Linking arable and livestock farms: Impact of grazing sheep on winter cereals and soil health

Given, in recent years, the UK has experienced a number of extreme weather events, and climate modellers are predicting these to occur more frequently in future, there is concern by some farmers in their ability to reliably provide sufficient homegrown forage for their ruminant livestock, especially over the winter period before grass fields are ready. There is also a desire by some arable farms to include livestock within their system in some way in order to try improving their soil health and in particular levels of residual nitrogen and organic matter through the act of animal manuring and urine deposition. These arable farmers do not necessarily want to change to a fully mixed farming system, or have overall responsibility for the animals involved. The grazing of winter cereals on arable farms by local shepherds / graziers has potential to provide a route to achieve this mutualistically beneficial relationship. This paper is based on a recent series of controlled field experiments and farmer led demonstrations in NE Scotland that have been used to test the hypothesis that the grazing of winter cereals can provide both a valuable late winter feed source for ruminants, as well as maintain acceptable grain and straw yields, while maintaining soil “health”. The overall aim was to assess a number of factors, including how crop establishment timing, grazing timing, intensity and stocking rate impacts on the performance of different winter cereals and the potential for economic and environmental benefits associated with this practice to be achieved.Results to date suggest that winter wheat, winter barley and winter oats can be grazed quite heavily, using either intensive grazing over a short period of time, or less intensive grazing over a longer period of time, without any clear negative impacts on a range of crop (including yield and quality) or soil factors. Analysis of the feed value of these crops at the time grazing has taken place, typically for between a few days and several weeks, within the period late November through to mid-March, has been consistently impressive. <br/

Linking arable and livestock farms: Impact of grazing sheep on winter cereals and soil health

Given, in recent years, the UK has experienced a number of extreme weather events, and climate modellers are predicting these to occur more frequently in future, there is concern by some farmers in their ability to reliably provide sufficient homegrown forage for their ruminant livestock, especially over the winter period before grass fields are ready. There is also a desire by some arable farms to include livestock within their system in some way in order to try improving their soil health and in particular levels of residual nitrogen and organic matter through the act of animal manuring and urine deposition. These arable farmers do not necessarily want to change to a fully mixed farming system, or have overall responsibility for the animals involved. The grazing of winter cereals on arable farms by local shepherds / graziers has potential to provide a route to achieve this mutualistically beneficial relationship. This paper is based on a recent series of controlled field experiments and farmer led demonstrations in NE Scotland that have been used to test the hypothesis that the grazing of winter cereals can provide both a valuable late winter feed source for ruminants, as well as maintain acceptable grain and straw yields, while maintaining soil “health”. The overall aim was to assess a number of factors, including how crop establishment timing, grazing timing, intensity and stocking rate impacts on the performance of different winter cereals and the potential for economic and environmental benefits associated with this practice to be achieved.Results to date suggest that winter wheat, winter barley and winter oats can be grazed quite heavily, using either intensive grazing over a short period of time, or less intensive grazing over a longer period of time, without any clear negative impacts on a range of crop (including yield and quality) or soil factors. Analysis of the feed value of these crops at the time grazing has taken place, typically for between a few days and several weeks, within the period late November through to mid-March, has been consistently impressive. <br/

Probabilistic forecasts: scoring rules and their decomposition and diagrammatic representation via Bregman divergences

A scoring rule is a device for evaluation of forecasts that are given in terms of the probability of an event. In this article we will restrict our attention to binary forecasts. We may think of a scoring rule as a penalty attached to a forecast after the event has been observed. Thus a relatively small penalty will accrue if a high probability forecast that an event will occur is followed by occurrence of the event. On the other hand, a relatively large penalty will accrue if this forecast is followed by non-occurrence of the event. Meteorologists have been foremost in developing scoring rules for the evaluation of probabilistic forecasts. Here we use a published meteorological data set to illustrate diagrammatically the Brier score and the divergence score, and their statistical decompositions, as examples of Bregman divergences. In writing this article, we have in mind environmental scientists and modellers for whom meteorological factors are important drivers of biological, physical and chemical processes of interest. In this context, we briefly draw attention to the potential for probabilistic forecasting of the within-season component of nitrous oxide emissions from agricultural soils