Following the planning article on developing a feed wedge, lets talk about the pasture height or quantity and the amount and type of nitrogen to apply.
Firstly, the nitrogen influences the size of the emerging leaf, often the number of tillers and not the time it takes for the leaf to emerge. Its best to have the grasses about 3 to 4 cm high and apply the nitrogen just after the stock have been removed. This season in some paddocks it might be necessary to apply before a grazing, but there needs to be sufficient leaf area.
Further it takes about 4 to 5 days for the plant uptake to begin. And its best to leave the pasture ungrazed for a further 10 to 12 days. This ensures leaf emergence to utilize the applied nitrogen. The time lapse can also help mitigate any likely health issues from very high plant nitrogen levels.
Urea and Ammonium sulphate individually or in a mix are usually the products to consider at this time of the year. If sulphur is not required then Urea often is the cheapest source per unit of nitrogen.
Generally 35 to 45 kg of actual nitrogen per hectare is considered the most economical. If the ryegrass is dominant and the growing conditions of soil temperature and moisture are ideal aim for the higher end of the rate.
Article by Peter Flavel, Agronomy Advisor Meridian Agriculture
M: 0427 755 507 E: firstname.lastname@example.org
Article Series – Nitrogen on Pastures Check List
This is the second article in a series of three with a focus on Nitrogen on Pastures. See below for links to the other two articles in the series: