Showing papers on "Organic matter published in 1974"
TL;DR: In this article, a modified ignition loss method is described for determining organic and carbonate carbon in calcareous sedimentary materials using equipment found in most laboratories and has been found to equal or excel the accuracy and precision of other methods tested and has the advantage of being considerably faster if large numbers of samples are to be analyzed.
Abstract: A modified ignition loss method is described for determining organic and carbonate carbon in calcareous sedimentary materials using equipment found in most laboratories. The method has been found to equal or excel the accuracy and precision of other methods tested and has the advantage of being considerably faster if large numbers of samples are to be analyzed.
2,939 citations
TL;DR: In this article, loss on ignition at 430C of calcareous and non-calcareous soils has been compared with organic matter contents estimated by a wet oxidation method, and the presence of CaCO₃ did not affect the magnitude of the ignition loss and the gravimetric method provided both a reliable and simple estimation of soil organic matter.
Abstract: Loss-on-ignition at 430C of calcareous and noncalcareous soils has been compared with organic matter contents estimated by a wet oxidation method. The presence of CaCO₃ did not affect the magnitude of the ignition-loss and the gravimetric method provides both a reliable and simple estimation of soil organic matter.
571 citations
TL;DR: In this paper, residues in fermentation tubes were filtered sequentially through glass wool mats, sintered glass crucibles, and glass fiber discs, and the results showed that residual organic matter which passed glass wool was not retained by glass fiber.
327 citations
309 citations
01 Jan 1974
TL;DR: In this article, the authors report the effects of deforestation on the export of particulate matter, erodi- bility of the ecosystem, and the relative importance of dissolved substances and particulate matters in exported materials.
Abstract: We report the effects of deforestation on the export of particulate matter, erodi- bility of the ecosystem, and the relative importance of dissolved substances and particulate matter in exported materials. The mature forested ecosystem is little affected by erosion, with an average annual particulate matter export of only 2.5 MT (metric tons) km-2 yr-1. Defor- estation and repression of growth for 3 yr increased export to a maximum of 38 MT km-2 yr-1, but the increase in export was exponential with rather minor increases in the first 2 yr after cutting and a sharp increase in the 3rd yr. This resulted because the ecosystem continued to exercise considerable control over erodibility for 2 yr after cutting without annual renewal of biotic regulation by primary productivity. Increases in particulate matter export are pri- marily due to increases in erodibility rather than increased flow rates. In the mature ecosystem, the average ratio of annual net export of dissolved substance to particulate matter is 2.3. Deforestation shifts this ratio to > 8.0 during the first 2 yr after cutting. This shift results because the export trends, for dissolved substances and particu- late matter following deforestation, are not synchronous. The first response to deforestation is mobilization of nutrients from the available nutrient and organic matter compartments and leakage in stream water. After 2 yr, particulate matter output rises sharply as biotic control of erodibility weakens, while dissolved substance export declines, probably because of diminu- tion of readily available nutrients stored within the system. This nonsynchrony, coupled with the action of natural species adapted to take advantage of the abundance of nutrients and water that results immediately after disturbance, may be considered as part of a homeostatic mechanism that allows rapid recovery of a forest ecosystem while minimizing the effects of erosion.
280 citations
TL;DR: Following destruction of the vegetation, the ecosystem maintains a residual resistance to erosion and has a high potential for repair through successional productivity, and the relative importance of dissolved substances and particulate matter in exported materials is reported.
Abstract: We report the effects of deforestation on the export of particulate matter, erodibility of the ecosystem, and the relative importance of dissolved substances and particulate matter in exported materials. The mature forested ecosystem is little affected by erosion, with an average annual particulate matter export of only 2.5 MT (metric tons) km—2 yr—1. Deforestation and repression of growth for 3 yr increased export to a maximum of 38 MT km—2 yr—1, but the increase in export was exponential with rather minor increases in the first 2 yr after cutting and a sharp increase in the 3rd yr. This resulted because the ecosystem continued to exercise considerable control over erodibility for 2 yr after cutting without annual renewal of biotic regulation by primary productivity. Increases in particulate matter export are primarily due to increases in erodibility rather than increased flow rates. In the mature ecosystem, the average ratio of annual net export of dissolved substance to particulate matter is 2.3. Deforestation shifts this ratio to >8.0 during the first 2 yr after cutting. This shift results because the export trends, for dissolved substances and particulate matter following deforestation, are not synchronous. The first response to deforestation is mobilization of nutrients from the available nutrient and organic matter compartments and leakage in stream water. After 2 yr, particulate matter output rises sharply as biotic control of erodibility weakens, while dissolved substance export declines, probably because of diminution of readily available nutrients stored within the system. This nonsynchrony, coupled with the action of natural species adapted to take advantage of the abundance of nutrients and water that results immediately after disturbance, may be considered as part of a homeostatic mechanism that allows rapid recovery of a forest ecosystem while minimizing the effects of erosion. Thus, following destruction of the vegetation, the ecosystem maintains a residual resistance to erosion and has a high potential for repair through successional productivity. Nutrient flux and erosion losses return to previous levels as the intrasystem aspects of the hydrologic—nutrient cycle interaction and erodibility are increasingly regulated by biotic factors. These results relative to stable conditions and their reestablishment following disturbance may have applicability to a wide range of terrestrial ecosystems.
272 citations
TL;DR: In this article, an increase in the rate of decomposition of a fraction of 14 C labeled organic matter in the soils was reported. But the effect of the treatment was least in the soil which had been incubated with the labeled material for the longest time.
Abstract: Repeated air drying and rewetting of three soils followed by incubation at 20°C resulted in an increase in the rate of decomposition of a fraction of 14 C labeled organic matter in the soils. The labeled organic matter originated from labeled glucose, cellulose and straw, respectively, metabolized in the soils during previous incubation periods ranging from 1.5 to 8 years. Air drying and rewetting every 30th day over an incubation period of 260–500 days caused an increase in the evolution of labeled CO 2 ranging from 16 to 121 per cent as compared to controls kept moist continuously. The effect of the treatment was least in the soil which had been incubated with the labeled material for the longest time. Additions of unlabeled, decomposable organic material also increased the rate of decomposition of the labeled organic matter. The evolution of labeled CO 2 during the 1st month of incubation after addition was in some cases 4–10 times larger than the evolution from the controls. During the continued incubation the evolution decreased almost to the level of the controls, indicating that the effect was related to the increased biological activity in the soils during decomposition of the added material. Three additions of organic material during the period of incubation resulted totally in an increase over the controls ranging from 36 to 146 per cent.
257 citations
TL;DR: In a comprehensive study of the distribution of organic and inorganic constituents in natural waters, the chemical compositions of several rivers flowing through the Coastal Plain of southeast Georgia (the Satilla River, in particular) have been investigated as discussed by the authors.
254 citations
TL;DR: In this paper, the effects of several soil factors on cadmium accumulation by plants were determined, and it was shown that the retaining power of organic matter for Cd is predominately through its CEC property rather than chelating ability.
Abstract: The effects of several soil factors on cadmium (Cd) accumulation by plants were determined. Cadmium concentration in oat shoots (Avena sativa L.) was decreased by increasing the cation exchange capacity (CEC) of the soil. Except for its CEC effect, organic matter did not influence the concentration of Cd in oat shoots. The results indicate that the retaining power of organic matter for Cd is predominately through its CEC property rather than chelating ability. Cadmium concentration of soybean shoots (Glycine max L.) increased soil temperature. In the presence of 10 ppm of soil-applied Cd, the addition of Zn from the 5 to 50 ppm range, apart from raising the Zn concentration, significantly increased the Cd concentration of soybean shoots. The increased Cd concentration was primarily due to decreased plant growth. A depression in Cd concentration of soybean shoots, relative to control, began to occur at the 100 ppm Zn level. 12 references, 5 tables.
208 citations
TL;DR: In this article, the English lakes are divided into three groups of low, intermediate, and high fertility, and the fertile lakes are proportionally poorer than the infertile lakes in p-algae, but richer in "large algae" and Cyanophyta.
Abstract: Estimates of standing crop, derived approximately from algal counts in surface waters, have been used to separate the English Lakes into three groups of low, intermediate, and high fertility. The fertile lakes are proportionally poorer than the infertile lakes in p-algae, but richer in “large algae” and Cyanophyta. The fertile lakes are richer in dissolved ions, especially calcium and bicarbonate, in filter-passing and particulate vitamin Bx, in sedimentary sulfur, and in sedimentary chlorophyll derivatives and carotenoids. The relationship noted by Pearsall between lake fertility and agricultural activity is shown by a strong correlation between algal standing crop and the pcrccntagc of the drainage basin under cultivation. Sediment ratios of carbon to sulfur and of chlorophyll derivatives to carotenoids decline with increasing lake fertility, whereas the ratio of carbon to nitrogen shows little change. This study lends support to the use of sedimentary pigments as indicts to lake productivity. The pigment data also indicate that much of the organic matter in sediments of productive lakes comes from autochthonous sources within the lakes.
153 citations
TL;DR: In this article, the authors present an analysis of the Anaerobic digestion of organic matter in the context of environmental control, and present a set of critical reviews in Environmental Control: Vol. 4, No. 1-4, pp 131-191.
Abstract: (1974). Anaerobic digestion of organic matter. C R C Critical Reviews in Environmental Control: Vol. 4, No. 1-4, pp. 131-191.
TL;DR: In this paper, the vertical diffusion-advection model was used to fit observed profiles of dissolved oxygen and total CO2 and the average oxygen consumption rates were calculated from 0.03 to 0.14 (μmoles kg−1)a−1.
01 Jan 1974
TL;DR: In this article, the stable carbon isotopic composition, δC 13 PDB, appears to vary with late diagenetic or incipient metamorphic rank as given by the hydrogen-to-carbon atomic ratio.
Abstract: Insoluble organic matter (kerogen) was isolated from a suite of 23 marine shales and carbonate rocks of early Proterozoic to Middle Cambrian age from Australia. The stable carbon isotopic composition, δC 13 PDB , of the organic matter appears to vary with late diagenetic or incipient metamorphic rank as given by the hydrogen-to-carbon atomic ratio. Geochemical maturation of the kerogen beyond a rank equivalent to 91 to 93 percent carbon results in marked enrichment of the residual organic matter in C 13 . Hence, low-rank (unmetamorphosed) organic matter is isotopically lighter (δC 13 PDB range = −31.3 to −18.6 per mil, mean = −26.9 per mil) than high-rank (metamorphosed) material (δC 13 PDB range = −25.8 to −10.8 per mil, mean = −17.2 per mil). Kerogens from two Precambrian evaporitic sedimentary rocks are isotopically heavier than normal marine organic matter of similar rank. New isotopic and rank data from 11 carbonaceous, chert samples from the Onverwacht Group, Swaziland Sequence, South Africa, indicate that postdepositional thermal alteration may account for the anomalously heavy reduced carbon in the Theespruit Formation.
TL;DR: In this paper, the same authors found that peatmoss, a rich source of humic acid, was found to absorb significant quantities of various metal ions, including Zn and Fe.
TL;DR: The generally lower values for extracellular release reported in this work as compared to other studies may be partly due to improved experimental techniques which minimized previously encountered artifacts.
Abstract: The release of photoassimilated carbon as dissolved organic matter was studied in situ in oligotrophic and eutrophic marine waters and in axenic laboratory cultures. Percentage extracellular release (PER), integrated for the trophogenic zone, ranged from 6 to 12% in eutrophic waters and from 17 to 27% in oligotrophic seas. Most of the algal cultures released low amounts of dissolved organic matter (∼5%) during exponential growth. The highest levels of PER were observed in surface and deep samples, possibly as a result of elevated photorespiration and senescent cells. The generally lower values for extracellular release reported in this work as compared to other studies may be partly due to improved experimental techniques which minimized previously encountered artifacts.
TL;DR: In this paper, the effects of cultivation on the net mineralization of carbon and nitrogen in a lacustrine Brown clay (Sceptre) and two Orthic Black soils on glacial till (Oxbow) were assessed with the aid of fractionation and radiocarbon dating techniques.
Abstract: The effects of cultivation on the net mineralization of carbon and nitrogen in a lacustrine Brown clay (Sceptre) and two Orthic Black soils on glacial till (Oxbow) were assessed with the aid of fractionation and radiocarbon dating techniques. Fractionation of the soil organic matter of comparative virgin and cultivated soils by acid hydrolysis and peptization in dilute NaOH showed that the distribution of carbon and nitrogen among fractions of these soils was similar. There was no measurable alteration in the mean residence time (MRT) of the soil during the first 15 to 20 yr of cultivation, during which time the Sceptre soil had lost 19% of its carbon and the Oxbow, 35%. However, the MRT increased from 250 yr before present (BP) to 710 years BP after 60 yr of cultivation of the Oxbow soil. The losses for nitrogen were 10% lower than for carbon in the Oxbow soil due to the recycling of nitrogen in the soil. The rate of loss of carbon from the Oxbow soil during the cultivation period was simulated by expres...
TL;DR: Feeding diets containing loose whole barley increased the firmness of the subcutaneous fat, and this was associated with a decrease in the proportion of propionic acid in the rumen fluid.
Abstract: 1. The effects of processing cereals on aspects of rumen metabolism, physiology and pathology were investigated in five experiments with lambs. Three experiments studied the effects of diets containing loose whole, pelleted whole or pelleted rolled barley on rumen volatile fatty acid ratios, rumen pH and digestibility. In a 4th experiment the effects, on the same measurements, of pelleting whole barley, maize, oats or wheat compared to feeding the whole grains in the loose form were studied. The firmness of subcutaneous fat was measured in two of these experiments when injections of cyanocobalamin or hydroxycobalamin were given and in one experiment when the diets were supplemented with two levels of cobalt. In a 5th experiment, the effect on rumination time of pelleting whole barley compared to feeding loose whole grain was assessed.2. When the diet contained whole barley in a loose mix and also when it contained whole maize, oats or wheat, the proportion of acetic acid in the rumen fluid was significantly increased and that of propionic acid decreased in comparison with the proportions observed when the pelleted diets were offered.3. The pH of the rumen liquor was not significantly changed by feeding pellets based on rolled or whole barley, but when barley, maize, oats or wheat was given in loose form, there was an increase in the pH by about 1 unit in comparison with the pelleted diets. This increase in pH was, for all cereals, associated with complete elimination of ruminitis which, except for the oat diet, was always apparent with the pelleted feeds.4. In general the digestibilities were not affected greatly by processing and in two experiments there were no significant differences. In one experiment pelleted whole barley was better digested than pelleted rolled barley. In another experiment the digestibility of barley was slightly greater when it was fed whole and loose compared to pelleted, while the digestibility of whole wheat was less than that of pelleted wheat. The mean digestibilities of organic matter for barley, maize, oats and wheat were 0.791, 0.832, 0.687 and 0.846 respectively.5. Neither injections of vitamin B12 nor cobalt supplementation of the diet had any effect on the firmness of subcutaneous fat. Feeding diets containing loose whole barley increased the firmness of the subcutaneous fat, and this was associated with a decrease in the proportion of propionic acid in the rumen fluid.6. The feeding of loose whole barley instead of pelleted whole barley caused an increase in time of rumination from 3.6 to 6.6 h/24 h.
TL;DR: It is suggested that microbial immobilization of nitrogen and phosphorus during decomposition of organic matter may limit nutrient availability to phytoplankton and in part account for the general paucity of inorganic nutrients present in this shallow estuarine system.
Abstract: Inorganic nutrients limiting phytoplankton production in the shallow estuarine system near Beaufort, N. C., were identified by nutrient enrichment techniques. Nitrogen was the primary limiting nutrient; phosphorus also was limiting at times. Samples receiving a complete enrichment medium plus organic substrates poor or lacking in nitrogen and phosphorus showed no significant increase in relative photosynthesis over unenriched controls, even though there was a significant decrease in the nitrogen and phosphorus concentrations in the enriched samples. This suggested that microbial immobilization of nitrogen and phosphorus during decomposition of organic matter may limit nutrient availability to phytoplankton and in part account for the general paucity of inorganic nutrients present in this shallow system. An estimated 6 x 109 g carbon, 1 x 108 g nitrogen and 2 x 107 g phosphorus enters the estuarine system in the form of partially decayedSpartina alterniflora each year, primarily from September–March. To utilize the readily available fraction of this detrital material estuarine microbes would have to immobilize 2.4 x 107 g nitrogen and 1.6 x 106 g phosphorus. The data also suggested that an annual cycle in nutrient concentration in the estuarine system in part may result from shifts in the equilibrium between microbial immobilization and remineralization.
TL;DR: The concentration of lignin degradation products (vanillin, p- hydroxybenzaldehyde and syringealdehyde) generated by oxidizing sediment samples with nitrobenzene were considered in an approach to follow the seaward transport of terrestrially derived organic matter as mentioned in this paper.
01 Jan 1974
TL;DR: In this article, the organic compounds in colored lake water, fallen leaves and surface sediment extracts were separated into molecular size fractions which varied from larger than 50,000 to less than 700 when compared to dextrans.
TL;DR: Two profiles from Muguga, Kenya, one cultivated and one under forest, contained similar contents of clay of apparently uniform composition, but the profiles differed in their organic matter contents, surface (0-15 cm) samples containing 68% C and 38% C in forest and cultivated profiles, respectively as discussed by the authors.
TL;DR: In this paper, the carbon-isotopic composition of fulvic and humic acid from the A horizons of eight soil types, developed under a wide variety of climatological conditions, was measured.
TL;DR: In this paper, the metal sorption is strongly suppressed by H+ but is only marginally influenced by the proportion of whole cells in the suspension and by complexing of metals in solution by the soluble organic matter.
TL;DR: McLean et al. as discussed by the authors measured topsoil and subsoil samples from twenty tropical and twenty British acidic soil profiles and found that extractable aluminium and free iron oxides were well correlated with phosphate sorption, free iron oxide being superior to aluminium in freely drained British soils but not in poorly drained ones.
Abstract: Summary
Phosphate sorption capacity estimated by Piper's (1942) ‘anion exchange capacity’ and Bache and Williams's (1971) phosphate sorption index were correlated with soil pH, clay, organic matter, ‘free iron oxides’ and ‘extractable aluminium’ (McLean et al., 1958) for topsoil and subsoil samples from twenty tropical and twenty British acidic soil profiles. These two groups of soils did not differ significantly in phosphate sorption. Extractable aluminium and free iron oxide were well correlated with phosphate sorption, free iron oxide being superior to aluminium in freely drained British soils but not in poorly drained ones. Organic matter content correlated well with phosphate sorption for the poorly drained British soils, and for the tropical soils when sorption capacitywas measured using a high phosphate concentration.
TL;DR: In this paper, the authors describe a feedlot profile as three layers: the organic matter, the interface, and the underlying soil, and show that the surface 15.2 cm depth of feedlot soils is compacted and has a high bulk density.
Abstract: Characterization of the conditions that exist in the feedlot surface and soil profile is important to evaluation of the potentials for soil and water pollution. Cattle action and management activities create a dynamic condition in the feedlot. The organic matter surface causes physical and biochemical changes in the soil that are unlike natural or cultivated soils. The feedlot profile can be described as three layers: the organic matter, the interface, and the underlying soil. Measurable characteristics include bulk density, infiltration, and content of organic matter, water, and nitrate-N. Generally, the surface 15.2-cm depth of feedlot soils is compacted and has a high bulk density. Infiltration into the feedlot surface layers is essentially zero. There is no transpiration, and the soilwater content is more uniform through the profile than on cropped land.
TL;DR: In this article, the effect of reduced tillage intensity on the accumulation of organic matter in Grey-brown podsolic soils near Gottingen (German Federal Republic) was evaluated in three field trials after at least 5 years of experimenting.
Abstract: In order to evaluate the effect of reduced tillage intensity on the accumulation of organic matter in Grey-brown podsolic soils near Gottingen (German Federal Republic), stratified soil analyses were made in three field trials after at least 5 years of experimenting. On old arable soil, zero-tillage increased the content of organic C of the 0–30 cm layer by mean annual rates of 0.59–1.30 tons/ha, and correspondingly the content of total N by 53.8–72.4 kg/ha. Killing a sod and cropping the former grassland with annual field crops, but without disturbing the soil, caused a mean annual loss of 2.29 tons/ha and 162.4 kg N/ha. This indicates that reduced tillage cannot preserve the original high content of soil organic matter maintained by a living sod. On arable soil, zero-tillage caused a mode of nitrogen distribution which is similar to that found in grassland soil. The N-content of fraction V (containing total amino-acid N and unknowns) increased at the expense of the ammonium-N (fraction I). The relative increase or loss of total N in the 0–5 cm layer, as caused by tillage and cropping practices, was most pronounced in fraction V, ranging between 53 and 67%.