Matches in SemOpenAlex for { <https://semopenalex.org/work/W2577905> ?p ?o ?g. }
Showing items 1 to 69 of
69
with 100 items per page.
- W2577905 abstract "IntroductionFor Western Europe it is estimated that, on average, 8% of total N excreted by dairy cattle is deposited during grazing (IPCC, 1997). The intake and excretion of N is influenced by factors such as feed composition, lactation stage and pasture quality, and the excretion of excess N as urea in the urine can therefore vary considerably. Urea can lead to high ammonium levels in the soil which may influence N dynamics and gaseous emissions. This laboratory study was conducted to investigate short-term effects of urea concentration on N2O emissions. MethodsSolutions containing 0 (CTL), 5 (LU) and 10 g l-1 urea-N (HU) were added to sieved and repacked soil cores of pasture soil at a rate of 4 l m-2. Also, 5 g l-1 urea-N was added to soil amended with 50 μg cm-3 nitrate-N in order to simulate N turnover in overlapping urine spots (LUN). The urea was labelled with 25 atom% 15N. Final soil moisture was 60% WFPS. All treatments were incubated at 14C. Carbon dioxide and N2O evolution rates were determined after c. 0.2, 0.5, 1, 3, 6 and 9 d. At the four last samplings, the replicates used for gas flux measurements were destructively sampled for determination of pH, electrical conductivity (EC), inorganic and total N, as well as dissolved organic C and phospholipid fatty acid composition. On Day 3, soil was also subsampled for determination of potential ammonium oxidation (PAO) and denitrifying enzyme activity (DEA). The amount and isotopic composition of soil N, nitrate, N2O and N2 was determined by IR-MS; labelling of N2 was insignificant.Results and discussionAccumulated CO2 evolution, corrected for CO2 added in urea, was twice as high from HU as from LU, whereas CO2 from LUN was at the level of the CTL treatment after correction. The lower CO2 emission from LUN was associated with a consistent increase in microbial biomass, as reflected in concentrations of PLFA, which suggested that the lower CO2 evolution rate was due to C assimilation rather than growth inhibition. The EC levels in LU, HU and LUN corresponded to osmotic potentials of -0.05 to -0.12 MPa after 1 d, decreasing to between -0.14 and -0.19 MPa after 9 d. These potentials would not normally be stressful, but a negative interaction with high ammonium concentrations has been observed for ammonium oxidation and, particularly, for nitrite oxidation (Harada and Kai, 1968; Stark and Firestone, 1995). PAO measurements after 3d did not indicate any detrimental effects on ammonium oxidisers. Total recovery of urea-N during the experiment was 801.5% (meanS.E.). Soil nitrate accumulated exponentially to concentrations of 90, 60 and 100 mg N kg-1 in LU, HU and LUN after 9 d. Of this, 47, 40 and 58 mg N kg-1 were derived from urea. Nitrification was thus delayed in the HU treatment. Here, a dramatic increase in nitrite concentration to 8 mg N kg-1 was observed between 6 and 9 d, suggesting a selective inhibition of nitrite oxidation. The fact that 33-52% of the nitrate produced was derived from soil N, points to a significant initial turnover of the ammonium pool. Total concentrations of ammonium after 1 d corresponded to 51-61% of urea-N added, and after 3 d to 80-85%. The transient disappearance could be due to microbial assimilation in response to the sudden decrease in osmotic potential. After 6 and 9 d, soil inorganic N corresponded to approximately 100% in LU and LUN, and to 90% in HU. Emissions of N2O during 0-9 d decreased in the order LU>HU>LUN>>CTL and corresponded to 0.1-0.2% of urea-N added. Emission rates for N2O derived from soil were relatively constant in LU, HU and LUN. In HU, the emission of N2O derived from urea increased dramatically between day 6 and 9, parallel to the accumulation of nitrite. Apparently the higher ammonium concentration resulted in accumulation of nitrite which, in turn, led to an accelerated loss of N2O via ammonium oxidation. This implies that management practices which reduce excess N in cattle urine may substantially reduce N2O emissions from grazed pastures." @default.
- W2577905 created "2016-06-24" @default.
- W2577905 creator A5026986779 @default.
- W2577905 creator A5029408978 @default.
- W2577905 creator A5038448586 @default.
- W2577905 creator A5089479898 @default.
- W2577905 creator A5090686878 @default.
- W2577905 date "2003-01-01" @default.
- W2577905 modified "2023-09-27" @default.
- W2577905 title "Urea concentration affects short-term N turnover and N2O production in grassland soil" @default.
- W2577905 hasPublicationYear "2003" @default.
- W2577905 type Work @default.
- W2577905 sameAs 2577905 @default.
- W2577905 citedByCount "1" @default.
- W2577905 crossrefType "journal-article" @default.
- W2577905 hasAuthorship W2577905A5026986779 @default.
- W2577905 hasAuthorship W2577905A5029408978 @default.
- W2577905 hasAuthorship W2577905A5038448586 @default.
- W2577905 hasAuthorship W2577905A5089479898 @default.
- W2577905 hasAuthorship W2577905A5090686878 @default.
- W2577905 hasConcept C10146269 @default.
- W2577905 hasConcept C107872376 @default.
- W2577905 hasConcept C140793950 @default.
- W2577905 hasConcept C178790620 @default.
- W2577905 hasConcept C185592680 @default.
- W2577905 hasConcept C2776384668 @default.
- W2577905 hasConcept C2779870022 @default.
- W2577905 hasConcept C2780365088 @default.
- W2577905 hasConcept C55493867 @default.
- W2577905 hasConcept C6557445 @default.
- W2577905 hasConcept C86803240 @default.
- W2577905 hasConceptScore W2577905C10146269 @default.
- W2577905 hasConceptScore W2577905C107872376 @default.
- W2577905 hasConceptScore W2577905C140793950 @default.
- W2577905 hasConceptScore W2577905C178790620 @default.
- W2577905 hasConceptScore W2577905C185592680 @default.
- W2577905 hasConceptScore W2577905C2776384668 @default.
- W2577905 hasConceptScore W2577905C2779870022 @default.
- W2577905 hasConceptScore W2577905C2780365088 @default.
- W2577905 hasConceptScore W2577905C55493867 @default.
- W2577905 hasConceptScore W2577905C6557445 @default.
- W2577905 hasConceptScore W2577905C86803240 @default.
- W2577905 hasLocation W25779051 @default.
- W2577905 hasOpenAccess W2577905 @default.
- W2577905 hasPrimaryLocation W25779051 @default.
- W2577905 hasRelatedWork W123433003 @default.
- W2577905 hasRelatedWork W1978335758 @default.
- W2577905 hasRelatedWork W1981590261 @default.
- W2577905 hasRelatedWork W1988694086 @default.
- W2577905 hasRelatedWork W1999073743 @default.
- W2577905 hasRelatedWork W2036172196 @default.
- W2577905 hasRelatedWork W2062991648 @default.
- W2577905 hasRelatedWork W2138185651 @default.
- W2577905 hasRelatedWork W2328532291 @default.
- W2577905 hasRelatedWork W2350426642 @default.
- W2577905 hasRelatedWork W2361020544 @default.
- W2577905 hasRelatedWork W2379014359 @default.
- W2577905 hasRelatedWork W2462496574 @default.
- W2577905 hasRelatedWork W2544613878 @default.
- W2577905 hasRelatedWork W2887033660 @default.
- W2577905 hasRelatedWork W2894676733 @default.
- W2577905 hasRelatedWork W2985842257 @default.
- W2577905 hasRelatedWork W2993056712 @default.
- W2577905 hasRelatedWork W3084549644 @default.
- W2577905 hasRelatedWork W3212954604 @default.
- W2577905 isParatext "false" @default.
- W2577905 isRetracted "false" @default.
- W2577905 magId "2577905" @default.
- W2577905 workType "article" @default.