Time to assess your pasture says expert
Growing a summer crop is a ‘‘green bridge’’ to renewing pastures in the autumn, says Bruce Paterson, ‘Barenbrug agriseeds’ area manager for Taranaki/Manawatu.
‘‘Farmers actually have to break that green bridge to get rid of weed issues and pest issues such as Argentine stem weevil which is in all pastures,’’ he says.
‘‘Cropping is a lead-in to getting the new pasture sown in the autumn. Instead of rushing to replace old pasture with new pasture, there is the option of going through a cropping regime which will increase dry matter production over summer when grass growth slows down and grass quality tapers off.’’
Paterson, a frequent guest speaker at farmer field days in Taranaki, says the most common reason for renovating (as opposed to renewing) Taranaki pastures in the spring is because they have been damaged over winter due to pugging by cattle.
‘‘It does become a springorientated exercise,’’ he says.
‘‘Good farmers are making assessments of their pastures now – they are spring renovating before the full growth of their standing pasture kicks in and causes problems.
‘‘Farmers should make a careful evaluation and come to an informed decision – not just
llthrow some seed in the ground!
‘‘When talking to farmer groups in Taranaki, I use an example where I take an A4 sheet of paper and place it on the ground. Science says that there should be five or more ryegrass plants in the area covered by that sheet of paper. If there are any less that’s when farmers should
llcontemplate under-sowing to get back to that figure of five or more.’’
Taranaki, says Paterson, is a prime example of a region in which native ryegrass thrives.
‘‘This is top quality New Zealand pastoral land and those ryegrasses have evolved to reproduce and drop a lot of seed in
llorder to carry that cycle on.
‘‘Old species survive and continuously come back because they seed prolifically – that’s their genetics. That’s how mother-nature makes the stayers stay.
‘‘The new varieties on the market are designed not to be as prolific with reproduction. The emphasis is on productive persistence rather than reproduction.
‘‘To me it’s a compromise in genetics.’’
The most important factors to get right when renewing pastures are fencing, drainage and fertility, stresses Paterson.
‘‘If these aren’t right, no grass will be of any use,’’ he says.
‘‘There is an important step on from this and farmers should make certain they have got rid of things like weeds and pest pressures. In coastal Taranaki, especially, we are seeing more and more black beetle appearing. Farmers are sometimes undersowing with the cheapest seed without having addressed the black beetle problem.’’
Taranaki has a wide variation in soil types and climatic factors, but generally, says Paterson, diploid ryegrasses are the preferred choice in terms of grass varieties.
‘‘My first choice for Taranaki, generally, is diploid because of its persistence over a wide variation of weather conditions. Tetraploid ryegrasses give fantastic production
lbut are less persistent under pressure.
‘‘However, farmers who are highly skilled in pasture management may well get good results from mixing diploids and tetraploids together.’’
When it comes to growing crops, the selection is so wide that Taranaki farmers are spoiled for choice, says Bruce Paterson.
‘‘A very important issue to me is that of farmers selecting which crop to grow because there is a raft of choices out there including fodder beet, chicory, turnips and brassicas,’’ he says.
‘‘Now we are faced with an issue.
‘‘We have acquired a disease called ‘watery soft rot’ which has been really bad for the last two years because of the wet weather. Farmers have had 14 tonne turnip crops that have turned into four tonne crops which have collapsed and gone rotten.
‘‘I have asked farmers at discussion groups whether they have encountered this disease and 99 per cent say yes.’’
‘‘The Fat Evaluation Index which is being used to monitor over-use of palm kernel, and mycoplasma bovis are also two very good reasons for growing more on farm.
‘‘The importance of FEI is not to force farmers to stop using palm kernel, but it’s a guide to help them stop over-using it.’’
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