Crop variety selection: Eliminate emotion, increase profitability
Figure 2. Blocking or splitting the area into four similar environments.
Another component of this process is replication or having the variety appear once in each of the four blocks at random within each block (Figure 3.). Replication is a means of estimating the amount of variation in experimental error within the same variety while randomization provides a valid estimation of that experimental error variance. This is a lot of words and just means that replication and randomization are needed to get reliable data.
Figure 3. Randomization of four varieties (Var.) within each block.
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.
The differences between varieties for yield and other important agronomic traits are posted annually for all major crops in South Dakota on the iGrow Variety Trial Results pages. 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. For example, within a company the cost difference per-bag (140,000 seeds) of soybeans is only about $9, but the yield differences may be 7 bushels-per-acre between varieties. Farmers generally have not even finished harvest before the earliest season seed discounts are available. Waiting until yield data is available to aid decision making on variety selection will pay off. Also, written descriptions for one variety may sound better than another, but the yield may not be.
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.
Source: Nathan Mueller