FutureDairy’s Yani Garcia says management has a big impact on the profitability of a high input crop such as maize.
“A profitable maize crop is achieved by optimising both yield and nutritive value,” Professor Garcia said.
“Very high yielding maize crops are not necessarily the most profitable as they tend to be higher in fibre and therefore have lower nutritional value.”
Prof Garcia has five tips for achieving a profitable maize crop:
Do not apply the full amount of nitrogen fertiliser unless you can ensure water will not be limiting.
If water is likely to be limiting, adjust nitrogen application. For example, N application at both pre-sowing and at V6 stage are highly recommended, but if you need to adjust, save the N for the V6 stage.
Time water application for greatest response.
If irrigation water is likely to be limiting, resist the temptation to under-irrigate throughout the whole season. You’ll get a much better response to water by timing water applications to the critical periods at crop establishment (up to about six leaf stage) and the five to six week period around tasselling.
Match fertiliser rates to target yield.
Aim to apply at least 80 per cent of nutrient requirements as fertiliser. Soil testing or tissue sampling is the best way to determine fertiliser rates.
However, as a rule of thumb, high yielding maize crops remove 10–12 kg N/tonne DM/ha, 2–3 kg P/tonne DM/ha and 8–10 kg K/tonne DM/ha grown
Time nitrogen applications for greatest response.
Ideally apply in four stages (if fertigation method is available): pre-planting, planting, at 45 cm high (V6) and at tassel emergence (V12). If this is not possible, split nitrogen application into about half pre-sowing and about half at V6.
If a limited amount of nitrogen is available (for example, less than 120 kg N/ha) it is better to save it for around the V6 stage.
Adjust plant density to nutrient and water availability.
Sow for a plant density of about 80 ,000 to 85 ,000 plants/ha if irrigation and fertigation (or pre- and post-sowing application of N) are available.
“With full irrigation and fertilisation regimes we have found that higher plant density (100,000 plants/ha) results in higher yield but overall silage quality drops due to excess fibre content,” Prof Garcia said.