Weather, primarily precipitation, plays an integral role in the life of crops and farmers. Too little and plants cannot grow. Too much and plants drown or succumb to disease. Either way results in yield losses a nightmare for farmers. But there is help available.
Researchers at North Dakota State University believe they have found a viable solution in a tile drainage system, which is a very popular water management system used in the Corn Belt and southern Minnesota.
"The objective of tile (drainage) is to remove excess moisture away from the roots of plants so the plant can grow without any stress," said Hans Kandel, Extension agronomist and lead researcher for the NDSU project. "The soil is able to hold water attached to the soil particles so only water that is not usable for plant growth is removed."
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Tile piping is laid 2 to 4 feet into the ground depending on soil type, to avoid being uprooted by farm machinery.
Essentially, a tile drainage system is a series of underground pipes with small holes drilled in that catch excess water and remove it from the field. Originally, the word 'tile' was used for small clay pipes that were put into the ground. When plastics became available it replaced the clay, but the name stuck.
In tile drainage, there is a main pipe that leads to the ditch or drainage point and then a series of lateral pipes that are connected at 90 degrees to the main pipe.
While the idea is simple, the process is not. Site specific details such as soil type, slope and size all need to be taken into consideration before tile is laid, making it a difficult process.
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DRAINAGE HISTORY
Some experts believe primative tile drainage systems were used throughout the Middle Ages in Europe, but it wasn't until 1835 that the technology was first documented in the United States on a farm in Geneva, New York. By 1856, farmer John Johnston had laid over 51 miles of tile on his clay-soil farmland, enabling him to double his wheat yields.
First and foremost, the availability of a ditch for the excess water to escape into is the most important factor, otherwise the tile system is not possible. If a ditch is available, even if it is not very deep, the field is capable of being tiled because a device similar to a sump pump can be installed, Kandel said, but water would not be flowing constantly because it is based on rainfall and excess moisture in the soil, so the necessity of a pump would be on a case-by-case basis.
Heavy-duty and specialized machinery is required to put the system into place, including a back hoe for installation of the main pipe and laterals, and a tile plough, which can be pulled by a tractor, to install the tiles. The pipes are placed about three feet into the ground and are laser-guided to ensure depth control and to assure that pipes match the slope toward the outlet. Kandel's team recommends a depth of three feet for tile placement to avoid damage from plows and other machinery, but he said depths can vary from two to four feet depending on the soil type and slope of the field.
Tile drainage systems do not have to encompass an entire field, Kandel added, but can be used in problem areas.
"The (tile) design is very specific for each concern," he said, "The only requirement would be to have an outlet, usually a ditch, for water to drain into."
Installation can be done within a matter of days, either by a contractor or by the farmer himself, but Kandel stressed that putting tile into the ground is an art and that there is a significant learning curve for someone new to the process.
Previous studies did not have tile drainage-specific research for different crops, so Kandel and his team created eight units, each less than one acre in size, and randomly selected units and installed open and closed tile systems. The open tile systems represent traditional tile drainage, and the closed tile systems have an outlet control box which can shut off the water, simulating non-tiled conditions.
The team plowed the tile in July and the first crops winter wheat and winter canola were planted equally in the different units.
All of the research is being conducted in the Red River Valley, Kandel said, because tile systems are more important in rainy areas due to the higher frequency of standing water on crop fields. He added that he has seen standing water on fields in the western part of the state in recent years, but rainfall has been more erratic overall.
The first phase of the research is looking at crop response for the major crops grown in North Dakota. The team will evaluate crops for disease, winter survivability, yields and other growth characteristics between the two systems. Kandel said he and his team expect to see a reduction of root disease and have higher yields for all the crops tested on the tiled fields.
Results from a previous study involving wheat, soybeans and sugarbeet crops indicated that tiled fields average a 10 percent increase in yields over non-tiled fields.
As for the current research, the team has already noticed a difference in the placement of water in the soil early on in the growing season of the wheat and canola winter crops. The non-tiled fields have water near the surface, while water in the tiled fields is three feet down into the soil.
Phase 2 will focus on testing other crops and validating data gathered in phase 1. Kandel added that the team plans to change the tile design in an attempt to control the water table.
Funding for the research comes from Field Drainage Inc., Minnesota Wheat Research and Promotion Council, Hancor Tile Co., NDSU Extension Service and NDSU ag experiment stations.
There is a standing debate about the potential hazards and benefits of a tile drainage system. Kandel said flat topography, economic uncertainty, tight soils and a long-standing tradition of surface drainage practices are among the reasons farmers have not adopted the practice. He noted there has also been concern that the tiles could potentially leech out nitrate, but he said fertilizer rates can be adjusted after tiles are laid.
"The upfront costs are one of the main concerns, but the longevity of the investment makes economical sense," Kendal said.
Costs, benefits
The overall cost of the plastic tile drainage system depends on a number of issues including soil type, installation or equipment fees and the price of the plastic pipes, which fluctuates with the price of petroleum. In sandy soil, the tiles would be spaced far apart, while clay soil types would require the tile space to be more narrow to catch the excess moisture.
Kandel said a general estimate would be $500 per acre, but stressed that the price would vary depending on an individual's specific circumstances.
"It's a fair amount of money, but it will last a lifetime, so the expense can be offset in a number of years," Kandel said. "There is enough expansion in the pipe so we have no record of pipe breakage in winter."
Kandel said the benefits of a tile drainage system far outweighs the cost and potential risks.
"Roots sitting in water cannot grow well and the result is yield reduction," Kandel said, "So tile drainage creates conditions favorable for plant growth and yield increases." The removal of excess moisture allows oxygen to penetrate around the plant's roots. In addition, the canopy, or leaves of the plant, develops more quickly.
Another benefit, Kandel said, is that in the event of a major rainfall, producers will be able to get into their fields faster because there is generally less compaction of the soil in tiled fields, resulting in more timely crop management. By the same token, he said, there is less erosion in tiled fields versus non-tiled fields because the water moves through the soil slowly and at a deeper level, whereas non-tiled fields have moisture near the top layer of soil, so a big rainfall washes away more soil.
Kandel said increased property values are the biggest advantage to installing a tile drainage system.
"Once you have a more productive field and yields increase and stabilize, the property values of the field goes up," he said, adding that tiled land has a higher rental rate than non-tiled fields.
Changing the hearts and minds of farmers won't be easy, but Kandel said he hopes the positive results of the research will help overcome tile adversity.
"The assumption here is that the land is too flat to tile, but it works everywhere in the world," he said. "The research is proving that it can be done here."
As for the adoption of tile drainage practices in the Dakotas, technical and economic feasibility must be considered before the practice will be widely accepted, he said. "The key is to remove excess moisture, so if a field doesn't have that issue, farmers won't see a return from their tile investment."
Because the cost of inputs and land has risen in recent years, many farmers are trying to be more efficient with what they have, including switching to beans and other legumes that require less fertilizer because they generally can fix their own nitrogen levels in the soil. Kandel argues that beans cannot fix nitrogen levels in waterlogged soil because there is less oxygen available.
For farmers interested in the drainage system, a joint venture by NDSU and the University of Minnesota could help them with general information and installation procedures for those would like to install the tile system themselves. Each year, the two schools hold a two-day educational seminar where participants get an overview of the drainage system, look at case studies and get hands-on experience by going through each step of the design process.
Having worked with tile for the last 12 years, Kandel said he has seen a steady increase in farmer's interest and its production.
"With production costs rising rapidly, farmers want to get a handle on things. If you get one or two inches of rain on a moisture-laden field, it affects yield potentials. But with tiles you can rest easy because you can get into the field faster and apply the fungicides. ... There's less risk because you can manage one more production factor.''
After the completion of the current study, Kandel said he plans to start another research project in 2010, one focused on combining the tile drainage system with strip-till the process of tilling a small band of land in which to plant the crop, leaving the rest undisturbed.