Investigating the pattern of Nitrogen release from a spring injection of liquid nitrogen on grazing ground

The Wheelers have used a spring injection of liquid urea/ammonium nitrate on their grazing ground for many years and are interested in understanding more about how efficient the practice is together with the pattern of release and mobilisation of the nitrogen(N) in the soil.

Liquid injection of N is thought to reduce the negative impacts of volatilisation and also maintain a continuous delivery of N to grass for several months after injection. While there are many anecdotal claims for a sustained and even supply of N and the potential benefits for supply at rooting depth and especially under drought conditions, there is almost no research on the use of injected liquid N.

With grass growth measurements already being recorded on the grazing platform by using a rising platemeter and recorded into AgriNet, there is scope to carry out an evaluation of this application method in terms of its NUE (Nitrogen Use Efficiency).

Aspects that will be investigated:

Is the system delivering an efficient use of N in terms of kg dry matter (DM) grown per kg N injected?
Does injection increase soil residual N and the risks of winter leaching losses?
Is the delivery of N constant, or is there a risk of excessive uptake of N by the grass with subsequent negative effects on grass quality, NUE, and animal performance (e.g.high milk urea levels)?

Through driving further improvement in efficiency in these key business areas, the project will also contribute to the Sustainable Land Management outcomes including:

  • Clean air
  • Clean water
  • Maximising carbon storage
  • Reduced greenhouse gas emissions
  • Mitigate flood and drought risk
  • Resource efficient

Alleviating soil compaction to improve soil health

Clyngwyn  is mainly on the brown podzolic soils of the Manod series.– These clay loamy soils are generally free draining but with high rainfall can become easily saturated and prone to compaction.

Research has looked at potential benefits of aeration machines (knifed rollers and legged machines) and results have been varied depending on soil type and timing of operations, but frequently show reductions in bulk density and soil moisture. See Batey (2009) for a review.The Wheelers have proposed using a knifed roller Grass Care / AerWorx to try and alleviate some of the damage and improve soil health. 

The project will contribute to the Sustainable Land Management outcomes including:

  • Clean water
  • Maximise carbon storage
  • Mitigate flood & drought risk
  • Reduced greenhouse gas emissions
  • Resource efficient