vegetablesWA
vegetablesWA
Install App?
vegetablesWA
wagrower.vegetableswa.com.au
This is how the Install App dialog will look like once your App goes live.
BY DAVID ROWE
DEPARTMENT OF PRIMARY INDUSTRIES
& REGIONAL DEVELOPMENT
Lower rainfall in response to a changing climate has seen significantly less water recharging the Gnangara system, a resource shared by the Water Corporation for public drinking water. The reduction is designed to balance the system and maintain access for both of these important users. However, to maintain or increase production going forward, improvements in water use efficiency will need to be found.
• reducing evaporation
• reducing the irrigated area
• increasing evenness of irrigation (uniformity)
• scheduling irrigation based on crop demand.
Reducing evaporation will deliver savings in water by reducing the amount of water a plant requires to remain healthy. Reducing evaporation can be achieved by influencing environmental factors such as wind speed, humidity, temperature, and solar radiation. This can be done by protecting the crop with windbreaks, shade netting, tunnel houses, or plastic mulch.
Reducing the irrigated area
Reducing the irrigated area can be achieved by applying water only to areas where the crop can use it. A good example of saving water this way is using drip irrigation. Well-designed drip irrigation systems apply water very evenly and directly to the base of the plant and, unlike overhead sprinklers, water is not applied to wheel tracks and headlands where there are no plants.
Distribution uniformity
Distribution uniformity (DU) describes how evenly an irrigation system applies water over the area being irrigated. It is calculated by dividing the average depth of water applied to the driest quarter of irrigated area by the average depth of water over the total irrigated area. DU is technically a ratio but is commonly expressed as a percentage where a higher percentage indicates greater evenness between the depths of water applied across the field. The minimum industry standard for DU on horticultural crops is 75% for overhead irrigation.
Irrigation Calculator (which estimates total plant water use of a crop based on crop factors and historical weather data) you can calculate that a lettuce crop planted in November in a sandy soil in Wanneroo will use approximately 4ML/ ha over a 45 day growing period.
Figure 1 shows the plant water requirements plus the additional irrigation water required to compensate for various levels of irrigation inefficiency (DU). An overhead irrigation system delivering water at 85% uniformity would require 18% less water than an irrigation system with 70% distribution uniformity.
Additional benefits of irrigation systems with higher DU are lower electricity cost for pumping and potentially reduced nutrient requirements resulting from reduced losses below the crop.
Even the most well designed system will fail to irrigate efficiently if not operated effectively. Learning how to schedule irrigation based on crop demand will lead to the most efficient use of any system. Crop water demand is directly related to evaporation, which is influenced more by solar radiation and wind speed, than by temperature and humidity. By using evaporation as a reference point, the daily plant water requirement can be calculated.
Calculating daily water requirement and applying the required amount of water can minimise both overwatering that wastes water and nutrients, and under watering that leads to crop stress and reduced yields or longer growth periods.
While it is daunting to face a reduction in water allocations, DPIRD is supporting growers by both demonstrating water saving techniques and assessing the cost versus the benefits of these techniques.
Keep an eye out for articles in upcoming WA Grower magazines and visit the DPIRD website for tips on irrigation scheduling and soil moisture monitoring.
Production calendar arrives in citrus mailboxes
production calendar was sent out to West Australian citrus growers in August. The poster was produced as part of an R&D project using State government funding, providing timely reminders for good management practices, such as irrigation, nutrition, pest management and canopy management.
Graduate students contribute to potato research
Potato is a crop of global importance, so it is not surprising that the potato research at Murdoch University is attracting the interest of post graduate applicants from a number of countries.
PNRM Smart Farms Project
In 2018 the National Landcare Program and the City of Wanneroo funded Perth NRM to assess the practical use and adoption of improved soil water monitoring practices by horticulturalists in the North of Perth Food Zone.
VegNET IEO update
Looking through the front window at home, sipping on the days first hot bean water and watching the pink and grey Galahs waddle around, I think to myself “No need to bundle up; today looks like a winner!” And then I go outside, where it’s freezing… however as the sun continues to shine, the day gets a little brighter.
Swan Coastal Plain
The main vegetable production region in Western Australia is the South West, including the Swan Coastal Plain from Gingin (100km north of Perth) to Myalup (100km south of Perth). Within this area, about 67 per cent of the total value1 of the State’s vegetables are produced.