Comparison of methodologies for determining the carbon content in wood

New procedures seek to subsidize studies on biomass and carbon in forests and wood, mainly of tropical species. Thus, the work aimed to compare four methods of carbon determination in wood. A pre-dried sample of tropical wood was prepared and previously ground. In this sample, the carbon content was determined, applying four different methodologies, namely: conversion of organic matter, volumetric method, colorimetric method and dry combustion (LECO). The Tukey test was performed to determine the difference between the carbon levels obtained by each method. As a result, all methods differed statistically from each other: the colorimetric method underestimated the levels of organic carbon in a tropical wood; although widely used, the volumetric method has become obsolete; and the organic matter conversion method requires specific conversion factors for each material. So, from the environmental point of view and accuracy in obtaining data, the dry combustion method, in addition to being the closest to the standard, is also the one that generates less waste, being the most suitable to determinate carbon in wood.

Features of determination of native carbon in carbon-containing rocks on the analyzer of carbon and water

The largest deposits of graphite in the Russian Federation are located in the Middle and South Urals. However, several manifestations, e.g., «Opytnyi» sector, which have not yet been placed under production, require substantiation of the strategies for their integrated development, which, in turn, requires gaining the reliable data on the content of graphite in carbon-containing rocks. A method for simultaneous determination of organic and native carbon in carbon-containing rocks using an ELTRA CW MULTIPHASE carbon and water analyzer is proposed. The method is based on the combustion of organic carbon (coal, shale) in a stream of oxygen at 550°C and native carbon (graphite) in the temperature range 550 – 1000°C with subsequent IR-spectroscopic determination of the content of gaseous carbon dioxide. The interfering effect of magnesium carbonate and calcium carbonate on the determination of organic and native carbon was taken into account in the calculations. The carbonate content was determined using a separate sample in a nitrogen flow by decomposition of magnesium carbonate at 550°C and calcium carbonate within a temperature range of 550 – 1000°C. The content of chemically bound water in the composition of the minerals of carbon-containing rocks, was determined simultaneously with carbon. The only one type of carbon — graphite — was observed in the studied samples of the carbon-containing rock from «Opytnyi». The different combustion capacity of graphite was revealed: some of the crystals almost completely burn out at a temperature below 800°C and others above 800°C, which suggests the presence of cryptocrystalline and explicit crystalline graphite in the rocks. The developed method is rapid and corresponds in accuracy to the method for native carbon determination ±0.27 C % – 0.01 C % developed and approved by the Research Council for Analytical Methods of Research (NSAM).

Fourier-transzformációs közép-infravörös spektroszkópia alapú szervesanyag-tartalom becslés tábla szintű reprezentativitás-vizsgálata kemometriai módszerekkel

Szervesszén térképezést segítő módszertani kutatásként vizsgáltuk egy szántóföldi művelés alatt álló terület, 3 mélységből származó mintáinak MIR reflektanciáját, illetve szervesszén tartalmát (Walkley-Black). Ezt követően a spektroszkópia mérések eredményeit használtuk a talaj szervesszén-mennyiségének (TOC %) becslésére. Tettük ezt 3 mintakijelölési módszer (Kennard-Stone Sampling - KSS, K-means Sampling - KMS, Latin Hypercube Sampling - LHS) bevonásával, az így kijelölt kalibrációs mintákkal a PLSR modell segítségével becslést végeztünk az adathalmaz további értékeire. Annak érdekében, hogy tábla szintű szervesszén meghatározás során teszteljük becslési pontosságukat, a modellek reprezentativitását – különböző validációs/kalibrációs arány esetén – statisztikai mutatókkal (R2, RMSE) ellenőriztük.Az eredményekben részleteiben vizsgáltuk a különböző becslési modellek reakcióját eltérő arányú kalibráció és validáció esetén. A modellek R2 és RMSE értékei alapján kijelöltük, hogy mely modellek működtek pontosan még alacsony kalibráció esetén is, illetve abszolút értelemben véve melyik modell volt leghatékonyabb.Az összehasonlítás eredményeként kijelenthető, hogy az általunk vizsgált talajkörülmények között a 30% alatti, valamint a 70% feletti mintaszámú kalibráció a mintakijelölési módszerek megbízhatóságának ingadozását eredményezte. Az összes minta 30%-val történő kalibráció esetén legjobb eredményt a KSS adta, így ez tekinthető a leggazdaságosabb módszernek. Az abszolút értékben vett legkisebb hibát a K-means sampling eredményezte, a minták 90%-val történő kalibrációt követően.Kijelenthető, hogy az alkalmazott módszertan esetünkben alkalmas volt – a reprezentativitás megtartása mellett – a szükséges minták számának, ergo a táblaszintű szervesszén-felmérés költségeinek csökkentésére. Továbbá a mintakijelölési módszerek becslési hatékonyságának összehasonlítására is megfelelt az általunk alkalmazott statisztikai vizsgálat. A módszertan a jövőben kiinduló alapja lehet hasonló jellegű kutatásoknak, valamint tábla szintű szervesszéntérképek elkészítésének. A szélesebb körű alkalmazást megelőzően a modelleket nagyobb varianciájú adathalmazok esetén is tesztelni szükséges.Within the framework of the present research, we mapped the organic carbon content of an arable area, during which we measured the MIR reflectance and organic carbon content (Walkley-Black) of the soil samples collected from the area at three different depths. Subsequently, the results of spectroscopic measurements were used to improve the estimation of the soil organic carbon content (TOC %). Three sample selection models were involved (KSS, KMS, LHS), and with the selected calibration samples, we estimated the additional values of the data set using the PLSR model. In order to test the accuracy of estimation for a table-level organic carbon determination, the representativeness level of the models was checked with statistical indicators (R2, RMSE) at different validation / calibration ratios.In the results, we thoroughly examined the response of different estimation models with different ratios of calibration and validation. Based on the R2 and RMSE values of the models, we determined which models worked precisely even at low calibration, and in absolute terms, which model was the most efficient.As a result of the comparison, it can be stated that under the soil conditions we examined, calibration with a sample number below 30% and above 70% caused significant fluctuations in the reliability of the sampling methods. Kennard-Stone sampling (KSS) gave the most precise results for calibration with 30% of all samples, thus it is considered the most economical method. The smallest error overall was given by K-means sampling after calibration of 90% of the samples.It can be stated that the methodology used in this study was suitable to reduce the samples required for analysis - while maintaining representativeness - therefore reducing the costs of the field-level organic carbon survey.Furthermore, the statistical analysis we used to compare the estimation efficiency of the sampling methods was also appropriate. The methodology we use may be the basis for similar research in the future, as well as for the production of table-level organic carbon maps. Prior to wider application, models also need to be tested for higher variance datasets.

Compost making from refuse sourced from Kano Metropolitan, Kano State, Nigeria

Municipal-solid waste (MSW) in towns and cities of Nigeria are either allowed to rot or burnt which causes the release of greenhouse gases in the process. The heap of uncollected refuse in Kano municipal causes serious health hazards and menacing public disorder. This research investigated the Kano municipal refuse for compost making, instead of using waste disposal technique such as landfilling. Refuse samples from Dorayi/Zage and Rimin Kira refuse dumping sites Kano Municipal, Kano State Nigeria were collected. The refuse samples were sorted and all the non-biodegradables materials were removed. A compost was made from Sample N in 20 days while 9 days was required to produce a compost from sample P. Kjeldahl Nitrogen determination method and simple procedure for total carbon determination method were used to determine the percentages of nitrogen and carbon in the samples. The results have shown that, the percentages of nitrogen in the samples were found to be 1.64% for sample N and 1.71% for sample P. The percentages of carbon in the samples are 6.8% for sample N and 6.3% for sample P. The C/N ratio for sample N was 4.15:1 and that of sample P was 3.69:1.Kano municipal refuse contains a lot of organic wastes which are very difficult to incinerate. Therefore, Composting method is the best option for the disposal of the refuse rather than directly dumped in the streets.

Eucalypt Clonal Hybrid Influences the Carbon Amount of Below-Ground Biomass in Oxisol, Brazil

The objective of this study was to evaluate whether there is an influence of different clonal hybrids of Eucalyptus urophylla on the carbon concentration and amount in below-ground biomass in trees cultivated in Oxisol, Brazil. Stumps and roots of three different eucalypt hybrid clones, AEC 0144, AEC 0223, and VM01, were selected, weighed immediately after being removed from the ground, and sampled for carbon determination and moisture content at the laboratory. The Shapiro-Wilk and Bartlett tests were used to evaluate data distribution and the homogeneity of variances, respectively. Analysis of variance (ANOVA) complemented by the Scott-Knott test was used to evaluate the effects of specie/hybrid on the below-ground biomass (dry matter) and carbon amount per stump. The hybrid type of Eucalyptus urophylla does not influence the carbon concentration; however, there is a difference in below-ground biomass production and carbon amount with it being higher for Eucalyptus urophylla × Eucalyptus camaldulensis when compared to the species Eucalyptus urophylla and hybrid Eucalyptus urophylla × Eucalyptus grandis.