Nitrogen application and budgeting

Case study: Chris Baker of Baker Ag Advantage, Forbes NSW – Managing his clients’ nitrogen applications and requirements in their stubble retained farming systems.

Overview:

Chris manages a consultancy business for dry land and irrigation, mixed and continuous cropping farming enterprises in Central West NSW, focusing on management of crop rotations, herbicide choices and crop nutrition.

His clients’ enterprises are an approximately a 50/50 mix of continuous cropping and more traditional mixed farming operations including livestock.

Although covering an area from North of Condobolin to south of Forbes it is more his clients’ preferences to a certain type of operation than any given area dictates.

Nitrogen requirements for his clients including the 2015 season:

The 2015 got off to a “perfect start” with a wet winter and good moisture profile, so nitrogen budgets were aimed at an above average crop. In some cases though possibly too much urea was applied considering the dry finish, leading to an overabundance of canopy for the available moisture.

Chris’s strategy for advising his clients on nitrogen management begins with soil testing to determine available N for the coming crop. He prefers a deep soil test to gain an understanding of N throughout the entire profile and uses the results as a benchmark to begin the crop’s requirements for the season ahead.

A soil test does not need to be done in a paddock every year as a nutrient budget can be also be determined by the previous year’s yield.

Then, once the available N is known and compared with available stored moisture and predicted season Chris has the conversation with his client to assess nitrogen requirements for the coming season.

This will also include what result the client is looking for. Are they are aiming to grow a 2.5 t/ha crop of APH wheat? Would earlier application of N be more beneficial than later applications?  Is the risk worth the possible reward?

With regards to time of application Chris goes by the old rule of thumb of applying 70% of N demand at sowing time and 30% in-crop. Better results are obtained from earlier applications in most seasons, and more N is available to plants when applied in soil than top dressed N.

2015 proved a difficult season as for some crops too much N was applied early leading to a large amount of leaf matter and a drier profile during the crops finish. A “trickle feed” approach would have been the better option, but in a drier growing zone the opportunities don’t always arise later in the season. However in 2015 growers who applied nitrogen still came out ahead in yield and protein at harvest.

One big change Chris has observed however is an improvement in machinery by many growers, allowing them to move in quickly and apply N when needed. The use of boom applied foliar applied N products should also be worth watching into the future. Until now these products have been a bit hit and miss but are improving.

Chris also maintains that yield increase should be the overriding goal rather than aiming to increase protein. Many barley crops this year also had extra N applied throughout the growing season. Yield is king.

Within his client base in central west NSW break crops and good nitrogen fixing pastures play a large role in maintaining N in the soil. Although last season the final yields of some break crops were low they still fixed a large amount of N as they grew well throughout the season and had good biomass.

Lupins are popular with many mixed farming clients for both stock feed and nitrogen fixing. Brown manuring is not done so much but Chris can see the benefit in growing a break crop to a point where it fixes N, then spraying it out to maintain ground cover and store moisture for the following crop.

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