Determining what a plant needs at precisely the right time is critical when a plant’s health is stressed through lack of nutrients or by weeds; but how can farmers know when the right time is?
This Grain Farmers of Ontario research project, led by Dr. Clarence Swanton, of the University of Guelph, and the University of Waterloo’s Dr. Roydon Fraser, has shown that a corn plant’s leaf temperature can tell you whether that plant is healthy or not – and do so before the problem is readily visible.
Supported by funding from Growing Forward 2, both Swanton and Fraser have been working on a prototype sensor for corn that can rapidly detect changes in leaf surface temperatures.
This will help farmers identify and respond to plant stress like nitrogen deficiency or weed competition quickly and accurately, and often before any visual evidence of stress, like yellowing leaves, becomes apparent.
There were four controlled environment trials using corn that were completed in the University of Guelph greenhouse which let the researchers control inputs like water and nitrogen. There were also three outdoor field trials conducted, two in Woodstock and one in Elora.
Swanton and Fraser observed that healthier plants had cooler temperatures during the day compared to plants lacking nitrogen or fighting weeds, especially when comparing low and high nitrogen rates. The results were less clear with nitrogen rates in the middle of the dose range. More research will be needed to establish what is causing that variability.
If growers were able to recognize stressed plants early, they could target applications of nitrogen or crop protection materials more precisely and rapidly. This would ensure that they’re only used where and in the quantities they’re needed – a benefit for both the environment and growers looking to manage costs.
Funding for this project was provided by Growing Forward 2 (GF2) a federal-provincial-territorial initiative. The Agricultural Adaptation Council assists with the delivery of GF2 programming in Ontario.