Nitrogen use efficiency: A potential performance indicator and policy tool for dairy farms

Powell, J. M.; Gourley, C. J. P.; Rotz, C. Alan; Weaver, David

doi:10.1016/j.envsci.2010.03.007

Cited by 170 publications

(130 citation statements)

References 43 publications

Supporting

Mentioning

116

Contrasting

Unclassified

Order By: Relevance

“…This assumption has been used previously with the objective of simplifying the calculation processes (e.g. Powell et al, 2010;Oenema et al,, 2012;Mihailescu et al,, 2014). Collecting data on changes in soil organic matter content is difficult and time consuming, or requires detailed modelling techniques.…”

Section: Justification Of Assumptionsmentioning

confidence: 99%

“…epistemic uncertainty), such as measurement errors around the feed intake of the cows. Most studies that benchmark the environmental performance of dairy farming systems, however, do not consider the impact of data uncertainty Powell, 2010). A few studies examined the impacts of epistemic uncertainty of nutrient flows on quantification of nutrient use efficiency and the impacts of uncertainties of emission factors and natural variability of farm data on LCA results for assessing environmental performance of milk production Chen et al, 2014).…”

Section: Knowledge Gapsmentioning

confidence: 99%

“…Gerber et al (2014) pointed out that the limitation of an NB approach is that the farm or system is considered as a black box and internal flows are not analysed. Despite this limitation, however, an NB can still be a valuable approach to benchmark farms rather than to diagnose detailed problems existing in the farming practice (Powell et al, 2010;Toma et al, 2013). Although a positive NB at farm level does not imply actual losses, it still provides insights in the potential losses in the future (Halberg, 1999, cited in Steinshamn et al, 2004.…”

Section: Justification Of Assumptionsmentioning

confidence: 99%

“…Due to the simplicity of an NB approach and relatively low data requirement, indicators derived from this method have been used widely to assess the environmental performance of dairy farming systems (Oenema et al, 2001;Powell et al, 2010;Toma et al, 2013). In general, indicators from an NB approach are computed at farm level and do not include nutrient losses related to the production of farm inputs, such as purchased concentrates.…”

Section: Knowledge Gapsmentioning

confidence: 99%

“…An NB approach has been used as a valuable approach to provide farmers with farm-specific advice (i.e. identify best practices) (Oenema et al, 2001) and to benchmark environmental impacts of livestock systems (Halberg, 1999;Bengtsson et al, 2003;Powell et al, 2010;Toma et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Benchmarking the environmental performance of dairy farming systems

Mu¹

View full text Add to dashboard Cite

Section: Justification Of Assumptionsmentioning

confidence: 99%

Section: Knowledge Gapsmentioning

confidence: 99%

Section: Justification Of Assumptionsmentioning

confidence: 99%

Section: Knowledge Gapsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Benchmarking the environmental performance of dairy farming systems

Mu¹

View full text Add to dashboard Cite

Spatial and temporal variations in nitrogen export from a New Zealand pastoral catchment revealed by stream water nitrate isotopic composition

Hipsey

Baisden

Horton

et al. 2016

Water Resources Research

View full text Add to dashboard Cite

Viable indicators of nitrogen (N) attenuation at the catchment scale are needed in order to sustainably manage global agricultural intensification. We hypothesized that the dominance of a single land use (pasture production) and strong ground‐to‐surface water connectivity would combine to create a system in which surface water nitrate isotopes (δ15N and δ18O of NO3−) could be used to monitor variations in catchment‐scale attenuation. Nitrate isotopes were measured monthly over a 2 year period in four reaches along a spring‐fed, gaining stream (mean NO3−‐N of 6 mg L−1) in Canterbury, New Zealand. The stream water NO3− pool indicated that the highest degree of denitrification occurred in the shallow upper reaches. Moving downstream through increasingly sandy soils, the isotopic signature of denitrification became progressively weaker. The lowest reaches fell into the expected range for NO3− produced from the nitrification of pasture N sources (urine and fertilizers), implying that the attenuation capacity of the groundwater and riparian systems was lower than the rate of N inputs. After excluding months affected by effluent spills or extreme weather (n = 4), variations in the degree of denitrification over stream distance were combined with the measured NO3− discharge to estimate N attenuation over time in the subcatchment. Attenuation was highly responsive to rainfall: 93% of calculated attenuation (20 kg NO3−‐N ha−1 yr−1) occurred within 48 h of rainfall. These findings demonstrate the potential for detailed NO3− stable isotope data to provide integrative measures of catchment NO3− loss pathways.

show abstract