What are Point Sources ?

Point sources are related to the handling of Plant Protection Products (PPP) mainly on the farm or farmyard. Point sources contribute > 50% (up to 90% in some studies) to the PPP entries into surface water. Point source can be largely avoided if the operator follows Best Management Practices and if the equipment and infrastructure measures are optimized.

Key risk areas for point source PPP – losses to water are:

     Cleaning of sprayers on farmyards

   Dosing of PPP / Filling  of the sprayers / Cleaning and storing of empty PPP containers

    Management of remnant liquids (Remnants are diluted spray liquids resulting from internal and external cleaning processes or the maintenance of sprayers

   Transport

     Storage

Mitigation measures concentrate to collect / avoid spills by optimizing sprayer equipment  (sprayers with cleaning systems, low residual volumes) and infrastructure (washing places, biobed/ -filter)

What are Diffuse Sources ?

Diffuse sources are mainly related to the PPP application in the field.

Main entry routes into surface waters are:

Runoff/erosion: transfer of PPP with excess water/ soil particles of the field.

Runoff/erosion is estimated as the most significant diffuse entry route. It can be significant if respective rain events, soil conditions and landscape factors (slope, field length, etc.) favour water transfer out of the field.

Mitigation measures concentrate to keep water in the field or catchment by increasing the water infiltration capacity of the soil, by agronomic practices, by vegetative buffers or retention structures.

Drain flow (Drainage); Drainage systems are mainly active in late autumn to early spring.

If PPP applications are made during this drain flow period, pollution of water via drainage can be at risk. Mitigation measures focus on optimizing the timing of crop protection practices and selecting the most suitable products.

  Spray drift: off target deposition by wind

Technical mitigation measures concentrate on reducing the amount of small droplets prone to drift and to improve adjustments of sprayers. Indirect measures focus on buffer zones/vegetative buffers.