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WATER QUALITY

(a) Arable reversion to grassland/unfertilised grassland (Rural Priorities)

Rationale for intervention

There are only small losses of nitrate in drainage waters from arable reversion grassland, and the permanent vegetation cover minimises the erosion of soil particles and loss of associated phosphate in surface run-off.

Low inputs will mean that high levels of nitrogen do not accumulate in the soil, and uptake by the continuous vegetative cover and immobilisation into accumulating soil organic matter will provide a sink for the nitrogen that is available. Changing from intensive arable agriculture to extensive grassland is therefore expected to markedly reduce nitrogen and, to a lesser extent, phosphate losses. In most cases, losses of nitrate in drainage water will respond rapidly to the change of land use. However, where previous intensive fertiliser use has raised soil P contents, significant reductions in the leaching of soluble phosphate are unlikely to be achieved in the short term, because there are only low off-takes of nutrients from extensive systems; elevated levels of phosphate will continue to be recycled through the soil. The more immediate effect of this measure will be to reduce phosphate losses in surface run-off, provided that the grassland is not poached. The change to soil with a permanent vegetative cover will reduce soil erosion and the transport of sediment and associated phosphate to watercourses.

Objectives

The aim of the measure is to reduce diffuse pollution, reduce soil erosion and associated nutrient loss in run-off and reduce emissions of nitrous oxide and ammonia by changing land previously in arable production to permanent grassland, either ungrazed or with low stocking rates and with zero or low fertiliser input.

Scope and actions

Support for reducing losses of N and P by changing the land use from arable cropping to permanent grassland with low stocking rates and with zero or low fertiliser input.

The measure is applicable to all forms of arable farmland but is potentially most suited to marginal arable land that was historically kept as grazing land. Benefits will be greatest on fine textured soils that are most prone to erosion.

It may be particularly suited to areas where the converted land would have amenity or conservation value.

Beneficiaries must carry out the following:

• Cultivate and establish a permanent grass sward
• Only apply sufficient fertiliser initially to establish the grass sward.

Once the sward is established:

• Control grazing to limit poaching and avoid damage to river and loch banks.
• Do not apply lime or fertilisers, including slurry or farmyard manure.
• Control statutory weeds, giant hogweed and Japanese knotweed (see control of invasive/non-native species measure).
• Do not cultivate.
• Do not clear existing drains or cut new drains except with prior written permission of Scottish Ministers.

Description and justification of the different types of commitments, based on their expected environmental impact in relation to environmental needs and priorities

Reduce losses of nitrogen and phosphate by changing the land use from arable cropping to permanent grassland, either ungrazed or with low stocking rates and with zero or low fertiliser input.

There are only small losses of nitrate in drainage waters from arable reversion grassland and the permanent vegetation cover minimises the erosion of soil particles and loss of associated phosphate in surface run-off.

Effectiveness:

Nitrogen: Very effective. Ungrazed grassland reduces N losses by over 95%. Annual losses can be about 2 kg N/ha of converted land, assuming a baseline leaching loss of 40-50 kg N/ha. For extensive grazing, losses are 20 kg N/ha per year.

Phosphate: A study in England, PE0203 Measure 14 'Convert arable to beef and sheep', was used. It was noted that the total phosphorus loss from all-arable land is some 3.8 kg/ha/year, whereas that from beef /sheep land is 1.6 kg TP/ha/year. However, this is more indicative of the long-term reduction, after a run-down of soil P contents over several years. For the short-term, a more valid comparison may be with intensive grassland where there will be high soil P contents. This suggests a smaller reduction.

Agri-environment Baseline

Amounts of support

The payment rate has been calculated on the basis of additional cost and income foregone from the commitment made. Hectarage limits apply.

Payment Rate: €351.48 per hectare. This includes the cost of establishing the grass sward.

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