Tea, Guillaume Tcherkez

Glutamine synthetase (GS, EC catalyzes the production of glutamine from glutamate, ammonium and ATP. Although being essential in plants for N assimilation and recycling, kinetic commitments and transition states of the reaction have not been clearly established yet. Here, we examined 12C/13C, 14N/15N and H2O/D2O isotope effects in Arabidopsis GS1 catalysis and compared to the prokaryotic (Escherichia coli) enzyme. A14N/15N isotope effect (15V/K ≈ 1.015, with respect to substrate NH4+) was observed in the prokaryotic enzyme, indicating that ammonium utilization (deprotonation and/or amidation) was partially rate-limiting. In the plant enzyme, the isotope effect was inverse (15V/K = 0.965), suggesting that the reaction intermediate is involved in an amidation-deamidation equilibrium favoring 15N. There was no 12C/13C kinetic isotope effect (13V/K = 1.000), suggesting that the amidation step of the catalytic cycle involves a transition state with minimal alteration of overall force constants at the C-5 carbon. Surprisingly, the solvent isotope effect was found to be inverse, that is, with a higher turn-over rate in heavy water (DV ≈ 0.5), showing that restructuration of the active site due to displacement of H2O by D2O facilitates the processing of intermediates.
Tags: carbon , nitrogen , soil , elem , liqfac

Mangrove degradation and response to anthropogenic disturbance in Maowei Sea (SW China) since 1926 AD: Mangrove-derived OM and pollen
Organic Geochemistry (2016)
Xianwei Meng, Peng Xia, Zhen Li, Dezhen Meng

Mangrove forests, located at the interface between land and sea, have been impacted by an increase in intensive anthropogenic disturbance in developing countries or regions. In order to study the impact of human activity on mangrove forests, mangrove development was reconstructed over the last 130 yr, using the contribution of mangrove-derived organic matter (OM) and mangrove pollen as proxies, from two sediment cores from the Maowei Sea (SW China). It is a semi-enclosed bay that receives a large amount of terrestrial material from the Qinjiang and Maoling rivers, with average sedimentation rate of 0.63–0.64 cm/yr. The material accumulates mainly in the coast and its adjacent region, owing to weak water exchange through the channel. Sediment samples had C:N and δ13Corg values intermediate between mangrove leaves and flood plain sediments, indicating that OM sources could be apportioned as a mixture from only these two sources. Based on k-mean cluster analysis, mangrove development was divided into three stages since 1880 AD: (i) a flourishing period (1880–1926 AD), (ii) a phase of slow degradation (1926–1980 AD) and (iii) a time of rapid degradation (1980 AD to the present). The study indicates that anthropogenic activity, including reclamation of mangrove swamps for farmland and shrimp ponds, is the primary reason for mangrove degradation since 1926 AD, rather than climate change (temperature and precipitation).
Tags: carbon , soil , ocea , poll , elem

Reclamation and Land Consolidation Effects on Organic Matter Sedimentation in Lake Kiba-Gata, Japan
Geomorphology and Society (2016)
Seiya Nagao, Hong Tuoi Bui, Yuriko Kawano, Tomoyo Suzuki, Shinya Ochiai, Koyo Yonebayashi, Masanori Okazaki, Akiko Goto, Takashi Hasegawa, Masayoshi Yamamoto

The effects of reclamation and land consolidation on organic matter sedimentation were studied in a small lagoon, Kiba-gata, which is one of the three Kaga lagoons (Shibayama-gata, Imae-gata, and Kiba-gata) located in central Japan. Reclamation work was conducted during 1954–1969 to increase the paddy field area and to improve the drainage system. Lake Kiba-gata was affected by changes in the drainage system and land consolidation around the lagoon. A sediment core was obtained in the central part of Lake Kiba-gata in June 2012. The organic matter flux recorded in the sediment core increased from 1.1 to 2.3 and from 3.9 to 7.5 g cm−2 year−1, respectively, during 1903–1974 and 1989–2012, although it was similar to the flux recorded for 1974–1989 following reclamation. The C/N ratio, δ13C, and δ15N values also changed during these time intervals. These results indicate that the primary productivity in the lagoon is increasing with time and that the recent contribution of phytoplankton to productivity has exceeded the level of past contributions because of changes in drainage and increase in human activity around the lake due to the reclamation and land consolidation
Tags: nitrogen , soil , geol , elem

Carbon Inputs from Miscanthus Displace Older Soil Organic Carbon Without Inducing Priming Soil Carbon Sequestration Below Miscanthus
BioEnergy Research (2016)
Andy D. Robertson, Christian A. Davies, Pete Smith, Andy W. Stott, Emily L. Clark, Niall P. McNamara

The carbon (C) dynamics of a bioenergy system are key to correctly defining its viability as a sustainable alternative to conventional fossil fuel energy sources. Recent studies have quantified the greenhouse gas mitigation potential of these bioenergy crops, often concluding that C sequestration in soils plays a primary role in offsetting emissions through energy generation. Miscanthus is a particularly promising bioenergy crop and research has shown that soil C stocks can increase by more than 2 t C ha−1 yr−1. In this study, we use a stable isotope (13C) technique to trace the inputs and outputs from soils below a commercial Miscanthus plantation in Lincolnshire, UK, over the first 7 years of growth after conversion from a conventional arable crop. Results suggest that an unchanging total topsoil (0–30 cm) C stock is caused by Miscanthus additions displacing older soil organic matter. Further, using a comparison between bare soil plots (no new Miscanthus inputs) and undisturbed Miscanthus controls, soil respiration was seen to be unaffected through priming by fresh inputs or rhizosphere. The temperature sensitivity of old soil C was also seen to be very similar with and without the presence of live root biomass. Total soil respiration from control plots was dominated by Miscanthus-derived emissions with autotrophic respiration alone accounting for ∼50 % of CO2. Although total soil C stocks did not change significantly over time, the Miscanthus-derived soil C accumulated at a rate of 860 kg C ha−1 yr−1 over the top 30 cm. Ultimately, the results from this study indicate that soil C stocks below Miscanthus plantations do not necessarily increase during the first 7 years.

Ecosystem nitrogen fixation throughout the snow-free period in subarctic tundra: effects of willow and birch litter addition and warming
Global Change Biology (2016)
Kathrin Rousk, Anders Michelsen

Nitrogen (N) fixation in moss-associated cyanobacteria is one of the main sources of available N for N-limited ecosystems such as subarctic tundra. Yet, N2 fixation in mosses is strongly influenced by soil moisture and temperature. Thus, temporal scaling up of low-frequency in situ measurements to several weeks, months or even the entire growing season without taking into account changes in abiotic conditions cannot capture the variation in moss-associated N2 fixation. We therefore aimed to estimate moss-associated N2 fixation throughout the snow-free period in subarctic tundra in field experiments simulating climate change: willow (Salix myrsinifolia) and birch (Betula pubescens spp. tortuosa) litter addition, and warming. To achieve this, we established relationships between measured in situ N2 fixation rates and soil moisture and soil temperature and used high-resolution measurements of soil moisture and soil temperature (hourly from May to October) to model N2 fixation. The modelled N2 fixation rates were highest in the warmed (2.8 ± 0.3 kg N ha−1) and birch litter addition plots (2.8 ± 0.2 kg N ha−1), and lowest in the plots receiving willow litter (1.6 ± 0.2 kg N ha−1). The control plots had intermediate rates (2.2 ± 0.2 kg N ha−1). Further, N2 fixation was highest during the summer in the warmed plots, but was lowest in the litter addition plots during the same period. The temperature and moisture dependence of N2 fixation was different between the climate change treatments, indicating a shift in the N2 fixer community. Our findings, using a combined empirical and modelling approach, suggest that a longer snow-free period and increased temperatures in a future climate will likely lead to higher N2 fixation rates in mosses. Yet, the consequences of increased litter fall on moss-associated N2 fixation due to shrub expansion in the Arctic will depend on the shrub species’ litter traits.
Tags: nitrogen , soil , clim , elem

Nitrogen Transfer from Four Nitrogen-Fixer Associations to Plants and Soils
Ecosystems (2016)
Kathrin Rousk, Pernille Laerkedal Sorensen, Anders Michelsen

Nitrogen (N) fixation is the main source of ‘new’ N for N-limited ecosystems like subarctic and arctic tundra. This crucial ecosystem function is performed by a wide range of N2 fixer (diazotroph) associations that could differ fundamentally in their timing and amount of N release to the soil. To assess the importance of different associative N2 fixers for ecosystem N cycling, we tracked 15N-N2 into four N2-fixer associations (with a legume, lichen, free-living, moss) and into soil, microbial biomass and non-diazotroph-associated plants 3 days and 5 weeks after in situ labelling. In addition, we tracked 13C from 13CO2 labelling to assess if N and C fixation are linked. Three days after labelling, half of the fixed 15N was recovered in the legume soils, indicating a fast release of fixed N2. Within 5 weeks, the free-living N2 fixers released two-thirds of the fixed 15N into the soil, whereas the lichen and moss retained the fixed 15N. Carbon and N2 fixation were linked in the lichen shortly after labelling, in free-living N2 fixers 5 weeks after labelling, and in the moss at both sampling times. The four investigated N2-fixer associations released fixed N2 at different rates into the soil, and non-diazotroph-associated plants have no access to ‘new’ N within several weeks after N2 fixation. Although legumes and free-living N2 fixers are immediate sources of ‘new’ N for N-limited tundra ecosystems, lichens and especially mosses, do not contribute to increase the N pool via N2 fixation in the short term.
Tags: carbon , nitrogen , soil , elem

Organic nitrogen uptake is a significant contributor to nitrogen economy of subtropical epiphytic bryophytes
Scientific Reports (2016)
Liang Song, Hua-Zheng Lu, Xing-Liang Xu, Su Li, Xian-Meng Shi, Xi Chen, Yi Wu, Jun-Biao Huang, Quan Chen, Shuai Liu, Chuan-Sheng Wu, Wen-Yao Liu, P. Kenrick, P. R. Crane, Y.-L. Qiu, Y. Cho, J. C. Cox, J. D. Palmer, P. G. Gensel, M. Proctor, B. D. Mishler,

Without any root contact with the soil, epiphytic bryophytes must experience and explore poor, patchy, and heterogeneous habitats; while, the nitrogen (N) uptake and use strategies of these organisms remain uncharacterized, which obscures their roles in the N cycle. To investigate the N sources, N preferences, and responses to enhanced N deposition in epiphytic bryophytes, we carried out an in situ manipulation experiment via the 15N labelling technique in an Asian cloud forest. Epiphytic bryophytes obtained more N from air deposition than from the bark, but the contribution of N from the bark was non-negligible. Glycine accounted for 28.4% to 44.5% of the total N in bryophyte tissue, which implies that organic N might serve as an important N source. Increased N deposition increased the total N uptake, but did not alter the N preference of the epiphytic bryophytes. This study provides sound evidence that epiphytic bryophytes could take up N from the bark and wet deposition in both organic and inorganic N forms. It is thus important to consider organic N and bark N sources, which were usually neglected, when estimating the role of epiphytic bryophytes in N cycling and the impacts of N deposition on epiphytic bryophytes in cloud forests.
Tags: nitrogen , soil , elem

Altitudinal changes in leaf hydraulic conductance across five Rhododendron species in eastern Nepal
Tree Physiology (2016)
Haruhiko Taneda, Dhan Raj Kandel, Atsushi Ishida, Hiroshi Ikeda

This study investigated altitudinal changes in leaf-lamina hydraulic conductance (KL) and leaf morphological traits related to KL using five Rhododendron species growing at different altitudes (2500–4500 m above sea level) in Jaljale Himal region in eastern Nepal. Sun leaves were collected from the highest and the lowest altitude populations of each species, and KL was measured with a high pressure flow meter method. Leaf-lamina hydraulic conductance ranged from 7.7 to 19.3 mmol m−2 s−1 MPa−1 and was significantly positively correlated with altitude. The systematic increase with altitude was also found in KL, leaf nitrogen content and stomatal pore index. These relationships suggest that plants from higher-altitude habitats had a large CO2 supply to the intercellular space in a leaf and high CO2 assimilation capacity, which enables efficient photosynthesis at high altitude. The variation in KL was associated with the variation in several leaf morphological traits. High KL was found in leaves with small leaf area and round shape, both of which result in shorter major veins. These results suggest that the short major veins were important for efficient water transport in unlobed leaves of Rhododendron species. The extent of lignification in bundle sheaths and bundle sheath extension was associated with KL. Lignified compound primary walls inhibit water conduction along apoplastic routes. All species analyzed had heterobaric leaves, in which bundle sheath extensions developed from minor veins, but strongly lignified compound primary walls were found in Rhododendron species with low KL. It is still unclear why cell walls in bundle sheath at minor veins were markedly lignified in Rhododendron species growing at lower altitude. The lignified cell wall provides a high pathogenic resistance to infection and increases the mechanical strength of cell wall. The data imply that lignified bundle sheath may provide a trade-off between leaf hydraulic efficiency and leaf mechanical toughness or longevity.

N/P imbalance as a key driver for the invasion of oligothrophic dune systems by a woody legume
Oikos (2016)
Florian Ulm, Christine Hellmann, Cristina Cruz, Cristina Máguas

Oligotrophic ecosystems, previously considered to be more resilient to invasive plants, are now recognised to be highly vulnerable to invasions. In these systems, woody legumes show belowground ecosystem engineering characteristics that enable invasion, however, the underlying processes are not well understood. Using a Portuguese primary dune ecosystem as an oligotrophic model system, belowground biomass pools, turnover rates and stoichiometry of a native (Stauracanthus spectabilis) and an invasive legume (Acacia longifolia) were compared and related to changes in the foliage of the surrounding native (Corema album) vegetation. We hypothesized that the invasive legume requires less phosphorus per unit of biomass produced and exhibits an enhanced nutrient turnover compared to the native vegetation, which could drive invasion by inducing a systemic N/P imbalance. Compared with the native legumes, A. longifolia plants had larger canopies, higher SOM levels and lower tissue P concentrations. These attributes were strongly related to legume influence as measured by increased foliar N content and less depleted δ15N signatures in the surrounding C. album vegetation. Furthermore, greater root and rhizosphere mass and increased nutrient turnover in the rhizosphere of the invader were associated with depleted foliar P in C. album. Our results emphasize that while A. longifolia itself maintains an efficient phosphorus use in biomass production, at the same time it exerts a strong impact on the N/P balance of the native system. Moreover, this study highlights the engineering of a belowground structure of roots and rhizosphere as a crucial driver for invasion, due to its central role in nutrient turnover. These findings provide new evidence that, under nutrient-limited conditions, considering co-limitation and nutrient cycling in oligotrophic systems is essential to understand the engineering character of invasive woody legumes.
Tags: nitrogen , soil , ecol , elem

Soil organic carbon stocks in estuarine and marine mangrove ecosystems are driven by nutrient colimitation of P and N
Ecology and Evolution (2016)
Christian Weiss, Joanna Weiss, Jens Boy, Issi Iskandar, Robert Mikutta, Georg Guggenberger

Mangroves play an important role in carbon sequestration, but soil organic carbon (SOC) stocks differ between marine and estuarine mangroves, suggesting differing processes and drivers of SOC accumulation. Here, we compared undegraded and degraded marine and estuarine mangroves in a regional approach across the Indonesian archipelago for their SOC stocks and evaluated possible drivers imposed by nutrient limitations along the land-to-sea gradients. SOC stocks in natural marine mangroves (271–572 Mg ha−1 m−1) were much higher than under estuarine mangroves (100–315 Mg ha−1 m−1) with a further decrease caused by degradation to 80–132 Mg ha−1 m−1. Soils differed in C/N ratio (marine: 29–64; estuarine: 9–28), δ15N (marine: −0.6 to 0.7‰; estuarine: 2.5 to 7.2‰), and plant-available P (marine: 2.3–6.3 mg kg−1; estuarine: 0.16–1.8 mg kg−1). We found N and P supply of sea-oriented mangroves primarily met by dominating symbiotic N2 fixation from air and P import from sea, while mangroves on the landward gradient increasingly covered their demand in N and P from allochthonous sources and SOM recycling. Pioneer plants favored by degradation further increased nutrient recycling from soil resulting in smaller SOC stocks in the topsoil. These processes explained the differences in SOC stocks along the land-to-sea gradient in each mangrove type as well as the SOC stock differences observed between estuarine and marine mangrove ecosystems. This first large-scale evaluation of drivers of SOC stocks under mangroves thus suggests a continuum in mangrove functioning across scales and ecotypes and additionally provides viable proxies for carbon stock estimations in PES or REDD schemes.
Tags: carbon , nitrogen , soil , ecol , elem