Soiled water and storage are hot topics at the minute, thanks to the Nitrates Action Programme review.
According to Dr Sara Vero from Waterford Institute of Technology, more storage isn’t the answer and we need to focus on partitioning waste and routing water properly.
Small changes can make a big difference, from the way you stack your silage bales to picking up the sweeping brush and avoiding contamination of water in the first place.
The agricultural science lecturer was speaking on a recent Teagasc Signposts webinar and described the farmyard as the hub of the farm, which provides inlets and outlets for most nutrients. It is also the most dangerous part of the farm and improving infrastructure for water quality can help with farm safety.
“The farmyard is where everything happens and a lot of the improvements – infrastructural improvements to your buildings, slurry and silage stores, hard standing [concrete] and livestock handling facilities – don’t just allow you to manage your nutrients better and keep your farm better, but they also have knock-on effects for other aspects, such as your time management and your physical safety,” she explained.
Do farmyards contribute to nutrient loss?
Sara had plenty of scientific evidence to show that farmyards do indeed contribute to nutrient loss to water. Nitrogen and phosphorus (P) levels in ditches and drains connected to farmyards have been shown to be elevated, compared with levels away from the farmyard.
More evidence showed how P levels spiked in the outlet of the Timoleague dairy catchment in Co Cork, twice per day, after milking in the drought of 2018. The drought allowed the losses to show up, as the dilution effect normally present was much less.
“Twice a day we see spikes, what else happens twice a day in a dairy catchment – well, usually milking.
“The total reactive phosphorus in this dairy catchment spiked, reliably, like clockwork, just after milking each day. That’s another clear sign of the farmyard contribution to watercourses,” Sara noted.
Farmyards aren’t simple
However, Sara did acknowledge that farmyards aren’t simple and that in order to manage something, we first have to break it down into different parts (Figure 1).
How many silage bales high?
Silage effluent is potent. It is full of nutrients, but can be reduced by ensiling silage at a dry matter percentage above 25% where possible. Keeping effluent drainage channels clear is essential. Ensuring that bales are sealed properly or wrapped well also helps to reduce the risk of effluent seeping from bales before they are set to be used.
Sara explained that the way bales are stacked can affect the amount of effluent produced and advised farmers not to stack bales on top of one another where space is available.
How to reduce soiled water?
Sara noted that a soiled yard results in soiled runoff.
Storage requirements are set to increase under the draft proposals of the Nitrates Action Programme, but will this solve problems for nutrient losses? Sara said farmers who run short of slurry storage every year need to increase storage capacity and ensure that tanks are empty before winter to maximize their use.
However, she noted: “Increasing the volume of storage capacity isn’t actually a silver bullet. If you have more storage capacity and you fill that, that’s more water or slurry that you have to spread during a narrower part of the year in principle, so it doesn’t solve your problem at all.
“It comes down to better partitioning and management. Whatever rain happens to fall, whether it’s a large or small amount, if you can separate your clean water from your soiled water and ensure that the water isn’t falling on a soiled surface, you don’t have to store that. If you don’t have to store that, you can allow natural soakage and drainage from your farm take care of it.”
She added that money spent on infrastructure – such as good partitioning and routing, good guttering, diversions and appropriate cambering and slopes – can go a long way to solving storage problems.
“I don’t think more policy or regulation is necessarily the answer. If you just say 30 weeks storage, now you have 30 weeks of slurry to dispose of. That doesn’t solve the problem at all. I really think it’s about managing our water more cleverly and efficiently,” Sara said.
Cleaning sediment from drains
Sediment in drains can also be a source of nutrient loss and in some cases, sediment traps may be needed. Nutrient loss to drains on farms can result in pollution and depleted oxygen levels in water, so it is important to avoid this problem.
Cleaning drains can take away sediment with high P concentrations, but the sediment should then be spread on land low in P to avoid it entering the drain again.
Consult with your adviser before cleaning to ensure best practice from an ecological point of view.