WSU’s On Solid Ground – Struvite, Cattle Fertility, New Apple – March 13, 2013

Comprehensive Effort to Create Sustainable Fertilizers

Adding fertilizers to marigolds and peppers in the greenhouse.
Adding fertilizers to marigolds and peppers in the greenhouse.

Phosphorus recycled from human and animal waste for plant fertilizer could ease demand for the dwindling, increasingly expensive rock-mined element. Scientists at WSU have found plants flourish with struvite, a waste ingredient composed of magnesium, nitrogen, and phosphorous. Teamed with Multiform Harvest, a Seattle phosphorous recovery company, the researchers are fine-tuning the application and proportion of essential components in the fertilizer with the goal of marketing a product and ultimately adding security to the world’s food supply.

“You can’t continue mining a finite resource forever,” said Rita Hummel, a scientist at the WSU Puyallup Research and Extension Center. “But as long as we can reclaim struvite from animal manure and sewage, we have a sustainable resource. We’re figuring out how to use it effectively and safely.”

Local Benefits

Hummel is using Multiform Harvest struvite from wastewater treatment plants at Yakima, Washington, and Boise, Idaho. She and her fellow researchers hope to include struvite extracted from manure from area dairy farms to develop regional nutrient recycling.

“When you feed a cow, about 20 to 25 percent of the phosphorus the cow eats ends up in the milk carton,” said Joe Harrison, Hummel’s scientist colleague at WSU. “That means about 75 to 80 percent ends up in the manure.”

Tomato (top) and marigold from early experiments with (l-r) no phosphorus, struvite, and triple superphosphate.
Tomato (top) and marigold from early experiments with (l-r) no phosphorus, struvite, and triple superphosphate.

Not only could reclaiming struvite from waste localize production and distribution, it could also help mitigate water pollution problems such as overloading phosphorus in agricultural soils. “The research being performed at WSU is central to us generating the hard data we must have to get this recycled phosphorus into the agricultural market, from large fields to specialized greenhouses and nurseries,” said Kevin Fullerton, product developer for Multiform Harvest.

Encouraging Results

In previous greenhouse crop studies, Hummel discovered struvite had a similar effect on plants as the commercial phosphorus source, triple superphosphate. Crops like basil, cucumber, marigold, and tomato barely sprouted without phosphorus, but flourished with struvite from King County municipal wastewater.

With support from a USDA small business innovation research grant, Hummel will experiment with different rates and ways of applying the struvite–adding it to the potting mix, sprinkling it on the surface, and placing it beneath the plant–to determine the rate at which it is released.

“One of the things we need here in western Washington is a slow-release product so it doesn’t leach out the bottom of pots and run down drains and into streams, rivers, and the Puget Sound,” Hummel explained.

Reliable Recycling

Most phosphorus in the United States comes from Florida, but this production could decline sharply in the next 30 years, Fullerton said. Current practices indicate such a loss would lead to dependence on the other known stockpiles in Morocco, China, South Africa, and Jordan.

“If we can take a waste disposal problem and turn it into a fertilizer that actually replaces something we have to mine and are running out of-–that’s sustainability,” Hummel said.

-Rachel Webber

Collaborative Management of Thrips-Caused Crop Losses

Thrips may be tiny, but the insects cause billions of dollars in damage to crops each year, which is why WSU scientists are taking part in a five-year, $3.75 million project to study the pests’ role in virus transmission and ways the resulting losses can be stopped.

Up close and personal: Thrips are typically 1 mm long (about the width of a sharpened pencil lead!) and have fringed wings.
Up close and personal: Thrips are typically 1 mm long (about the width of a sharpened pencil lead!) and have fringed wings.

The multi-institutional, multi-disciplinary research team is generating new knowledge on thrips-transmitted tospoviruses–infectious agents that cause a variety of crops to wilt and eventually die. Tospoviruses also lower the quality of fruits and vegetables produced by their infected plants, said Naidu Rayapati, a researcher at the WSU Irrigated Agriculture Research and Extension Center in Prosser and a co-principal investigator on the USDA grant.

“We are looking at the epidemiology of diseases caused by tospoviruses, especially the role of vectors (carriers) in the spread of these viruses at the fundamental level,” Rayapati said. “We want to know how these viruses spread and contribute to the evolution of new strains. For example, can a single insect acquire and transmit two viruses to the same plant simultaneously?”

The project will focus on areas in California and the southeastern United States where thrips damage is most severe. The collaboration includes entomologists, plant pathologists, molecular breeders, and extension faculty from UC Davis, Kansas State University, North Carolina State University, Cornell University, the University of Georgia, and the USDA Horticultural Research Laboratory. Rayapati said the team is also interested in understanding how management techniques applied in one region might work in another.

“As a team, we are bringing different expertise to bear on a common problem,” Rayapati said. “We hope to generate appropriate knowledge of thrips and tospoviruses and come up with improved strategies that can really help provide management of thrips-transmitted tospoviruses to multiple crops in different regions.”

Maximized Scope

Rayapati said he is also actively recruiting students, with an emphasis on those from minority communities in the Yakima valley, to begin work on the project for summer and fall 2013. “This project has an extension component in terms of working with the stakeholders to convey science-based information for practical applications, but we are also focusing on training the next generation of scientists,” he said.

Learn more about Naidu Rayapati’s research by visiting

-Rachel Webber

Improving Dairy Cattle Fertility

WSU’s Neibergs, left, and Spencer.
WSU’s Neibergs, left, and Spencer.

The National Institute of Food and Agriculture has invested $3 million to help address cattle infertility, which is one of the biggest barriers to global competitiveness for American dairy farmers. The five-year grant, announced this week, includes scientists from WSU, the University of Idaho, and the University of Florida working on research, outreach, and teaching components.

Tom Spencer, who holds the Baxter Endowed Chair in Beef Cattle Research in the Department of Animal Sciences at WSU, explained that the conception rate in an average herd of dairy cows has dropped from 50 percent in the 1980s to 35 percent today. “In general, there has been a 1 percent per year decline in fertility,” he said. An infertile animal has to be culled from the herd, leaving the producer with the expense of supporting the animal until infertility is confirmed, as well as the cost of replacing the animal.

Early Detection

“Fertility is a complex polygenic trait, so it is harder to select for than other traits,” Spencer said. “If we can identify and isolate the multiple genes responsible for fertility, we may be able to tell earlier what cows are going to be fertile-–maybe as early as at birth.” He and WSU animal scientist Holly Neibergs plan to work with UI Extension Dairy Specialist Joseph Dalton to collect blood samples from Northwest cows for DNA analysis.

The goal of the project is to increase the sustainability, profitability, and international competitiveness of the US dairy industry, Spencer said.

“Our hypothesis is that dairy cow fertility can be increased through genetic selection for maternal fertility in heifers and cows and the use of sires with high daughter pregnancy rates,” he said.

Read the rest of this story by Kathy Barnard on the WSU News website.

Licensee Needed to Commercialize New Apple

wa38WSU has just released ‘WA 38,’ an eye-catching new apple cultivar with with a remarkably firm, crisp, and juicy texture that also stores well. The large, dark red apple has outstanding eating quality, exceptional flavor, ample sweetness, and sufficient tartness to impart distinct character.

“Our feeling is that when it comes to the combination of taste, texture, and beauty, WA 38 has no equal in today’s marketplace,” said WSU apple breeder Kate Evans. A trademark is under development.

The WSU Research Foundation, the licensing arm of WSU and assigned owner of WA 38, desires to find, through an announcement of opportunity, an exclusive licensee to manage commercialization of the apple. This would involve contracting tree propagation to nurseries, sublicensing to growers, managing the trademark, and collecting royalties.

Qualified applicants, which includes individuals, individual companies, groups of companies, cooperatives, groups of individuals, and/or companies banded together under a cooperative arrangement, can download a copy of the announcement from and email Tom Kelly at with any questions.

-Brian Clark