Pesticides, soil erosion and water Understanding the interactions and some management solutions

Contents Background Pesticides and water Soil erosion Managing soils

There is a problem! Frequency of detection above 0.1 ppb of PPP’s since 1995

IPU levels and River Flow Intense rainfall on Nov increased river flow, water very turbid (soil particles) likely to be surface run off taking IPU to river

Water movement from Fields

Environmental Quality Triangle Soil Air Water Q Soil Quality is the Basement of Environmental Quality

Rilling Deposition Runoff Compaction / Capping => Soil Erosion

Soil Erosion In England and Wales, Erosion moves some 2.2 million tonnes of arable topsoil every year This contains nutrients &pesticides The equivalent of a 1cm layer of soil lost each year! It all ends up in water

Minimise Erosion Crop or Trash Cover avoid bare ground drill early

Stop raindrop impact! Small rills in tractor wheelings Larger rill along a headland wheeling

Minimise Erosion Cultivation Type Don’t create very fine seedbeds which can cap and slake if heavy rainfall occurs, stopping infiltration Soil Organic Matter Helps keep stable soil structure which is less likely to be broken by raindrops

Capping and Compaction will promote soil run-off, containing nutrients and pesticides and reduce pesticide efficacy This headland would be ideal for an ELS buffer strip

Beetle Banks or Grass Strips can slow water movement to watercourses at least 6m wide site across slopes where gradient increases Spot the error! This strip runs up/down slope rather than across

High Risk Situations Soil type sandy soils are the least able to retain pesticides and nutrients; drained, structured clay soils can rapidly transport pollutants. Crop cover bare ground over the winter is most at risk. Capping and compaction promotes soil run-off containing nutrients and pesticides.

Soil Organic Matter Higher levels are a good thing Improve soil structure Binds nutrients and pesticides But High levels of organic matter and associated microbial activity in the topsoil enhances pesticide breakdown and lock-up. This may reduce pesticide efficacy and losses off the field.

Things to consider Slope – particularly if tramlines are compacted Use a buffer strip to protect a water course, provided that the water reaching it is moving at low velocity Plough the land way from the buffer strip to leave a furrow (but not a watercourse!) Don’t access the field by driving through a buffer strip Don’t let wheelings enhance run-off to buffers

Buffer strips against watercourses reduce the loss of pesticides, nutrients and sediment to water. Use Setaside, ELS, or HLS options

Where buffer strips will not work Buffer strips can’t stop everything! Buffer strips need time to establish; even this one is better than nothing

Risks and Solutions Activity Risk Solution Run-off Moderate Minimise erosion to high Use buffer zones Drain flowVery high Consider soil, SOM or leaching Better management

40-60% 5-10% 10-20% Typical ways in which agricultural pesticides can reach water from the field Promoting Best Practice In the Field

Follow VI H2OK Best Practice Advice Crop Protection Management Plans Soil Management Plans Environmental Stewardship Scheme Environmental Information Sheets Decision Support Systems Use available tools to minimise risks to water

How might Environmental Stewardship help? Valuable options in ELS include: Crop Protection Management Plan Soil Management Plan Not growing certain high-risk crops Creating buffer strips alongside watercourses Planting beetle banks Managing hedgerows Organic management opportunities for higher payments Targeted areas HLS may provide some solutions too

Avoiding diffuse pollution Farmers and agronomists need to identify risks to water from the rotation and crop protection plans Consider if lower doses and pre-emergent treatments are appropriate Listen to weather forecasts pre–spraying Avoid spraying if soils are heavily cracked Follow Decision Trees especially if rain is predicted or soils are near field capacity and drains are likely to flow On steeply sloping/poorly drained fields, only spray when run-off risk is low

Soil Management Manage soils to ensure that water cannot run-off from the treated area onto another field, road, track or other feature from where it could directly enter a watercourse Do not overwork the soil so that it becomes slaked or capped; Delay pesticide applications until after the first rains when deep cracks in the soil have closed; Tramlines should run across slopes NOT down slopes leading to a watercourse; Drill in tramlines where possible; 50% trash cover and rapid crop establishment can reduce the impact of raindrops which break down soil crumbs and can trigger soil erosion. Risks can be reduced further by the additional measures listed below. These require long term planning. Review rotations to avoid cropping practices and cultivations on soils and slopes which are at risk of erosion. This should be part of your Soil Management Plan. On slopes over 5% (1 in 20) running for more than 200m, establish a beetle bank or at least 6m grass strip across the entire field. Locate this break where the slope increases; Grass down valley bottoms leading to any watercourse.

Decision Trees IPU CTU and Simazine Mecoprop-p

In Summary Soil erosion and surface run-off can result in pesticides, nutrients and sediment reaching water. Awareness of the issue, thoughtful planning and good soil management can reduce the risks Careful soil management does not solve all pesticide problems because not all pesticide losses are linked with cultivation. E.g. filling, washdown, disposal, drift Soil and water interactions are variable; delivery of environmental benefits requires a constant high standard of management and agronomic skill.

Prepared by Paddy Johnson and Vic Jordan on behalf of SMI, with the help of CPA staff & members, TAG, and AIC members Photos - from above, AMEWAM, Jim Orson and padre productions