The effect of increasing application rate of granular calcium ammonium nitrate on net nitrification in a laboratory study of grassland soils

Watson, C. J.; Kilpatrick, D. J.; Cooper, J. E.

doi:10.1007/bf00750101

Cited by 12 publications

(13 citation statements)

References 16 publications

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“…The application of mineral fertilizers resulted in a significantly decreased soil pH. This has been repeatedly observed in long-term fertilization trials with application of ammonium fertilizers (Witter et al 1993;Christensen 1996;Birkhofer et al 2008), although calcium ammonium nitrate has often been judged to have only little effect on acidification (Watson et al 1995). In contrast, the application of farmyard manure usually leads to higher soil pH, Table 6 Mean microbial biomass quotients, ergosterol to microbial biomass C ratio and metabolic quotient of the soils with different fertilizer treatment over all fertilizer rates (n=144), effects of soil pH as covariate…”

Section: Discussionmentioning

confidence: 85%

Effects of fertilizer and spatial heterogeneity in soil pH on microbial biomass indices in a long-term field trial of organic agriculture

Raupp²,

2009

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In the Darmstadt long-term fertilization trial, the application of composted cattle farmyard manure without (CM) and with (CMBD) biodynamic preparations was compared to mineral fertilization with straw return (MIN). The present study was conducted to investigate the effects of spatial variability, especially of soil pH in these three treatments, on soil organic matter and soil microbial biomass (C, N, P, S), activity (basal CO 2 production and O 2 consumption), and fungal colonization (ergosterol). Soil pH was significantly lower in the MIN treatments than in the organic fertilizer treatments. In the MIN treatments, the contents of soil organic C and total N were also significantly lower (13% and 16%, respectively) than those of the organic fertilizer treatments. In addition, the total S content increased significantly in the order MIN < CM < CMBD. The microbial biomass C content was significantly lower (9%) in the MIN treatments than in the organic fertilizer treatments. Microbial biomass N and biomass P followed microbial biomass C, with a mean C/N ratio of 7.9 and a mean C/P ratio of 23. Neither the microbial biomass C to soil organic C ratio, the metabolic quotient qCO 2 , nor the respiratory quotient (mol CO 2 / mol O 2 ) revealed any clear differences between the MIN and organic fertilizer treatments. The mean microbial biomass S content was 50% and the mean ergosterol content was 40% higher in the MIN treatments compared to the organic fertilizer treatments. The increased presence of saprotrophic fungi in the MIN treatments was indicated by significantly increased ratios of ergosterol-to-microbial biomass C and the microbial biomass C/S ratio. Our results showed that complex interactions between the effects of fertilizer treatments and natural heterogeneity of soil pH existed for the majority of microbial biomass and activity indices.

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Section: Discussionmentioning

confidence: 85%

Effects of fertilizer and spatial heterogeneity in soil pH on microbial biomass indices in a long-term field trial of organic agriculture

Raupp²,

2009

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“…Urine patches represent localized areas of high pH (circa. 8–10) due to hydrolysis reactions 40 41 . See Supplementary Figure S1 online for pH under urine-affected soil.…”

Section: Resultsmentioning

confidence: 99%

Confirmation of co-denitrification in grazed grassland

Selbie

Lanigan

Laughlin

et al. 2015

Sci Rep

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Pasture-based livestock systems are often associated with losses of reactive forms of nitrogen (N) to the environment. Research has focused on losses to air and water due to the health, economic and environmental impacts of reactive N. Di-nitrogen (N2) emissions are still poorly characterized, both in terms of the processes involved and their magnitude, due to financial and methodological constraints. Relatively few studies have focused on quantifying N2 losses in vivo and fewer still have examined the relative contribution of the different N2 emission processes, particularly in grazed pastures. We used a combination of a high 15N isotopic enrichment of applied N with a high precision of determination of 15N isotopic enrichment by isotope-ratio mass spectrometry to measure N2 emissions in the field. We report that 55.8 g N m−2 (95%, CI 38 to 77 g m−2) was emitted as N2 by the process of co-denitrification in pastoral soils over 123 days following urine deposition (100 g N m−2), compared to only 1.1 g N m−2 (0.4 to 2.8 g m−2) from denitrification. This study provides strong evidence for co-denitrification as a major N2 production pathway, which has significant implications for understanding the N budgets of pastoral ecosystems.

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“…This either may have been caused by toxic levels of NH 3 /NH 4 + (Clough et al, 2003) and/or increased levels of ammonium bicarbonate (NH 4 HCO 3 ) driven by urea hydrolysis and nitrification (Malhi and McGill, 1982). The former mechanism is supported by calculated NH 3 concentrations of ∼730 mg N/kg across both soils for the 1000 kg N/ha treatment (Watson et al, 1994;Smith et al, 1997). Clough et al (2003) found nitrification to be inhibited by a 1000 kg N/ha treatment, resulting in NO 2 − accumulation and subsequent N losses occurring as NO 2 − , rather than denitrification via NO 3…”

Section: The Journal Of Agricultural Sciencementioning

confidence: 97%

“…A sub-sample of the KCl extract was allowed to return to room temperature (20°C) and analysed for pH (1:5 ratio). Ammonium concentrations and pH were subsequently used to calculate concentrations of free NH 3 (Watson et al, 1994;Smith et al, 1997):…”

Section: Soil and Gas Samplingmentioning

confidence: 99%

The effects of urine nitrogen application rate on nitrogen transformations in grassland soils

et al. 2019

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Urine is a critical nitrogen (N) input in temperate grazed grasslands and can drive substantial nitrous oxide (N2O) production in soils. However, it remains unclear how differences in the N input rate affect N2O fluxes and vary between different grassland soils. The effect of increasing urine N application on ammonium (NH4+), nitrite (NO2−) and nitrate (NO3−) concentrations and N2O production was tested in two grassland soils, a free-draining loam and an imperfectly drained sandy-loam. It was hypothesized that high-urine N application rates would lead to ammonia/ammonium (NH3/NH4+) accumulation influencing N transformation rates and N2O production which differ between grassland soils. Fresh cattle urine was applied at rates equivalent to 300 and 1000 kg N/ha in an aerobic incubation experiment. Soils were destructively sampled over 80 days to measure changes in inorganic-N and pH. The higher N addition rate was associated with elevated NH3 concentrations up to day 35 in soils, probably inhibiting NO2− to NO3− reduction. In contrast, there was no inhibition of nitrification in the 300 kg N/ha treatment. Cumulative N2O fluxes were greatest from the 300 kg N/ha treatment for the loam soil, but were greater for the sandy-loam under the 1000 kg N/ha treatment. The results also show that differences in soil properties, in particular carbon availability, can be important in regulating N transformation and N2O production. Collectively, these results demonstrate the proposed mechanism of nitrification inhibition at high-N input rates, driven by either high NH3/NH4 and/or increased levels of NH4HCO3 from urea hydrolysis.

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The effect of increasing application rate of granular calcium ammonium nitrate on net nitrification in a laboratory study of grassland soils

Cited by 12 publications

References 16 publications

Effects of fertilizer and spatial heterogeneity in soil pH on microbial biomass indices in a long-term field trial of organic agriculture

Effects of fertilizer and spatial heterogeneity in soil pH on microbial biomass indices in a long-term field trial of organic agriculture

Confirmation of co-denitrification in grazed grassland

The effects of urine nitrogen application rate on nitrogen transformations in grassland soils

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