The Art of Managing Native Pollinators
Square plastic sheets of black, white, red, and blue decorate a farm field in Walla Walla County’s Touchet Valley. While some might guess it to be a exhibit by Christo, the environmental artist, it is actually an innovative experiment to influence the emergence of a native ground-nesting bee. And producers of alfalfa seed in eastern Washington may soon see improved pollination and higher profits due to the results of this scientific research.
For plants to create seeds, the blossoms need to be pollinated. This comes easier to some plants than others. With alfalfa, the stamen, or pollen-producing part of the flower, is contained in a chamber, and that chamber has to be opened by an insect. When opening the chamber, the insect gets hit on the head by the stamen, releasing a shower of pollen, which the insect carries to the next flower. While honey bees carry a huge burden of pollinating many commercial crops, they really don’t fancy being crowned by the dusty stamen of alfalfa. They learn instead to carefully extract nectar without tripping the mechanism that releases the pollen.
Fortunately for alfalfa growers and consumers, another bee, native to the Walla Walla area, shows great affinity for this crop. The alkali bee, Nomia melanderi, is the only native, ground-nesting solitary bee species used for pollination in commercial agriculture in the world. In late spring, they emerge by the millions from patches of highly alkaline soil, seek out alfalfa, and welcome the shower of pollen that fertilizes the flowers and guarantees a strong seed crop. In fact, the alkali bee, which typically emerges at the same time that alfalfa blooms, helps farmers in the Walla Walla valley produce seed yields that are twice the national average.
Some years, however, the weather interferes. Late spring rains may prompt the alfalfa to bloom earlier, while delaying the emergence of the alkali bees. When the pollinators are not available for alfalfa, farmers see a smaller seed crop and reduced sales. This fate could be avoided if farmers could control the timing of alkali bee emergence, so researchers have been trying to figure out how to do this.
A Clear Solution
Because previous research showed alkali bee pupation and emergence to be dependent on soil temperature, Amber Vinchesi, working on a master’s degree under Doug Walsh, entomologist at the WSU Irrigated Agriculture Research and Extension Center (IAREC) in Prosser, figured plastic sheeting was worth trying to heat and cool alkali bee habitat. Doug Cobos, an instructor of environmental biophysics in the WSU Department of Crop and Soil Sciences, assisted with data from soil temperature sensors.
Three years of testing showed that alkali bee emergence could be either sped up or delayed, depending on the soil surface treatment. Every week during the time of emergence, Vinchesi counted the holes through which the solitary bees exited the soil. White chalk dust and white-on-black plastic with the white side facing up both reflected sunlight and warmth, which slowed the warming of the soil, and delayed bee emergence by a week. Clear plastic sheeting allowed heat retention, which sped up the bee emergence by a week to ten days. Plastic sheeting of other colors also influenced soil temperature, but not to the extent of the clear and white plastic.
“Some varieties of alfalfa bloom earlier, and some later,” said Vinchesi. “By selectively applying plastic or chalk to the soil, farmers can improve the chance that the alkali bees will be available when the alfalfa blooms.”
A scientific paper detailing the study has been published in the May 2013 edition of Apidologie and is available online. For more information on research at the IAREC, see http://bit.ly/wsuprosser.
-Bob Hoffmann
Technology Turns Manure into a Money-Maker
WSU scientists are proving that dairy manure management does not have to be an environmental liability. New technologies that complement anaerobic digestion (AD), a biological process of breaking down organic waste material, were showcased last month at the WSU Anaerobic Digestion Field Day in Lynden.
Manure management has long been a challenge for dairy operations because it can contribute to air and water quality problems, including greenhouse gas emissions and excess nutrients (nitrogen and phosphorus) in soil and water. However, over the last decade, advances in AD systems have evolved not only to manage waste, but to help dairies address pressing environmental problems and generate revenue at the same time.
At Vanderhaak and Edaleen Dairies, over 115 field day participants could see–but not smell–ADs at work. This technology greatly diminishes manure odors. It also decreases pathogens in dairy waste and captures methane, thereby reducing greenhouse gas emissions and producing biogas which can be used to produce electricity to power the AD system or send to the grid.
To broaden the circle of organic waste management, the digesters at Vanderhaak and Edaleen Dairies also recycle food waste like processed raspberry culls from nearby Maberry Farm.
New Green Fuel Technology
A new add-on technology called biogas scrubbing allows the biogas produced through AD to be refined into renewable natural gas, or RNG, which is clean and ready to use as vehicle fuel. RNG can directly replace compressed natural gas or liquid natural gas for use in trucks and cars. According to Dan Evans of the renewable energy company Promus Energy LLC, “RNG can be delivered to trucking fleets at half the price of diesel and may be the greenest of all fuels.” Evans explained that RNG is green not only because it is derived from a process that reduces greenhouse gas emissions, but because it comes from a renewable source.
“The system pays for itself right out of the chute because we’re signing up buyers now. We’re selling renewable natural gas to compressed natural gas users who are willing to change the type of fuel they use,” Evans said. Existing demand and environmental credit and incentive programs are expected to make this manure-derived fuel product profitable.
Recovering Nutrients for Cash and Compliance
Another new technology that can be integrated with ADs is the recovery of excess nutrients which are a problem for the environment and a concern for dairies that face increasing regulations. Nutrient recovery systems such as AIR-TRAP, developed by WSU scientist Craig Frear and industrial partners DVO Incorporated and Andgar Corporation, promise to turn excess nitrogen and phosphorus into marketable fertilizers and soil amendments before they ever become a problem in soil and water.
The list of recovered nutrient products that are beginning to emerge on the market includes a fiber material that can be used to replace peat moss, a pathogen-free ammonium sulfate fertilizer, and a phosphorus-rich soil amendment. These products can be more easily transported and more precisely applied to fields than manure and have greatly reduced the potential for pathogens. Continued development of markets and improvements in product quality are ongoing.
The Bottom Line
Nutrient recovery is quickly gaining attention among dairy operators, environmental regulatory agencies, and entrepreneurs. However, the WSU team lead by Frear recognizes that keeping the bottom line in sight is critical in developing technologies that dairies and other livestock operations will adopt. According to Chad Kruger, director of the WSU Center for Sustaining Agriculture and Natural Resources (CSANR), the not-insignificant cost of the AD itself is a small portion of the capital and operating costs of the whole AD system.
“What’s more important to consider is the profitability of the project scenario that you put together,” Kruger said. “Adding nutrient recovery to the system adds capital and operating costs, but for the most part it is cost-neutral if scaled appropriately and if there is a market for the resulting products.” Several reports published by CSANR spell out the details of the economic feasibility of AD systems and newer add-on technologies, and are available on their website.
The U.S. Environmental Protection Agency estimates that currently there are 167 AD systems operating at commercial dairies in the United States and eight in Washington. The potential to help livestock operations comply with environmental regulations while turning a profit and reducing greenhouse gas emissions suggests that more ADs are likely in the cards.
For more information on AD, see http://csanr.wsu.edu/pages/Anaerobic_Digestion and http://youtu.be/Ei49Z4oeUtY.
-Sylvia Kantor