Last month Taranaki Technical Sales Rep (TSR) Nev Giddy discussed tips for planning your maize crop to help ensure an optimum yield. Here, Nev talks about the next steps to manage your maize from the point that the seed goes in the ground.
Now your paddock is prepped for sowing and your starter fertiliser is on farm ready to go in with seed.
"Base fertiliser should be applied, depending on the results of your soil testing," Nev says. "Your fertiliser requirements will vary depending on the history of the paddock. For example, if the area has been an effluent paddock, expect high nitrogen results."
Starter fertiliser by soil type
Starter fertiliser is a mixture of N-P or N-P-K formula fertiliser. "Out of pasture on lighter loam and ash soils, an N-P selection is normally chosen. On peats an N-P-K blend is sometimes chosen if the potash requirement was not met with the base fertiliser application," says Nev.
Talk to your local Farm Source TSR or your fertiliser representative to confirm the right mixture for your paddocks.
Starter fertilisers: Di-ammonium Phosphate (DAP) 18-20-0, or 12-10-10, also many other formulations.
Weed control
"Weeds fall into two main categories - grass weeds and broad leaf weeds," explains Nev. "Some sprays control mainly grass weeds, others only broad leaf weeds and a third group give control of both."
Time of application varies depending on the chemical and the weed species present. The best weed control option will vary from farm to farm depending on the soil type and the number and species of weeds present. Plan pre and/or post planting herbicide applications based on specific weed problems by paddock.
Pre-emergent herbicide (such as Roustabout and Atrazine) will bemost effective if applied within 24 hours of planting.
The type of post-emergent weed control herbicide used is determined by the variety of weeds present. Seek specialist advice from your local Farm Source TSR.
Crop checks
From about six days after planting check crop emergence. Full emergence normally occurs seven to 14 days from planting depending on temperature. Continue to walk the crop, preferably daily, checking for insect and bird damage and weeds.
Argentine Stem Weevil
Plants that have been damaged by the Argentine Stem Weevil (ASW) turn a blue-grey colour, the inside leaves wilt and then the plant dies. There is no known spray to control ASW in seedling maize. Significant seedling damage is uncommon where insecticide-treated seed has been planted.
Greasy Cutworm
The symptoms of Greasy Cutworm in the crop are plants that have been cut off at ground level. Greasy Cutworm is a dark coloured caterpillar that feeds at night and burrows down into the soil during the day. It is easily located in the early morning and if significant numbers of the plants are affected an urgent spray programme is required.
Bird damage
If you find small seedling plants pulled out of the ground with the roots still attached, it is probably bird damage. Birds can be attracted to the area by seed left on the surface of the ground when the planter lifts at the end of each planter run or on tightly turned corners. If you note seed on the ground at planting, draw your contractor's attention to the problem. If ducks are a problem and soil temperature is 14ºC or higher, adjust the planting depth to 65mm. Bird seed treatment will help to repel birds from planted maize seed.
Seedling weeds
Contact the field staff of your local merchant or chemical company if you see weed seedlings in your crop. Control steps can be taken to keep the crop clear of weeds and maximise crop yield. Satisfactory weed control can only be achieved if crops are sprayed prior to row cover.
Sidedressing
Sidedressing usually occurs six weeks post planting or just prior to row cover. Urea and Sustain are the most commonly used nitrogen product for sidedressing.
Methods of application range from broadcasting the urea just prior to rain to specific machines that knife the urea into the soil between the rows. There are also combination knives that apply nitrogen to the ground and inter-row mould covering the nitrogen in the process.
Please note there are a wide number of herbicides and fertilisers available. Some of the herbicides and fertilisers that can be used are listed in the text above - this list is not complete and no particular preference is indicated by the inclusion (or omission) of herbicides.