Extension Ag Update
September/October 2004
Articles Research Resources Internet Links Ag Facts Education


Livestock Systems Benefit Watersheds


A Minnesota study showed that farming systems incorporating permanent pasture or hay systems and dairy or another livestock could significantly improve Minnesota’s water quality. On steep land, replacing corn/ soybean rotations with a more diverse crop rotation that incorporated hay and pasture substantially reduced sedimentation, pollution runoff and flooding in the two watersheds of the study. The study also estimated that policies to encourage and support this change in crop rotation could benefit the farmer financially while not affecting costs to taxpayers.

Drift Retardant Chemicals Serve Their Purpose

Candace Pollock, Communications and Technology, Ohio State University (614) 292-3799, pollock.58@osu.edu; Source: Erdal Ozkan, (614) 292-3006, ozkan.2@osu.edu

Drift retardant chemicals may be an option to help reduce spray drift on field crops, but their effectiveness continues to be questioned. An Ohio State University agricultural engineering study has shown that the products live up to their purpose. The study, conducted by Ohio State agricultural engineers, examined the effects of drift retardant chemicals on spray pattern, droplet size and spray drift.

“Spray drift is a serious concern for all who apply pesticides. Yet many wonder if these products actually do what they are advertised to do: reduce drift,” said Erdal Ozkan, an Ohio State agricultural engineer with the Department of Food, Agricultural and Biological Engineering. “Results of these tests indicate that if used properly at appropriate rates, products indeed reduce spray drift by hindering formation of small, drift-prone droplets.”

Drift retardant chemicals are normally made up of types of long-chain polymers or gums that increases the viscosity of the spray mixture, ultimately impacting the size of the droplets and the amount of spray concentrated in each droplet. Yet, little research on the performance of the products has been documented. Results of one study conducted by USDA-ARS engineers in Texas, for example, indicated that the effect of polymer concentration on droplet size is dependent on polymer type, and that certain types of polymers increase droplet size, thereby reducing the percentage of spray volume composed of small droplets subject to spray drift.

In the Ohio State study, Ozkan and his colleagues tested five drift retardant chemicals and found that, in comparison to spraying only water, all the products reduced the percent of spray volume contained in small droplets, but at varying magnitudes. “For example, the reduction of spray volume contained in droplets smaller than 100 microns ranged from 30 percent with the least effective product, to 68 percent with the most effective product,” said Ozkan. “There is a direct correlation between the amount of active ingredients in the spray mixture and effectiveness of the spray mixture in drift control. The higher the active ingredient amount, the more effective the fight against drift is.” Which means, said Ozkan, that when buying drift retardant chemicals, growers should always read the label and compare products based on the active ingredient concentrations, and the total cost of making a mixture of a tank full of spray solution.

“Some products are expensive but require only a few ounces per 100 gallons of mixture, while others, containing the same active ingredients but at a much lower concentration, may be less expensive. But they may require several quarts of product to achieve the same level of protection against drift,” he said. Ozkan stated that some drift retardant products lose their effectiveness when passed through a typical sprayer pump.

“Some studies have found that some of these polymers tend to be sheared by passing through a sprayer pump, as would occur in a normal bypass, hydraulic mixing in common agricultural sprayers. This means that the drift retardant would lose its ability to increase droplet size - its ability to reduce drift- as the spray tank became empty,” said Ozkan. “Gums are not sheared as easily as the long chain polymers, and some types of polymers (poly-ethylene oxide) are sheared in fewer passes through a pump than other types of polymers (polyacrylamides).”

Over 30 drift retardant chemicals are commercially available to pesticide applicators, but Ozkan encourages growers to use the products as a last resort. “Although drift retardant chemicals are effective in reducing the number of drift-prone droplets, in most cases, using low-drift nozzles and operating sprayers at lower pressures seems to be a better and more cost-effective approach to reducing spray drift,” said Ozkan. “Drift retardant chemicals should be the last source of defense against drift, not the first.”

Survey of Upper Midwest Community Supported Agriculture (CSA)


This survey evaluated CSA’s viability and provides a regional characterization of this movement. Community Supported Agriculture systems tend to charge an annual fee for membership. A box with a variety of produce is then delivered to the member on a regular schedule throughout the growing season. Some CSA’s allow for an exchange of labor for produce. The average net return per acre for CSA farmers is $2,467, in contrast to the return per acre of corn ($172.11), soybeans ($134.46) and wheat ($38.10) in the United States. About 57 percent of CSA farmers indicated that their share price did not provide them with a fair wage. Almost 97 percent of the farmers indicated that they were completely satisfied or satisfied most of the time with their CSA operations.

Economics of Sequestering Carbon in the U.S. Agricultural Sector, Tech Bull. 1909


Atmospheric concentrations of greenhouse gases can be reduced by withdrawing carbon from the atmosphere and sequestering it in soils and biomass. This report analyzes the performance of alternative incentive designs and payment levels if farmers were paid to adopt land uses and management practices that raise soil carbon levels. At payment levels below $10 per metric ton for permanently sequestered carbon, analysis suggests landowners would find it more cost effective to adopt changes in rotations and tillage practices. At higher payment levels, afforestation dominates sequestration activities, mostly through conversion of pastureland. Across payment levels, the economic potential to sequester carbon is much lower than the technical potential reported in soil science studies. The most cost-effective payment design adjusts payment levels to account both for the length of time farmers are willing to commit to sequestration activities and for net sequestration. A 50-percent cost-share for cropland conversion to forestry or grasslands would increase sequestration at low carbon payment levels but not at high payment levels.

Hard White Wheat at a Crossroads


This article provides background on the forces that led to the expansion of hard white wheat (HWW) production, its milling and baking qualities that make it particularly suited for certain products, the adaptation of the marketing system to preserve its identity, and the prospects for HWW's production expansion. Up to now, HWW sales have been largely confined to the domestic market because the volume of production is not sufficiently large to sustain steady exports. HWW's end-use characteristics are particularly suited for whole-wheat products, pan breads, tortillas, and certain kinds of oriental noodles. Continuing expansion of HWW production would depend on the development of new, higher-yielding varieties that are more tolerant to sprout damage—a major problem in 2004—and continuation of the government incentive program.