Water is an essential input into the nursery industry, not only is vital for production but it is also vital for the maintenance of our product within the landscape. The industry has experienced the impacts of drought and with the uncertainty of climate change it is likely that drought will remain a threat to the industries future viability. It is also likely that the cost of water will increase and pressures upon the responsible use and stewardship will become more stringent.
A range of simple calculators which forms part of the Water Management Toolbox are available for download from here. The calculators are excel based and a cover a range of applications including; system design, operation & maintenance, drainage and fertigation.
http://nurseryproductionfms.com.au/irrigation-toolbox-calculators/
Iron makes up at least 5% of the earth’s crust. Rainfall seeping through the crust dissolves this iron and transports it into water sources, so, generally all groundwater sources will contain some level of dissolved iron.
In a process known as precipitation, oxygen in the air reacts with dissolved iron in the water and causes it to become insoluble, forming an insoluble reddish-brown sediment. Levels of soluble iron in water above 1 mg/L (parts per million (ppm)) will cause excessive sediment and growth of slime (biofilm)leading to:
• Blocked drippers, filters and spray nozzles ;
• Scale build-up in irrigation pipes;
• Reduced irrigation efficiency through reduced flow and pressure;
• Increasing maintenance and replacement costs;
• Staining of nursery structures, plants and containers.
Regular on-site irrigation water testing is recommended for all production nurseries, but the limitation of this testing is it doesn’t show the amount of specific nutrients present in the water.
While water quality may fall within acceptable limits for pH and Electrical Conductivity (EC) there may be specific nutrients, or other parameters, that fall outside the range suitable for production nursery irrigation water. A full laboratory analysis is required to determine the levels of these nutrients. For example, EC, a measure of the total amount of salts in a water source, doesn't provide information on which salts are present, if the salts are beneficial or not, or if individual elements are present in excessive amounts.
How much do you know about your irrigation and drainage? Knowledge of your irrigation and drainage systems helps you to make informed decisions on required system changes. The following short questionnaire will help to identify those areas you may need to look at to improve your irrigation and drainage systems.
One of the common questions asked about newly installed irrigation layouts is, ‘How long do I need to run the system for’. Sometimes it’s assumed the length of time is the same as the old system, but this is rarely the case, as the new system will generally have a different Mean Application Rate (MAR) and improved uniformity, which changes the length of time the system needs to run. So how do you work out the appropriate time to run the irrigation for? One method that can be used is by measuring the proportion of the applied water which drains from the pot after irrigation. This is known as the Leaching Fraction (LF). The LF can be used as a guide as to how appropriate the irrigation time is. A high LF indicates water application that is either too often, too long or both.
Irrigation pumping can be a significant cost for production nurseries, with many growers often moving water for irrigation a number of times, transferring between storages, pumping through disinfestation systems, moving into storage tanks and finally, pressurising for irrigation.
Pump choices can be many and varied, and the decision to purchase should be taken carefully, keeping in mind the life cycle costs of pumping systems. It is generally recognised that the purchase or capital cost makes up just ten percent of the life cycle cost of owning and operating a pump, while the operating cost makes up approximately forty percent. With the increasing costs of fuel and electricity, it is essential to ensure the purchase of the pumping system is undertaken with the assistance of an irrigation professional.
As with all machinery, pumping systems will decline in efficiency over time, either due to abnormal operating conditions, or through normal wear and tear. To keep a pumping system functioning at peak efficiency it’s important to monitor performance on a regular basis, but it can be difficult to pick up gradual declines in performance by observation only. Unless regular checks on the system are made, it’s likely the decline in efficiency won’t be noticed until the system reaches the point where there are significant equipment failures, and or crop losses.
The most significant raw material to the human race is water. Water in its clean, uncontaminated and unpolluted form is colourless, odourless and tasteless. However, in nature pure water is not commonly found. Ninety seven percent of all the earths’ water is located in the oceans and polar ice caps, with only a small fraction (0.65%) available for use by humans domestically and industrially. Pure water will not conduct electricity and therefore will not have a total dissolved solids (TDS) or an electrical conductivity (EC) reading. Almost all natural waters contain different types and quantities of impurities, even rainwater, depending on location, may contain carbonic acid, nitrogen and/or other industrial pollutants.
When compared to other disinfestation methods, slow flow filtration (SFF) systems can be constructed from a variety of components without specialist skills being required. In designing SFF systems, the size and distribution of sand particles, the ratio of filter bed surface area to depth, the flow rate of water through the filter and penetration of light to the sand bed all affect the efficiency of the filter. Because other types of media can be used in place of sand in these systems, the nursery industry now uses the term ‘slow flow filtration’ instead of ‘slow flow sand filtration’.
With the increasing cost of energy from the grid, the option of using renewable energy for pumping is becoming more attractive. Renewable energy driven systems have been installed for applications as varied as household pressure pumps to large cotton farms (with diesel backup). Careful analysis of system requirements must be made to ensure energy generation capabilities of the system are sufficient, and that the installation is cost effective. Renewable energy driven systems incur higher capital expenditure, but can provide savings in the long term from reduced energy and maintenance costs.
A recent development in the way electricity companies provide power to businesses, is the requirement that a customer ensure that the power factor of any electrical installation measured at the consumer's terminals is not less than the power factor listed in Table 1.
Variable frequency drive (VFD) controllers are an efficient and reliable way of using the same pump for varying flows and heads, and still keep it as close as possible to the best efficiency point on the pump's curve. This helps to increase irrigation efficiency and reduces electricity costs. However, not all pumps or irrigation systems will benefit from the installation of a VFD controller. Each pump and irrigation system needs to be assessed to determine if a VFD controller is appropriate, and what type of VFD controller should be installed. In some cases the pump may need to be upgraded before the benefits of a VFD will be achieved.
Water quality and quantity is essential for nursery production to facilitate the growing of healthy crops in a reasonable time frame.
Throughout Queensland and indeed throughout Australia, water availability has been in question as a result of recent drought periods, water quality in many waterways and, in some localities, over allocation of the resource.
In 1994 the Council of Australian Governments (COAG) released the National Water Reform Framework which has been the catalyst for many of the water related activities governments, around Australia, have undertaken over the past 10 years. COAG is a combination of the commonwealth, state, and territory governments joining to address issues on a national front with significant incentive payments on offer from the Commonwealth government to the states if reform is implemented.
A weather station comprises a number of instruments that measure atmospheric, and in some cases, soil conditions, then records this information, allowing the data to be displayed and used to manage or control production nursery systems.