23 Oct 2012

N & P responses for oaten hay

Presentation at 2012 ASA Meeting, Armidale, NSW.

Robert M Norton1, Peter Howie2 and Charlie Walker3.

Oaten hay has found an important place in cropping rotations with around 550,000 t produced for export. This crop is grown as a cash crop as well as a rotational crop to manage herbicide resistant ryegrass. Despite this importance, there is little information on the nutrient demands and removals of oaten hay and to address this, the Dahlen long term fertilizer experiment at Horsham in Victoria, was sown to oaten hay in 2012. The experiment was established in 1996 with five rates of nitrogen (0, 20, 40, 80, 160 kg as urea) and four rates of phosphorus (0, 9, 18, 36 kg as triple super) applied annually over the past 16 years.

The site mean yield was around 6 t/ha of dry matter and samples from each plot were tested for quality through Feedtest (digestibility, crude protein, neutral detergent fibre and the estimated metabolizable energy) as well as the mineral nutrient content. The effect of added P was clear in this experiment, with the first 9 kg of P giving a 77% increase in dry matter. Increasing P from 9 to 18 kg gave an additional 24% in dry matter. However, the higher hay yield was of a lower quality, with lower crude protein, higher fibre content and a lower ME.

Like phosphorus, applied nitrogen had a significant effect on the quality of fodder produced, and extra N increased crude protein content from 8.4% (nil N) to 13.1% (80N). Balancing N and P meant that the yield gains due to the added P also maintained quality by maintaining N supply.

1 International Plant Nutrition Institute, http://anz.ipni.net Email rnorton@ipni.net
2 Melbourne School of Land and Environment, Private Bag 260, Horsham, Vic 3402. www.unimelb.edu.au, Email peterwh@unimelb.edu.au
3 Incitec Pivot Fertilizers, PO Box 54, North Geelong, Vic 3214. www.incitecpivot.com.au, Email charlie.walker@incitecpivot.com.au
N P Oaten Hay.pdf (size: 0.7 MB)

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