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Fine tuning fertiliser applications in 2022 on tillage farms

The situation in crop production has certainly changed with current high fertiliser prices. In 2022 managing production costs will need extra attention in order to maintain profitability. The following are a number of steps to consider when making fertiliser decisions over the coming weeks and months.

  1. Up to date soil analysis will provide a great insight to soil fertility levels of major plant nutrients such as soil pH, P and K. For spring crops where soil pH levels are below the target soil pH 6.5 it is recommended to apply lime to correct soils pH to the optimum range. In addition, up to date soil results for P and K provide the basis for planning P and K applications.  On index 4 soils, omit P and K’s for Index 1, 2 & 3 fertiliser crops based on crop yield potential in 2022.
  2. Nitrogen is a key nutrient in crop production but due to escalating prices, it is recommended to adjust N rates based on fertiliser N costs and grain price. For example in the past the break even ratio (BER) was generally 6:1 meaning that 6 kilos of grain was required to pay for each 1 kilo of N applied.  Currently that has now moved to 11:1 which means nearly double the amount of grain is now required to pay for each kilo of applied N. Based on current fertiliser N prices and projected grain prices the economic optimum rates of N have reduced by ~ 25 to 35kg N/ha.  Research indicates that this will have a small effect on grain yield of approximately 0.2 to 03t/ha but will maximise return from N applied.
  3. Where break crops such as peas / beans / beet / OSR are grown in rotation, these crops return a level of residual N to the soil, which is available for the current crop. It is recommended to reduce N rates up to 30kgN/ha following a break crop.  This offers a large N saving in the current year.
  4. Organic manures are a valuable source of N, P & K and where available again offer a great opportunity to reduce the impact of high fertiliser prices on a proportion of the farm. To maximise the N values of high N manures such as pig slurry it is recommended that manures are well agitated, applied evenly and incorporated within 3 to 6 hrs.  It is also recommended to have manures tested to determine their nutrient values. 
  5. Green covers on stubble fields are exceptionally good in 2021 due to the very mild autumn and good growing conditions. Measurements show that these crops have taken up from 10 to 60kgN/ha over the winter period depending on crop type and sowing date. It is estimated that ~ 0 to 20% of the N in these crops maybe available to the current crop depending on the crop type.