Effects of nitrogen load variation in animal urination events on nitrogen leaching from grazed pasture

Li, Frank Y.; Betteridge, K.; Cichota, Rogerio; Hoogendoorn, C. J.; Jolly, Ben

doi:10.1016/j.agee.2012.07.003

Cited by 53 publications

(39 citation statements)

References 33 publications

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“…Both Li et al (2012) and Betteridge et al (2013) showed that considering mean values (rather than varied values) for cattle urine volume, frequency and N concentration causes differences of~5-10% in modelled NO 3 -leaching losses. The mean values for urine volume and N concentration are also often used in plot-based studies of urine-patch N 2 O emissions, which may also cause inaccuracies when upscaling such emissions.…”

Section: Discussionmentioning

confidence: 99%

“…Nevertheless, on the basis of the results of the present study and the sheep urine patch sizes used here, it would seem that sheep that urinate more frequently in smaller volumes would emit more N 2 O than sheep urinating less frequently in larger volumes, given the same high urinary N concentration. Further work is required to determine how this effects other N-loss processes such as NO 3 -leaching and NH 3 volatilisation, as, given the range of patch sizes excreted by cattle, increasing patch size has been shown to logarithmically increase NO 3 -leaching (Li et al 2012).…”

Section: Discussionmentioning

confidence: 99%

“…The wetted area of a urine patch has been defined as the surface area covered by urine following deposition to soil, as opposed to the pasture response area, which can extend beyond the wetted area (Lantinga et al 1987;Li et al 2012). A typical wetted area for a sheep urine event with a volume of 150 mL is reported to be 300 cm 2 (Doak 1952) and for 200 mL it is reported to be 430-550 cm 2 (Williams and Haynes 1994).…”

Section: Introductionmentioning

confidence: 99%

“…- (Li et al 2012). The default IPCC N 2 O emission factor for both cattle and sheep was 2% of applied N; however, due to the lower volume and higher frequency of sheep urine events, and more moderate levels of soil compaction under sheep-grazed pastures, the default emission factor has been lowered for sheep from 2% to 1% of the applied N (IPCC 2006).…”

Section: Introductionmentioning

confidence: 99%

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Disentangling the effect of sheep urine patch size and nitrogen loading rate on cumulative N2O emissions

2016

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Abstract. Ruminant urine nitrogen (N) concentration and volume are important parameters influencing the size and N loading rate of urine patches deposited to soil. Such parameters can influence N cycling and emissions of the greenhouse gas, nitrous oxide (N 2 O) from grazed grassland, yet, there is limited information on the effect of these parameters within typical ranges reported for sheep. We used an automated, high-frequency gas monitoring system to investigate N 2 O emissions from varying urine N application rates and patch sizes under field conditions. Using artificial sheep urine, we manipulated urine N concentration to provide two urine N application rates (4 and 16 g N/L; equivalent to 200 and 800 kg N/ha). We investigated the effect of urine patch size with equal N application rates (4 · 125 cm 2 vs 500 cm 2 , at 200 and 800 kg N/ha) and the effect of patch size with unequal N application rates, but the same total amount of N applied (62.5 mL over 125 cm 2 at 800 kg N/ha and 250 mL over 500 cm 2 at 200 kg N/ha). Cumulative emissions of N 2 O generally increased with N loading rate, whether applied as one large urine patch or four smaller ones. Cumulative N 2 O emissions increased when the N was applied in four smaller urine patches compared with one large patch; this difference was significant at 800 kg N/ha, but not at 200 kg N/ha. When the total amount of N applied was held constant (1 g of N), the amount of N 2 O released was similar when urine was applied as a high N concentration small patch (800 kg N/ha) compared with a low N concentration large patch (200 kg N/ha). Urine N 2 O emission factors in this study were, on average, 10 times lower than the IPCC default of 1% for sheep excreta. This research clearly demonstrates that the chemical and physical nature of the urine patch influences N 2 O emissions, yet further research is required to gather more data on typical sheep urine volumes (individual and daily), urination frequency, urine N concentrations and the typical volumes of soil influenced by urine deposition, to provide more accurate estimates of emissions from sheep grazed pastures.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Disentangling the effect of sheep urine patch size and nitrogen loading rate on cumulative N2O emissions

2016

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“…To approach this task, firstly c k N values have to be randomized for every urination event from an estimated statistical distribution of c N . Li et al (2012) fitted a log-normal distribution (Eq. 17) to a c N data set, originating from the observation of two Aberdeen Angus steers over three 24 h periods (Betteridge et al, 1986).…”

Section: Methods Used In the Sensitivity Analysis 331 Perturbation mentioning

confidence: 99%

Process-based modelling of NH<sub>3</sub> exchange with grazed grasslands

et al. 2017

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Abstract. In this study the GAG model, a process-based ammonia (NH 3 ) emission model for urine patches, was extended and applied for the field scale. The new model (GAG_field) was tested over two modelling periods, for which micrometeorological NH 3 flux data were available. Acknowledging uncertainties in the measurements, the model was able to simulate the main features of the observed fluxes. The temporal evolution of the simulated NH 3 exchange flux was found to be dominated by NH 3 emission from the urine patches, offset by simultaneous NH 3 deposition to areas of the field not affected by urine. The simulations show how NH 3 fluxes over a grazed field in a given day can be affected by urine patches deposited several days earlier, linked to the interaction of volatilization processes with soil pH dynamics. Sensitivity analysis showed that GAG_field was more sensitive to soil buffering capacity (β), field capacity (θ fc ) and permanent wilting point (θ pwp ) than the patch-scale model. The reason for these different sensitivities is dual. Firstly, the difference originates from the different scales. Secondly, the difference can be explained by the different initial soil pH and physical properties, which determine the maximum volume of urine that can be stored in the NH 3 source layer. It was found that in the case of urine patches with a higher initial soil pH and higher initial soil water content, the sensitivity of NH 3 exchange to β was stronger. Also, in the case of a higher initial soil water content, NH 3 exchange was more sensitive to the changes in θ fc and θ pwp . The sensitivity analysis showed that the nitrogen content of urine (c N ) is associated with high uncertainty in the simulated fluxes. However, model experiments based on c N values randomized from an estimated statistical distribution indicated that this uncertainty is considerably smaller in practice.Finally, GAG_field was tested with a constant soil pH of 7.5. The variation of NH 3 fluxes simulated in this way showed a good agreement with those from the simulations with the original approach, accounting for a dynamically changing soil pH. These results suggest a way for model simplification when GAG_field is applied later at regional scale.

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Nutrient excretion from cattle grazing nitrogen‐fertilized grass or grass–legume pastures

et al. 2021

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Nutrient cycling via livestock excreta is an important grassland ecosystem service.This study was conducted in 2016 and 2017 and determined nutrient excretion from cattle grazing three systems: (a) N-fertilized bahiagrass (Paspalum notatum Flüggé) overseeded with rye (Secale cereale L.) and oat (Avena sativa L.) during winter (Grass+N), (b) unfertilized bahiagrass overseeded with rye-oat-clover (Trifolium sp.) mixture (Grass+clover), and (c) rhizoma peanut (Arachis glabrata Benth.)bahiagrass mixture overseeded with a rye-oat-clover mixture (Grass+CL+RP). Urinary volume excreted in the warm season ranged from 122 to 182 L ha −1 d −1 , more than double that in the cool season (56-70 L ha −1 d −1 ). Urinary N concentration during the warm season was greater in Grass+CL+RP compared with Grass+N (4.4 vs.3.1 g kg −1 , respectively). In addition, fecal dry matter and organic matter output was greater for Grass+N than for steers grazing Grass+CL+RP during the warm season (3.8 and 3.2 vs. 2.8 and 2.2 kg hd −1 d −1 , respectively). Total annual feces excretion concentrations of P, K, Mg, and N were greater in the Grass+N than in Grass+CL+RP system. The introduction of legumes increased the proportion of N returning via urine. However, when summed across seasons, total N excretion (feces and urine) was greater in Grass+N than in Grass+CL+RP (89 vs. 71 kg ha −1 yr −1 ), mainly due to the greater stocking rate in the former. Grass-legume systems receiving 34 kg N ha −1 yr −1 recycled 80% of the N recycled in the grass system receiving 224 kg N ha −1 yr −1 , indicating the potential of forage legumes to add N to grasslands.In grazing systems, nutrient cycling is a complex network of interactions between plant growth, type of livestock grazing, grazing intensity, and soil fauna and flora (Burns & Sollenberger, 2001). Nutrients such as C, N, P, and S reside temporarily in various reservoirs or different pools in the Abbreviations: DM, dry matter; IVDOM, in vitro digestible organic matter; OM, organic matterThis is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

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Effects of nitrogen load variation in animal urination events on nitrogen leaching from grazed pasture

Cited by 53 publications

References 33 publications

Disentangling the effect of sheep urine patch size and nitrogen loading rate on cumulative N2O emissions

Disentangling the effect of sheep urine patch size and nitrogen loading rate on cumulative N2O emissions

Process-based modelling of NH<sub>3</sub> exchange with grazed grasslands

Nutrient excretion from cattle grazing nitrogen‐fertilized grass or grass–legume pastures

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Effects of nitrogen load variation in animal urination events on nitrogen leaching from grazed pasture

Cited by 53 publications

References 33 publications

Disentangling the effect of sheep urine patch size and nitrogen loading rate on cumulative N2O emissions

Disentangling the effect of sheep urine patch size and nitrogen loading rate on cumulative N2O emissions

Process-based modelling of NH&lt;sub&gt;3&lt;/sub&gt; exchange with grazed grasslands

Nutrient excretion from cattle grazing nitrogen‐fertilized grass or grass–legume pastures

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Process-based modelling of NH<sub>3</sub> exchange with grazed grasslands