Profitable Stonefruit Research

Dr Mark O'Connell introduces the Nectarine, Open Tatura trellis, irrigation experiments.
  • Nectarine cv. September Bright with Rootstock: Elberta
  • Planted winter 2014 in Open Tatura tree training at a density of 2222 trees/ha

The experiment has three irrigation levels and four irrigation application timings as treatments.

The irrigation levels (% of tree evapotranspiration), applied using drip irrigation, are:

  • 0: extreme deficit irrigation to impose high level of water stress
  • 20 & 40: deficit irrigation to impose severe and moderate level of water stress
  • 100: control irrigation, crop water requirement to maximise yield

The experiment has four irrigation application timings and likely crop responses:

  • Stage I of fruit development: cell division (rapid fruit growth) - water stress restricts cell division, reduces fruit size and yield
  • Stage II of fruit development: pit hardening (slow fruit growth, maximum vegetative growth) - water stress reduces vegetative vigour
  • Stage IIIa of fruit development (early): cell expansion - water stress reduces fruit size and yield
  • Stage IIIb of fruit development (late): cell expansion (sugar accumulation, chlorophyll degradation) - water stress reduces fruit size and yield

Table 1: Irrigation experimental treatments

2016-2017 Irrigation Experiment table 2016/17 irrigation experiment

Regulated deficit irrigation (RDI) occurs during stage 2 of development. See Graph below.

Shoot & Fruit Growth graph Shoot and fruit growth graph