Making up for lost planting days

The Importance of Photosynthesis

It's a cloudy rainy day here in Alpena SD. Yet again we aren't out in the field due to weather. This got me thinking about what are we actually missing out on, and what impacts yield the most when it comes to later planting dates. I believe the best and most basic answer is the loss of sugar production. Plant growth and development, rooting depth, protein synthesis, defensive mechanisms, etc... are all powered by photosynthesis. This blog is the first of a two-part series explaining the basics of photosynthesis, and how we can strive to produce sugar at a much higher rate.

What if I told you that the amount of sugar your plants produce today will affect photosynthesis and yield for next year.

Photosynthesis is the process by which plants convert light energy (photons) into chemical energy in the form of glucose (sugar). The basic components of photosynthesis are: light, water, carbon dioxide.

Plants are very poor at performing this function. An average plant is only making sugar at 15- 20% of its potential. We need to push and strive for greater sugar production!

Why is this important right now?

With the weather pattern we are in, it is obvious from the phone calls and conversations that tension is building. Everyone is concerned about the potential of their crop due to the loss of growing days. Historically we understand that the later we plant we lose yield potential.

Corn - After May 15th, the capacity to maximize yield potential at 100% is greatly reduced (-0.4% per day). – from Bayer Crop Science data is from South Dakota and North Dakota.

Soybeans – After May 15th, the capacity to maximize yield at 100% is greatly reduced (-0.7% per day through June 10th and from June 10th – June 30th 1.25% per day) – source Pioneer Hybrids.

What drives the yield loss?

The plant grows faster the later we plant, and we do make up days from planting to harvest with later planting corn or soybeans. For example, if we plant soybeans 30 days later, we typically only harvest 10 days later. The plants compensated for 20 missing days. What happened in those 20 days that affected yield? The plant puts more energy into above ground growth than that of below ground growth.

I'm sure by now you have heard us talk about the hormonal balance of a plant

When a plant grows vertically quickly it creates an auxin dominant plant, that lacks stem or stalk circumference and the girth of the stalk relates well to the size of the transportation system which brings great value too late season nutrient, sugar and water uptake and movement within the plant. We also understand that when a plant puts all the energy into above ground growth, the plant often sacrifices root growth and development. However, we can use the auxin development in our favor. Auxins are developed from any shoot tip growth, so as plants grow vertically, we are producing auxins. If we can carry the auxins down the plant, they will help us create roots, but the key to doing this is to push the plant to create an abundance of sugars. The plant will grow quickly, which is good for moving up harvest dates but poor for sugar production, sugar movement and ultimately root growth and the plant and biology association which drives nutrient uptake.

Where do we lose days? The plant will sacrifice calendar days in both the vegetative stages and the reproductive stages, but it is weighted more in the vegetative stages, which is a good thing as more yield is achieved per day in reproduction then that of vegetation, but don’t forget about the nutrient uptake on a per day basis in the mid to late vegetative stages. A corn plant for instance takes up to 65% of its total needs of N, K, Mg, Mn, Fe, B in the vegetative stages and as much as 55% of its P, Zn, Cu, S needs in the reproductive stages. What does that mean to you as a grower or an advisor? Maximizing each day of a plant’s life is important in any given year, but in years that we have days stolen from us due to weather we need to manage better to maximize potential.

Tips to make up for lost days:

We need to maximize the sun!! This is why data suggests that in crops that can be raised successfully in multiple row spacings that the later we plant the better the advantage leans towards narrow rows (example 30-inch vs 15-inch soybeans). Less soil is catching the light and more of the solar panel from the plant.

How can we do this other than planting density? Create the right nutrient uptake at the right time, nutrients have individual purposes for the plant, and balancing the correct nutrients at the right crop stages can have significant impacts on the crop. Again, the more sugars we create the better the yield potential. Increase the size of the solar panels (leaves) of the plant, increase the color intensity of the leaf, the darker the green the better light capture. The greater amount of light that we capture the better the photosynthetic process works, the better the photosynthetic process becomes the more sugars we create. The more sugar created the healthier the crop becomes due to the energy the sugar provides. Once you have a plant that has excess sugar (energy) to sustain above ground growth the excess energy is used to build roots and allows the plants to be able to create more root exudation which then allows for a better plant and microbe association which results in better nutrient and water uptake. This is an amazing cycle that drives production and plant efficiencies.

Agronomy 365 Tips: The basic steps of photosynthesis

1. Absorption of Light: Photosynthesis begins when light energy (photons) is absorbed by chlorophyll (Green Pigment). The chlorophyll density determines how much light energy that plant can absorb. What nutrients make up chlorophyll density? Magnesium, Nitrogen, Iron, Manganese, Zinc, and Sulfur are the key nutrients that determine leaf color.

2. Water Splitting: The absorbed light energy is used to split water molecules into oxygen, protons, and electrons. This process releases oxygen out into the atmosphere. Manganese is responsible for triggering and being a part of key enzymes that help split the water molecule. Potassium is needed to open the stomata so that the oxygen can be released into the atmosphere. Some things that affect this process in a negative way are Water availability, Temperature (too hot or too cold), pH level in the plant (caused by nutrient imbalances).

3. Production of ATP and NADPH (Energy): The electrons produced during the water- splitting step are used to generate chemical in the form of adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide phosphate (NADPH). These molecules will provide the energy needed for the next stage in photosynthesis. Phosphorus’ number one job in the plant is to create ATP and NADPH. This is why so many people call phosphorus the energy nutrient. Zinc and Calcium are building blocks of key enzymes and proteins that contribute in the creation of ATP. Temperature determines how efficient this process is.

4. Carbon Fixation (Calvin Cycle): In the Calvin Cycle, carbon dioxide from the atmosphere is combined with the ATP and NADPH produced in the light-dependent reactions to form glucose. This process is also known as carbon fixation, as it converts inorganic carbon into glucose (Sugar). RuBisCO is the single most important enzyme that makes this process happen. Nitrogen and Sulfur are the key building blocks of this enzyme. Magnesium acts as the trigger to this enzyme. Environmental stress plays a big role in shutting this process down, but the sole most limiting stress that the plant goes through is oxidative stress. When there is oxidative stress present, the plant cannot take in CO2.

5. Glucose Production: Glucose (Sugar) is the primary product of photosynthesis. It serves as the main source of energy for plants and is also used to synthesize other types of sugar, necessary for growth and development.

BW Fusion Solutions

BioBoost:
1. Contributes to greater chlorophyll density.
2. Larger leaves to help capture sunlight.
3. Larger stem diameter to help with movement of minerals and sugar.
4. Establishes a larger root.

Full Sun:
1. Contributes to all 5 steps of photosynthesis!
2. Larger leaves to help capture sunlight.
3. Larger midrib on a corn plant, which contributes mineral and sugar movement.
4. Larger stem diameter to help with movement of minerals and sugar.
5. Drives deeper rooting!

In part two we will get into why a healthy plant creates a healthy soil. Along with revolutionary data that supports this hypothesis.

Jaren Schley, Technical Agronomist