Southwest Environmental Limited

Agricultural Benefit Statement

Spreading compost on farm land is almost certainly going to be beneficial, compost is rich in trace elements, and organic material, and provide an excellent nutrient balance. Even in rich soils it can enhance soil structure and improve water retention.

The difficulty lies in proving agricultural benefit, the addition of compost to a soil will change the balance of minerals within the soil, hopefully providing a benefit.

However, this is not a given fact, and quantitative soil nutrient balancing must be provided with  any deployment application.

Agricultural benefit will be proven when it can be shown that the nutrients in the compost help provide a better growing medium for crops than before it was applied.

Nitrogen, Phosphate and Potassium (N,P,K) values must be established for the soils, and the compost (or other wastes) that are to be applied.

The amount of waste that can be applied whilst still providing a benefit will rely on the following factors.

Image: Michael Trolove / Loading The Muck, via Wikimedia Commons

1 - What is the condition of the soil at present?

In order to assess you soil you must have soil samples taken and sent to an approved laboratory, for testing.

Don't skimp on testing get a full analysis done on the soil samples, to include macro and micro nutrients, to prove benefit you will need to show that the soil is deficient in something. So the more variables you test for the greater chance your consultant will have in proving benefit.

Soil sampling can be carried out using a hand auger, or scissor shovels, and good laboratory to use in NRM, or Mole Valley Farmers offer a Forage Services, Soil Analysis.

2 - How much "off take" did the last crop provide.

"Off take" is how much soil nutrient the last crop "used up", crops differ in the amount of nutrients they use up, if you wish to maximize you waste usage on agricultural land, then proving benefit may be easier if you grow crops that are heavy users of minerals and nutrients.

When you have worked out the soils "need" and the last crops "off-take" you are ready to add up you finding to give your nutrient demand for your soil.

3 - How "rich" is your waste in nutrients.

If your compost is very rich in nutrients you will need less of it to meet the soil's needs.

4 - Timing

The timing of the waste application to land has become a challenging  issue.

A good indicator of whether the activity is appropriate is to review the  General Principles of Waste Recovery or Waste Disposal in the TGN. If  your material was not a waste, would you purchase it to apply at the  proposed time? This is one of the things Permitting Officer's have to  consider when they make their decisions.

If this principle is not being met then it is unlikely we will agree the  activity.

We know some industries rely on the land bank to manage some of their wastes. The land bank  may operate and produce waste for 12 months of the year, however, this does not necessarily  mean that the land bank is available 12 months of the year for all wastes. If your clients are  relying on this then you should discuss other options or increase onsite storage for those months  when the waste can't be sent to land.

5 - Physical Contaminants in Compost or Sludge's

The impact that plastic pollution has on our environment is a current hot topic.  We all have a part to play in ensuring plastics from waste do not enter the  environment through landspreading activities. As a reminder for those deploying  waste composts, the How to Comply guidance document TGN 8.01 states: “The  incidental presence of low levels of contaminants may be acceptable, for  example in accordance with the levels set out in the PAS 100 specification for  compost. Where physical contaminants are known to be present in the input  materials they should be removed prior to the composting or in the final  screening process i.e. in order to achieve the levels set out in PAS 100 Quality  Protocol.”

Therefore if physical contaminants have not been analysed for in compost, then our Permitting Officers will ask  you for it. The limit set out for plastic contamination is 0.12% by weight, and for total contaminants it is 0.25%  by weight. If your compost has levels of plastic and/or physical contaminants higher than the thresholds set out.