Sign up for email alerts of new Fluid Journal issues!
Fluid Journal : Fluid Journal 2008-2009
intended target rate and actual rate can vary significantly for several reasons such as: Speed of machine exceeds the capability of the applicator to achieve the target rate Rapid speed changes cause over- or under-application Uneven product flow from the machine Mechanical breakdown Accidental skip and overlap Spatial variability. One of the most commonly used approaches to on-farm research is field-length strips. These strips are set up to compare a local farming practice against some new fertilizer product or method. In fields where soil type, drainage, and other yield-influencing factors are significant, this spatial variability alone can induce yield differences that can mask an anticipated response in the study. This can be a limitation of field length strip trials in on-farm research when variability is not managed by replications or by analyzing data within each strip. Data analysis. At harvest, a farmer will look at the screen of his yield monitor to gauge the success of a new product or method. This often is the extent of the analysis with the conclusions based solely on the numbers computed by the yield monitor and not any additional statistical or economic analysis. Current mapping software is making this process easier, but data analysis is still viewed by many as a complex procedure.A unique approach Beginning in 2003, Mosaic partnered with the Crop Physiology Laboratory at the University of Illinois to study the spatial variability of corn response to nitrogen (N). During the development of this approach, both the university and Mosaic balanced a scientific approach with the capabilities of current precision agriculture technologies and commercial application equipment. This N rate study was adopted to work in situations across the corn growing regions of the Midwest including Illinois, Iowa, Indiana, Minnesota, and Nebraska. The research methodology pushed the limits of the equipment and technology, and created a significant amount of yield response data. Methodology Equipment selection. Nitrogen fertilizer application can be accomplished by the farmer or dealer, depending on local farming customs, farm acreage, application timing, and form of fertilizer used. For example, farmers in Illinois who sidedress ammonia will usually manage their own equipment and application. By comparison, a farmer in Minnesota who is applying urea often will have it applied by his dealer. In every case, when conducting on-farm research it is important to have a discussion with involved parties to determine the capabilities of the equipment and the training and competency level of the people who will be making the application. Field selection. For a N rate study, it is important to restrict other additions of N to the field beyond the experiment. A quick discussion with the farmer can identify fields that have applications of N from other sources, and also provide field history and other yield limiting problems such as pH and drainage. GPS soil tests can be used to review other possible nutrient deficiencies. A final consideration is to limit the research field to a single hybrid or variety in an effort to Figure 2. Digital Othophoto. Figure 3. GPS yield map. Figure 4. Typical stamp.
Fluid Journal 2005-2007