North Coast Local Land Services recommended best practices for Fertilising Pasture

Soil deficiencies of nitrogen, phosphorus, potassium, sulphur and molybdenum can limit plant growth. Soil analyses done well before planting, or plant tissue tests done to sort out nutrient deficiency symptoms, will aid fertilizer and lime application decisions. Talk to our friendly team for more detail.

Fertiliser recommendations in this guide are given as ratesof actual nitrogen (N), phosphorus (P), potassium (K) or sulphur (S). Different fertilisers contain different quantities of each element.

NOTE: To avoid fertiliser burn to seedlings avoid drilling more than 20 kg N + K/ha in direct contact with seed in narrow rows (around 18cm)

Fertiliser Recommendations:-

Nitrogen (N)

Promotes growth of grasses like setaria, kikuyu, ryegrass and oats and also brassicas. Broadcast up to 60 kg N/ha for establishment and up to 60 kg N/ha/month (or after grazing) to maximise temperate and tropical grass as well as winter cereal growth.

Legumes also add nitrogen. Ensure effective nitrogen fixation in legumes by inoculating and lime coating all legume seeds (clover, lotus etc) with the correct inoculum.

Phosphorus (P) and Potassium (K)

To achieve good pasture performance with good legume growth, aim to maintain soil P at or above the following levels:

Soils much higher than these levels (eg. many chocolate basalts and Kyogle alluvials) are fairly unresponsive to P fertiliser. However, low P soils (eg. Sandstones, shales and granites) generally require up to 35 kg P/ha in the first year and then 25 kg P/ha/year for at least 3 years to achieve these levels.

Farmers are encouraged to balance any P loss from their system with added P fertiliser. Dairy farmers growing intensive pastures will often need to balance K loss with added K fertiliser. For example, a dairy farm running 2 cows/ha and averaging 5800 L milk/cow off pasture and 1.2 tonne concentrate/cow/year needs about 27 kg P/ha/year and 25 kg K/ha/year to balance losses.

Potassium - apply up to 50 kg K/ha to intensive dairy pastures on low K soil up to three times a year when you expect good growing conditions. Plants can take up more K than they need, so do not apply any more than about 50 kg K/ha (100 kg/ha muriate of potash) in one application.

Sulfur (S)

Pastures on most north coast soils, especially those containing ryegrass or clovers, usually respond to S. High P soils such as chocolate basalts are especially S responsive. Seedbed cultivation often releases enough S for one year. However, pastures sown into uncultivated seedbeds require about 25 kg S/ha at sowing. Up to 30 kg S/ha/year is usually enough for less intensive pastures, however intensive temperate dairy pasture (especially high N rye) often needs more, so apply 20 kg S/ha in about April, and again in about August to ensure needs are met.

Note: Superphosphate, SuPer 40S, and gypsum are good sources of Sulfur. Fertilisers containing sulfate of ammonia are a convenient but far less desirable source of S, because of their acidifying effect on soil.

Molybdenum (Mo)

About 50 g Mo/ha is needed, particularly by legumes on acid soils. The higher P sorbing basalts need this every 3 years, and the sandier soils every 5 years.

200 kg of Super Mo 0.025/ha gives 50 g Mo/ha.
100 kg of Super Mo 0.05/ha gives 50 g Mo/ha.

Do not apply more Mo than recommended as it can cause copper deficiency in animals

Lime

Very acid soil with high aluminium restricts growth of crops and pastures, particularly legumes (lucerne is most sensitive). Lime or dolomite rectifies high acidity. Use lime if calcium is down, or dolomite if magnesium is down. On intensive pasture try to maintain pH (CaCl2 method) at or above 5. For lucerne try to get pH to 6 or more.

Valleyr Rural and Pet Supplies would like to acknowledge this extract is taken from  - http://northcoast.lls.nsw.gov.au/__data/assets/pdf_file/0003/511662/Pasture-sowing-guide-AW-2014.pdf