The term constructed wetland refers to a specially designed and constructed area containing wetland plants through which wastewater is passed to provide treatment. There are two basic types of constructed wetlands. One is a surface flow wetland where there is an open water surface and the second is a subsurface flow wetland where water is not visible nor directly exposed to the atmosphere. Both types are shallow excavations, lined to prevent infiltration and filled with gravel or stone. The gravel or stone supports the plant roots and provides surfaces on which microorganisms grow. Both the plants and microbes are involved in the wastewater treatment process. Constructed wetlands are sized to retain wastewater for several days as it flows through. The exact time depends upon the strength of the wastewater being applied and climatic conditions. Many constructed wetlands consists of two or three cells in series The wetland plants used are varied from inlet to outlet with the plants near the inlet being shallow rooted and capable of dealing with higher wastewater strengths; deeper rooted plants are located near the outlet end.

During Agriculture & Natural Resources Week, a special program was held on constructed wetland applications in cold climates. Speakers were invited from Indiana, Wisconsin and Minnesota to discuss experiences and present data from constructed wetlands for domestic wastewaters, milking center wastewater and agricultural processing waste. In addition, speakers from Michigan discussed applications of constructed wetlands for individual home wastewater treatment and larger domestic wastewater facilities.

Even in winter, constructed wetland treatment results in an effluent that is greatly reduced in pollutant concentration compared to effluent from a septic tank where the waste has simply undergone primary treatment. Some of the concentration reduction in wetlands is due to dilution by precipitation but significant biological treatment occurs as well. The data presented at the workshop showed that most of the oxygen demanding organic matter is removed as wastewater flows through constructed wetland. Pathogenic bacteria are reduced along with concentrations of both nitrogen and phosphorus. Data presented show a nitrogen concentration reduction in the range of 40-60%. Phosphorus reduction varied from a low of 7% for one milking center wastewater system to over 75% for some domestic wastewater systems.

Clearly, constructed wetlands have the potential to improve the quality of dilute wastewaters but probably not to the point where they could be surface-discharged. These wastewaters will still need to be land applied either in subsurface soil absorption systems, in the case of domestic effluents, or on agricultural land in the case of agricultural effluents. The improved effluent quality will allow higher soil application rates either in subsurface trenches or on the surface of agricultural lands. For subsurface systems, it will reduce or eliminate soil-clogging resulting in systems of much longer life.

With all the interest in precision farming these days, it is too easy to lose sight of the fact that not all agricultural producers are ready to include precision farming technologies and practices in their farming practices. Neil Miller of Agri-Business Consultants recently proposed the following self-evaluation. The concept is if you are now doing these, the jump to precision farming is only a step up in the intensity of the information that you are using. If you are not doing many of these, you may not be ready to make the jump.

Circle one no < ----- > yes

 

1-2-3-4-5	Do you keep complete records of crop inputs in an accessible form?
1-2-3-4-5	Do you calibrate planter equipment before each season?
1-2-3-4-5	Do you calibrate sprayer equipment before each season?
1-2-3-4-5	Do you test your soils at least every 3 years?
1-2-3-4-5	Do you vary fertilizers on a field to field basis (rate and/or analysis)?
1-2-3-4-5	Do you vary planting rate on a field by field basis (for example by soil type or seed variety)?
1-2-3-4-5	Do you vary rates of pre-emergence herbicides by soil characteristics?
1-2-3-4-5	Do you scout fields regularly for pest outbreaks?
1-2-3-4-5	Do you record crop yields accurately, by field, in an accessible form?
1-2-3-4-5	Do you have a written marketing plan?
1-2-3-4-5	Do you use an enterprise accounting system?

Catching Rays - http://www.kaj.dk/weed-by-uv.htm
There are many ways to zap a weed. If you're not big on chemicals then maybe you'll see some promise in this method, which uses ultra-violet light to basically cook the nasty little critters.

Event Finder - http://www.agrisurf.com/agrisurfcalendar/
Keep yourself and others up to date with all that's happening in the world of agriculture by using this calendar service. You can browse by day or month, as well as search for events. Add your own events to help publicize things. Currently there are over 800 events listed.

Pesticide Storage and Handling Tutorial - http://ingis.acn.ces.purdue.edu:9999/cttpp/pest.html
http://www.msue.msu.edu/msue/imp/modad/23359601.html
Farmers pride themselves on being good environmental stewards. Proper handling and storage of ag chemicals is one good way to show it. Download this little DOS application for a quick tutorial on proper procedures.

Farmer Medicine -
Ever heard of Agromedicine? We hadn't either, but apparently there is such a beast. Evidently it relates to those ailments that are more likely to occur amongst farmers (pesticide poisoning, noise induced hearing loss, skin cancer etc). For information check these links:

http://www.oznet.ksu.edu/
health/agromed/links.html
http://www.musc.edu/oem/topics.html

An article in the March, 1999, issue of this newsletter described the choice of freestall bedding as a critical decision in manure system design. Freestalls designed on the basis of meeting the fundamental needs of the cow will lead to the greatest success. Sand best meets that requirement. But using sand has a profound impact on manure system design—limiting choices of equipment, type of storage and land application method. Moreover, sand complicates the operation of any system selected.

Choosing freestall bedding is an example of decision-making based on understanding the available choices, examining the consequences of each choice and ending with a compromise. Simply put, the decision finally is whether to favor cow comfort and udder health or manure handling and storage.

Moreover, choosing freestall bedding is not the only instance where manure system planning goes beyond our traditional view of system design; i.e., beyond decisions involving collection, transfer, storage, possible treatment and land application. Of even higher priority are decisions that consider the dairy farm in the broadest possible context; e.g., choosing freestall base and bedding, are even higher in priority.

In my opinion, four high priority decisions must be addressed even before we select handling equipment or type of storage. Briefly, the four decisions involve:

The Ultimate Fate of the Manure.
Basically, this amounts to having access to land that needs the nutrients along with determining if ownership is desirable. Having adequate land area is especially important to farmers planning to expand or relocate.

Choice of Freestall Base and Bedding.
This was discussed previously.

How will the Manure be Applied?
Choices of handling and application equipment depend upon regulations, public relations, location of land and choice of freestall bedding.

Will Manure be Handled as a Semi-Solid or a Liquid?
Handling manure as a semi-solid has largely gone out of favor, but may reemerge when considering transport of manure or alternative end uses.

Facing these higher priority decisions early in the planning process and considering the dairy farm in the broadest possible context both are essential. We must assure that the eventual system design will meet all of the needs of the dairy farm in the best possible way as well as satisfying the interests of the rest of society.

SAFETY TIP: Some farm tractors and construction equipment can "freewheel" and provide no engine braking at certain speeds, especially when traveling downhill. If your tractor or equipment has this characteristic, travel downhill using only shift positions (specific gear locations) that provide engine braking. Fish-tailing or severe braking at high speeds when going downhill can cause jack knifing and rollovers. Shift to a lower gear before going downhill. Check to see that your farm tractor brakes are locked together. Braking just one wheel can swerve a tractor out of control. Wide wheel spacing on tractors also adds to the lateral stability of your tractor.

His mother discovered her son and with the help from a passerby managed to free him. He was transported to a local hospital and then to a regional trauma center. The victim died later that evening.

SAFETY TIP: Starting equipment from the ground rather than from the operator’s platform contains the risk of being run-over by a tractor left in gear or, in this case, by contacting a control lever resulting in the unexpected movement of an attached implement. Taking the time to get into the operator’s seat can prevent this form of injury or death.

Several calls by farmers, parents and extension offices trying to find a tractor training certification class have found their way to my office. The three MSUE offices that have conducted tractor training certification for youth who are 14-15 years old are Sanilac, Huron and Berrien. Also, an agricultural science teacher in Coldwater conducted a training program. If you have conducted a training program and I have omitted your county from my short list, e-mail me to correct my fall 1998 through June of 1999 records. This training should be considered a priority for MSUE offices. Farmers can then employ 14- and 15-year-olds legally. As a result of this federal exemption training certificate, employment opportunities for rural area youth have expanded. Training is unique in that only extension offices and teachers of agriculture can offer it to youth. Your thoughts on this priority?

In the February Newsletter we discussed dealing with drainfield failures and indicated that the next subject would be repairing failed systems. Before a failed system is repaired the cause of failure should be determined and eliminated unless it is failure due to old age. See the February Newsletter for this discussion.

The most common approach to system repair is to install a completely new soil absorption system in an isolated area so the old system is not disturbed in the process. A diversion valve should be installed so that in the future it will be possible to direct the flow from the septic tank to either of the soil absorption systems. After the failed system is replaced and the flow diverted from it, it will slowly rejuvenate itself and be available for use in the future. The rejuvenation process takes at least two years and involves naturally occurring organisms which decompose the clogging mat that has formed and return the absorptive system to near original capacity. The rejuvenation process can be accelerated if a septic tank pumper opens the field and removes all the ponded wastewater that he can possibly pump out.

After a replacement system has been installed, a homeowner should plan to switch back to the old system after about two years and then switch back and forth between the two systems about annually. This will result in a continuous use and rejuvenation cycle for both drainfields and should prevent future failures. It is a good idea to install an observation tube in each drainfield so that it is possible to monitor the amount of wastewater that ponds. That can be a guide to the frequency of alternating between the two fields. (We'll deal with observation tubes next month)

If the old system is a trench system with at least six feet of undisturbed soil between the trenches, it is possible to install replacement trenches between the old trenches if an adequate area for a new system does not exist in a separate location. However, the plumbing for the new and old system must be entirety separate so that when one is in operation the other has the opportunity to completely dry out.

In very sandy soils, it is possible to completely excavate the old system and install a new system in the site of the old one, but this eliminates the opportunity to have alternating fields. This would be a last resort if there is no space available.

Another repair process that has proved very effective, based upon research at the University of Wisconsin, is to improve the wastewater treatment prior to soil disposal by adding an aerobic treatment unit or sand filter between the septic tank and the soil absorption system (SAS). This might be done where there is no space to install a replacement system or where it is difficult or undesirable to do the excavation work to install a new SAS. By providing enhanced treatment and discharging an aerobic effluent rather than anaerobic effluent to the soil, aerobic organisms are enhanced in the SAS and they decompose the clogging mat. Research has shown that if the septic tank and the drainfield are pumped out as completely as possible when the aerobic unit is installed, the system can be put back into use and expected to function. The original drainfield must be of adequate size for the amount of wastewater being generated based on current specifications.

The Wisconsin research showed a success rate of about 95% in rejuvenating systems by this method. This process might also be attractive if the system needing repair is located in an area that is sensitive to pollution from septic systems. Much cleaner effluent is discharged to the soil.

Agricultural Engineering Extension Faculty

William G. Bickert. Livestock Facilities and Environment.
Roger C. Brook. Handling, Storage and Drying of Agricultural Products; Computer Applications in Agriculture.
Howard J. Doss. Safety Leader for Michigan Cooperative Extension Service; Agricultural Safety Specialist.
Daniel E. Guyer. Post-Harvest Storage and Handling and Value-Added Processes for Fruit and Vegetables; Machine Vision and Pattern Recognition.
Timothy M. Harrigan. Forage and Field Crop Power and Machinery. Ag Expo Chairman.
Richard L. Ledebuhr. Fruit and Vegetable Mechanization. Chemical application equipment.
Theodore L. Loudon. On-Site Wastewater Treatment; Agricultural Water Quality Impacts; Irrigation; Drainage; Livestock Waste.
Howard L. Person. Livestock Facilities; Environmental Control; Management Of Manure and Organic Residues.
Robert D. von Bernuth. Irrigation and Water Management; Coordinator, Animal Waste Management Programs. 

Nancy Aitcheson - Plan Service Secretary, Co-Editor
William Bickert - Extension Agricultural Engineer, Co-Editor