Soils

Owl Farm has some of the best soils in New Zealand, ideally suited to horticulture or intensive pastoral farming. Healthy soil provides the optimal environment for plants to access the water and nutrients they need to grow. Regular testing helps us understand what’s going on in the soil, and how we can improve it.  When the balance is right, healthy soil grows healthy food, protects water quality and even helps reduce greenhouse gases.

The three main elements of soil health are:

  1. Physical – the way in which soil components (sand, silt, clay, organic matter, pore spaces) are grouped together to form soil structure.
  2. Chemical – the cycling of nutrients (e.g. nitrogen, phosphorus) in soil for plants to grow.
  3. Biological – the living organisms that decompose organic matter, providing nutrients to plants.
  

The New Zealand land resource inventory uses Land Use Capability (LUC) to describe soil characteristics. 89% of the farm area at Owl Farm is classified as 1s1, with the remainder at 3s20.  This indicates high suitability for a range of land uses including cropping, horticulture and pastoral farming.  The “s” indicates the main physical limitation of the soil being shallow, stony and low water holding capacity – which makes us prone to summer dry.

The soils are predominantly Allophanic soils (Otor_41) with pockets of Gley soil (Puhin_8) and Brown soil (Kainu_2) and some Pumice soils on the lower terraces (Turan _35). 

How we protect the quality of our natural soil resources

Owl Farm has a 600ml soil moisture and temperature probe installed in the middle of the farm.  The data it provides is published in our weekly notes.  We use this data to plan our N fertiliser use and to predict changes in growth rate for the coming weeks.  We analyse long term trends to plan for the impact of summer droughts and prolonged wet and cold periods on feed supplies.  

Visual Soil Assessments (VSA) are used to evaluate the physical health of the soil.  By understanding what is happening in the soil we are able to manage it better.  We also:

  • Direct drill crops and new grasses to minimise soil disturbance (no cultivation)
  • Complete annual soil tests to ensure correct fertiliser application
  • Avoid excessive nutrient levels and maintain pH between 5.8-6.2
  • Have planted buffers between the farm and the river (including the Te Awa cycleway)
  • Retire any steep land that carries the risk of erosion when grazed by cattle
  • Avoid pugging damage in the winter by moving cows onto a new break during wet periods