Bench Over Troubled Water

Paul Fisher & Bruce McKay

This past week, we were reviewing the water quality analysis of a grower in California, with an EC of 1.7 mS/cm before adding fertilizer, and very high sodium and chloride levels above 200 ppm. Runoff of water and fertilizer is prohibited by local regulators. Imagine trying to irrigate and fertilize your crop in that situation! Reverse osmosis, leaching during irrigation, collection of rainwater, and capture and reuse of leachate are all strategies the grower is using.

Water-quality issues are multi-dimensional and every growing situation is different. Challenges include waterborne plant pathogens that spread disease from infected crops, salts that affect fertilization, biofilm and particles that clog irrigation emitters or agrichemical residues (Figure 1). It’s important to clearly define the issues you want to address before seeking solutions. A few technology companies oversell their water treatment products as a silver bullet, one-size-fits-all solution, which is simply not possible.

Figure 1. Define the important water quality and quantity issues at your location before you start looking for a solution.

Water quality is a hot research topic. For example, a national team of 21 researchers from nine institutions—led by Dr. Sarah White from Clemson University—recently obtained an $8.7 million federal research grant called “Clean WateR3—Reduce, Remediate, Recycle.” The team includes sociologists to identify barriers to adopting water-conserving practices, engineers to help with irrigation design, modelers and economics to map water use and costs, pathologists focused on disease control and horticulturists figuring out practical solutions for a greenhouse or nursery business. This is just one of several research teams coming out with new findings each year.

You can access presentations on water-quality topics through our websites. Our desktop site WaterEducationAlliance.org is a primary way to communicate new research from Clean WateR3 and other sources. To view videos on mobile devices, go to BackPocketGrower.org under “Training” and “Water Quality” (Figure 2). Here are a few of the available video resources:

Monitoring: How to check for pathogens, bacteria, particles and chemical water quality by the University of Florida
Manage salts, pH: Fertilizer implications by Dr. Bill Argo of Blackmore Co.
Pathogen biology: Pointers from plant pathologists, including Dr. Jennifer Parke (Oregon State University), Dr. Aaron Palmateer (University of Florida), Dr. Robert Wick (University of Massachusetts) and Dr. Warren Copes (USDA-ARS)
Pathogen control: Perspectives from University of Florida, Dr. Walter Wohanka (Germany) and Dr. Karan Khurana (Pulse Instruments)
Remove N, P and agrichemicals: Ecological options, including constructed wetlands and slow sand filtration are discussed by Dr. Sarah White (Clemson University) and Dr. Loren Oki (University of California Davis)
Remove particles: Filtration options by Al Zylstra, DRAMMwater
Pond and tanks: Solutions to pond issues by Dr. Ken Wagner from Water Resources Services

Over the coming five years, we’ll regularly post new videos on reducing runoff, nutritional water quality and water-treatment technologies. You can even post questions on the homepage of WaterEducationAlliance.org to get free advice from our expert team, using a new FAQ function.

If water quality is a thorn in the side of your business, check in on our websites for upcoming webinars, workshops and new research reports. Take advantage of this online help to solve your water problems. GT

Paul Fisher is a professor of floriculture at the University of Florida and Bruce MacKay is Managing Director of thomasBaine Ltd. in New Zealand.