Gross nitrogen transformations in grassland soils as affected by previous management intensity

Watson, C. J.; Mills, Clare

doi:10.1016/s0038-0717(97)00179-x

Cited by 37 publications

(31 citation statements)

References 29 publications

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“…The gross rates of nitrification measured under optimal laboratory conditions in our study are comparable to those measured in other grassland systems; 3.8 mg N kg −1 d −1 (Ambus 2005;Rosenkranz et al 2006), 2.7 to 7.8 mg N kg −1 d −1 (Watson and Mills 1998) and 1.1 to 1.7 mg N kg −1 d −1 in ungrazed pasture (Corre et al 2002).…”

Section: N 2 O Emissionsupporting

confidence: 85%

“…Watson and Mills (1998) observed a significant increase in gross nitrification with increasing N fertiliser addition (100 to 500 kg N ha −1 yr −1 ) to pasture soils follow 15 N isotope studies, and discerned that the majority of N 2 O produced was derived through denitrification. In our study the mean N 2 O emissions were slightly greater in the High P pasture soil as compared to the No P treatment, but this difference was not likely to be significant and was not mirrored by a consistent significant difference in either soil mineral N pool size or gross nitrification rates.…”

Section: N 2 O Emissionmentioning

confidence: 83%

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Trace gas flux and the influence of short-term soil water and temperature dynamics in Australian sheep grazed pastures of differing productivity

Livesley

Kiese²,

Graham³

et al. 2008

Plant Soil

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Temperate pastures are often managed with P fertilizers and N 2 -fixing legumes to maintain and increase pasture productivity which may lead to greater nitrous oxide (N 2 O) emissions and reduced methane (CH 4 ) uptake. However, the diel and interdaily variation in N 2 O and CH 4 flux in pastures is poorly understood, especially in relation to key environmental drivers. We investigated the effect of pasture productivity, rainfall, and changing soil moisture and temperature upon short-term soil N 2 O and CH 4 flux dynamics during spring in sheep grazed pasture systems in southeastern Australia. N 2 O and CH 4 flux was measured continuously in a High P (23 kg P ha −1 yr −1 ) and No P pasture treatment and in a sheep camp area in a Low P (4 kg P ha −1 yr −1 ) pasture for a four week period in spring 2005 using an automated trace gas system. Although pasture productivity was three-fold greater in the High P than No P treatment, mean CH 4 uptake was similar (−6.3±SE 0.3 to −8.6±0.4 μg C m −2 hr −1 ) as were mean N 2 O emissions (6.5 to 7.9±0.8 μg N m −2 hr −1 ), although N 2 O flux in the No P pasture did not respond to changing soil water conditions. N 2 O emissions were greatest in the Low P sheep camp (12.4 μg±1.1 N m −2 hr −1 ) where there were also net CH 4 emissions of 5.2±0.5 μg C m −2 hr −1 . There were significant, but weak, relationships between soil water and N 2 O emissions, but not between soil water and CH 4 flux. The diel temperature cycle strongly influenced CH 4 and N 2 O emissions, but this was often masked by the confounding covariate effects of changing soil water content. There were no consistently significant differences in soil mineral N or gross N transformation rates, however, measurements of substrate induced respiration (SIR) indicated that soil microbial processes in the highly productive pasture are more N limited than P limited after >20 years of P fertilizer addition. Increased productivity, through P fertilizer and legume management, did not significantly increase N 2 O emissions, or reduce CH 4 uptake, during this 4 week measurement period, but the lack of an N 2 O response to rainfall in the No P pasture suggests this may be evident over a Plant Soil (longer measurement period. This study also suggests that small compacted and nutrient enriched areas of grazed pastures may contribute greatly to the overall N 2 O and CH 4 trace gas balance.

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Section: N 2 O Emissionsupporting

confidence: 85%

Section: N 2 O Emissionmentioning

confidence: 83%

Trace gas flux and the influence of short-term soil water and temperature dynamics in Australian sheep grazed pastures of differing productivity

Livesley

Kiese²,

Graham³

et al. 2008

Plant Soil

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“…Changes in 15 N enrichment of NH 4 + -N and NO 3 − -N pools during 1-month incubation confirmed that there was substantial nitrification during the incubation (Watson and Mills 1998). The 15 N recovery in the NO 3 − -N pool in the nonmulched soil was higher than in the mulched soil, which showed that soil net nitrification was greater in the nonmulching treatment than in the mulching treatment.…”

Section: Discussionmentioning

confidence: 68%

Soil nitrogen mineralization and fate of (15NH4)2SO4 in field-incubated soil in a hardwood plantation of subtropical Australia: the effect of mulching

Huang

Blumfield

et al. 2008

J Soils Sediments

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Background, aim, and scope Mulching is frequently used to overcome the drought problem in hardwood plantations that are increasingly being established in lower rainfall areas of Queensland, Australia because of increasing land values. In addition to soil water content, soil nitrogen (N) availability is another critical determinant of plantation productivity in these areas. The purpose of this study was to understand how soil mineral N dynamics, in situ N mineralization, and the fate of fertilized N would be affected by mulching during the early establishment of hardwood plantations. Materials and methods Two treatments (mulching, 1.57-kg m −2 site preparation residues, and nonmulching) were applied to six 24-m-wide by 67.2-m-long plots at Pechey (27°18′ S, 152°3′

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“…Immobilisation rates for our calcareous and acidic grasslands are not known, and reported values in other grasslands vary greatly. However, NH 4 + immobilisation rates up to 10 kg N ha −1 day −1 have been observed (Watson and Mills, 1998;Barrett and Burke, 2000;Corre et al, 2002) which would immobilise the 15 NH 4 + used in this study in less than 4 hours. Similarly, Bardgett et al (2003) observed that more than 70% of labelled inorganic and organic N was immobilised into microbial biomass in just 50 hours following application to unimproved grassland.…”

Section: N Tracer Study -Short-term Fate Of Pollutant Nmentioning

confidence: 66%

Accumulation of pollutant nitrogen in calcareous and acidic grasslands: Evidence from N flux and 15N tracer studies

Phoenix¹,

Leake²,

Read³

et al. 2005

Water Air Soil Pollut: Focus

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Semi-natural calcareous and acidic grasslands are known to be sensitive to increased atmospheric N deposition. However, the fate of pollutant N within these systems is unknown. This paper reports on the first studies to determine the fate of added N within a calcareous and an acidic grassland subject to long-term simulated enhanced N deposition. Intact soil/turf cores were removed from field plots treated for six years with enhanced N deposition (ambient +0, +35 and +140 kg N ha −1 year −1 ). Cores were inserted into lysimeters and output fluxes of N were monitored in detail. Complete N budgets -calculated from the N flux data -showed considerable accumulation of N within the treated grasslands, up to 76% and 38% of pollutant N in the calcareous and acidic grasslands respectively. In the second study, the short-term (21 day) fate of pollutant N was determined by tracing 15 N labelled ammonium nitrate (+35 kg N ha −1 year −1 ) though the acidic and calcareous lysimeters into plant, soil and leachate pools. Up to 91% and 59% of 15 N was recovered in soils and vegetation of the calcareous and acidic grasslands respectively, with negligible amounts recovered in soil extractable ammonium and nitrate (<0.3%) and in leachate (<0.02%). This rapid short-term immobilisation of pollutant N supports the long-term accumulation of the element calculated from the N flux study.

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Gross nitrogen transformations in grassland soils as affected by previous management intensity

Cited by 37 publications

References 29 publications

Trace gas flux and the influence of short-term soil water and temperature dynamics in Australian sheep grazed pastures of differing productivity

Trace gas flux and the influence of short-term soil water and temperature dynamics in Australian sheep grazed pastures of differing productivity

Soil nitrogen mineralization and fate of (15NH4)2SO4 in field-incubated soil in a hardwood plantation of subtropical Australia: the effect of mulching

Accumulation of pollutant nitrogen in calcareous and acidic grasslands: Evidence from N flux and 15N tracer studies

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