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Four geographically distinct regions of Scotland are used to describe temporal and spatial trends in soil phosphorus (P) using ca. 180 000 routine advisory samples which included information on previous and next crop. Regional differences in Modified Morgan's extractable P concentrations exist primarily in response to differences in land use and particularly the greater role of livestock in the west compared to arable cropping in the east. No obvious or consistent temporal trend in extractable P was apparent, but a very wide range of soil properties and extractable P concentrations was evident. The current (since 2010) target soil P status is moderate (M) for cereal-based arable rotations and the upper half of moderate (M+) for rotations with potatoes, and more than half the samples fell into this range (with 40% M−). Some ca. 30% of samples fell below this, while 14% had high or very high P status, most noticeably where the previous crop was either potatoes, vegetables or berries. Half (ca. 13 000) of the samples with a low soil P status also had a below optimum pH. An apparent contradiction between the regularly reported long-term declines in agricultural P surplus not being matched by a drop in extractable soil P status is discussed. This 'lag effect' means many Scottish agricultural soils have the capability to buffer change in extractable soil P. We make the first attempt to link advisory P data with information from the National Soil Database of Scotland and explore the value of introducing 'soil type' into the P fertilizer recommendation system. [ABSTRACT FROM AUTHOR]

A comprehensive assessment of nitrogen (N) flows at the landscape scale is fundamental to understand spatial interactions in the N cascade and to inform the development of locally optimised N management strategies. To explore these interactions, complete N budgets were estimated for two contrasting hydrological catchments (dominated by agricultural grassland vs. semi-natural peat-dominated moorland), forming part of an intensively studied landscape in southern Scotland. Local scale atmospheric dispersion modelling and detailed farm and field inventories provided high resolution estimations of input fluxes. Direct agricultural inputs (i.e. grazing excreta, N2 fixation, organic and synthetic fertiliser) accounted for most of the catchment N inputs, representing 82% in the grassland and 62% in the moorland catchment, while atmospheric deposition made a significant contribution, particularly in the moorland catchment, contributing 38% of the N inputs. The estimated catchment N budgets highlighted areas of key uncertainty, particularly N2 exchange and stream N export. The resulting N balances suggest that the study catchments have a limited capacity to store N within soils, vegetation and groundwater. The "catchment N retention", i.e. the amount of N which is either stored within the catchment or lost through atmospheric emissions, was estimated to be 13% of the net anthropogenic input in the moorland and 61% in the grassland catchment. These values contrast with regional scale estimates: Catchment retentions of net anthropogenic input estimated within Europe at the regional scale range from 50% to 90%, with an average of 82% (Billen et al., 2011). This study emphasises the need for detailed budget analyses to identify the N status of European landscapes. [ABSTRACT FROM AUTHOR]

The article focuses on the accuracy comparison between the non-steady static chamber and eddy covariance measurements in ascertaining the nitrous oxide emissions from grasslands in the southeast region of Scotland. These measurements were tested their effectiveness during the fertilization of grasslands, where nitrous oxide emissions are prevalent. These emissions have been detected after the application of nitrogen. The fluxes of emissions are also determined.

Intensification of grasslands is necessary to meet the increasing demand of livestock products. The application of nitrogen (N) on grasslands affects the N balance therefore the nitrogen use efficiency (NUE). Emissions of nitrous oxide (N 2 O) are produced due to N fertilisation and low NUE. These emissions depend on the type and rates of N applied. In this study we have compiled data from 5 UK N fertilised grassland sites (Crichton, Drayton, North Wyke, Hillsborough and Pwllpeiran) covering a range of soil types and climates. The experiments evaluated the effect of increasing rates of inorganic N fertiliser provided as ammonium nitrate (AN) or calcium ammonium nitrate (CAN). The following fertiliser strategies were also explored for a rate of 320 kg N ha -1 : using the nitrification inhibitor dicyandiamide (DCD), changing to urea as an N source and splitting fertiliser applications. We measured N 2 O emissions for a full year in each experiment, as well as soil mineral N, climate data, pasture yield and N offtake. N 2 O emissions were greater at Crichton and North Wyke whereas Drayton, Hillsborough and Pwllpeiran had the smallest emissions. The resulting average emission factor (EF) of 1.12% total N applied showed a range of values for all the sites between 0.6 and 2.08%. NUE depended on the site and for an application rate of 320 kg N ha -1 , N surplus was on average higher than 80 kg N ha -1 , which is proposed as a maximum by the EU Nitrogen Expert Panel. N 2 O emissions tended to be lower when urea was applied instead of AN or CAN, and were particularly reduced when using urea with DCD. Finally, correlations between the factors studied showed that total N input was related to Nofftake and Nexcess; while cumulative emissions and EF were related to yield scaled emissions., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)

Dung and urine excreted onto grasslands are a major source of nitrous oxide (N2O). These N2O emissions stem from inefficient utilisation of nitrogen (N) ingested by ruminants, and the inability of pasture to utilise the deposited N. Predicted growth in dairy and meat consumption means that there is a requirement to quantify N2O emissions, and investigate emission reduction mechanisms. Three 12 month 'seasonal' experiments were undertaken at Crichton, SW Scotland, where N2O emissions were measured from applications of cattle urine, dung, artificial urine and urine+a nitrification inhibitor (NI), dicyandiamide (DCD). The three application timings were 'spring', 'summer' and 'autumn', representative of early-, mid- and late grazing seasons. N2O emissions were measured from static chambers for 12 months. The aim was to quantify emissions from cattle excreta, and determine their dependence on the season of application, and the respective contribution of dung and urine to total excreta emissions. Measurement from NI amended urine was made to assess DCD's potential as an emission mitigation tool. Emissions were compared to the IPCC's default emission factor (EF) of 2% for cattle excreted N. Mean annual cumulative emissions from urine were the highest when applied in summer (5034 g N2O-N ha(-1)), with lower emissions from spring (1903 g N2O-N ha(-1)) and autumn (2014 g N2O-N ha(-1)) application, most likely due to higher temperatures and soil moisture conducive to both nitrification and denitrification in the summer months. Calculated EFs were significantly greater from urine (1.1%) than dung (0.2%) when excreta was applied in summer, and EFs varied with season of application, but in all experiments were lower than the IPCC default of 2%. These results support both lowering and disaggregating this EF into individual EFs for dung and urine. Addition of DCD to urine caused no significant reduction in emissions, suggesting that more research is required into its use as a mitigation option., (Copyright © 2014 Elsevier B.V. All rights reserved.)