Many farmers who visited the Marshfield Agricultural Research Station”s New Technology Field Day last month received their first exposure to precision farming – but probably not their last. Precision farming can help farmers cut input costs and reduce pollution.
Precision farming, also known as site-specific management (SSM), is a process of assessing and managing variability within a field. First, the variability of crop input needs within a field is assessed, including fertilizer, chemicals and seeding rates. The variability is mapped, and then managed within the field by varying the rates of input applications.
According to Dick Wolkowski, an extension specialist and soils scientist at UW-Madison”s College of Agricultural and Life Sciences, both farmers and the environment benefit from information gathered through the SSM process. Wolkowski, who hosted the display at Marshfield, defines SSM as “doing the right thing, in the right place, in the right way, at the right time.”
“Farmers already know their fields have variability within them,” Wolkowski says. “Up until now they haven”t had tools to manage it. SSM got off the ground with access to Global Positioning Satellites (GPS), which allows farmers to know their location in a field to within a yard.” (GPS was developed by the military to pinpoint a position on earth within a few feet. A GPS receiver uses satellite transmissions to precisely determine latitude, longitude and altitude.) While developed for the battlefield, GPS can also work on the back 40.
For example, a manure spreader equipped with GPS could help farmers comply with guidelines that prohibit spreading manure within 200 feet of a stream. GPS would shut down the manure spreader”s operation as it approaches the 200-foot boundary, thus avoiding potentially harmful nitrogen runoff and leaching.
SSM offers farmers cost-effective benefits to their business. On a 40-acre field, a farmer using SSM can spend $6 to $8 per acre on grid soil sampling a field to assess variability. The grid soil sampling method divides a field into 1- to 3-acre regions. Samples are then taken within these regions at precise locations as identified by GPS on computer software. Finally, the sample data are evaluated, organized and mapped so the farmer can use the information to determine future applications. Several fertilizer companies, independent crop consultants and soil testing labs in Wisconsin offer grid soil sampling and mapping services.
Eight dollars an acre may sound steep, but the cost of soil sampling is spread over four to five years, Wolkowski points out. Likewise, the information can be used to make predictions about the field for several years, he says. The farmer”s future costs are cut because the information describes which areas of the field already have enough fertilizer and which areas need more fertilizer to boost yield and future profits. The environment wins because fewer unused fertilizer nutrients, such as nitrogen and phosphorus, can leach into surface or groundwater.
Major obstacles to widespread use of SSM include high-tech equipment such as computers, cost, and time commitment. “Common SSM adaptation in Wisconsin has been the purchasing of yield monitors for combines, which range from $2,000 to $5,000,” Wolkowski says. “Also, all of this SSM data has to be incorporated during the very busy seasons of planting and harvesting.”
Wolkowski suggests interested producers read all they can about SSM, attend meetings and have one or two of their fields grid soil sampled. “I try to emphasize to farmers that they don”t have to jump in and incorporate the whole nine yards of SSM technology,” Wolkowski says. “To ease themselves into the process, it is as simple as taking a grid sample of one field, determining any distinct regions that are manageable and mark the boundary between regions with flags for reference while spreading manure.” Manageable factors include fertility rate, water availability and pH; soil texture, slopes and rocky spots are considered unmanageable.
“Science is all about trying to figure out what you”re doing,” Wolkowski says. “SSM is about buying information. At the very least SSM can give farmers peace of mind by knowing that all portions of a field have adequate levels of crop inputs.”
Research and development continues to improve SSM, according to Wolkowski. As companies begin manufacturing “farmer friendly” equipment for varying inputs, the process will be adapted to seed rates, pesticides and herbicides.
For more information, contact Dick Wolkowski
UW-Madison Department of Soil Science
Rm. 263, 1525 Observatory Drive
Madison, WI 53706
(608) 263- 3913