Evaluating herbicide-induced stress on crops yields

Herbicides are precious allies for farmers. Without these products, yields would drop drastically. Crops are herbicide tolerant; they can neutralise, at least partially, the active ingredients of herbicides. However, this tolerance comes at an energy cost and is not always perfect. Symptoms of phytotoxicity, most often taking the form of rolled-up leaves or deformed stalks, are often observed in the fields.
Will this chemical stress impact crop yield ? Although more than two thirds of farms use herbicides (Statistics Canada, 2013), researchers have not really answered that question, focusing on other abiotic stresses, like drought and extreme temperatures.
Dr. Don L. Smith, of McGill University in Montreal, has been studying the phytotoxic effect of herbicides on corn, wheat and soybeans since 2015. His results confirm that this type of abiotic stress will have a real effect on the crop’s physiology.
Dr. Smith’s team used photosynthetic activity to measure the importance of this effect. It has been clearly demonstrated that the growth and development of crops is tightly linked to the photosynthetic activity.
In greenhouse and field trials, Dr .Smith’s team measured photosynthetic activity when crops were treated with herbicides and with a mixture of herbicides and a biostimulant. Different herbicides were tested : bromoxynil/MCPA in wheat, glyphosate plus atrazine/dicamba in corn and glyphosate plus chlorimuron ethyl in soybeans. The biostimulant used was the 2.0 Technology included in CropBooster 2.0 and RR SoyBooster 2.0.
The application of herbicides reduced photosynthesis by 32% in corn, 25% in soybeans and 47% in wheat. This reduction lasted for a period of up to five days. The addition of the 2.0 technology significantly improved photosynthesis in soybeans and wheat, and when added to the herbicides, the 2.0 technology significantly reduced the negative impact of the herbicide by more than 50%, to 17% in corn, 13% in soybeans and 17% in wheat.

 

 
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