Pulse School: Be mindful of maximum residue limits


If you are considering spraying either a pre-harvest application of herbicide or a desiccant on your pulse crops, keeping maximum residue limits —MRLs — in mind is imperative.

In order to do this, growers have to be very cognizant and aware of how mature the crop is and the crop’s moisture level.

“If you aren’t below 30 per cent [moisture level], you are going to have seeds that will not be formed,” explains Nevin Rosaasen to RealAgriculture’s Kara Oosterhuis in this Pulse School. If you terminate the crop too early, you’ll end up with seeds that are misshaped and shrivelled, lower weight, or be so light and small they’ll be blown out the back of the combine, costing yield.

The other important reason for right-timing a desiccant or herbicide application is because we need to ensure we don’t have any residues in the crop so that it’s ready for export, Rosaasen says.

When it comes to controlling residue limits, it’s important to mind the pre-harvest intervals that coincide with whatever product you are using.

Rosaasen says that it’s very important that growers double check the pre-harvest internal on each product. The PHI can be as short as a few days for some desiccants, or as long as seven to ten days. Fungicides and insecticides also have pre-harvest intervals, so be mindful of to check those labels as well.

But why do MRLs matter? Why is this so important to keep at top of mind for pulse producers?

“MRL’s are so important to maintain market access. Again, these are trade and market access maximum residue limits that are set. They are very low — in the parts per million, parts per billion even — so we need to make sure that we are keeping our fields clean and that we aren’t spoiling the bunch, so to speak,” Rosaasen says.

Some pulse buyers also have added restrictions on pre-harvest applications of products, so be sure to check with your buyer before applying.

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