With lower milk prices and the possibility of limited irrigation water at their disposal, regular maize growers will be thinking hard about whether it suits this season as dairy farmers plan their summer crops.
FutureDairy’s Yani Garci said management had 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. 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 said.
Prof Garcia offered the following tips:
Do not apply the full amount of nitrogen fertiliser unless you can ensure water will not be limited. If water is likely to be limited, adjust nitrogen application. For example, nitrogen application both pre-sowing and at V6 stage are highly recommended, but if you need to adjust, save the nitrogen for the V6 stage.
Time water application for greatest response. If irrigation water is likely to be limited, 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 nitrogen/tonne DM/ha, 2–3 kg phosphorus/tonne DM/ha and 8–10 kg potassium/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 half at V6. If a limited amount of nitrogen is available (eg. 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 80–85 000 plants/ha if irrigation and fertigation (or pre- and post-sowing application of nitrogen) are available. With full irrigation and fertilisation regimes we have found that higher plant density (100 000) results in higher yield but overall silage quality drops due to excess fibre content.
For more information phone Prof Garcia on (02) 9351 1621 or email [email protected]