Slurry spreading plan beside a stream
A 55 ha dairy farm milks 130 cows and has slurry storage for 14 weeks. The yard drains to a stream that runs along the lower boundary; the stream is also a source of drinking water for a neighbour's cattle. Soil tests show P index 4 in four paddocks beside the stream and index 2 in the drier paddocks on the upper farm. The farmer plans to spread slurry in February on the low-lying riverside paddocks because they are closest to the yard and the tank is nearly full. The weather has been wet, with more rain forecast, and some paddocks are waterlogged. The farmer has a trailing shoe applicator and a contractor with a dribble bar. A nitrates inspection is due in three weeks. The farmer asks for a spreading plan that avoids trouble and uses the slurry where it is most needed.
1. Identify the main environmental and compliance risks in the farmer's plan, and explain why the riverside paddocks are the worst choice.
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The riverside paddocks are already at P index 4, so they do not need more phosphorus and are likely to lose it in runoff. They are low-lying, close to the stream and waterlogged, so slurry and nutrients can move directly into the water. The stream supplies a neighbour's cattle, which adds a public health and nuisance risk. Spreading in February with rain forecast increases the chance of runoff and of slurry being washed off before it is taken up by grass. The yard drains to the stream, so any spill or dirty water from the yard is also a risk. The farmer is spreading near the stream mainly for convenience, not because the land needs nutrients. The upcoming nitrates inspection makes record-keeping and compliance important, and a visible breach could lead to enforcement action.
2. Set out a spreading plan for the next few weeks. Say where the slurry should go, which fields should not receive it, and what equipment and timing you would use.
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Do not spread on the riverside paddocks while they are waterlogged, frozen or within the required buffer zone of the stream. Keep a generous uncultivated buffer strip beside the watercourse. Prioritise the drier upper paddocks at P index 2, because they need the nutrients and are further from water. Use the trailing shoe or dribble bar rather than a splash plate to reduce contamination of grass and runoff. Check the weather and soil conditions before each load; spread when the soil is trafficable and rain is not imminent. Work on the flatter, drier parts first and keep away from ditches, drains and the yard drain. Reduce the application rate and increase the area covered rather than applying a heavy dose in one place. Keep records of date, field, quantity and weather. If storage is still tight, move slurry to a safe storage area or have it exported rather than spreading it on unsuitable land.
3. What longer-term changes should the farmer make to reduce the risk of this situation recurring?
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The farm needs more slurry storage, because 14 weeks is tight for 130 cows and encourages spreading when conditions are poor. The farmer should prepare a nutrient management plan using soil tests, calculate the slurry and fertiliser balance for each paddock, and stop applying phosphorus to index 4 fields. The riverside paddocks should be fenced off from the stream, and the buffer strip should be maintained. Roof clean water should be separated from dirty water to reduce the volume entering storage. The farmer should consider low-emission spreading equipment, clover in the sward and reduced chemical phosphorus, and should keep accurate records for inspections. Regular soil testing and a rotation that uses nutrients where they are needed would reduce the pressure to spread near the stream. These changes address the cause, not just the next inspection.