Extension Ag Update
September/October 2004
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Toxicity of Chemicals Depends on Soil

Joe Stucki, 217-333-9636, jstucki@uiuc.edu, Source: Gary Beaumont, 217-333-9440, beaumont@uiuc.edu

It was thought that as farm chemicals start degrading in contact with soil they become less toxic, but new research from the University of Illinois, published in the August 15, 2004 issue of Environmental Science & Technology, suggests that certain pesticide can actually become more toxic in contact with reduced, iron-bearing clays commonly found in soils.

The long held theory was that farm chemicals became less harmful in the soil through a process of microbial degradation and sequestration. No one expected, therefore, to discover a chemical reaction with clay particles that increased the toxicity of a compound. "We expected to see some reaction because other studies we have done showed that reduced clay is more reactive than oxidized clay," said Joe Stucki, University of Illinois professor of soil chemistry. "But we were surprised that the toxicity of one of the compounds increased."

The researchers in this project mixed four different herbicides with reduced or unoxidized ferruginous smectite, a specific group of clay minerals. They compared the toxicity of the pesticide on its own to the toxicity of the pesticide that had reacted with the smectite. They used a widely accepted toxicity test employing mammalian cells of a hamster.

Treatment with reduced smectite, or clay mineral with little or no oxygen attached to it, substantially increased the toxicity of dicamba by as much as 33 percent, decreased the toxicity of oxamyl by 50 percent, slightly decreased the toxicity of alachlor, and for 2,4-D toxicity remained about the same.

Dicamba is one of the most widely used products for controlling broadleaf weeds in corn. Oxamyl is widely used for control of insects, mites and nematodes on field crops, fruits and ornamentals. The majority of oxamyl is applied to apples, potatoes, and tomatoes.

Alachlor is a herbicide for control of annual grasses and broadleaf weeds in crops, primarily on corn, sorghum and soybeans. Alachlor is the second most widely used herbicide in the United States, with particularly heavy use on corn and soybeans in Illinois, Indiana, Iowa, Minnesota, Nebraska, Ohio, and Wisconsin.

2,4-D is a herbicide for the control of broad-leaf weeds in agriculture, and for control of woody plants along roadsides, railways, and utilities rights of way. It has been most widely used on such crops as wheat and corn, and on pasture and rangelands.

"Virtually every study looking at the effect of soil and clay minerals on the fate of pesticides has ignored oxidization state. That's an omission because soils are commonly in a reduced condition and now we have shown that the oxidation state makes a big difference," said Stucki. "What we're showing here, at least in the case of dicamba, is that the compound became more toxic when it came into contact with the reduced clay, so we can't always assume that when a compound comes into contact with the soil it’s a positive environmental outcome," he said.

The pesticide levels tested were comparable to pesticide concentrations commonly found on farms. Also, smectite clays are abundant in many soil profiles. Reduced smectite clay particles are often found near the soil surface due to rainfall events and microbial activity. Stucki says other degradation products were found in the research and the research team is currently attempting to identify those compounds and measure their toxicity.

The research was part of a dissertation project of Kara Sorensen, who now works for the Naval Research Laboratory in San Diego. Her initial interest grew out of a desire to study cancer in wildlife and what might cause it. Funding came, in part, from the Department of Energy, National Science Foundation, U.S. Israel Bi-National Agricultural Research Fund, International Arid Lands Consortium, and the U of I Agricultural Experiment Station.

Penn State Evaluating European Haydryer

Glen Cauffman, 814-865-4433, grc1@psu.edu, Author: Jeff Mulhollem, 814,863-2719, jjm29@psu.edu

In an ironic twist of technology that has Penn State farm operations manager Glen Cauffman feeling like a bit player in the hit movie "Back to The Future," the College of Agricultural Sciences is evaluating a new European spin on a 50-year-old hay-drying process that has major implications for Pennsylvania farmers.

That the evaluation is coming in a very wet summer is another quirk of fate. "In the 1950s and '60s, it was common for Pennsylvania farmers to use haydryers," Cauffman explained recently, while watching a demonstration of the haydryer made by Feribale Manufacturing, an Italian forage equipment maker, at Penn State's Ag Progress Days. "But they disappeared in the United States. "Haydryers made economic sense when diesel fuel was selling for 2 cents a gallon," Cauffman added, "but not when it rose to 80 cents a gallon. The last one I remember was a New Holland model that went out of production in the 1960s."

Cauffman estimates that 100 or so haydryers are in use in Europe. Penn State is doing the only evaluation of a haydryer in this country, an arrangement resulting from a representative of the Italian forage equipment maker approaching Cauffman about giving the machine a try. "I was skeptical at first," he admits. "But it looks like advances in energy efficiency make the haydryer a possibility for Pennsylvania farmers. We have been evaluating the machine since May, and the results are not yet in, but it looks like it offers some distinct advantages."

The theory behind a haydryer, which can be fueled by fuel oil, natural gas or propane, is that after farmers cut hay and allow it to partially dry in the field, and before it reaches a moisture level safe to store in a barn, the hay is put into a haydryer for six or seven hours. The resulting forage, because it was dried relatively quickly and soon after it was cut, retains a higher nutritional value for livestock. "I think this machine will interest a lot of Pennsylvania farmers," Cauffman says. "A big advantage is that the more hay dries in the field, the more leaves it loses. So the advantage of baling it at a higher moisture level is that it retains more leaves and more nutritional value. And in theory, that higher nutritional value will pay for the drying costs. The jury is still out on that, however, and that is what we are evaluating here at Penn State."

According to Cauffman, having a haydryer has been a particular blessing during this rainy summer, which has been one of Pennsylvania's wettest ever. "We haven't had many three-consecutive-dry-day periods that we need to dry hay in the field before bringing it in," he says. "We were able to partially dry hay in the field and finish it in the haydryer. Without it, we'd have lost a lot of hay. And last fall, we were able to make hay clear into November with it, and we never could do that before."

Further Testing and Simulation of Hay Bale Loading on Semi-Trailers

Robert Di Cristoforo and Dr Peter F Sweatman, Roaduser Systems Pty Ltd, July 2004, RIRDC Publication No 04/124 RIRDC Project No ROA-2A


The study aimed to provide a sound technical basis to aid State jurisdictions in developing consistent hay bale loading rules which are more clearly related to safety objectives. There was a need to address the effects of load dimensions on both vehicle stability and road width requirements; these two vehicle performance measures are effectively controlled by PBS, which allows flexibility in vehicle regulation by exempting vehicles from prescriptive regulations without adversely affecting safety.

The assessment covered the four common hay bale sizes (nominally expressed as 3’x3’x8’ rectangular, 4’x3’x8’ rectangular, 4’x4’x8’ rectangular and 5’x4’ round), along with the common stacking arrangements employed by industry, a variety of load restraint methods and a set of representative hay truck configurations, providing a total of 77 combinations. The assessment process [1] included two parts. Firstly, each load type was physically tested in a specially designed rig to determine its lateral rigidity when properly restrained on a trailer deck. The load types included all bale sizes, stacking arrangements and load restraint methods for a total of 31 test set-ups.

Lateral rigidity characteristics were recorded as force-displacement plots that were used in further analysis. Secondly, the stability and road width requirements were determined for each vehicle configuration and load type by computer simulation of vehicle dynamics. The lateral rigidity parameters obtained from the tests were incorporated into the models to pass the effect of load movement on to roll stability performance. These simulation models provided valuable information regarding the effect of load height and bale type on stability, with effects due to load restraint methods also observed.

The physical tests revealed enormous variations in lateral rigidity between the different types of bales, with round bales offering the least rigidity. The 4’x4’x8’ rectangular bales were by far the best performers, with more than twice the rigidity of round bales at 4.6m high. The computer simulation models predicted considerable variation in rollover stability. The biggest contributing factor was bale type, followed by stacking arrangement, vehicle configuration and finally load restraint method.

Wind Power’s Contribution to Electric Power Generation and Impact on Farms and Rural Communities


A Government Accountability Office report found that while wind power does not contribute significantly to total farm income in the 10 states with the highest installed wind power capacity, it has great benefit for some farmers and rural communities. The report, states that a farmer who leases land for a wind project can expect to receive $2,000 to $5,000 per turbine per year in lease payments. The study found that most of the nations wind potential remains untapped, accounting for only about one-tenth of one percent of total U.S. electric power generation capacity in 2003. Wind power’s growth will depend largely on the continued availability of federal and state financial incentives, including tax credits, and expected increases in prices for fossil fuels.