Forecast | Maps | Radar
WATER REQUIREMENTS TRIALS

Ian Smith HortiCulture
Introduction

Most major Australian cities have experienced drought for many years, water reserves are low and consequently restrictions have been applied to garden and landscape irrigation. Though reference evapotranspiration is available from the Australian Bureau of Meteorology, it has not been routinely applied to water scheduling for garden and landscape plantings. Irrigation scheduling based on evapotranspiration, soil moisture levels etc. has been applied to crops, but very little data is available on the response of ornamental species to reduced irrigation levels. Landscape plants are valued for their appearance and the concept of yield is not relevant. It has been reported that some species utilized for landscapes have the ability to maintain acceptable aesthetic quality under reduced irrigation (Pittenger, et al.
2001). Landscapes are also difficult to characterize because they often consist of small plantings of numerous species.

Objective

The primary objective of this project was to determine the response of 37 ornamental species to irrigation treatments based on evapotranspiration and to define estimates of ornamental plant water needs for acceptable aesthetic appearance.
 
Based on performance in relation to applied irrigation, develop a classification system for the selected plants indicating their ability to tolerate dry conditions with low irrigation input. Use this classification system as a basis for the promotion and sale of ornamental plants with reference to their water requirements during on-going drought and water restrictions in many areas of Australia.

Null hypothesis

All plants will respond identically to various levels of irrigation based on a percentage of full replacement of evapotranspiration losses.
Evaluation of the performance of landscape ornamental plants in response to irrigation treatments based on evapotranspiration
Abstract
The objectives was to determine the response of 37 ornamental plants to irrigation treatments with respect to evapotranspiration and to define estimates of ornamental plant water needs for acceptable aesthetic appearance.

Experimental plots were established at Silvan, Victoria, Australia, consisting of five 100 m2 blocks allowing four irrigation treatments replicated five times. Single plants of each of 37 species were planted into 20 m2 experimental units within the drip-irrigated blocks.
Irrigation treatments were initiated in November 2005 and consisted of 1.0, 0.75, 0.50, 0.25 evapotranspiration.

Irrigation scheduling was determined by a Weathertrak Pro controller utilising evapotranspiration generated from Bureau of Meteorology weather data calculated by the Penmen-Monteith formula and forwarded daily to the controller through a GPRS modem connection.
Continue