Planting natives for the future
Te Awamutu dairy farmers Doug, Penny, Josh and Bayley Storey have planted more than 25,000 native trees on the family farm, adding to a generations-old native forest.
So, why isn’t New Zealand following the US trend?
For the last 15 years, recommended planting rates for medium to long maturity maize silage hybrids in New Zealand have remained static at between 105,000 and 110,000 a hectare. Maize grain planting rates have lifted marginally to just above 95,000/ ha. In comparison, US Department of Agriculture data shows that maize planting rates have increased on average by 900 seeds/ha a year since the 1960s, doubling from 40,000 to 80,000/ha. Over the same timeframe, maize grain yield has continued to increase on average at a rate of about 125 kg/ha/year. Many in the US believe that this increasing trend in plant population will continue well into the future.
The US yield increase is attributed to genetic gain, agronomic improvements and increasing plant population. Maize grain is a massive crop in the US, with 32 to 36 million hectare planted each year.
Foundation for Arable Research senior maize researcher David Densley told growers at a series of winter maize workshops that maize silage and grain seeding rates have more or less remained static since the inception of maize production in New Zealand in the early 1990s.
“Some research and commercial observations suggest that under current management practices and climatic conditions, seeding rates may be about right.”
David Densley asked those attending the workshops as to why they believed recommended seeding rates have more or less remained flat despite increases overseas.
Some suggested that in the US they were starting from much lower densities and are only catching up to New Zealand seeding rates, while some thought farmers are possibly deterred by the cost of the additional seed required. Higher planting rates mean a higher yield is required just to break even on costs.
Factors in New Zealand that support higher populations include a maritime climate, which results in lower overnight temperatures than those experienced in the US. New Zealand’s soils also contain much higher organic matter.
