managing organic matter inputs

On-farm practices that increase the amount and manage the quality of organic matter inputs generally have positive benefits for soil biota, with expected enhancement of, or low risk to, other soil functions and the wider environment. Impacts are driven by the increase in energy and nutrient sources for the soil food web and hence are broad-scale with increases in both biomass and activity of all soil organisms commonly measured.

Consider the following recommended practices

  • Using mixed methods for on-farm manure handling –  in particular, reduce direct use of slurry and improve composting
  • Access local sources of waste organic materials (composted or for composting with manures on-farm ) e.g. green-waste composts, paper waste, coffee grounds

In livestock systems, on-farm management changes to manure handling with reduced direct use of slurry and more on-farm composting provide an opportunity to enhance soil health with benefits for soil organisms and soil structure. Similar changes are separately recommended as part of water protection measures. Positive benefits of changes in manure handling seem to accrue largely as a result of the reduced negative effects of slurry application. More work is needed to assess whether there are specific benefits of composting organic matter inputs as part of an integrated strategy to manage soil-borne disease, as well the role of composts as soil conditioners.

In arable crops, repeated regular applications of waste organic matter (local and composted), e.g. green waste compost, mushroom compost, paper waste, coffee grounds, have been shown to have significant benefits for soil biota. The greatest limitation to increased uptake of such organic matter imports and their application seems to be the availability and cost of materials. Where particular materials (seaweed, biochar) are promoted more widely as inputs, they should be assessed with due care in relation to all aspects of soil function; there is currently no evidence that these particular sources provide any additional benefit to soil biota, beyond that of an energy/nutrient source.

In a Natural England project (2011-12) expert judgement on the impacts of the practices was linked with farmer feedback on their likely uptake and effectiveness. A summary of the recommended practices for organic matter management for grassland systems can be downloaded here. Stockdale, E.A. & Watson, C.A. 2012. Managing soil biota to deliver ecosystem services.  Natural England Commissioned Report, No. 100.