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An application of 18:6:12 is needed after the difficult spring. Most dairy farms need to have 60-70 units of Nitrogen/ac applied by early April.
Due to the difficult spring, fertiliser application has been delayed. The next target is to have 90-100 units of fertiliser N/ac applied by May 1st.
Remember that many farms are deficient in P and K (and sulphur) so applying compound fertiliser e.g. 18:6:12 + S (2 bags/acre) needs to be considered.
Application of fertiliser P & K will also help damaged pasture recover. Phosphorus (P) in particular is very important for growth of grass in spring.
Many dairy farms will also respond well to Sulphur (S) application. The target is to have 15-20 units/ac of Sulphur applied by late June.
This can be achieved by spreading Nitrogen + S type fertiliser eg CAN + S (5 units of S), ASN (14 units of S), sulpha 33 (12 units of S).
If you are going to use Nitrogen + S type fertiliser then you need to start in April as there are only about 5 units of S per 50kg bag.