My husband & I are setting up an olive grove in Hanmer Springs. We plan to
have @ 1500 trees comprised of 5 different cultivars. Organic management of
the grove is our goal, though we have used contact herbicides and
non-organic fertilisers in establishing the first planting.
We would be very interested in learning about what on-going organic
practices we could use to:
<li>Control weed growth (ie. we have grass between rows & mow it periodically,
but in tree rows we have sprayed off the grass & have weed re-growth. A
groundcover that did not require tillage back into the soil, but that could
aid water retention & build up soil nutrients would be good) </li>
<li>Control insects (we are experiencing insect damage to new growth - green
caterpillars that wrap leaves around themselves, also something else is
taking bites out of more mature leaves - night beetles?) </li>
<li>Mulch (we have no mulch currently, but we do have drip irrigation - water
comes from a spring fed stream & is gravity fed from two 25k litre water
tanks. Currently we have @420 shelterbelt trees and 371 olive trees on
drippers. In Oct. 2000 we will plant another 1200 olive trees. We would
like to start applying mulch to conserve water) </li></ul>
We do not currently live on the property, but in Wellington. We go down to
Hanmer @ 5/yr, usually for long weekends. We do have adjoining neighbours
who monitor the irrigation requirements (we have 2 tensiometers at different
depths that we use to gauge water requirement). In short - we are 'townies'
who are trying to learn as much as we can, as quickly as we can, about
resource management & organic farming. We would appreciate your help.
Lisa & Chris Preston
First immediate comments are: Are you sure you have suitable cultivars for the climate (I am surprised to hear about commercial plantings in such a cold climate) Do you know what your market is, e.g. high quality virgin oil, pickled, table olives. How will you harvest, process and market?
A herbal ley groundcover which can mowed and provide mulch material ( no tillage back into the soil ) would be a good idea. There are mowers available which throw the mown material in a windrow on the treelines for mulching.
Consider management of groundcover and soil texture and structure before deciding on irrigation system.
Do you want to fertilise through the irrigation system?
Good advice on herbal leys and possibly a source for purchasing is Waihi Bush (Simon/David Musgrave in Geraldine). Email David at firstname.lastname@example.org
Pest problems – usually not a big problem with olives. The caterpillar sounds like a leafroller, organic controls include B.T. (bacillus thuringienis/biologcial control), various products on the market (Dipel, Thuricide etc) but encourage the whole environment to attract beneficials.
"Taking bites out" problem is hard to judge from here, could be possibly the grass grub beetle (encouraged by long grass). Immediate help could be Pyrethrum (BetaCrop) – but not likely to still occur now as the adult beetles would stop flying -, long term requires ‘Invade’ (biological control) into the sward, get manufacturers advice on timing.
Christchurch Polytechnic is offering a distance programme for growers who want to convert to certified organic production (12 different courses), contact Rachel Worsfold for more info email@example.com or (03-364 9074).
Professional advice/consultancy available from Christchurch Polytechnic staff contact Gilda Otway
There could be a possibility that Polytechnic students could assist with the tree planting if a work crew is required (they are trained in planting and staking).