Earthworms improve the general condition of farming soils, reduce surface runoff of contaminants from pasture and prevent soil erosion.
Far better is to use a dedicated, specially built pad to feed out supplements or to prevent stock from wandering all over the farm and damaging pasture along the way.
However, the use of sacrifice paddocks is better than no winter stock management at all to protect pasture. So there are recommended ways to minimise the bad effects of using sacrifice paddocks – if they have to be used.
Before detailing those practices it’s worth recapping on why winter stock management to protect pasture is so important.
Winter grazing can markedly affect late winter and early spring feed supply from pasture, damage soil health and undermine the health of waterways.
With soil health, every effort must be made to keep soils in good physical and biological health as they are the farm’s most valuable resource.
Moist and wet soils are less able to support the weight of grazing stock than dry soils and are susceptible to compaction and pugging. Treading on moist soils can lead to compaction and grazing on wet soils can lead to pugging damage. The resulting damage to pastures influences their current and future use.
Compaction and pugging influence the supply of air, water and nutrients to the roots, which significantly affects pasture productivity. It also creates the potential for sediment and nutrients to affect the health of waterways and groundwater.
Research data indicates that spring pasture production may be reduced by about 10% for every 10% of the paddock pugged.
As I’ve indicated, treading damage and compaction can be minimised by confining stock to stand-off pads or feed pads at times of greatest risk. That’s the best bet for minimising pasture and general environmental damage.
For those who cannot do this, selecting a sacrifice paddock on which to stand off stock from other pasture or to feed out is the last resort option.
Usually a paddock with rundown pasture is selected. Ideally, there should be enough shelter available that stock can be continuously housed in these paddocks without undue stress.
As part of ‘on-off’ grazing, stock are moved between normal pasture and the sacrifice paddock. If used in this way for more than a few days, the sacrifice paddock will likely be severely damaged and require a full pasture renovation.
Aside from that severe damage, other disadvantages of sacrifice paddock use include damage leading to improper drainage, more runoff and a higher risk of sediment, effluent and nutrients getting in waterways and groundwater.
There’s also an increased risk of mastitis and lameness in muddy conditions, and animals may not get their full daily feed requirements.
A further risk is that soil potassium levels can get too high, as a result of potassium being excreted in stock urine, which can predispose calving cows to metabolic problems.
Some of these risks can be lessened by a range of techniques.
Don’t spread feed in the same area all the time. Use different spots around the paddock.
Drag a set of light harrows around the paddock occasionally to help break up excreta. This ensures good exposure to sunlight that will kill pathogens and parasites that could otherwise build up in the paddock.
Avoid use of sacrifice paddocks closer to waterways, property boundaries and significant ecological features such as wetlands, caves and geothermal features.
Direct any runoff in the paddock on to flat ground with rank grass.
When use of a sacrifice paddock finishes, re-sowing should be done after a light cultivation. With any renovation it is important not to leave it too long before the first grazing. A simple way to check when pasture is ready is to grab some grass between thumb and forefinger and gently pull upwards. If roots come up, wait a bit longer.