Plot side 2009
OCPA Special Report brought to you by Greg Stewart, OMAFRA Corn Specialist
An update on what's happening in the research plots around the province
STARTER FERTILIZER TRIAL
Frequently asked questions in regards to starter fertilizer strategies relate to liquid versus dry, banded versus broadcast, and the impact of soil test levels. This year, plots at Elora are looking at no-till, conventional tillage and strip –till with four different starter fertilizer treatments.
With soil tests at nine parts per million (PPM) for phosphorous (P) and 65 PPM for potassium (K) the impact of zero starter compared to 175 pounds of 15-15-15 is huge. Interestingly other plots seem to highlight the relative importance of K over P under these conditions.
LATE WEED CONTROL
When looking out the pick-up truck window, walking fields, or examining plots once again in 2009 the impact of late weed control on corn was easy to spot. It is intriguing to note that in fields where the weed pressure is heavy, a delay in bringing those weeds under control can have dramatic effects on the corn crop. In that early/mid June timeframe spraying delays caused by two weddings and golf tournament could cost you 20 bushels per acre.
A classic example of stunted corn appears when you are looking for clues as to what happened all you have to do is look down to see a mat of weed carcasses from a delayed spray application.
POTASH DEFICIENCY
Research at the University of Guelph by Dr. Clarence Swanton has highlighted the impact that weed competition can have on the corn roots systems. Swanton outlines that this interference is able to seriously reduce corn root development.
Plots in Perth County captured the interesting phenomenon this year. Delayed weed control reduced root size and this resulted in significantly stunted corn growth and classic potash deficiency symptoms especially on those plants that received 11-52-0 as starter fertilizer. A soil test for K at this site was 95 PPM.
The impact of the delayed weed control was much less noticeable where potash was supplied through the starter with a 5-20-20 blend.
NEW HYBRIDS AND NITROGEN USE EFFICIENCY
Although nitrogen (N) prices have retreated substantially since last winter we are still very interested in evaluating the impact that new hybrids may have on N use efficiency and future N rates.
Trials at Woodstock compare four unique hybrids conventional and multi trait, under two plant densities and a wide range of nitrogen regimes. The photo below has lower leaves showing nitrogen deficiencies in the zero N plots. Will yields under low N be significantly different for the various hybrids?
Remember yellowing at the tip and then spreading down the middle of the leaf is N deficiency; yellowing at the tip and then spreading down the edges of the leaf is K deficiency.
LOW BUDGET DROUGHT TOLERANCE TESTING
And finally out on the lunatic fringe is some plot initiatives to develop a low cost system for imposing drought on plots to test for water use efficiency (see bottom photo below). As this is an initial foray into low budget drought tolerance, there are certainly a few glitches to work out. With the current research methods, a fair bit of water does reach the plot because of stem flow, especially when rainfall is light.
This represents a first step in developing economical techniques that would allow for the evaluation of hybrids that are developed and marketed with drought resistant characteristics.
ACKNOWLEDGEMENTS
A special note of thanks to technical assistance from M. Caldecott, T. Meekes, G. Lee and A. Dunk in 2009 and to OCPA, IFAO, and Monsanto Canada for supporting various aspects of the aforementioned research.