Savanna Crossman, Precision Agriculture Research Coordinator
New York Corn and Soybean Growers Association
The 2016 field season marked the first year of testing for the variable rate planting model that is being developed by the Precision Ag Research Project. Growers across New York State know the challenges that the severe summer drought brought to our region. Crop yields were impacted across the state and the research was no exception. While unfortunate, it is advantageous to be able to test the model during a dry year and learn from how the crops reacts to the stress.
Across the board, the mid-to-lower seeding rates fared the best in the corn and soybean trials. The model was tested on five fields this year and only four made it to grain harvest due to severe drought stress. The results revealed that in three of the fields, there was not a significant difference in the profit produced by the model. While the average yield of the model was significantly less, the model was able to achieve similar profit per acre by using lower seeding rates. (Table 1) 
A variation of the model design was planted on one field, Beach 2, in a split planter fashion with two contrasting hybrids. This varied design was used as it allowed for of multiple points of comparison, including hybrid comparison. Check strips were integrated every two passes to allows direct comparison of how the model performed to the typical grower practice rate. From there, the design becomes more complicated. The first pass would be planted at the model optimized rate for hybrid A, which meant hybrid B was also being planted at that same rate. Then the next pass would plant at the rate optimized for hybrid B while hybrid A was being planted at that rate as well. This allows us to examine the hybrid response to population in more depth. (Figure 1)
The hybrids P0216 and P0533 were selected due to their differences in plant architecture and responses to stress. In years of excellent growing conditions, the tight leaf structure and short stature of P0533 will produce aggressive yields. The hybrid P0216 will produce average yields in years of stress as well as in excellent conditions.
A 4,000 foot view of this field would show that there was not a significant yield difference between the model and the grower’s flat rate. The model yielded about 2 bu/ac more than the flat rate, but that difference was not statistically significant. When we separate the results out by hybrid, we see a much more telling story.
These hybrids resulted in a wonderful side-by-side comparison this year. When compared to the flat rate, P0533, regardless of optimization, yielded significantly more per acre and yielded an astounding $64/ac more. Conversely, P0216, regardless of optimization, yielded less than the flat rate and produced a profit $22/ac less than the flat rate.
A deeper look into the results showed that that when both hybrids were planted optimally, P0216 yielded almost 18 bu/acre higher than P0533 (Figure 2). It also demonstrated that P0533 exhibited a statistical significant response to model optimization. Meaning, when it was optimized the yield significantly improved over not being optimized (Figure 3). This is likely due to the fact that in a stressful year, P0216’s yields will not fall apart due to seeding rate while P0533 benefited from precise placement.
These same hybrids in Beach 2, however, exhibited the exact opposite hybrid response in 2014 which was a normal year in terms of weather conditions. Knowing this emphasizes the importance of multiple years of testing and data collection to create a robust algorithm. The biggest gain from the 2016 season has been the strong design and analysis process that has been developed. What the project has accomplished in these terms, is at the leading edge of the scientific community.
In order to build upon what the project has already accomplished, the project is still looking to get more producers involved and participating. The project aims to get fields in the research that have a large amount of variation and are fifty acres or greater. Any interested growers are highly encouraged to get in touch with the Project Coordinator, Savanna Crossman, at 802-393-0709 or savanna@nycornsoy.com.
