November 2009
What can we learn from the last six months (May – November)
In a single word, tough, is perhaps the best word to describe pastoral farming from our perspective over the last six months.
Exceprts from Coldest October in over 25 years, nzherald.co.nz, 2nd November 2009
“New Zealanders have just shivered through the coldest October in more than 25 years – not long after they enjoyed the warmest August on record, says a climate analyst.
After a winter of wild swings, temperatures are expected to be closer to normal in November, December and January.
The topsy-turvy weather began in May, which was the coldest recorded in many parts of New Zealand.
June was colder to than normal before temperatures returned closer to normal in July.
The came August – the warmest New Zealand has seen since temperatures were first recorded 155 years ago – with an average temperature almost 2°C warmer than usual at a spring-like 10.4°C.”
The response from one astute long time farmer when asked, “has this been a normal spring?” was “I no longer know what a normal spring is.” Tough times do however provide excellent learning situations. The philosophy used by many has been to plan for a top spring with a Plan B to fall back on should conditions not be favourable.
Right at the moment the option of planning for an average spring and making some early supplement should conditions provide surplus growth seems a more pragmatic approach to future seasons.
The farms we have close contact with have come through winter and spring well and are in good shape with few deaths, low somatic cell counts, and cows gaining weight.
Some operations have fared better than others and those that have fared best are where longer grazing intervals have been maintained during that time.
The following excerpts from Grass Productivity by André Voison may provide an insight into the advantages gained from a longer interval between grazings particularly during this September and October.
“The curve of re-growth in grass is also sigmoid in shape, that is S-shaped, the characteristic and universal form of growth in all living organisms.
At first the grass, having only its reserves and an infinitesimal number of chlorophyll workshops at its disposal, grows slowly and with difficulty. Then it succeeds in creating a sufficiency of green cells, the photosynthesis of which will furnish building material for the rapid creation of other green cells, that is, a large mass of growth per unit time. This is the blaze of the grass’s growth. Towards the end of this period of rapid growth the grass renews its reserves and then slows down its synthesis of green cells in order to devote all its efforts to the production of flowers and seed.
A British observation on grass growth noted that during the first 21 days of the re-growth period, there was daily growth of 30kg/ha, in the following ten days (from the 21st to the 30th day) there was growth of 82kg/ha/day.”
This equates to 46.8kg DM/ha/day over 31 days.
Excerpt from Grass Productivity by André Voison
The optimum height of grass for grazing is that which allows for maximum grass yield while at the same time making it possible for the animal to harvest the greatest quantities of herbage with optimum nutritive value.
It has been shown that the maximum yield of fresh grass is obtained by observing the rest periods which give greatest productivity per day.
In the case of permanent pastures this result is attained with a sward 6 inches (15cm) high.
It will be seen later that it is at this same height that the cow harvests the greatest quantities of grass.
It therefore seems important to examine the relationship between the height of the grass and the quantity present.
But, as it will be seen, the factors entering into play are so numerous that each case presents its own particular problem which cannot be solved by any rule or mathematical formula.
Fertiliser nitrogen has a place. We use it in small quantities (15kgN/ha) in our programmes particularly in autumn to stimulate rye growth and build a buffer of feed to carry ahead through winter.
Nitrogen is often again included in winter in order stimulate early season growth. Stronger growth stimulated ten days each end of winter effectively reduces the winter ‘slow- growth’ by close to 3 weeks.
There is ample evidence to show that applying fertiliser nitrogen now in late spring early summer will reduce clover growth over summer and early autumn reducing the amount of nitrogen fixed free-of-charge.
