Dr. Paul Murphy:

I thank the Chairman and members for this opportunity to present to the joint committee. Picking up where Dr. Sheridan left off, I will focus more on water quality and, to a lesser extent, greenhouse gases, with more of a focus on more intensive systems in the agricultural sector, in particular, the dairy sector. As one of the key targets of the Food Harvest 2020 report is a 50% increase in output from this sector and with the milk quota system ending in 2015, the dairy sector deserves particular attention.

As the previous contributions from Teagasc and the Environmental Protection Agency have covered many of the salient points, I will not recap these. Instead, I will highlight some of the research in which I and my colleagues have been involved that may contribute to the work of the joint committee.

I will first introduce a widely used indicator of the environmental performance of a farming system, namely, the nutrient surplus. If we take the example of nitrogen, this surplus is equal to the import of nitrogen on to the farm in fertilisers and feed, for example, minus the nitrogen export off the farm in, for example, milk, animals and crops. The remaining nitrogen is the surplus and this will be either stored in the system or lost from the system to the environment. In the case of nitrogen, most of the surplus can be expected to be lost to the environment. This loss can have impacts on water quality through eutrophication and on greenhouse gas emissions when it is emitted as nitrous oxide, a potent greenhouse gas. Therefore, a lower nitrogen surplus for a farm indicates a lower pressure on the environment and a more sustainable system of production. There is a double dividend here in that lower surpluses also indicate more efficient use of nitrogen and a potentially more profitable system as nitrogen inputs in feed and fertiliser are one of the main variable input costs on any farm.

As part of the INTERREG funded Dairyman project, we examined nitrogen surpluses on 21 intensive Irish dairy farms and compared them to other published work internationally. The first slide shows this comparison across a number of countries. The reference to this work is provided at the bottom of the slide. It is clear that Irish dairy farms - shown on the left of the slide - have relatively low nitrogen surpluses by international standards. The first bar shown is from some further work I was involved in using data from 195 Irish dairy farms in the national farm survey. It shows the average surplus for Irish dairy farms at 143 kg of nitrogen per hectare, N/ha. The results of studies in other countries are also shown. The figure for Ireland is largely due to the relatively low input systems of dairy production that operate here, which are based mostly on grazed grass. This low nitrogen surplus is also associated with the relatively low carbon footprint of Irish milk production that was pointed out in a previous submission to the committee by Teagasc. Lower inputs and more efficient use of nitrogen fertilisers lead to lower surpluses and losses to the environment as the greenhouse gas nitrous oxide or to ground and surface water systems.

As I stated, we also studied nitrogen surpluses on a nationally representative sample of 195 Irish dairy farms. The reference to this work is provided at the bottom of the second slide. In this figure, we plot milk production per hectare on the horizontal axis against nitrogen surplus on the vertical axis. Members should bear in mind the average surplus of 143 kg N/ha we saw in the previous slide. We can see that this average value hides a range extending from less than 50 kg N/ha to more than 400 kg N/ha. I will highlight a few key points from this figure. First, if we look at a production level of 10,000 litres of milk per hectare, l/ha, as represented on the blue line on the slide, there is a range from farms operating a surplus of less than 50 kg N/ha to farms operating a surplus of almost 300 kg N/ha. This gives an idea of the range of variability in our production systems.

Second, this also indicates the potential room for improvement within our systems. What is the farmer with a nitrogen surplus of 50 kg N/ha doing that the farmer with a surplus of 300 kg N/ha is not doing? Many factors determine the surplus, some of which are beyond the direct control of the farmer. However, the management of the system is clearly a critical factor. In that case, what better management practices could be implemented to bring farmer A's nitrogen surplus closer to farmer B's surplus? Our research needs to identify these better management practices, our education and advisory services need to disseminate them and our policy framework needs to encourage them and give credit for them in areas such as greenhouse gas inventories, water quality programmes and even product labelling and marketing.

Third, in the context of the ending of quotas in 2015 and the Food Harvest 2020 targets for increased dairy production, if we consider a farmer who is currently producing at 5,000 litres of milk per hectare and plans to increase production to 10,000 litres of milk per hectare, we could consider, within the range of observable outcomes for Irish dairy farms, three different scenarios for achieving this increased output. The first of these, as shown on the second slide, would result in an increased nitrogen surplus. The second would result in no change in nitrogen surplus, while the third would result in a decrease in nitrogen surplus. Obviously, the third scenario is the optimal one in terms of the sustainability of the system and likely impacts on greenhouse gas emissions and water quality. Again, many factors influence the efficiency of nitrogen use and the resulting nitrogen surplus on a farm, some of which are beyond the control of the farmer. However, a large part of this is down to management.

I suggest that metrics such as nitrogen surplus could act as an indicator of the performance of a farm and could be used as management targets for farmers to try to achieve and to compare themselves to the top performers in their sector. This could be done in the context of farmer discussion groups, for example, in a similar way to the agronomic indicators such as herd economic breeding indexes, EBI, are done at the moment.

This approach was indicated in the previous Teagasc submission to this committee. Metrics such as this also have potential to be incorporated into more integrated measures of sustainability that could form the basis of some certification and product labelling that could allow Ireland to capitalise on the relatively low environmental footprint of its dairy production system.

The third slide deals with the fate of nitrogen and phosphorous on farms. Whether these result in greenhouse gas emissions or losses to water is dependent not just on management but on biophysical conditions. To illustrate this, I will show some results from the agricultural catchments programme. The reference to this work is provided at the bottom of the slide. This was a research programme in which I was involved and which was based primarily at Teagasc and funded by the Department of Agriculture, Food and the Marine. In this case, we compared two catchments dominated by arable farming. The catchments are instrumented to monitor nutrient loss in the stream draining the catchment. Under the nitrate regulations, soil phosphorous concentrations are divided into four indices.

As can be seen on the slide, index 4 is considered excessive and a potential risk for phosphorous loss to water. The two catchments have similar proportions of soils in index 4, indicating a similar level of pressure for phosphorous loss to water, from soils at least. We might expect in that case that they might have a similar outcome in terms of phosphorous loss to water. However, the result is that over the period monitored, the losses from one catchment were much higher than the other, roughly three times higher. What we found was that the principal apparent reason for this difference was that one catchment had predominantly well-drained soils while the other had predominantly poorly drained soils. The pie chart displays this result and indicates the area distribution of the different soil types and their drainage characteristics.

The catchment with the more poorly drained soils is more prone to generating overland flow run-off and this makes it more vulnerable to phosphorous loss, particularly during heavy rain events. This illustrates, and this is the reason I am showing this, the fact that biophysical conditions need to be accounted for and that one size does not fit all in terms of identifying better management practices to reduce emissions to air or water. The suite of better management practices that might be most effective may vary depending on factors such as soil type, climate and topography.

On the pressing question of whether the Food Harvest 2020 targets as well as Ireland's commitments on greenhouse gas emissions and water quality can be met, I would suggest that, in principle, they can. However, I would emphasise that this is only in principle. These targets pose a significant challenge to agriculture and other sectors of the economy and I would not under-emphasise these challenges. I would argue that management will be key to determining whether these targets can be achieved. In this, I refer to both the optimisation of land use at the catchment or landscape scale and also soil and nutrient management, which occurs more at farm level. The correct better management practices need to be identified and implemented. Ultimately, management on the farm determines the fate of nutrients, whether they are taken up in crops and animals or lost to the environment with a resultant impact.

Effective policy, therefore, needs to encourage better management practices that are effective at this scale. Already, the national action programme and the nitrates regulations target nutrient losses to water from farms, but there may be further scope for development of more integrated catchment or landscape management approaches addressing the full range of ecosystem services, land uses and stakeholders. I would argue that advisory, education and knowledge transfer will also be critical. Initiatives such as the Teagasc Better Farms, discussion groups and the SmartFarm programme point at innovative ways to encourage adoption of better management practices.

It is important that Ireland and the agricultural sector are able to get credit for improvements that are made - in greenhouse gas inventories and product labelling, for example. Emissions estimates, whether for greenhouse gases or emissions to water based on simple measures of intensity, can be misleading. Further work is required in this area. In terms of identifying suitable best management practices for different production systems and biophysical conditions, one size does not fit all. Future policies may need to be more flexible in this regard.