The fate of labelled mineral nitrogen after addition to three pasture soils of different organic matter contents

1967 ◽  
Vol 18 (4) ◽  
pp. 613 ◽  
Author(s):  
JR Simpson ◽  
JR Freney
Keyword(s):  
Organic Matter ◽  
Organic Nitrogen ◽  
Isotopic Exchange ◽  
Mineral Nitrogen ◽  
Fertilizer Efficiency ◽  
Labelled Nitrogen ◽  
Isotopic Exchange Reaction ◽  
Total Plant ◽  
Organic Fractions ◽  
Low Nitrogen

Ammonium and nitrate labelled with 15N were added separately to three soils representing different stages of organic matter accumulation under pasture. The fate of the labelled nitrogen was determined after 6 weeks, and again after a further 29 weeks in the presence and absence of ryegrass plants. Recoveries of the labelled nitrogen within the soil–plant system were high (90–l00%), except where nitrate was added to the high-nitrogen soil (69%). The labelled ammonium was immobilized rapidly, particularly in the low-nitrogen soil, but nitrate reacted with the soils much more slowly. Thus recovery of labelled nitrate nitrogen by the plants was generally greater than that of ammonium. However, the total mineral nitrogen (labelled and indigenous) in unplanted soils and the total plant uptake of nitrogen were not appreciably affected by the chemical form of the added nitrogen. This suggested that an isotopic exchange reaction had occurred between the labelled mineral nitrogen and indigenous organic nitrogen. The greatest increase in total nitrogen uptake by the plants after addition of nitrogen (i.e. the apparent fertilizer efficiency of the added nitrogen) occurred in the low-nitrogen soil (85% and 81% recovery for ammonium and nitrate respectively). The highest recovery of labelled nitrogen by the plants occurred where nitrate was added to the low- and intermediate-nitrogen soils (both 80%). The indigenous organic nitrogen of the three soils was distributed between four fractions in similar patterns. The labelled nitrogen was incorporated into each of these organic fractions, but there was a tendency for greater amounts to remain in the non-distillable acid-soluble fraction.

Changes in chemical fractions of nitrogen during incubation of soils with histories of large organic matter increase under pasture

Soil Research ◽  
1970 ◽  
Vol 8 (1) ◽  
pp. 21 ◽  
Author(s):  
AW Moore ◽  
JS Russell
Keyword(s):  
Organic Matter ◽  
Total Nitrogen ◽  
Podzolic Soil ◽  
Clay Soil ◽  
Nitrate Nitrogen ◽  
Ammonium Nitrogen ◽  
Mineral Nitrogen ◽  
Chemical Fractions ◽  
Labelled Nitrogen ◽  
Organic Fractions

A lateritic podzolic soil and a solodized solonetz soil, with histories of organic matter increase under tropical and temperate pastures respectively, were incubated over a period of a year with a weekly wetting and drying cycle. Decreases in organic matter (7 and 11%), total nitrogen (12 and 10%), and non-distillable acid-soluble nitrogen (30 and 25%) occurred, but there were no significant changes in residual nitrogen. Although there were marked increases in mineral nitrogen at the beginning of the incubation in both soils, nitrification was relatively poor in both soils. In a short-term (4 weeks) incubation of a lateritic podzolic soil and a grey clay soil the addition of labelled nitrogen followed by fractionation allowed nitrogen transformations to be examined precisely. Although differences in total nitrogen (labelled + unlabelled) with time were not statistically significant (P = 0.05) in the sandy soil (lateritic podzolic) a loss (28%) of total labelled nitrogen did occur. Parallel with this was an increasing incorporation of labelled nitrogen in all three organic fractions and a disappearance of ammonium nitrogen without the appearance of an equivalent amount of nitrate nitrogen. On the other hand, in the clay soil there was no loss of total labelled nitrogen with time and little incorporation of labelled nitrogen in the organic fractions after the first week. There was little change in the pool of labelled mineral nitrogen between the first and fourth weeks, but virtually complete and quantitative conversion from ammonium nitrogen to nitrate nitrogen. Some of the results point to varying biological lability of chemical fractions of soil nitrogen. These fractions are unlikely to be of much use as indices for sensitive measurement of nitrogen changes in the field, however, possibly because of the continuing accretion and losses which occur in the field.

scholarly journals Assessment of the Trophic State of a Small Plain Reservoir during Different Periods of Its Existence (a Case Study of the Penza Reservoir on the Sura River)

2020 ◽  
pp. 368-386
Author(s):  
Elena A. Shashulovskaya ◽  
Svetlana A. Mosiyash ◽  
Inna N. Dalechina ◽  
Irina G. Filimonova ◽  
Liliya V. Grishina ◽  
...  
Keyword(s):  
Organic Matter ◽  
Negative Relationship ◽  
Mineral Nitrogen ◽  
Nitrogen And Phosphorus ◽  
Low Light ◽  
Significant Negative Relationship ◽  
Flood Period ◽  
Low Nitrogen

The present study provides comparative characterization of the contents of nutrients and organic matter and quantitative parameters of phytoplankton of the Sura (Penza) reservoir during 1984–1992 and 2016–2019. At present, the content of phosphates has increased by 3 times while the concentration of mineral nitrogen has remained unchanged. The seasonal dynamics of phosphorus and mineral nitrogen are different: the maximum phosphate concentrations are observed in summer and autumn, but nitrogen is the highest during the flood period. At the present time, phosphorus is mainly generated in intra-reservoir processes. Nitrates were the predominant form of mineral nitrogen in 2016–2019, and their spring maximum suggests predominant intake with the flood flow. The ratio of the mineral forms of nitrogen and phosphorus indicates that, at the present time, phosphorus is not the element that limits the development of algae. In certain periods (summer 2017–2018), a significant negative relationship was observed between the algal biomass and the total iron content in water (r = -0.81, p = 0.016). No Cyanoprocaryota “blooms” have been observed in recent years. In 2019, the abundance of Cyanoprocaryota increased, but in some regions, biomass was no more than 2.18–2.42 mg/dm3. In 2019, the dominant Cyanoprocaryota group did not contain Microcystis aeruginosa (Kütz.), but a new species was identified – Planktothrix agardhii (Gom.) Anagn. et Kom., which is resistant to low light and the low nitrogen to phosphorus ratio. The proportion of readily oxidized organic matter in the total organic matter, both at the end of the 20th century and recently, characterizes the reservoir as stably eutrophic, although the quantitative characteristics of phytoplankton in recent years indicate declining trophic status

Suivi du fonctionnement d'une station d'epuration associant physico-chimie et biofiltration = Metabief (France)

1990 ◽  
Vol 22 (1-2) ◽  
pp. 251-259 ◽  
Author(s):  
R. Pujol
Keyword(s):  
Organic Matter ◽  
Biological Process ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Cold Temperatures ◽  
Biological Sludge ◽  
Physico Chemical ◽  
Total Plant ◽  
Sludge Characteristic

The sewage treatment plant of Metabief (East of France) has been monitored during three weeks in winter 1988. The treatment associates a physico-chemical treatment with a biological process of biofiltration. The first step eliminates about 60 % of the organic matter (COD and BOD). The biofliters improve the treatment removing 60 % of COD influent and 65 % of TSS. The process is efficient (N excepted) under conditions of the experiment but nitrification is limited by cold temperatures (< 10°C). Important results related to biological sludge product are presented (sludge characteristic, microscopic data, sludge production). Power consumption of biofliters represents 70 % of the total plant needs. Adequate control of washing cycles and close survey of numerous movable devices are of the utmost importance to guarantee the proper operating of biofliters.

scholarly journals Benthic fluxes of dissolved organic nitrogen in the lower St. Lawrence estuary and implications for selective organic matter degradation

2013 ◽  
Vol 10 (11) ◽  
pp. 7609-7622 ◽  
Author(s):  
M. Alkhatib ◽  
P. A. del Giorgio ◽  
Y. Gelinas ◽  
M. F. Lehmann
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Bottom Water ◽  
Estuarine Sediments ◽  
Internal Source ◽  
Lawrence Estuary ◽  
Element Partitioning ◽  
Sediment Porewaters ◽  
St Lawrence Estuary

Abstract. The distribution of dissolved organic nitrogen (DON) and carbon (DOC) in sediment porewaters was determined at nine locations along the St. Lawrence estuary and in the gulf of St. Lawrence. In a previous manuscript (Alkhatib et al., 2012a), we have shown that this study area is characterized by gradients in the sedimentary particulate organic matter (POM) reactivity, bottom water oxygen concentrations, and benthic respiration rates. Based on the porewater profiles, we estimated the benthic diffusive fluxes of DON and DOC in the same area. Our results show that DON fluxed out of the sediments at significant rates (110 to 430 μmol m−2 d−1). DON fluxes were positively correlated with sedimentary POM reactivity and varied inversely with sediment oxygen exposure time (OET), suggesting direct links between POM quality, aerobic remineralization and the release of DON to the water column. DON fluxes were on the order of 30 to 64% of the total benthic inorganic fixed N loss due to denitrification, and often exceeded the diffusive nitrate fluxes into the sediments. Hence they represented a large fraction of the total benthic N exchange, a result that is particularly important in light of the fact that DON fluxes are usually not accounted for in estuarine and coastal zone nutrient budgets. In contrast to DON, DOC fluxes out of the sediments did not show any significant spatial variation along the Laurentian Channel (LC) between the estuary and the gulf (2100 ± 100 μmol m−2 d−1). The molar C / N ratio of dissolved organic matter (DOM) in porewater and the overlying bottom water varied significantly along the transect, with lowest C / N in the lower estuary (5–6) and highest C / N (> 10) in the gulf. Large differences between the C / N ratios of porewater DOM and POM are mainly attributed to a combination of selective POM hydrolysis and elemental fractionation during subsequent DOM mineralization, but selective adsorption of DOM to mineral phases could not be excluded as a potential C / N fractionating process. The extent of this C- versus N- element partitioning seems to be linked to POM reactivity and redox conditions in the sediment porewaters. Our results thus highlight the variable effects selective organic matter (OM) preservation can have on bulk sedimentary C / N ratios, decoupling the primary source C / N signatures from those in sedimentary paleoenvironmental archives. Our study further underscores that the role of estuarine sediments as efficient sinks of bioavailable nitrogen is strongly influenced by the release of DON during early diagenetic reactions, and that DON fluxes from continental margin sediments represent an important internal source of N to the ocean.

Natural organic matter from catchment to drinking water: a case study of Pori waterworks, Finland

2008 ◽  
Vol 8 (6) ◽  
pp. 681-690 ◽  
Author(s):  
H. M. Szabo ◽  
I. Lindfors ◽  
T. Tuhkanen
Keyword(s):  
Drinking Water ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Raw Water ◽  
Lake Waters ◽  
Molecular Weight Fractions ◽  
Uv And Fluorescence Detection

In this study Natural organic matter (NOM) characteristics and variations of catchment samples (brooks and collector lakes) from Western Finland, and drinking water produced from the same catchment were examined. Seasonal and spatial NOM variations were followed by means of DOC and HPLC-SEC with UV and fluorescence detection. NOM decreased from drains to lakes by 35 to 75% and from drains to drinking water by 73 to 94%. Drains had a higher NOM content in summer and a lower NOM content in winter and spring. Lakes showed inverse patterns and had a higher NOM content in winter and spring and a lower NOM content in summer. HPLC-SEC separated 8 molecular weight fractions. In drains the HMW fractions represented up to 80% of the NOM, in lake waters HMW fractions accounted for 50 to 70% of the NOM. In drinking water IMW fractions dominated. Increased NOM in raw water during winter was associated with increased IMW fractions and the appearance of HMW fractions in drinking water, DOC increasing from 1.4 mg C/L in summer to 5.8 mg C/L in winter. SPH-Tryptophan correlated with the dissolved organic nitrogen and DOC of the samples. The drain affected by agriculture generally presented higher SPH-Tryptophan values than the unaffected drain.

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