North Coast Local Land Services, Far North Coast Dairy Industry Group and Norco Foods are conducting local trial work at NSW Department of Primary Industries Wollongbar to assess the benefits of foliar urea applications to pastures.
The trials are managed by Nathan Jennings (Senior Land Services Officer North Coast Local Land Services) & Dr Bill Fulkerson (Research & Development Officer Norco Foods).
Nathan Jennings, Senior Land Services Officer said of the trial, “If we can confirm for the North Coast region that there are benefits of applying Urea as a foliar spray to short term ryegrass and kikuyu pastures, it would likely have a significant reduction in on farm fertiliser costs, improve pasture production, and help with environmental concerns over nitrogen leaching/volatilisation.”
In recent years there has been an increasing interest in the southern states of Australia and in New Zealand, in applying Urea or other Nitrogen based fertilisers as a foliar spray. In theory, applying Urea (nitrogen) to the leaves of the grass plant directly as a foliar spray should be more efficient than traditional urea granules applied to the soil.
Nathan explained further, “Direct spray is perceived as more efficient because with a foliar application the Nitrogen does not have to move through the soil to the plant roots before it is taken up by the plant, rather the nitrogen is absorbed through the plant leaves.
“It is in the soil where a high proportion of the total Nitrogen loss typically occurs such as volatilisation to the air, leaching beyond the root zone, or leaching under waterlogged conditions.”
Results of some basic studies over very short times frames of one to three grazings, have indicated that Nitrogen application rates can be reduced to 40% if applied as a foliar spray compared to granular, but other results have been more variable. However, all the research on this has been on perennial ryegrass which has a higher plant density than short term ryegrass, meaning that a short term ryegrass pasture may result in a lower proportion of spray Nitrogen being taken up by the leaves.
The combined study will run for twelve months and will examine foliar Nitrogen applications on short term ryegrass and kikuyu.
Nathan continued, “It is important in our environment to assess the potential benefits of foliar Nitrogen application to a tropical grass pasture such as kikuyu because tropical grasses always have a lot of green leaf or stem/stolons left after grazing and our theory is that tropical grasses should be able to capture even more foliar Nitrogen.
“The study will also look at the effect of foliar Nitrogen application on the pasture plants and changes in soil Nitrogen levels by intensive grass and soil sampling to enable us to clearly understand the way the foliar Nitrogen application to pastures works.”