'Discipline’ key in regrassing

Date: 2010-05-07 | Category: News

Discipline is the key to maximising the benefits of a regrassing programme, according to Neil McLean of Agricultural Business Associates.

His analysis showed a planned regrassing policy extended the length of herd lactation and increased total milksolids (MS) production. The additional production generated by the new pasture alone was equivalent to an extra 70kg of MS/ha which, at an assumed payout of $5.20/ kg MS, is worth $350/ha, net of expenses.

The finding is perhaps not surprising, as DairyNZ figures show that new pastures grow on average 10 percent more in their first year and have a more uniform quality, which declines steadily over the subsequent four or five years.

They are also more easily digestible and show faster regrowth especially in the shoulder seasons.

However, McLean said that using a programmed pasture renewal approach over 26 months incorporating brassicas, the additional production rises to an extra 194kg MS/ha, giving an additional $700/ha compared with traditional pasture, net of all direct costs at the $5.20/kg MS payout.

Sprayed out

Under the programmed approach, old pasture is sprayed out in February and resown with an annual ryegrass such as Delish or Maverick. McLean said it’s important to choose an annual that can last up to 18 months, so for Waikato pastures it needs to have enough stem weevil resistance to get through one summer.

He also recommends adding some chicory to help supplement the ryegrass during the summer. Then 18 months later, the pasture is sprayed out again in spring and sown with a brassica crop. This is best grazed in January, before the summer dry sets in, and can then be sprayed out in March, when permanent pasture is sown.

McLean said this process effectively wipes out grass and clover pests from the soil and gives an ideal sward with the best chance of success. While the brassica crop provides additional feed and, properly managed, will pay for itself, the real advantage is delivered by the new grass.

However, he believes farmers will embrace this approach only if they are successful with brassicas – hence the need for greater discipline in their cultivation.

McLean suggests farmers, contractors and seed merchants take a leaf out of the maize industry’s book.

She’ll be right

He said that 15 years ago “we just used out to chuck out the maize seed and take a she’ll be right approach.

“But the maize companies recognised this wasn’t maximising the yield potential of the crop and the industry has developed the discipline of fertiliser application, weed and pest control and planting, harvesting and storage practices we have now,” he said. “We need a similar approach to brassica cropping, and a move from passive to active management of our pasture renewal.”

He believes seed companies have a greater role to play in helping farmers decide which varieties to plant for their requirements, soil and climatic conditions, by providing hard facts about the specific attributes of the different cultivars rather than what he described as “feel good publicity”.

McLean’s analysis compared two dairy farms in Waikato’s Taupiri district on the same soil type, using farm data from the 2008/09 season. He stripped out the effects of the different management approaches through the UDDER computer modelling system. One farm had not had any form of pasture renewal for the previous five years, while the other had applied the full programme.

At the beginning of this year, the farm using the programmed approach was 20 percent ahead of last year’s production, while the district average was only two percent up.

The report was commissioned by the Pasture Renewal Charitable Trust (PRCT). For further information or a copy of the full report phone 07 824 3834 or email neil.mclean@xtra.co.nz.

Published courtesy Dairy Exporter February 2010

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