The planting season is starting to sneak up on us, now less than two months away for crops like spring wheat. If farmers have not selected or made 100% of their seed purchases, Nathan Mueller, SDSU Extension Agronomist may have a few tips for ways they can buy the variety that returns the highest profit per acre.
 
"Most people justify a buying decision after they have already made it, based on emotion. Unfortunately, seed purchases often do not escape this blight. Things that influence our selection and purchase of varieties include brand reputation, loyalty and tradition, friends and family members, advertising, and company representatives," Mueller said.
 
To increase farm level yields, Mueller encourages growers to utilize yield data in their variety selection process.
 
Yield data can be collected from side-by-side comparisons on the farm, company variety trials, and third-party variety trials.
 
"Reliability of this yield data is not equal. I am not talking about who (farmer, company, university) does the work, but the methodology," he said.
 
The three key methods growers can use to increase their confidence in one variety's performance over another include:
1. Blocking or splitting the test plot into similar environments;
2. Randomization or random placement of varieties within the test plot; and
3. Replication or the same variety appears in the test plot several times. 
Another key term Mueller explains is experimental error.
 
"This is simply variation in yield measured in the same variety that was tested independently several times within a test plot. The source of this variation can be soil difference in the test plot or even inability to reproduce the exact same conditions with equipment operations and measurements," Mueller said.
 
A closer look at three methods
Mueller explains why these three methods, blocking, randomization, and replication, are important when making yield data comparisons among varieties. The use of blocking, replication, and randomization helps managers of crop testing performance trials like the ones we conduct at South Dakota State University (SDSU) determine whether varieties perform differently at a location, the margin of difference between varieties, and confidence that the differences measured are attributed to the variety, not experimental error.
 
To review examples Mueller provides in an iGrow.org article visit, http://iGrow.org/agronomy/corn.
 
Check out iGrow.org
The differences between varieties for yield and other important agronomic traits are posted annually for all major crops in South Dakota at www.iGrow.org. These results provide an opportunity for growers to make informed purchasing decisions when seed is ordered for their farm. The magnitude of performance differences between varieties or hybrids can be significant enough to create a $250 profit per acre swing.
 
So before you buy any more seed, please consider more data-driven decisions that increase your farm's profitability by using crop yield results determined by using blocking, randomization, and replication. SDSU research and extension staff conducts yield performance trials on commercially available varieties either submitted by private companies or public entities. If you would like to learn more about the crops tested by SDSU and the results, please see visit http://igrow.org/agronomy/profit-tips/variety-trial-results/ or contact Nathan Mueller, SDSU Extension Agronomy Specialist at nathan.mueller@sdstate.edu.