Soil can’t be replaced in your lifetime…..look after it.

A new report1 has found New Zealand is losing 192 million tonnes of soil every year from erosion with 44 percent of soil losses came from pasture land. This is equivalent to 84 million tonnes of soil lost each year.  The erosion problem is severe, and this report indicated that even grass cover is failing to prevent it and the loss of tree cover was largely responsible.

Soil is formed through the complex interaction of factors such as climate, underlying geological material, vegetation, animals, humans, topography, and time3.  It can take hundreds to thousands of years to form just one centimetre, meaning soil resources are non-renewable in a human lifetime2.  The saying ‘out of sight, out of mind’ holds true with soil. Considering so much of the Earth is covered with soil, it is easy to think of it as a never ending resource3.

Soil loss through erosion can occur across large areas when wind, rain, and/or land use disrupt the soil. This type of erosion occurs predominantly in areas with bare or cultivated ground and heavily grazed or drought-affected flat land and hilly slopes.

Soil productivity can be affected when the topsoil is lost. Topsoil loss associated with landslides can result in soil degradation and pasture productivity losses that may not be regained within human timescales. Reduced soil productivity can lead to a greater demand for the addition of nutrients (typically through fertiliser) which brings its own financial and environmental burden. The economic losses associated with soil erosion and landslides are estimated to be at least $250–300 million a year1.

How to minimise soil loss on your property4:

- Use minimum or no-till cultivation practices, such as direct drilling
- Re-sow areas of bare or damaged soil as soon as possible
- Avoid heavy stock grazing on steeper, more vulnerable soils, especially when wet
- Fence stock out of waterways
- Plant riparian margins
- Leave buffers when cultivating, over sowing, topdressing and/or burning
- Install sediment traps (such as decanting dams or detainment bunds) where appropriate
- Plant trees on vulnerable areas of the farm, to stabilise the soil and reduce erosion.

Information Sources:

  1. http://www.mfe.govt.nz/publications/environmental-reporting/our-land-2018
  2. MPI 2015 https://www.mpi.govt.nz/dmsdocument/10397/loggedIn
  3. Soil Science of NZ website https://nzsss.science.org.nz/i-love-soil/
  4. Beef and Lamb Website https://beeflambnz.com/compliance/environment/holding-soil