USA, Lexington Kentucky - March 23, 2009 (Joe Omielan) - Project Update
As mentioned in the May update the design of the experiment has been modified to better “simulate” the effects of SBR. We will be defoliating plots over the course of the season to reduce their Effective Leaf Area Index (ELAI) as a percentage of the control plots. These reductions over time will “match” what was found in our 2007 Brazil trial when SBR started at R1 and at R5 (see the graph below). The yield reductions in this experiment will be compared to the Brazil trial.
Reductions in % of Control ELAI in plots when SBR started at R1 or R5. Data from 2006/2007 trial at Londrina, Brazil.
We need to know the LAI of the control plots to calculate our defoliation targets. This means we need to take destructive samples, remove the leaves and run them through the leaf area meter. Here are Elena Prior and our summer students, Sri (Sri Lakshmi Movva) and Josiah Frey, putting leaflets through the instrument.
Josiah’s internship research project was to measure the impact of the herbicide, Gramoxone Max, on leaf photosynthesis. The photo above shows the instrument clamped onto a damaged leaflet. Note the other damaged leaves and the leaflet on the right with the template indicating where a previous measurement had been taken.
The photosynthetic rates of control and damaged leaves were compared. The question was can Gramoxone Max be used to simulate soybean rust damage? In this photo everyone is watching the data from the LI-6400.
A Field Day at Spindletop Farm gave us an opportunity to showcase our work to the public. From left to right we have Elena, Saratha, Josiah, and Sri.