The cropping program is based on a full stubble retention system using a Cross Slot No Till seeder. A 3m controlled traffic system is used with 9m (seeder, combine/header, lime/gypsum spreader) and 27m (SP sprayer, urea spreader) working widths. All crops are direct headed.
The soils are predominantly duplex and range from fine sandy clay loams to light clays and the annual rainfall is 500mm/20", with the majority of the rain falling from March to October. Seeding occurs in April/May with harvest in November/December.
I became interested in cover cropping/opportunistic summer cropping after visiting Dwayne Beck in South Dakota in 2004 and seeing the trials with summer crops in a low rainfall environment (350mm/14" from memory) and the trials showed positive crop responses in the following wheat crop after sunflowers and millet compared to the stubble fallow treatment. The lesson I remember from Dwayne was to plan for failure in the rotation - it was better to have something growing in the paddock and have it fail. The adoption of a no till system with full stubble retention 4 years later gave me the opportunity to test the system if the opportunity arose.
A summer crop trial was established on my farm in spring 2009 with University of Melbourne and the National Water Commission looking at the potential for sunflowers, mung beans, white French millet, lab lab and safflower. The crops were seeded into a wheat stubble and with above summer rainfall, all crops were harvested except the lab lab, which had DM cuts taken off it as it is a forage crop.
The millet crop was the standout financially and given we had wet harvests the 2 following years, shirohie millet was sown as a cover crop, but both years the crop was harvested for seed due to the high summer rainfall. As in the trial, the millet crops were the the best ever gross margins and wheat was able to be seeded straight back into the millet for a double crop.
The cover crop interest has developed as I look at how to increase the diversity in the rotation of
3 main crops currently grown. With the cover crops/summer crops, the seeding window is opened up from 2 months to potentially 8 months of the year with the various crops we can grow. Although in an area where farmers wouldn't traditionally consider growing summer crops without irrigation, the variability and intensity of out of season rainfall may allow increasing opportunities for seeding. There are many potential benefits from the cover crops, the question is what role they can play in a farming system such as ours.
As with the cover crops, I have been interested in managing Nitrogen (N) in the farming system. The faba bean part of the rotation obviously plays an important role in N supply for the following 1-2 crops, but as there are four crops until the following faba bean crop, the need for artificial fertiliser is required. urea is the main N fertiliser used and is spread on the crops, according to a N budget for each paddock, just before a rain front to minimise volatilisation losses. The efficiency of urea uptake is only 40-50% in this system, so I am interested in what options there are in terms of application equipment and fertilisers to increase this N efficiency. The CULTAN (Controlled Uptake Long Term Ammonium Nitrogen) system I saw in Germany in 2012 and was impressed with the technique, and so I am interested to see what application it could have for Australian conditions.
The opportunity to undertake travels around the world under the banner of a Nuffield Scholarship is a fantastic opportunity not to be missed. I am always looking at how and why we do the things we do, and I'm sure I will be able to provide some options and answers to these questions.