Extension Ag Update
January/February 2001
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Research Results

The Economics of Non-GMO Segregation and Identity Preservation

The conclusion of this extensive research report reads: "The major costs of non-GMO segregation and identity preservation will depend crucially on the tolerance levels that governments set with their laws or consumers set with their preferences. Currently, it seems that a major cost in non-GMO segregation and identity preservation does not come from cleaning machinery or testing, but rather from the "reshuffling" of the grain handling system. This cost of reshuffling invites change in the infrastructure of grain handling. But because of the large fixed costs of building grain handling facilities, the adjustment to a new economic equilibrium in which there are more and smaller handling facilities located in the economically efficient places is likely to be a very lengthy one. It seems most likely that in anything but the very long run, a higher level of segregation and identity preservation will be managed at a lower cost within the current grain handling infrastructure. The effect of labeling, segregation and identity preservation on grain prices at various stages of the grain production and handling industry is theoretically ambiguous. In this paper, we report the start of what should be further empirical investigations into the effects of segregation and identity preservation on grain production and handling costs."

New Tool Improves No-Till Seeding

A new attachment designed by Agricultural Research Service scientists can improve performance of seed drills for growers who want to use no-till planting techniques.

No-till--placing seeds into soil through the leftover plant stalks, known as crop residue-- improves water use and reduces erosion. But even drills designed for no-till are not without problems. In heavy residue, plant material lodges on the seed drill's furrow opening shank and gets dragged along as the equipment moves forward. Piles of residue up to four feet long and one foot high can spill over into the adjacent seedbed, smothering seedlings as they try to emerge. ARS researchers in Pendleton, Ore. set out to make existing seed drills more effective. Their hope is that by reducing problems with the drills, more farmers will adopt no-till practices.

The new device consists of a rubber wheel with flexible "fingers" that attaches next to each furrow opener on the drill. The fingers pin the residue to the soil surface and hold it in place as the seed gets planted, preventing the plant material from lodging onto the drill. The scientists tested their prototype in eastern Oregon, where narrow-row crops like wheat with heavy residue are common. Their results showed that seeding with the wheel attachment increased the number of seedlings 10 to 50 percent, depending on field conditions. ARS has applied for a patent on the equipment, which is available for licensing (Patent application 09/594,659).

Fitting Farming Practices to Minimize Water Pollution

How much herbicide or fertilizer runs off farm fields to pollute streams and rivers may depend less on the amount of the chemical applied and more on other factors such as soil characteristics, farming systems, and how soon it rains after the chemicals are applied, according to studies by Agricultural Research Service scientists. For example, ARS scientists at Columbia, Mo., found that heavy rains that often fall on Midwest claypan soil soon after fertilizer application may pose the greatest risk for nitrogen losses in the forms of nitrate and ammonium. That's why, in the five-year study on the claypan soil that is representative of 10 million acres, 75 percent of such losses occurred within six weeks of application. Fertilizer was also more susceptible to runoff when it was spread evenly and then incorporated into the soil by tilling than when it was knifed into the soil surface in narrow bands. And the herbicides atrazine and alachlor were more prone to runoff in a no-till farming system than when they were incorporated into the soil in a minimum-tillage system.

In another watershed study with different soil characteristics and amounts of row cropping, the influences of agricultural chemicals on water quality were nearly the opposite. The scientists found that herbicide concentrations were much lower in streamwater from watersheds with soils having good structure and pore space. However, nitrate concentrations were higher because farmers in such watersheds typically rotate soybeans and corn and apply more nitrogen fertilizer. Nitrate moves easily with percolating water heading toward the stream.

Iowa Census Shows Where Milkweed Grows

A census of the common milkweed in Iowa by USDA scientists indicates the plant can be found along almost three-quarters of the roadsides and in about half of the state's corn and soybean fields. Corn and soybean fields had the lowest average percent area infested with common milkweed-- less than 0.03 percent--but these crops cover 78 percent of Iowa's landmass. Of the various other habitats surveyed--pasture, roadsides and undisturbed areas--lands in USDA's Natural Resources Conservation Service Conservation Reserve Program (CPR) had the highest percentage of area infested with milkweed (2 percent).

Common milkweed, Asclepias syriaca, is a native of the northeastern and north central United States and adjacent areas of Canada. It is the primary plant on which monarch butterfly eggs are laid and the main food source for monarch caterpillars. The study is part of the research response to concerns raised by a note published in Nature in June, 1999 about a small, preliminary laboratory study on the potential for the pollen of Bt corn to cause harm to monarch caterpillars. Bt corn is corn that has been genetically modified to express proteins found in the bacteria Bacillus thuringiensis, to reduce the need for applying chemical insecticide to the crop.

The distribution of common milkweed is simply one piece of the picture helping to clarify the true risk, if any, that Bt corn might pose to monarch butterflies. Other pieces needed to complete the risk assessment include identifying monarch preferences for milkweed in particular habitats, the distribution and extent of Bt corn pollen during pollen shed, and the actual toxicity of Bt corn pollen to monarchs.