The American Society of Agricultural and Biological Engineers has released its first draft of the proposed ANSI/ASABE S623 standard for Determining Landscape Plant Water Requirements.
Below, Brent Mecham, the Irrigation Association’s industry development director, summarized for L&L what this will mean for irrigation contractors:
The standard has brought together a number of experts from universities and extension programs that have interest and research into landscape plant water use. The standard provides an easier way to calculate plant water use based on ET data without having to know so much about specific plants. The goal was to have an easy, scientifically based and defensible methodology to estimate landscape plant water use to keep it healthy, functional and have acceptable appearance.
As it turns out, there is potentially a lot of water to be conserved if we are considering those three items instead of the greatest biomass production or yield which will require more water. That is one of the major differences between production agriculture (growing plants for food, feed, fiber or fuel) and landscapes which we like nice appearance without having to prune or mow so much.
For the person who is installing landscape and irrigation, it may not have much importance. However, their role in water use is still important by the way they prep the soil for planting or install irrigation to apply water correctly. For those who are designing irrigation systems or for those who are landscape water managers, it can have a big impact on how much water we estimate it will take to maintain an established landscape.
While there has been lots of research on turfgrasses, there is relatively very little known about how much water woody plants use for individual species. However, general groups of plants we can estimate an adequate amount of water.
The standard also looks at climate and its impact on plant water usage. Desert type plants logically require less water and so the standard addresses that. I think it will be a change in thinking to consider how much plants require compared to how much they will use if water readily available.
So bottom line – the plant factors or turf factors are rather simple to use and remember. If we claim to be good stewards of water resources, then the standard will influence how we create landscape water budgets, design hydrozones and ultimately how we can create meaningful irrigation schedules. The information might actually be useful to help someone know that they have been doing a good job all along when comparing water applied to how much was estimated it would take.