What’s in a Yield Goal?
A yield goal is a pre-planting metric used to make the best growing and economic decisions throughout the growing season.
WHY SHOULD YOU BE SETTING A REALISTIC YIELD GOAL?
Setting a realistic yield goal each and every year is one of the most important steps in both crop stewardship and farm economics. Accurate projections for a specific crop, on a specific field, on a specific year can make or break the profitability of a growing season.
Yield goals should impact every aspect of production: from choosing the right crop species, to fertilizer recommendations and seeding rates.
A yield goal that is unrealistically high, for example, may result in expensive and wasteful use of fertilizers — especially nitrogen and phosphorus inputs— which can not only increase production costs, but can also be environmentally hazardous and result in runoff and leaching into aquatic ecosystems.
Realistic yield goals are also vital in marketing and selling, especially with futures contracts that require accurate estimates of production costs, which are, in turn, dependent on seed and fertilizer decisions. A profitable operation puts stock in accurate and achievable yield goals.
HOW ARE YIELD GOALS CALCULATED?
Estimated in different units of measurement such as bushels per acre (bu/a), tonnes per hectare and other measurement units, yield goals can be calculated in a variety of ways.
One of the most reliable calculation methods for a slightly optimistic estimate is using what is called an optimal rolling average.
This can be calculated as follows:
- Calculate the yield averages for a particular crop on a particular field for the last seven years.
- Eliminate the three worst years to exclude exceptional or catastrophic circumstances.
- Estimate the yield goal using the average of the previous best four years.
In circumstances where 5 or 7 years yield data is not available, it is also possible to average the previous three years and multiply by a factor of 1.05 or 1.10. This should ideally account for accelerating advances in technology, plant genetics, equipment, and agricultural decision support systems, as well as the inability to eliminate less successful years from the optimal calculation.
Keep in mind that since crops should ideally be grown in rotation, the yield goals for a field are not calculated with consecutive years of data, but rather with data from the same crop on the same field.
In the absence of any crop data from previous years, yield goals for common regional crops can also be estimated from soil productivity charts, which are usually available from recent local soil surveys.
Different states may use different indexes to estimate yield goals based on soil maps. For example, Iowa corn growers use an index named CSR (Corn Suitability Rating) to estimate yield goals for different parts of the field.
These estimates will usually be more conservative than optimal rolling averages, owing to the fact that they often rely on older data sets, and are not re-calibrated as often to account for the aforementioned advances in agricultural science and praxis.
SETTING YIELD GOALS WITH SMART SOFTWARE
Setting realistic yield goals year after year is more easily achieved with a reliable Agricultural Decision Support Systems (DSS), such as SMART! Fertilizer Management Software, which can help in managing the variables necessary to not only account for previous years’ data, but also to make informative decisions about fertilization management and field operation for the years that follow.