Summer cropping options for north
From the April 2007 edition of Agriculture Today.
Although sorghum accounts for 60 per cent of the summer crop area sown in NSW, maize and sunflower may be better options in the north of the state.
While sorghum has many advantages, it is generally recommended that the soil temperature at sowing depth reach 17 degrees, normally delaying sowing until at least early October.
Maize can be planted when soil temperatures reach 12 to 14 degrees, allowing planting about four to six weeks earlier than sorghum, at a similar time to sunflower.
Sunflower is seen as adding flexibility to the response cropping toolkit because it can be sown earlier than other summer crops, while sorghum has the potential disadvantage of not being able to use prevailing soil moisture.
Because of summer rainfall variability, in some seasons having the opportunity to sow a summer crop four to six weeks earlier could mean the difference between sowing and not sowing a summer crop.
Many farmers were not able to sow sorghum in 2006-07 because of the dry conditions.
In the Moree district, only 25,000ha of sorghum was sown - 40pc down on the potential area.
Where farmers were able to plant sorghum, they managed to get through with a little help from the February rain.
The Australian Centre for International Agricultural Research (ACIAR) is funding research to investigate summer crop alternatives to sorghum.
NSW DPI district agronomists, Loretta Serafin and Stephanie Belfield planted trials in early September to compare a range of 12 maize varieties with 17 of sunflower, as alternatives to sorghum.
The plantings included early, mid season and late maturing varieties.
The idea was to take advantage of an early sowing opportunity before the surface soil became too dry to sow and to have crops flowering before the heat of summer.
The sorghum crops are not all in yet but yields of up to four tonnes per hectare are expected in the Tamworth district.
The bottom line was that the best of the sunflower in the trials yielded around 1.5t/ha.
The best maize at Tamworth was an early variety which yielded 2.5t/ha on minimal in-crop rain.
At Moree, the trial received an extra 50 millimetres of rain at a critical time in November and the best maize was a mid-season variety which yielded 3.5t/ha.
Gross incomes of $870/ha from sunflower and $825- $1150/ha from maize compare favourably with an estimated 3.5-4.0t/ha sorghum crop at $840-960/ha.
Contact Dr Bob Martin, Tamworth, (02) 6763 1258, bob.martin@dpi.nsw.gov.au
