Growth Spurts

Ohio State University researchers have found that the surface makeup of a plant’s leaves – hairy or waxy or varying degrees of both – plays a huge role in the effectiveness of liquid pesticide applications.

“The ultimate goal is to get the most out of pesticides, to get the biggest bang for your buck – achieving maximum efficiency while promoting environmental sustainability,” said Erdal Ozkan, an Ohio State University Extension agricultural engineer. “One way of doing that is make sure that the droplets hit the target, remain on the target and the pesticide active ingredients in droplets are taken up by the target.”

How that product is deposited is just as important as how much is being deposited, and knowing what kind of plant surface a grower is dealing with can help tremendously.

Ozkan and his colleagues studied the impact of liquid pesticide applications on waxy and hairy geranium leaves and found that hairy leaves captured and retained the droplets more effectively than waxy leaves. In addition, droplets deposited on hairy leaves covered more surface area as they evaporated and spread over the leaf more quickly, increasing plant uptake of the pesticide by 50 percent.

“Foliar uptake efficiency is affected by chemistry of the product applied, target surface characteristics, droplet size, evaporation time, and how much the surface area is wetted. Our objective was to investigate those parameters.”

Ozkan said that the “hairy” characteristic of the plant leaf is more effective than a smooth or waxy leaf because the hairs protect the droplets from rebounding and drifting and allows the droplets to spread out over a larger contact area.

“Hairy leaves are hydrophilic (water-loving) and so evaporation times are short, Waxy leaves are hydrophobic (water-hating) and so evaporation times are much longer for those droplets that do manage to remain on the leaf.”

In addition, researchers found that by adding a surfactant (a wetting agent that lowers the surface tension of a liquid) to the pesticide application mix, droplets cling better and are taken up by the plant much more readily.

“Adding a surfactant reduces the contact angle the droplet has with the leaf, making the droplet more stable and less likely to roll off. We found that in medium-sized droplets, the surfactant helped increase the contact area with the leaf by a faction of 2 for waxy leaves and a faction of 4 for hairy leaves.”

Ozkan said that the findings are useful for chemical companies who can recommend specific pesticide dosage and application methods when target surfaces are known to achieve maximum product benefit. For example, a farmer may only need to apply half of the application on surfaces with hydrophilic characteristics.

Source: Ohio State University College of Food, Agricultural, and Environmental Sciences

• Growth Spurts
• Pesticides

After over 10 years of lobbying, family farmers across the United States who produce organic milk are celebrating the release of strict new USDA regulations that establish distinct benchmarks requiring the grazing and pasturing of dairy cows and other livestock.

Many hope that the new rule will put an end to the abuses that have flooded the organic market with suspect milk from a handful of mega-dairies generally confining thousands of animals in feed lots and barns.

The issue has been a lightning rod for controversy in the organic community. At least five times during the last decade, the National Organic Standards Board – a key USDA advisory panel made-up of industry stakeholders – passed guidance or recommended regulatory changes clarifying the requirement that dairy cows and other ruminants must be allowed to exhibit their native behavior and consume a meaningful amount of their feed from grazing on pastures.

New rulemaking had been delayed by the Bush administration, using a myriad of tactics, some of which are being scrutinized in an ongoing investigation by the USDA’s office of Inspector General.

The USDA has announced that they will begin this month hosting a series of workshops around the country with the nation’s 50+ organic certification agencies and other industry stakeholders. The sessions are intended to clearly define the meaning and intent of the new rule so that certifiers, who conduct annual farm inspections and review organic system management plans, will understand what the regulations require from farmers and only approve management practices that strictly conform to it.

Specifically, the new rules require that dairy cows and other ruminants be out on pasture for the entire growing season, but for not less than 120 days. It also requires that the animals receive at least 30% of their feed, or dry matter intake (DMI), from pasturing. In addition, organic livestock will be required to have access to the outdoors year-round with the exception of temporary confinement due to mitigating and documentable environmental or health considerations.

National Organic Program (NOP) – Access to Pasture (Livestock)
Final rule with request for comments.
Namebrand Organic Dairy Products Scorecard

Source: The Cornucopia Institute

• The Handbook of Organic and Fair Trade Food Marketing

Rising levels of atmospheric carbon dioxide is doing more than changing climates. It is also making some trees grow like crazy.

In a new study of natural stands of quaking aspen, elevated levels of atmospheric carbon dioxide during the past 50 years boosted aspen growth rates by an astonishing 50 percent.

“Trees are already responding to a relatively nominal increase in atmospheric carbon dioxide over the past 50 years,” says Rick Lindroth, a University of Wisconsin-Madison professor of entomology and zoology and an expert on plant responses to climate change.

The accelerated growth rates of aspen could have widespread consequences. Aspen is a dominant tree in mountainous and northern forested regions of North America, including 42 million acres of Canadian forest and up to 6.5 million acres in Wisconsin and Minnesota. Aspen and their poplar cousins are considered “foundation species,” meaning they exert a strong influence on the plant and animal communities and dynamics of the forest ecosystems where they reside.

Previously, scientists have shown that plants and trees in growth chambers respond to levels of carbon dioxide well above levels in the atmosphere. The new study is the first to show that aspen in their native forest environments are already growing at accelerated rates due to rising ambient levels of carbon dioxide in the atmosphere.

“It’s a change hiding right in front of us,” says biologist Christopher Cole of the University of Minnesota at Morris. “Aspens respond to all sorts of things we had to account for – water, genetics and other factors – but the strong response to carbon dioxide surprised all of us.”

The study measured the growth rates of 919 trees from Wisconsin forests dominated by aspen and birch. Trees ranging in age from 5 to 76 years old were sampled and subjected to tree-ring analysis. Comparing the tree-ring data, a measure of annual tree growth, with records of atmospheric carbon dioxide, the researchers were able to correlate increased rates of growth with changes in the chemistry of the air.

The surprising increase in growth rates for the trees sampled in the study is coupled with moist conditions. By contrast, aspen in the western United States do not seem to grow as fast as those in the American Midwest, most likely due to recent extended periods of drought.

While the researchers found that aspen grow much faster in response to elevated carbon dioxide, similar effects have not been observed in other trees species, notably oak and pine.

The world’s forests, which cover about 30 percent of the Earth’s land surface, play an important role in regulating climate and sequestering greenhouses gases. The forests of the Northern Hemisphere, in particular, act as sinks for carbon dioxide, helping to offset the increase in levels of the greenhouse gas, widely viewed as a threat to global climate stability.

Source: University of Wisconsin College of Agricultural and Life Sciences

• Growth Spurts
• Aspen Glow by Gary Max Collins

Used coffee grounds are effective at destroying the larvae of mosquitoes carrying dengue, yellow fever, West Nile virus, malaria and other diseases.

Biocontrol Beat reports on the promising research of Hermione Bicudo at Universidade Estadual Paulista in Sao Paulo, Brazil:

“Approximately four full soup spoons of used coffee grounds in a 250 mL glass of water killed 100% of aquatic mosquito larvae. This translated into fewer adult mosquitoes (the biting, blood-sucking stage) and less new mosquito egg laying (thus, lower mosquito populations over time).”

Combined with elimination of mosquito breeding sites, used coffee grounds could be useful in integrated pest management programs to slow pesticide resistance and reduce mosquito breeding.

Three new leaf lettuce breeding lines with resistance to corky root, a serious disease of lettuce, have been released by the Agricultural Research Service of the U.S. Department of Agriculture.

Corky root is caused by a bacterium called Sphingomonas suberifaciens which lives in the soil and attacks the plant’s roots, causing them to enlarge and develop yellow to brown lesions and longitudinal cracks, taking on a cork-like appearance. Once infected, the roots are unable to effectively absorb water and nutrients, resulting in smaller lettuce heads and yield loss.

Cultural practices and fumigation techniques used to treat corky root are costly and labor-intensive. Developing lines with genetic resistance is still the most common and preferred method to combat the disease.

The new leaf lettuce breeding lines — one red leaf lettuce and two green leaf lettuces — have plant weight comparable to or higher than commercial cultivars. The breeding lines have also showed little to no tipburn in test trials. They can be used commercially for production of fresh lettuce or to develop new cultivars.

Source: Agricultural Research Service

Corrugated plastic bins can be reused durable nesting shelters for wild bees, according to an Agricultural Research Service (ARS) research entomologist.

Female wild bees will readily use a properly placed, suitably furnished tote as a shelter for their nests, according to James H. Caneof the ARS Pollinating Insects Biology, Management and Systematics Research Unit in Logan, Utah.

Turned on their long side, the totes can be held firmly in place on a wooden or metal post by means of a lightweight steel chain and a customized metal support frame.

Cane came up with the idea of using corrugated plastic totes (like those used for handling mail and packages) as nesting shelters, and has tested them during spring and summer in California, Oregon, Wyoming and Utah. His experiments show that the lightweight, rectangular bins, each 23-1/2 inches long by 15-1/2 inches wide by 15-1/2 inches high, serve as a sturdy, inexpensive and reusable shelter for protecting bee nests against wind and rain.

Growers, professional and hobbyist beekeepers, and backyard gardeners who want wild bees to live near and work in their fields, orchards, vineyards or home gardens can use the totes to house nesting materials, such as five-sixteenths-inch diameter paper drinking straws enclosed in cardboard tubes and stuffed inside empty cardboard milk cartons. Wild female bees such as the blue orchard bee, Osmia lignaria, can use the straws as homes for a new generation of pollinators.

Wild bees are needed now, perhaps more than ever, to help with jobs usually handled by America’s premier pollinator, the European honey bee, Apis mellifera. Many of the nation’s honey bee colonies have been decimated by the puzzling colony collapse disorder or weakened by varroa and tracheal mites or the microbes that cause diseases such as chalkbrood and foulbrood.

A single corrugated plastic tote can accommodate as many as 3,000 young, enough to pollinate one-half to one-acre of orchard. And, unlike bulky or stationary shelters, the tote houses can easily be moved from one site to the next.

Source: Agricultural Research Service

Recognized globally as an ideal means of conserving soil and water while also storing soil carbon, the agricultural practice known as “no-till” may not be applicable under all environmental conditions.

No-till farming means leaving residue left on the soil surface after harvest in place rather than plowing it under. Compared to plowing, no-till has myriad benefits: less labor, less machinery wear, decreased fossil fuel consumption, reduced soil erosion, improved soil productivity, increased wildlife habitats and a better method of maintaining and conserving soil water.

No-till is considered a successful carbon sequestration practice when carbon input (storage) exceeds carbon output (loss). Carbon input includes crop residues, winter cover crops, complex farming systems, and use of compost and manure. The output includes losses of carbon by decompositon, erosion and leaching.

Ohio State University soil scientists recently measured carbon levels in no-till fields throughout seven states and found that soil texture, moisture, temperature, and terrain parameters affected the amount of carbon stored on the soil surface.

“No-till is not applicable everywhere as a means of practicing carbon sequestration,” says Rattan Lal, soil scientist at Ohio State’s Ohio Agricultural Research and Development Center. “There are situations where other carbon sequestration methods would be more effective. I’m not saying that no-till is not good. It is a good practice, but it does not work for all soils, for all crops and all conditions. We must not make carbon sequestration synonymous with no-till. The strategy is to develop a system of soil management in which carbon input into the system exceeds the output.”

Lal and his colleagues studied no-till fields in Ohio, Michigan, Indiana, Pennsylvania, Kentucky, West Virginia and Maryland and identified situations where the practice was the most effective in storing carbon and where it was not.

“Basically, those soils that are well-drained, are silt/silt-loam in texture, warm quickly and have some sloping characteristics prone to erosion are excellent candidates for no-till. Clay soils or other heavy soils that drain poorly, are prone to compaction and are in areas where the ground stays cooler may not always increase carbon storage through no-till.”

In Ohio, for example, the researchers found that no-till would store carbon on about 40 percent of the state’s cropland. In actuality, no-till is practiced on 35 percent of Ohio’s field crops, said Lal.

“Globally, no-till is practiced on only 6 percent of the total cropland and mostly practiced in the United States, Canada, Brazil, Australia, Argentina and Chile. There’s a reason for that — because it can be worked into practices in which carbon input exceeds carbon output.”

In situations where no-till may not be ideal, there are plenty of other carbon sequestration methods available, including mulching, cover crops, complex crop rotations, mixed farming systems, agroforestry, and biochar (a charcoal-like biomass material).

The study also compared carbon levels between no-till and conventional tillage fields and found that, in some cases, carbon storage was greater in conventional tillage fields. But the key is soil depth.

“If you compare carbon storage between no-till and plowed fields with the plow depth, or the first 8 inches of the soil, carbon storage is generally much greater in no-till fields than in plowed fields. But if you go deeper, say 12 inches and deeper, one may find more carbon stored in plowed fields than in no-till.”

Farmers should not measure soil carbon based just on surface depth. Lal recommends going to as much as 1 meter (3.25 feet) below the soil surface.

Lal said that the study is not a criticism of no-till and its benefits, but simply a way of determining where the practice best fits and where other carbon sequestration methods may work better.

“In situations where no-till is ideal, it’s a sustainable soil management practice that simply can’t be ignored,” said Lal. “It saves time, money and wear on machinery and its profit margin is much higher than plowing.”

Source: Ohio State University College of Food, Agricultural, and Environmental Sciences

Researchers at Virginia Tech, Oak Ridge National Laboratory, and the University of Georgia have produced hydrogen gas pure enough to power fuel cells by mixing 14 enzymes, one coenzyme, and cellulosic materials like woodchips or grass.

The group announced three advances from their “one pot” process: 1) a novel combination of enzymes, 2) an increased hydrogen generation rate — to as fast as natural hydrogen fermentation, and 3) a chemical energy output greater than the chemical energy stored in sugars – the highest hydrogen yield previously reported from cellulosic materials.

“In addition to converting the chemical energy from the sugar, the process also converts the low-temperature thermal energy into high-quality hydrogen energy – like Prometheus stealing fire,” said Percival Zhang, assistant professor of biological systems engineering at Virginia Tech.

The researchers used cellulosic materials isolated from wood chips, but crop waste or switchgrass could also be used. Using cellulose instead of starch expands the renewable resource for producing hydrogen to include biomass.

“If a small fraction – 2 or 3 percent – of yearly biomass production were used for sugar-to-hydrogen fuel cells for transportation, we could reach transportation fuel independence,” Zhang said.

The research results have been published in the Wiley journal ChemSusChem (Chemistry and Sustainability), in an article titled “Spontaneous High-Yield Production of Hydrogen from Cellulosic Materials and Water Catalyzed by Enzyme Cocktails.”

• Growth Spurts
• Designing and Building Fuel Cells

Grass filter strips placed in riparian zones not only curb soil erosion, but also block and degrade the widely used herbicide atrazine, Agricultural Research Service (ARS) scientists report.

Atrazine has been used extensively to suppress weeds in corn production for decades, but because it’s applied directly to soil it’s especially prone to losses in surface runoff. The contamination of surface water by atrazine and its less-toxic breakdown components has raised ecological concerns.

Riparian zones are transitional areas between upland areas, such as crop fields, and water bodies. The grasses and other vegetation in these zones help reduce pollution in streams and lakes.

In studies of the effect of different grass species on herbicide transport and degradation, eastern gammagrass showed the highest capacity for promoting atrazine degradation. Orchardgrass, smooth bromegrass, and switchgrass were also effective.

The studies have shown that grass buffers reduced the transport of herbicides to shallow groundwater and in runoff. These buffers can reduce herbicide transport through trapping of sediment and by increased infiltration of water into the soil.

Source: Agricultural Research Service, USDA

• Plants and Seeds

With U.S. milk prices collapsing after two years of historical highs, an old dairy program reauthorized by the 2008 Farm Bill may aid dairy producers by adding additional income over the coming months.

Dairy producers are being encouraged to sign up for the Milk Income Loss Contract (MILC) — a program that provides monthly payments to producers when market prices drop below the program’s defined trigger price.

MILC was first authorized by the dairy title of the 2002 Farm Bill, and after years of extensions has been included in the 2008 dairy title of the Food, Conservation and Energy Act. MILC now includes a feed cost adjuster and increases in both the payment rate and production eligibility among small to medium-sized dairy farms.

“MILC functions similarly to the old grain countercyclical payment programs,” says Cameron Thraen, an Ohio State University Extension dairy economist. “The program has an identified target or trigger price and when the market price drops below that trigger price, the difference between the two is calculated and farmers receive 45 percent of that difference.”

With milk prices tumbling nearly 35 percent in just the past few weeks due to decreased domestic and global demand and the outlook for 2009 looking grim, Thraen said that dairy producers should act quickly to sign up for the MILC program.

“There is absolutely no cost to sign up for the progrom. Any producer who is not signed up for the program or is not thinking about signing up is missing an excellent opportunity.”

Thraen reminds producers that participating in the previous MILC program does not automatically enroll a producer in the current program. New sign-up forms must be completed and submitted.

Details of how the program works are available in a series of documents located on Thraen’s OSU Extension website. The information includes a spreadsheet that allows dairy producers to calculate monthly eligible milk shipments, MILC payments, and total anticipated revenue from the program based on actual or estimated monthly milk and feed prices throughout fiscal year 2009.

The following are some basics dairy producers should know about MILC:

• Sign-ups for MILC began on Dec. 22, 2008. Producers can sign up anytime during 2009 to be eligible to receive potential payments, but must do so the month prior to when they would like to enter the program. Producers can sign up to participate in MILC by contacting their local Farm Service Agency.
• The cap on milk production to remain eligible is 2.985 million pounds per fiscal year. Once a dairy farm’s monthly milk shipment reaches the cap, the producer is no longer eligible to receive payments for the current fiscal year.
• There is no cost to sign up for the program. But once sign-up occurs and a start month is selected, there can be no adjustments. That is, if a farmer enters the program during a time when there are no triggered payments, that farmer cannot readjust eligibility to a future date.
• New to MILC for the 2008 Farm Bill is the inclusion of dairy feed costs, which are calculated into the projected payment. The adjustment was made to reflect market shifts based on corn, soybeans and alfalfa prices.
• Payment per hundredweight is based on 45 percent of the difference between the market price and feed price adjusted MILC trigger price.

Source: Ohio State University College of Food, Agricultural, and Environmental Sciences

• Growth Spurts
• Husbandry
• Market Watch