Good pasture growth and utilisation is the backbone of any profitable and sustainable dairy operation. A combination of sunlight, soil moisture, soil temperature and the availability of plant nutrients is required for optimum pasture growth.

Nitrogen (N) is a key component of chlorophyl (important for photosynthesis), amino acids (for the production of proteins) and nucleic acids (for cell growth and reproduction) in plants. Pastures need large amounts of N and therefore N is generally the major limiting nutrient in terms of  plant growth.

When selecting your source of N fertiliser it is suggested that growers follow best practice guidelines set out by the  4Rs  Nutrient Stewardship program Doing so will help to ensure nutrient applications are made at the right time, rate, or place, which can ultimately affect your bottom line.

cows in field

Nitrogen Loss in Dairy

Illustrating the Issue

In some regions, the planting of legume crops can improve soil nitrogen, however in southern Australia where dairy farms are more intensive and have higher stocking rates farmers instead opt for Urea fertiliser to meet their soil nitrogen shortfalls

When considering the true cost of fertiliser application growers must account for wasted fertiliser. That is, fertiliser that is lost to the environment before being absorbed by the plant. This can occur through several methods namely, volatilisation, denitrification and leaching. These processes not only result in lost N, they also have potential environmental impacts such as nutrient leaching into water tables, creeks, streams and other waterways.

Poor fertiliser management can lead to reduced production as a result of N losses. It can also create higher greenhouse gas emissions and nutrient loss that all hit the operation’s bottom line.

If we look at nitrogen loss, Dairy Australia estimates up to 74 kilograms per hectare of the nutrient is lost every year to volatilisation, a process where nitrogen is converted into an ammonium gas and evaporates shortly after the fertiliser is applied.

It’s caused by a number of factors, including weather conditions particularly in summer with its high evaporation, dry and warm winds that cause urea to go up like smoke as ammonia gas.

One way to avoid losses to volatilisation is to get lucky with a downpour of rain shortly after application. However, this downpour needs to wash the fertiliser into a depth of greater than 20mm to eliminate loss to volatilisation. And with only 10% of rainfall events heavy enough to do this, it isn’t the most reliable of methods.

Layers of Protection

A more reliable method is to adopt the 4Rs approach as mentioned above. This approach is easily summed as, selecting the right source of fertiliser, applying it at the right rate, at the right time, in the right place.

By adopting this approach you’ll also get the benefit of getting more efficient plant growth, and less nutrient loss that ultimately costs in the form of labour and input. The farmer gets the added benefit of not needing to supplement cattle feed to support milk production as a poorly fertilised operation.

Working alongside the 4Rs approach is the use of a nitrogen stabiliser like Koch Fertiliser Australia’s NEXEN that is urea pre-treated with AGROTAIN.

AGROTAIN has been tested for local conditions in southern Australia and has been tested under a range of conditions by respected research agencies including the University of Melbourne and the CSIRO.

In these field trials undertaken on dairy operations, AGROTAIN reduced nitrogen loss highlighting its efficacy in mitigating the loss of N through volatilisation.

NEXEN benefits the producer as it both supplies and stabilisers nitrogen in one surface application which is achieved as it delays the hydrolysis of urea and stops ammonia volatilisation in the process.

To learn more about how you can protect your nitrogen investment, speak with your KFAUS sales representative.

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