By Shane Thomas
Plant nutrients are always big driving factors in how our crops yield, with macronutrients getting the majority of the attention. However, micronutrients can be limiting factors in a lot of our cropping systems, especially for those really pushing yield with intense management. One micronutrient that gets discussed a lot is copper. This is for good reason, as copper is an important constituent of many enzymes in plants, acts as a catalyst in photosynthesis and is a key component of lignin formation. This means that having sufficient copper levels can have an impact on things like flowering and standability of cereals.
Most discussions on ergot incidence in cereals, and especially wheat, end up focused on copper. I’ve often heard the connection that if you’ve got ergot in wheat, you must also have a copper deficiency. While this may be the case in a some situations, it isn’t always true.
Copper, as stated earlier, can have an impact on the ability of a wheat crop to properly flower and pollinate itself (wheat is self-pollinated). If copper is limiting at the high-demand time of flowering then there is potential for the flowers to open unfertilized which heightens the risk of infection by ergot spores. Now, with that said, there are other reasons for a wheat plant to struggle to pollinate itself — either from other nutrient deficiencies or due to other biotic or abiotic stresses.
The next issue that research shows can be a sign of a copper issue is lodging. Lignin is important in cell walls of plants which are key in stem strength. Now, a copper deficiency isn’t the only cause of lodging, however. Weather, a potassium deficiency, genetics and more can have an effect on how well your crop stands.
Lodging or ergot infection can happen before any other significant deficiency symptoms would show up, such as leaf pig tailing, so they may act as earlier warning signs that your soil is lacking copper. So how can you be better prepared? It all starts with a soil test and properly identifying the levels in your soil and whether those levels are going to be available to your crop, as things like high organic matter can decrease copper availability.
If you are low on copper then there are many granular/liquid forms available to increase soil levels. If you want to make sure what you put in the soil or already have in your soil is getting into the plants, then a tissue test prior flag leaf can be very beneficial as you can make some foliar copper applications prior to heading to try and kick those levels up.
Copper may not be the best thing since sliced bread, but without it we couldn’t even make a loaf!
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