Vol. 1, No. 1 -- April 15, 2004

	Hello and welcome to the New Agriculture Network
	Can organic practices compete with no-tillage systems for carbon or conservation credits?
	The time of tillage and weed emergence
	Avoiding problems with nitrate leaching into tile drains
	Hyperlinked corn and soybean seedling insect diagnostic guides
	Reports from organic growers - April 14

Next issue posted April 29

Hello and welcome to the New Agriculture Network

This network is a collaboration between farmers, researchers and educators in three states. Nine organic farmers from the three states will share crop updates and advice with Extension personnel from the University of Illinois, Purdue and Michigan State University to generate information throughout the 2004 growing season. This exchange will occur the day before we post the articles and reports at the network web site. You can read a summary of the growers’ reports in the Reports from organic growers section of each issue.

We are excited to provide biological farming information to you. We encourage you to read the reports, articles and other organic farming information. If you have topics you would like addressed during this season, please submit them to: newagnet@msue.msu.edu and we will do our best to develop articles for them.

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Michelle Wander
Natural Resources and Environmental Sciences, University of Illinois

Producers are coming to grips with the fact that climate of the Great Lakes region will change notably within their lifetimes. Current projections suggest that within three decades a summer in Illinois will feel like a summer in Oklahoma today. By the end of the century, an Illinois summer will have moved on to today’s West Texas, while the Illinois winter will feel like today’s Oklahoma winter. By 2035, Michigan summers may resemble the climate of Illinois or Indiana in terms of average temperature and rainfall while by the end of the century, summer climate will resemble that of current Tennessee or Arkansas. Winters will also change, albeit less drastically. For more information see: http://www.ucsusa.org/greatlakes/glchallengereport.html

Todd Nissen and I estimated the dollar value of increasing carbon in soils assuming sequestration rates of 0.35 tons of carbon per hectare per year. Returns derived from enhanced soil quality (N replacement, erosion prevention, water quality improvements, enhanced soil productivity) were worth $230 per hectare per year compared to only $140 paid for carbon emissions offsets. The benefits derived from soil quality are reaped each year while the payment for carbon storage is a one-time deal. Finally, we assumed the value of C sequestered was $20 a ton, which might be reasonable for Kyoto signatories but is higher than values ($1 ton carbon!) presently set for U.S. trades. More information available upon request (Wander at mwander@uiuc.edu 217-333-9471), or see Wander and Nissen, 2004.

Table 1. Carbon storage in agricultural systems. CRP = Conservation Reserve Program. MT = tons x 10⁶. (Adapted from Eve et al. 2002).

Lake States include Minnesota, Wisconsin, and Michigan. Corn Belt states include Iowa, Missouri, Illinois, Indiana, and Ohio. Range reported is for all data across the conterminous United States.

Emissions accounting strategies presently focus on carbon dioxide because it is by far the most abundant and best quantified greenhouse gas. While agriculture contributes relatively little (4%) to North America's carbon dioxide emissions it emits 30 percent of methane and over 70 percent of all nitrous oxide emissions. This is important because the heat trapping capacity of methane and nitrous oxides are much higher than carbon dioxide. Methane emissions are principally associated with the livestock industry while nitrous oxide emissions are associated with direct and indirect effects of nitrogen fertilization. The comparison of Michigan production systems shows how fuller accounting can be made. When additions of lime, fertilizers, and requirements for fuel, which all add to the climate problem, are considered, it is clear that all the annual systems are net sources for GHGs and that only the successional forests are sinks.

Table 2. Changes in production, carbon sequestration, and global warming potential of Michigan LTER cropping systems. GWP is global warming potential in CO₂ equivalents. From Robertson et al. 2000.

ANPP = annual net primary productivity. DC represents the change in SOC that occurred during the 8-year study. MT = tons x 10⁶.

It is not clear that organic agriculture will benefit from carbon trading opportunities.

The National Corn Growers Association and the American Soybean Associations both support efforts to mitigate climate change through producer participation in voluntary trading programs (http://www.ncga.com and http://www.soygrowers.com/membership/federal03.htm ). The Chicago Climate Exchange's contract choices likely reflect this kind of input and relative ease of practice adoption by mainstream producers. To be included as choices in voluntary trading schemes or in federally supported conservation programs, organic systems will need to demonstrate they can effectively sequester carbon and, possibly, prove they deliver added value in terms of ecosystem services, nutrient and/or energy use efficiency. It is ironic that organic practices are not being included as options given that organic farming is the only system of sustainable agriculture that is legally defined. More than payments may be at stake for organic agriculture; exclusion from trading and conservation programs might suggest to some that organic methods are not "best management practices.”

References
Eve, M.D., M. Sperow, K. Paustian, and R.F. Follett. 2002. National-scale estimation of changes in soil carbon stocks on agricultural lands. Environmental Pollution 116: 431-438.

Robertson, G.P., E.A. Paul, and R.R. Harwood. 2000. Greenhouse gases in intensive agriculture: Contributions of individual gases to the radiative forcing of the atmosphere. Science 289:1922-1925.

Wander, M.M. and T.M. Nissen. 2004. Value of soil organic carbon in agricultural lands. Mitigation and Adaptation for Global Climate Change Special Issue on Climate Change and Environmental Policy (Eds) HS Khesgi and M. Khanna. On line publication 11/24/2003. In press.

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The time of tillage and weed emergence

Karen Renner and Doug Buhler
MSU Crop & Soil Sciences

In the 1960's weed researchers in Europe thought about the light requirement for weed seed germination. These researchers tried tilling fields in the dark to reduce weed emergence. In one study emergence of br oadleaf weeds was reduced by 60 percent when tillage was completed in the darkness compared to tillage during the light of the day. There was a resurgence of interest in this concept in the 1990's as researchers in the United States looked into tilling in the dark to reduce weed emergence. In one study, redroot pigweed and nightshade species emergence was reduced as much as five times when tillage was completed in the dark (Scopel et al. 1994). Other researchers reported a 40 percent (Ascard 1994) or more reduction in weed emergence when light was excluded but it varied by weed species (Ascard 1994; Jensen 1995). In 1994 and 1995, research was conducted in Minnesota to determine the effect of tillage and the light environment on the emergence of 13 annual weeds (Buhler 1997). Could tilling in the dark reduce weed emergence in the upper Midwest?

Since all weed species don’t have a light requirement for germination, tillage in the dark should reduce the germination of some weed species but not others. Furthermore, would the elimination of tillage in the spring reduce weed emergence of all species or just the light sensitive species? Here are the results of this research.

1. The light environment had no effect on emergence of barnyardgrass, green foxtail, yellowfoxtail, and giant foxtail. (So no need to invest in night vision goggles for these four weed species!)

2. The effect of tillage on barnyardgrass and green foxtail emergence varied by year and the time of tillage. It was difficult to draw conclusions from the emergence data for these two species.

3. When tillage occurred in early May, giant foxtail and yellow foxtail emergence was not increased by tillage. However, tillage increased emergence of these two grass species 30 to 60 percent compared to no tillage when tillage occurred in late May. This is probably because peak emergence of these grasses occurred prior to the late May tillage. Therefore, tilling in late May moved more grass seed into the upper inch of the soil profile where soil temperature and conditions was favorable for seed germination.

4. The light environment had no effect on emergence of common cocklebur, giant ragweed, or velvetleaf. (So again, no need to invest in night vision goggles for these three weed species!)

5. Tillage increased emergence of common cocklebur and giant ragweed by 0 to 30 percent and velvetleaf by 30 to 60 percent. So, emergence of these three weed species was reduced by not tilling in early or late May.

6. Common lambsquarters emergence was reduced by 70 percent when tillage was completed in the dark compared to the daylight. Day tillage increased common lambsquarters emergence by 70 percent compared to no tillage.

7. Redroot pigweed emergence was reduced by 50 percent when tillage was completed in the dark compared to the daylight. Day tillage increased redroot pigweed emergence by 50 percent compared to no tillage.

8. Eastern black nightshade emergence was reduced 40 to 50 percent when tillage was completed in the dark compared to the daylight. Day tillage in early May increased eastern black nightshade emergence by 60 percent compared to no tillage.

9. Pennsylvania smartweed emergence was reduced by 60 percent when tillage was completed in the dark compared to the daylight. Day tillage increased Pennsylvania smartweed emergence 0 to 20 percent compared to no tillage.

10. Common ragweed emergence was reduced by 45 percent when tillage was completed in the dark compared to the daylight. Day tillage increase common ragweed emergence 35 to 65 percent compared to no tillage.

11. Wild mustard emergence was reduced by 40 percent when tillage was completed in the dark compared to the daylight. Day tillage increased wild mustard emergence 70 percent compared to no tillage.

What are the important implications of this research?

1. Tillage at any time (day or night) will increase emergence of annual grasses, large-seeded broadleaf, and small-seeded broadleaf weeds. Therefore, if the goal is to maximize weed emergence prior to planting, it is best to till during the day.

2. Tilling at night in complete darkness will decrease emergence of small-seeded broadleaf weeds but will not decrease emergence of annual grasses and velvetleaf, cocklebur, or giant ragweed. Therefore, if the goal is to minimize total weed emergence it is best to till at night.

References

Ascard, J. 1994. Soil cultivation in darkness reduced weed emergence. Acta Hortic. 372:167-177.

Buhler, D.D. 1997. Effect of tillage and light environment on emergence of 13 annual weeds. Weed Technology 11:496-501.

Jensen, P. K. 1995. Effect of light environment during soil disturbance on germination and emergence pattern of weeds. Ann. Appl. Biol. 127:561-571.

Scopel, A. L. C. L. Ballare, and S. R. Radosevich. 1994. Photostimulation of seed germination during soil tillage. New Phytol. 126:145-152.

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Avoiding problems with nitrate leaching into tile drains

Eileen Kladivko
Agronomy Dept., Purdue University

It is springtime in the Midwest, and tile drains are flowing. These tile drains provide many benefits for agricultural production such as removing excess water from the fields, improving field trafficability and timeliness of operations, reducing surface runoff and erosion, and improving crop growth and yield. But tile drainage water also contributes nitrates to surface ditches and streams. It is important to try to reduce the amount of nitrate leaching through the root zone in order to protect surface water quality.

Nitrate leaching to tile drains cannot be completely controlled but can be reduced by appropriate management practices. Nitrate leaching is determined by both the amount of water moving through the soil and the amount of nitrate in the soil. Strategies to reduce nitrate leaching can therefore be categorized in several ways: 1) practices that lower the amount of nitrate in the soil, and 2) practices that lower the amount of water draining through the soil.

N application rates/timing
The amount of N applied, whether from organic or inorganic sources, should be matched as closely as possible to the needs of the crop. Nitrogen applications in excess of what the crop needs will be available for leaching after the growing season. In general, applying the N closer to the time the crop needs it (preplant or sidedress) will reduce nitrate leaching compared with applications in the previous fall.

Cover crops
Keeping something growing for longer periods of the year can greatly reduce nitrate leaching into tile drains. Even with optimal N application rates, there is nitrate available in the soil in the fallow seasons after crop harvest. Some of this nitrate is produced from mineralization of soil organic matter, as well as from manures or organic fertilizers, during the fall and early spring when the field is usually fallow. Winter cover crops take up some of this nitrate and reduce nitrate concentrations and loads in the drainage water.

Perennials in rotation
Perennial crops, both legumes and non-legumes, generally have lower nitrate leaching losses than annual crops. This is due in part to the longer growing season and greater transpiration of these crops compared to annual crops, which results in greater N uptake and less drainflow. A perennial legume such as alfalfa has the potential for large leaching losses after it is killed and tilled into the soil, however, and management practices should be implemented to better match the timing of N release with the growth of the next crop.

Drainage water volume
Nitrate leaching varies greatly from year-to-year depending on rainfall amounts and timing and the resulting drainflow amounts. While the rainfall is not controllable, the amount of drainflow may be somewhat reduced by growing winter cover crops. Some newer technologies such as drainage water management are designed to reduce drainflows during the fallow season by temporarily raising the height of the drain outlet. Even after the drain outlet is lowered again in early April, the total amount of drainage and nitrate loss is less than with the standard free drainage system. And for growers who use irrigation, fine-tuning the irrigation rates to minimize drainage waters would also reduce nitrate leaching.

The overall strategy is to use more of the N that is in the system as well as more of the water. Because nitrate is continually being produced from soil organic matter as well as originating from manures or other N additions, having a living cover for more of the year is an excellent way to capture some of this nitrate and recycle it back into the root zone. Cropping systems that also use more of the water available in late fall or early spring would reduce the volume of drainflow as well as the nitrate concentrations and, therefore, produce even greater reductions in nitrate loads to surface waters.

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Hyper-linked corn and soybean seedling insect diagnostic guide

John Obermeyer and Larry Bledsoe
Purdue Extension Entomology

The 2004 field scouting season is here! Two diagnostic guides have been developed to facilitate the field problem-solving process for corn and soybeans early in the season. Follow these links for photos of insect damage symptoms, possible causes, and scouting methods.

Corn seedling insect diagnostic guide
Soybean seedling insect diagnostic guide

Happy and accurate scouting!

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During the conference call, some of the questions that were raised for future articles involved nitrogen sources for corn; no-tilling organic crops; the potential for alternative crops like spelt, amaranths, and buckwheat; and the effectiveness of organic methods for controlling soybean aphids. Six of our nine growers were on the April 14 conference call. We will introduce them further in the next issue (April 29).

Illinois
Dave Campbell is located in Northeastern Illinois where he has a 200-acre cash-grain operation. His rotation is soybean, wheat and corn, some oats -- no livestock. The farm has been certified organic since 1991. It has been pretty dry this winter, especially the past three weeks. Dave did sow some oats and hay mix for his neighbor’s large horse farm this past week. It appears that there is enough moisture to get the oats to germinate although the alfalfa/grass seed is laying in the dry dirt.

Dave will be sowing a small amount of oats and hay mix later today. He also plans to do some moldboard plowing of cornstalks in a test plot later this week. He will be comparing what he moldboarded this early spring versus what he chisel plowed last fall. This field will be going to soybeans. He also plans to field cultivate a field that has moderate quackgrass pressure tomorrow. This field is going to corn. Later this week, he will broadcast some organic nitrogen fertilizer on his winter wheat ground. Next week, he will possibly go over his ground for the first time this year with a field cultivator if conditions are right. This is ground that will be planted to corn and soybeans this year.

Jon Cherniss is in the Urbana-Champaign area of Central Illinois. He farms vegetable crops on 5 acres. He has 1.5 acres of vetch planted. The farm has had a lot of rain and has a lot of crusting. Currently he is reworking beds and transplanting assorted vegetables (onions, garlic, asparagus, etc.). He plants on cycles (second planting of peas, turnips, radishes, etc.). His method is to weed control-till and make beds a month in advance, flame prior to planting and cultivate if necessary. Usually he flames once and doesn=t let weeds get too high or flaming doesn’t work.

Indiana
In Southeast Indiana, Gary Reding operates an intensive rotational grazing operation. At this point his pastures are in fine shape after a good winter followed by nice moisture levels this spring. This is in contrast to the past three years, when he has experienced extreme drought, extreme wet, hot and cold. All of these conditions occurred in one year in the 2001 season, when the pastures were just getting started. In the next two weeks the grazing will begin and he will be inter-seeding some clovers into areas that need more legumes. He also plans to experiment with no-tilling corn into some areas that are thinly populated with grass but have a good ladino clover stand. He hopes to be able to graze the corn as a warm season annual grass later in the summer, and will also leave some to determine if there is potential for ear development if it is left to mature. The next two weeks will also be the time to start turning compost piles made from hay and straw that were used as animal bedding over the winter and during wet weather last summer.

Michigan
Matt Wiley farms in Southwest Michigan near the town of Schoolcraft. He reports that it has been an early, dry spring. In Southeast Michigan, Rob Malcomnson farms near Davison where moisture is better from the heavy snowfall this winter. John and Curtis Simmons farm in the region of Michigan fondly referred as “The Thumb.” If you view the lower peninsula of Michigan as a left hand, their farm is near the Thumb’s "knuckle" near North Branch. Weather conditions there this spring have been similar to Southeast Michigan – moisture from heavy snowfall.

It’s early in Michigan’s spring. The farmers are beginning to initiate tillage and are planning the use of rotovators, field cultivators, plow and chisel plows depending on soil conditions. Frost seeding has been completed for several weeks into wheat and spelt. During the next two weeks, the Michigan farmers will be preparing to plant, hoping for warmer weather and in Southwest Michigan, rain.

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