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Published: 2009-08-19 00:00:00

Growing maize silage on-farm is an option many dairy farmers are currently considering to reduce the cost of feed and to boost profits.

Now the Foundation for Arable Research (FAR), Environment Waikato (EW) and DairyNZ are offering a workshop in Hamilton where farmers will be able to get advice and guidance on how to get the best results from the crop.

This workshop, on Monday 21 September, is particularly valuable for dairy farmers and comes amidst a three-year Sustainable Farming Fund project. Dairy farmers who are planning to grow their own maize this season will benefit from the hands-on management tips provided, said Gabriele Kaufler, sustainable agriculture coordinator with EW.

Besides FAR and EW, other funders of three years’ worth of maize silage trials are the Ministry of Agriculture and Forestry (MAF) Sustainable Farming Fund and Genetic Technologies Ltd. The project has a year to go but has already gathered substantial data and produced results which are helping answer dairy farmers’ questions about best management practices for growing maize.

"Results from two years of trials confirm that if maize is planted on high-fertility land on dairy farms no extra fertiliser is needed to produce a high-yielding crop," Ms Kaufler said. Maize can be used strategically to manage nutrient loading on the effluent block, offering a win-win solution economically and environmentally.

Typically soil tests on the effluent irrigation block reveal high levels of plant available nutrients. On the trial sites Olsen P levels ranged from 26 to 92 and K-levels were between 6 and 25.

Soil testing the effluent block separately from the rest of the farm provides farmers with an important piece of information to start with, says Ms Kaufler. "It will enable a tailored approach to nutrient application when planning to plant a crop there."

Maize is able to remove some of the excess nutrients if grown on the effluent block. In the trials the average silage yield in year two was 26.7 t DM per hectare without any fertiliser applied. These crops removed 282 to 314 kg nitrogen per hectare – nitrogen that could potentially leach from the soil if it was not utilised by plants.

Similar to the observations in the first year trials, none of the trial sites showed a significant effect of the starter fertiliser treatment. This equates to potential savings on fertiliser cost of $149 to 333 per hectare maize.

Compared to pastoral species maize has the ability to grow roots deeper into the soil - up to 1.5m if there are no other restrictions. Therefore the crop can uptake nutrients which might have washed deeper into the soil, bringing them back into the farm system and avoiding environmental issues plus reducing costs.

Foundation for Arable Research project manager Mike Parker said: "Research shows that large amounts of nitrogen can be released from the soil when pasture is cultivated to plant a crop. Working the soil and aerating it will result in the breakdown of organic matter and organic nitrogen will then become plant available, ready for the crop to uptake."

With significant levels of nitrogen being released from the soil not a lot of extra fertiliser is needed to meet crop requirements. Consequently it is good management practice to deep soil test the paddocks prior to side dressing. Mr Parker recommends sampling the paddocks four weeks after planting down to 60cm. This sample will pick up the amount of plant available mineral nitrogen. "Most farmers will be surprised to find that in many cases no nitrogen fertiliser will be necessary at side dressing, saving farmers money and reducing the leaching risk," said Mr Parker.

Detailed advice based on the trial results will be presented at the workshop specifically designed for dairy farmers who are growing their own maize. A booklet which outlines best management practices for growing maize on dairy farms will also be available free of charge at the workshop.

Date and venue of the workshop:

Monday 21. September 09 at the Hamilton Airport Motel, from 11am to 1pm, followed by a light lunch.

Farmers who want to attend are advised to please register with Mel Bond at the FAR office, phone 03 325 6353 or email: bondm@far.org.nz no later than Wednesday 16 September.