Assessment 4

Fencing off farm dams can reduce methane emissions and improve water quality. A study found that fenced dams had less nitrogen and phosphorus, more oxygen, and produced less methane. Vegetation growth and exclusion of livestock contribute to these improvements. The results are expected to be similar in other locations. Farmers can benefit from better livestock health and growth, although transitioning from dams to troughs may incur costs. More research is needed to explore long-term impacts and economic feasibility. Farmers are encouraged to consider fencing their dams and raise awareness about the benefits to support funding and further research. Hello and welcome to the Everyday Ag podcast. I'm Zoe and today we're exploring an innovative way of reducing methane emissions produced on farms. Climate change is a hot topic in the ag industry with farmers facing growing pressure to reduce methane emissions. You've probably all heard of farmers feeding their cattle seaweed to reduce greenhouse gas production but have you ever heard that simply fencing off your farms reduces emissions? A recent study into the benefits of fencing farm dams found this one action could halve the amount of methane produced by farm dams. Heidi from Deakin's Blue Carbon Lab joins me now to discuss this idea. Heidi, can you start by giving us a bit of a background into the study? We all know that the amount of methane produced is increasing rapidly with agricultural systems across the world responsible for a lot of these emissions. Cattle are the most widely known source of methane, however other farm aspects including farm dams also produce greenhouse gases. Many people may be unaware that farm dams are the perfect environment for methane production due to their high nitrogen and phosphorus concentrations and as agricultural production has increased across the world so has the number of dams. Therefore the management of farm dams has the potential to help the ag industry combat climate change. So based off this idea we conducted an experiment where simply fencing off farm dams could reduce methane emissions. We used different sheep and cattle properties across South East and New South Wales to compare fenced and unfenced dams. We ignored dams which had only been fenced recently, like in the last two years, then using these dams in April of 2021 we measured methane production as well as nutrient levels and water quality. That sounds really interesting Heidi, what did you find? So I made findings that fenced farm dams improved water quality and reduced the amount of methane produced. The fenced dams had 32% less nitrogen, 39% less phosphorus and 22% more oxygen which explains why the water quality was better. Naturally by excluding livestock from around the dam there is less soil disturbance and more vegetation growth. Plants growing on the edge of dams act as filters and prevent excess nutrients from entering the water. And this occurs without any kind of practice to increase vegetation so if we went the next step and planted trees around dams as well as fencing them off the increase in water quality would be even greater. Also because manure and fertilizer won't be directly entering the dam there will be less nutrients in the first place. Then in terms of methane the fenced dams produce less than half the amount of methane as the unfenced dams but this is mainly due to the increase in dissolved oxygen in the water. Methane production is optimal in anaerobic conditions which basically means when oxygen isn't present so by increasing the amount of oxygen in the water methane production is slowed. Also if there is enough oxygen present instead of methane being produced the dam will actually absorb methane and carbon dioxide from the atmosphere and suddenly you have a carbon sink on your farm. We also tested temperature and pH of the water but did not find any differences between the dams. You said Heidi that your study focused on dams in South East New South Wales. Do you expect your findings to be comparable across Australia? That's a good question Zoe and based on the current research yes we expect similar results to be seen in other locations. Obviously we can't say for certain without more research but all farm dams have a similar design and are used to collect water so we would expect similar results. The magnitude of these results might vary but I can pretty confidently say that I would think that fencing farm dams would improve water quality and reduce methane emissions regardless of the location. I'm sure farmers in other states will be pleased to hear that Heidi. So what do these results really mean for farmers? Farmers listing today could properly compare different farms on their property and identify that the ones with greater vegetation and less livestock access are in better condition and look to be healthier so our results just confirm this and explain why. People in the ag industry know that the health of the environment is very important and without it production would be impossible. Through this idea of fencing off farm dams gives farmers a way of getting back to the environment in a way which won't negatively impact production. Instead it may actually provide benefits as livestock will have access to better quality drinking water therefore higher growth may be seen. We are also aware that farmers need to make money and the change from dams to troughs can be an expensive shift by the time you account for all the plumbing required however we believe that the increased weight gain and improved livestock health will offset this cost. Also growing up on a farm myself I'm aware that many paddocks have both dams and troughs already so the change might not be as drastic as it seems. My last question for you Heidi is where are you hoping to go from here and do you have any final messages for farmers listening today? This is a fairly new idea so more research is needed before the practice can become widespread. We need to explore carbon cycles in farm dams to better understand the results as well as look at the long term impacts and economic implications. We can't expect farmers to adopt a strategy that isn't feasible in the long term so this research is required. We are also looking at conducting similar studies at other locations to confirm that the results are transferable. I'd just encourage farmers to consider fencing their dams as the benefits on water quality and methane emissions are significant. This could be as simple as one dam on their farm but it will still make a difference. Or even just have a conversation with other producers about the benefits of fenced dams as the more awareness and interest there is into this topic the easier it is to get funding for grants and further research. Thank you for joining us today Heidi. I hope you all enjoyed this episode of the Everyday Ag podcast. If you have any suggestions on future topics or any general enquiries feel free to contact me at zoe.everydayag.gmail.com. I'll see you all next time where we will be discussing carbon farming.