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:

Biochar nutrient availability rather than its water holding capacity governs the growth of both C3 and C4 plants
Journal of Soils and Sediments (2016)
Yuzhe Wang, Lianwei Zhang, Hong Yang, Guijun Yan, Zhihong Xu, Chengrong Chen, Dongke Zhang

Purpose: Biochar has been suggested as a soil conditioner to improve soil fertility and crop productivity while simultaneously mitigate global climate change by storing carbon in the soil. This study investigated the effect of pine (Pinus radiata) biochar application on soil water availability, nitrogen (N) and carbon (C) pools and growth of C3 and C4 plants. Materials and methods: In a glasshouse pot trial, a pine biochar (untreated) and nutrient-enriched pine biochar were applied to a market garden soil with C3 (Spinacia oleracea L.) and C4 (Amaranthus paniculatus L.) plants at rates of 0, 1.0, 2.0, and 4.0 % (w/w). Plant biomass, soil pH, moisture content, water holding capacity (WHC), hot water extractable organic C (HWEOC), and total N (HWETN), total C and N, and their isotope compositions (δ 13C and δ 15N) of soils and plants were measured at the end of the experimentation. Results and discussion: The soil moisture content increased while plant biomass decreased with increasing untreated biochar application rates. The addition of nutrient-enriched biochar significantly improved plant biomass in comparison to the untreated biochar addition at most application rates. Biochar application also increased the levels of labile organic C and N pools as indicated by HWEOC and HWETN. Conclusions: The results suggested that the addition of pine biochar significantly improved soil water availability but not plant growth. The application of nutrient-enriched pine biochar demonstrated that the growth of C3 and C4 plants was governed by biochar nutrient availability rather than its water holding capacity under the pot trial condition.
Tags: carbon , nitrogen , soil , elem

δ13C and Water Use Efficiency in the Glucose of Annual Pine Tree Rings as Ecological Indicators of the Forests in the Most Industrialized Part of Poland
Water, Air, & Soil Pollution (2016)
Barbara M. Sensuła

In this study, stable carbon isotope ratios in the glucose samples were extracted from annual pine tree rings as bio-indicators of contemporary environmental changes in heavily urbanized areas. The sampling sites were located in close proximity to point source pollution emitters, such as a heat and power plant “Łaziska” and steelworks “Huta Katowice” in Silesia (Poland). The analysed samples covered the time span from 1975 to 2012 AD, the time period of the development of industrialization and the modernization in the industrial sector in Poland, similarly as in Eastern Europe. This modernization was connected with EU legislation and the implementation of restrictive governmental regulations on emissions. The carbon isotope discrimination has been proposed as a method for evaluating water use efficiency. The measurements of carbon isotopes were carried out using the continuous flow isotope ratio mass spectrometer coupled to the elemental analyser. The δ13C values were calibrated relative to the C-3 and C-5 international standards. Diffuse air pollution caused the variation in δ13C and iWUE (the ratio between CO2 assimilation and stomatal conductance) dependency on the type of emitter and some local effects of other human activities. In this study, the first results of water use efficiency in glucose are presented. In the period of time from 1975 to 2012, the water use efficiency values increased from 98 to 122 μmol/mol.

Apical dominance ratio as an indicator of the growth conditions favouring Abies alba natural regeneration under Mediterranean environment
European Journal of Forest Research (2016)
Francesco Ripullone, Tiziana Gentilesca, Marco Lauteri, Angelo Rita, Anna Rita Rivelli, Aldo Schettino, Marco Borghetti

As reported in several studies, the presence of Abies alba Mill (silver fir) has been declining throughout its natural range over a large part of mountainous belt in the Mediterranean area. In such a context, regeneration establishment depends mainly on the occurrence of a suitable combination of water and light availability. Thus, before planning any forest management practice, it is essential to investigate on the optimal microclimate conditions influencing the success of natural regeneration of silver fir. To this aim, changes in growth and photosynthesis together with C, N and O isotope compositions have been investigated on silver fir naturally recruited saplings, growing in mixed stands with Fagus sylvatica on Apennine mountains (southern Italy). The apical dominance ratio (ADR, ratio between apical shoot length and length of first whorl lateral twigs) has been used as an indicator for microclimate conditions in which saplings grow. Based on the range of ADR values (i.e. from 0.10 to 1.30), saplings were distributed in four classes. As expected, increases in height, root collar diameter and radial growth correspond to enhancing ADR values, gaining the optimal conditions in class IV. This latter also displayed the best performance in terms of maximum CO2 assimilation at saturating light (A max) and water-use efficiency as assessed by carbon isotope discrimination analysis. Conversely, class I and II seem to display the highest performance in terms of CO2 respiration rate (R d) and absolute water loss saving as assessed by the application of oxygen isotopes. We conclude that, in relatively mild Mediterranean areas, forest managers should promote silvicultural treatments favouring light conditions and migration of saplings towards class IV of ADR. This class represents the optimal microclimate for regeneration establishment of silver fir.
Tags: carbon , nitrogen , oxygen , soil , elem

Increased water use efficiency does not prevent growth decline of Pinus canariensis in a semi-arid treeline ecotone in Tenerife, Canary Islands (Spain)
Annals of Forest Science (2016)
Patricia Brito, Thorsten E. E. Grams, Rainer Matysssek, Maria S. Jimenez, Agueda M. Gonzalez-Rodríguez, Walter Oberhuber, Gerhard Wieser

Intrinsic water use efficiency of Pinus canariensis (Sweet ex Spreng.) growing at a semi-arid treeline has increased during the past 37 years. Tree ring width by contrast has declined, likely caused by reduced stomatal conductance due to increasing aridity. Context Rising atmospheric CO2 concentration (C a ) has been related to tree growth enhancement accompanied by increasing intrinsic water use efficiency (iWUE). Nevertheless, the extent of rising C a on long-term changes in iWUE and growth has remained poorly understood to date in Mediterranean treeline ecosystems. Aims This study aimed to examine radial growth and physiological responses of P. canariensis in relation to rising C a and increasing aridity at treeline in Tenerife, Canary Islands, Spain. Methods We evaluated temporal changes in secondary growth (tree ring width; TRW) and tree ring stable C isotope signature for assessing iWUE from 1975 through 2011. Results Precipitation was the main factor controlling secondary growth. Over the last 36 years P. canariensis showed a decline in TRW at enhanced iWUE, likely caused by reduced stomatal conductance due to increasing aridity. Conclusion Our results indicate that increasing aridity has overridden the potential CO2 fertilization on tree growth of P. canariensis at its upper distribution limit.

Compound‐specific amino acid 15N stable isotope probing of nitrogen assimilation by the soil microbial biomass using gas chromatography/combustion/isotope ratio mass spectrometry
Rapid Communications in Mass Spectrometry (2016)
A. F. Charteris, T. D. J. Knowles, K. Michaelides, R. P. Evershed

Rationale Organic nitrogen (N) greatly exceeds inorganic N in soils, but the complexity and heterogeneity of this important soil N pool make investigations into the fate of N-containing additions and soil organic N cycling challenging. This paper details a novel approach to investigate the fate of applied N in soils, generating quantitative measures of microbial assimilation and of newly synthesized soil protein. Methods Laboratory incubation experiments applying 15N-ammonium, 15N-nitrate and 15N-glutamate were carried out and the high sensitivity and selectivity of gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) exploited for compound-specific 15N stable isotope probing (15N-SIP) of extracted incubation soil amino acids (AAs; as N-acetyl, O-isopropyl derivatives). We then describe the interpretation of these data to obtain a measure of the assimilation of the applied 15N-labelled substrate by the soil microbial biomass and an estimate of newly synthesised soil protein. Results The cycling of agriculturally relevant N additions is undetectable via bulk soil N content and δ15N values and AA concentrations. The assimilation pathways of the three substrates were revealed via patterns in AA δ15N values with time, reflecting known biosynthetic pathways (e.g. ammonium uptake occurs first via glutamate) and these data were used to expose differences in the rates and fluxes of the applied N substrates into the soil protein pool (glutamate > ammonium > nitrate). Conclusions Our compound-specific 15N-SIP approach using GC/C/IRMS offers a number of insights, inaccessible via existing techniques, into the fate of applied 15N in soils and is potentially widely applicable to the study of N cycling in any soil, or indeed, in any complex ecosystem.
Tags: nitrogen , soil , elem

Plant-mediated rhizospheric interactions in maize-pigeon pea intercropping enhance soil aggregation and organic phosphorus storage
Plant and Soil (2016)
Gina Garland, E. K. Bünemann, A. Oberson, E. Frossard, J. Six

Background and aims In Malawi, strategies are being sought to boost maize production through improvements in soil fertility. This study assessed the impact of intercropping maize (Zea mays) with pigeon pea (Cajanus cajan) in Lixisols of Malawi on yield, biological N fixation, soil aggregation, and P forms within soil aggregates. Methods Maize and pigeon pea were grown intercropped in pots, with varying degrees of root interaction in order to understand the relative importance of biochemical versus physical rhizospheric interactions. Following harvest, soils were separated into aggregate fractions using wet-sieving, and the nutrient content of all fractions was assessed. Results The proportion of macroaggregates and microaggregates increased by 52 and 111%, respectively, in the intercropping treatment compared to sole maize, which significantly increased organic P storage in the microaggregates of intercropped compared to sole maize (84 versus 29 mg P kg−1, respectively). Biologically fixed N increased from 89% in the sole pigeon pea to 96% in the intercropped system. Conclusions Intercropping maize with pigeon pea can have a significant and positive impact on soil structure as well as nutrient storage in these high P-sorbing soils. This is caused primarily by physical root contact and to a lesser degree by biochemical activities.

A Spatially Explicit Dual-Isotope Approach to Map Regions of Plant-Plant Interaction after Exotic Plant Invasion
PLOS ONE (2016)
Christine Hellmann, Christiane Werner, Jens Oldeland, MRT Dale, M-J Fortin, WW Hargrove, FM Hoffman, J Kumar, RT Mills, FM Hoffman, WW Hargrove, MP Ward, TE Carpenter, S Brooker, S Clarke, JK Njagi, S Polack, B Mugo, B Estambale, F Tanser, T Bärnighausen,

Understanding interactions between native and invasive plant species in field settings and quantifying the impact of invaders in heterogeneous native ecosystems requires resolving the spatial scale on which these processes take place. Therefore, functional tracers are needed that enable resolving the alterations induced by exotic plant invasion in contrast to natural variation in a spatially explicit way. 15N isoscapes, i.e., spatially referenced representations of stable nitrogen isotopic signatures, have recently provided such a tracer. However, different processes, e.g. water, nitrogen or carbon cycles, may be affected at different spatial scales. Thus multi-isotope studies, by using different functional tracers, can potentially return a more integrated picture of invader impact. This is particularly true when isoscapes are submitted to statistical methods suitable to find homogeneous subgroups in multivariate data such as cluster analysis. Here, we used model-based clustering of spatially explicit foliar δ15N and δ13C isoscapes together with N concentration of a native indicator species, Corema album, to map regions of influence in a Portuguese dune ecosystem invaded by the N2-fixing Acacia longifolia. Cluster analysis identified regions with pronounced alterations in N budget and water use efficiency in the native species, with a more than twofold increase in foliar N, and δ13C and δ15N enrichment of up to 2‰ and 8‰ closer to the invader, respectively. Furthermore, clusters of multiple functional tracers indicated a spatial shift from facilitation through N addition in the proximity of the invader to competition for resources other than N in close contact. Finding homogeneous subgroups in multi-isotope data by means of model-based cluster analysis provided an effective tool for detecting spatial structure in processes affecting plant physiology and performance. The proposed method can give an objective measure of the spatial extent of influence of plant-plant interactions, thus improving our understanding of spatial pattern and interactions in plant communities.
Tags: carbon , nitrogen , soil , elem

Particulate organic matter higher concentrations, terrestrial sources and losses in bottom waters of the turbidity maximum, Delaware Estuary, U.S.A.
Estuarine, Coastal and Shelf Science (2016)
Anna L. Hermes, Elisabeth L. Sikes

The pathway and fate of land-derived suspended particulate organic matter (POM) as it passes through estuaries remains a poorly constrained component of coastal carbon dynamics. The δ13C of bulk POC (particulate organic carbon; δ13C-POC) and n-alkane biomarkers were used to assess the proportion of algal- and land- (vascular plant) derived POM through the Delaware Estuary, on five cruises in 2010–2011. We found that POC was highly correlated with suspended sediment concentrations (SSC). Higher SSC was present in bottom waters, causing bottom waters to have consistently higher concentrations of POC than surface waters, with the bottom waters of the estuarine turbidity maximum (ETM) exhibiting maximum POC concentrations for all seasons and flow regimes. Algal-derived POM seasonally affected the δ13C-POC and n-alkane geochemical signatures of surface waters, whereas bottom waters were dominated by vascular plant-derived POM. δ13C-POC results suggested a gradual loss in vascular plant-derived POM between the riverine and marine endmember stations. In contrast, n-alkane concentrations peaked in bottom waters of the ETM at 2–5 times surface water concentrations. Indices of the relative proportions of n-alkanes and n-alkanes as a proportion of total POC had their levels decrease considerably downstream of the ETM. These biomarker analyses suggest enhanced loss of land-derived material across the ETM and that the ETM acts as a geochemical filter for vascular plant-derived POM in a classic well mixed estuary.
Tags: carbon , soil , elem

Interactions between biochar and soil organic carbon decomposition: Effects of nitrogen and low molecular weight carbon compound addition
Soil Biology and Biochemistry (2016)
Xinyu Jiang, Michelle L. Haddix, M. Francesca Cotrufo

Conversion of plant residues to biochar is an attractive strategy for atmospheric CO2 emission mitigation and soil carbon (C) storage enhancement. However, our understanding of the factors controlling biochar persistence in soil is still limited, and generally based on biochar chemical recalcitrance. In addition to its chemical properties, biochar C decomposition might be limited by other factors, such as N and low molecular weight C compounds (LMW-C) availability. We presented results from a laboratory incubation experiment, where 4 atom% 13C enriched biochar was added at a rate of 10% by weight to two different soils, with or without N and LMW-C additions. Sucrose was used as the LMW-C, and its 13C natural abundance composition was manipulated, by mixing sucrose from sugar beet (C3) and from sugar cane (C4), to make it equal or dissimilar to the native soil organic carbon (SOC). This approach allowed partitioning the biochar-C from the ‘soil + LMW-C’ in the biochar amendment units and the LMW-C from SOC in the non-biochar amended units. Biochar-C, SOC and LMW-C were traced into CO2 throughout the 112 day incubation and into microbial biomass C (MBC) and dissolved organic C (DOC) at the end of the incubation. Compared to LMW-C addition, N was a more significant factor stimulating biochar-C mineralization and biochar-C incorporation in microbial biomass. Biochar significantly decreased SOC mineralization and this negative effect was not influenced by N and LMW-C additions. Biochar addition promoted formation of SOC derived DOC; however, DOC accumulated in soil rather than being mineralized to CO2. According to our study, biochar was confirmed to be highly resistant to decomposition, and N or LMW-C availability did not affect the overall soil C sequestration potential of biochar. Biochar effects on soil DOC dynamics will need to be farther investigated in the field to better constrain the overall C sequestration potential of biochar.
Tags: carbon , soil , elem

Peat porewaters have contrasting geochemical fingerprints for groundwater recharge and discharge due to matrix diffusion in a large, northern bog-fen complex
Journal of Hydrology (2016)
Zeno F. Levy, Donald I. Siegel, Paul H. Glaser, Scott D. Samson, Soumitri S. Dasgupta

Although northern peatlands represent a globally significant reservoir for carbon, considerable uncertainty exists concerning solute transport systems within large (>1000 km2) peat deposits. We therefore delineated geochemical gradients linked to groundwater recharge and discharge along a 6 km transect within the 1200 km2 Red Lake Peatland of northwestern Minnesota. We used ratios of Ca/Mg and 87Sr/86Sr to distinguish discharge of calcareous groundwater (∼1.4 and 0.7155, respectively) to the peatland from the mineral substratum along a topographic gradient from a bog crest downslope to an internal fen water track and bog islands. In contrast, the stable isotopes of the porewaters (δ18O from -12.8 ‰ to -7.8 ‰) show that the active pore-spaces in these peat profiles has been flushed by recharge from the near-surface peat. We hypothesize that back-diffusion of groundwater-derived solutes from the peat matrix to active pore-spaces has allowed the geochemical signal from paleo-hydrogeologic discharge to persist into the current regime of dilute recharge. This effect has not been observed previously on the landform-scale and has important implications for carbon cycling in peatlands.
Tags: hydrogen , oxygen , soil , gashead