C4 & C3 Plants
Maximizing Photosynthesis
You don’t have to look further than your own farm to understand how C4 plants, like Kochia, have evolved to thrive in conditions of little moisture & high temperatures. How can we learn from plants like Kochia? How can we better utilize free resources such as sunlight and rainfall? Let’s dive in.
96 percent of a plant is composed of three elements: Carbon, Hydrogen & Oxygen (sunlight & rain).
Notice Sorghum Sudan (C4 Grass) capturing sunlight above the canopy in 30+ degree conditions.
c4 & C3 plants
understanding the basics
All plant species in Western Canada can be divided into two main categories based on how they use carbon dioxide to photosynthesize.
C3 Plants close their leaf stomata when it is hot and dry in order to conserve water within the plant, limiting photosynthesis.
C4 Plants have evolved another form of photosynthesis to adapt in hot, dry environments. In C4 photosynthesis, a four-carbon compound is produced and gives the plant the ability to continue fixing carbon while stomata are closed.
In other words, C4 plants are capturing more carbon & feeding more soil biology.
Source: Kahn Academy: C3, C4, and CAM plants.
Timelapse
The Value of c3 & C4 Plants in a blend
To better demonstrate this phenomenon, consider watching this timelapse video of the Full Season Cover grown in 2022.
Early season growth from C3 plants results in a dark green colour throughout the canopy.
Later season growth from C4 plants results in a light green colour throughout the canopy.
THE AGRONOMY
A blend of warm & cool-season plant species provides an insurance policy with Mother Nature. If hot/dry conditions are present, warm-season plant species will accumulate biomass. If cool/wet conditions are present, cool-season plant species will accumulate biomass. In other words, aligning plant species with the right time of year.
This is how we maximize the 96%.
Evolutionary Advantage
Waxy leaf surfaces
One of the evolutionary traits of a C4 grass such as Sorghum Sudan or German Millet is the waxy leaf surface that reduces water evaporation from the leaf surface.
These waxy leaf surfaces are also ideal to shed water when placed in a swath - preventing spoilage and holding palatability.
Click Here to view a Farmer Panel Discussion around swath grazing & the value these waxy leaf surfaces can bring to your operation.
“Warm-season plants grow relatively slowly during the first four to five weeks after seeding due to the biological taxing process of cell division. Once the cell divisions are complete, C4 plants can grow quite rapidly. The optimum daytime temperature for growth is 30+ C. C4 plants are more water-efficient and drought-tolerant than C3 plants. C4s have a waxy leaf surface that reduces water evaporation from the leaf surface.”
Source: Government of Saskatchewan