Gunnar Ogner

31P-NMR spectra of humic acids: A comparison of four different raw humus types in Norway

Abstract Humic acids have been prepared from four Norwegian forest soils, namely crust, felty, greasy and granular raw humus. 31P-NMR spectra demonstrated the presence of a variety of phosphorus esters and diesters in all the humic acids investigated. Alkylphosphonic acids and/or esters were present in humic acids from crust and felty raw humus.

A comparison of four different raw humus types in Norway using chemical degradations and CPMAS 13C NMR spectroscopy

Abstract Crust, felty, greasy and granular raw humus were analysed by wet chemical methods and by 13C NMR. The amounts of amino acids, monosaccharides and aliphatic dicarboxylic acids were determined and the yields compared with the 13C NMR spectra. Protein carbon constitutes 9–13%, polysaccharide carbon 8–19% dicarboxylic acids 1–2% and free carboxylic acid groups 2–4% of the total sample carbon. Degradation of greasy raw humus yields half the amount of monosaccharides and twice the amount of aliphatic dicarboxylic acids found in the other raw humus types. This result is confirmed by 13C NMR. Forty to fifty percent of the soil carbon is unaccounted for among the degradation products identified. Based on estimates of 13C NMR data, the unknown part consists of aliphatic carbon, where the C:O ratio ranges between 1 1.1:1 and 1.8:1. All data indicate great similarity between crust and felty raw humus, whereas greasy raw humus differs clearly from those two. Granular raw humus gives approximately the same amount of degradation products as crust and felty raw humus but differs in its 13C NMR spectrum. The relative proportions of all compounds identified, including aliphatic dicarboxylic acids, are approximately constant, indicating a difference in degree rather than kind of the four raw humus types.

No general effect of ozone on foliar nutrient concentrations in mature scions of grafted Picea abies trees

The effect of ozone (< 10, 200, or 400 microg m(-3)), on foliar nutrient concentrations of Picea abies were determined by fumigating potted grafts from mature trees (> 55 and 125 years), representing six clones, in open-top chambers at two locations in Norway. The concentration of nutrients in needles of grafted plants were significantly affected by clone and location. Generally, the concentrations of nutrients were not affected by ozone, but a significant increase in the concentrations of potassium and iron in two of the clones were found. These two clones were the only ones injured (yellow needles) by the fumigation.

Analysis of the carbohydrates of fulvic and humic acids as their partially methylated alditol acetates.

Abstract The carbohydrates of humic and fulvic acids were investigated using methylation analysis. The humic acid contains slightly more rhamnose and fucose than does fulvic acid and raw humus, the arabinose content of fulvic acid is less when compared to that of humic acid and raw humus. In addition to the common aldoses, the unmethylated humic samples contained small amounts of 2,3-di-O-methyl-rhamnose, 2,3-di-O-methyl-fucose, 2-O-methyl-rhamnose, 4-O-methyl-rhamnose, 3-O-methyl-rhamnose, 3-O-methyl-fucose and a 6-deoxy-hexose. The “average” polysaccharides of humic and fulvic acids are highly branched and extremely complex in composition. They contain at least 34 different aldose building units in addition to O-methyl-, di-O-methyl-, and amino-derivatives, ketoses and uronic acids. On average, the polysaccharides of fulvic acid are slightly less branched than those of humic acid, as indicated by a higher content of the chain unit 2,4,6-tri-O-methyl-glucose in the hydrolysate of methylated samples. In total, the polysaccharides of the different fractions are of great similarity. The common aldoses all participate as 1–2 different terminating units, 1–3 different chain units, and the hexoses as 2–4 different branching units. In methylated samples, only one 6-deoxy-hexose branching unit is found, 3-O-methyl-rhamnose, and no pentose unit. 3-O-methyl-rhamnose may also be a branching unit in unmethylated samples. The most important terminating units are 2,3,4,6-tetra-O-methyl-gluco- plus 2,3,4,6-tetra-O-methyl-manno- (15%), 2,3,4-tri-O-methyl-xylo- (6%) and 2,3,4-tri-O-methyl-fuco-pyranose (5%) units. Terminal 2,3,5-tri-O-methyl-xylo-, 2,3,5-tri-O-methyl-arabino- and 2,3,5,6-tetra-O-methyl-galacto-furanosidic units are also present (2.7-1.2%). The most important chain units are 2,4,6-tri-O-methyl-glucose (11–15%), 2,3-(or 3,4-) di-O-methylxylose (6.6%) and 3,4,6-tri-O-methyl-galactose (3.3%). The individual polysaccharides of the humic and fulvic acids are also of high complexity and most probably are present in a large number of varieties. All polysaccharides are strongly associated with the humic matrix, i.e., the aromatic and aliphatic polymeric structure composing the major part of the humic and fulvic acids.

Pigment composition in Norway spruce needles suffering from different types of nutrient deficiency

Abstract Concentrations of pigments in needles of yellowish Norway spruce [Picea abies (L.) Karst] trees suffering from either N, Mg or K deficiency in field sites in southeast Norway are reported. The yellowish trees had a considerably lower (roughly 50%) pigment concentration, as well as a lower chlorophyll/carotenoid ratio, compared to green trees within the same sites. Yellowing was interpreted as a general bleaching of colour, as well as a slight turn from the green (chlorophylls) towards yellow (lutein). Concentrations of pigments were highly intercorrelated. N deficiency was especially associated with low α-carotene concentrations. This was interpreted as α-carotene being the most sensitive pigment to stress. However, this pigment might be specifically sensitive to N deficiency. Carbohydrate concentrations were slightly higher in yellowish trees.

Glyphosate application in forest—ecological aspects

The vegetation of four different forest soils in lysimeters was killed with glyphosate. New vegetation became established in some of the treated lysimeters the year after application. During this year, leachates from lysimeters without vegetation had nitrate concentrations up to 4.5 mM NO3 − in the fall. A corresponding increase in leached cations was evident. The settlement of one raspberry or one willow herb in treated lysimeters effectively hindered nitrate leaching as soon as the plants were sufficiently large (in mid‐summer). As plants became established in treated lysimeters, the chemistry of these leachates approached those of untreated lysimeters. The absolute effect of even small plants in controlling water regime and water chemistry was evident.

Determination of CH4, CO2 and N2O in air samples and soil atmosphere by gas chromatography mass spectrometry, GC-MS

A method for determination of the climate gases CH4, CO2 and N2O in air samples and soil atmosphere was developed using GC-MS. The method uses straightforward gas chromatography (separation of the gases) with a mass spectrometric detector in single ion mode (specific determination). The gases were determined with high sensitivity and high sample throughput (18 samples h(-1)). The LOD (3sigma) for the gases were 0.10 micro L L(-1) for CH4, 20 microL L(-1) for CO2 and 0.02 microL L(-1) for N2O. The linear range (R2 = 0.999) was up to 500 microL L(-1) for CH4, 4000 microL L(-1) for CO2 and 80 microL L(-1) for N2O. The samples were collected in 10 mL vials and a 5 microL aliquot was injected on column. The method was tested against certified gas references, the analytical data gave an accuracy within +/-5% and a precision of +/-3%. The presence of < or = 10% by volume of C2H2 (often used experimentally to prevent N2 formation from N2O) did not interfere with detection for the targeted trace gases.

Automatic determination of boron in water samples and soil extracts

Abstract An automatic fluorimetric method for the determination of boron in water samples and soil extracts is described. Automatic wet digestion of the samples by UV irradiation, eliminates interference by organic matter. An ion exchange resin incorporated in the system removed interference caused by metal cations. The analysis is performed at pH 7. The linear working range is 0 ‐ 3 mg 1−1 of boron with a detection limit of 0.01 mg 1−1 of boron. The capacity of the method is a minimum of 20 samples per hour and the precision is s = 0.004 mg 1−1 of boron in the range 0 ‐ 3 mg 1−1 of boron.

No general ozone-specific indicator among the hexane- and dichloromethane-soluble components of Picea abies needles exposed to ozone in open-top chambers

The effect of ozone (< 10, 200 or 400 microg m(-3) on hexane- and dichloromethane-soluble components of Picea abies needles was determined by fumigating potted grafts from mature trees. The trees (>55 and 125 years, 2.5 m high), representing six clones of Norway spruce, were fumigated in open-top chambers at two locations in Norway for one growth season. The needles were extracted with hexane and dichloromethane; 142 compounds from the hexane extract and 164 silylated compounds from the dichloromethane extract were analysed by gas chromatography although no identifications were made. The concentration of four of the compounds from the hexane extract changed with ozone dose in a way that made them promising as indicators, but the present analytical method could not verify this possibility. None of the other 302 compounds qualified as a general indicator of ozone stress in Norway spruce, as none changed its concentration with ozone dose consistently in all romets of all clones. Most of the variation in the experiment is mainly attributable to genetic variation and to climate.

Permanganate oxidation of methylated and non-methylated aquatic humus in Norway

The chemical composition of aquatic humus was investigated by permanganate oxidation. Both methylated and non-methylated samples were investigated and the results compared with those of different soil humic fractions investigated earlier. The total amount of oxidation products identified from the methylated sample was 2%, and from the non-methylated sample 0.9%. The composition of the oxidation products from methylated aquatic humus was 42% benzenecarboxylic acid methyl esters (8 different compounds), 43% methoxy-benzenecarboxylic acid methyl esters (12 compounds), 10% dimethoxy-benzenecarboxylic acid methyl esters (4 compounds), and 5% of 1, 2, 3-propanetricarboxylic acid trimethyl ester. The unmethylated aquatic humus yielded 84% benzenecarboxylic acid methyl ester (7 compounds), 7% methoxy-benzenecarboxylic acid methyl esters (2 compounds), and 9% of 1, 2, 3-propanetricarboxylic acid trimethyl ester. Three diazines isolated from methylated material were believed to be artefacts from diazomethane treatment. Two of the diazines have earlier been found by oxidation of methylated soil samples, the third, C10H12N2O6, is an oxidation product of methylated aquatic humus only. Oxidation of aquatic humus yielded more benzenecarboxylic acids and methoxy-benzenecarboxylic acids than soil humic fractions, and less dimethoxy-benzenecarboxylic acids. No aliphatic dicarboxylic acids were detected among the oxidation products of the aquatic humus. The compounds identified are mainly the same as those found by oxidation of different soil humic fractions, although their yields clearly demonstrated that the aquatic humus differed in composition from the soil fractions.