In precision agriculture, we often focus on seed and fertilizer to optimize crop production.
But, the longest day of the year was on June 21, so all that extra daylight brings to mind one of the most important (and often overlooked) inputs…sunlight.
How does sunlight increase your crop production?
You probably learned about the basic mechanics of photosynthesis in your elementary school science class. In this process, plants take water from their roots and carbon dioxide from the air.
Using energy from sunlight, plants then convert these raw ingredients into carbohydrates (sugars), which are a plant’s building blocks. This process occurs in all plants, from the grass in your lawn to the corn and soybean growing in the fields.
Plants utilize sunlight to build carbohydrates, which then produce the parts of the plant, including leaves, roots, and grain. More sunlight for the plant means more carbohydrate production, providing the plant additional resources to put towards growth, and ultimately, yield.
The Four Tools to Get 100% Light Interception
While sunlight is a “no-cost” input, it’s availability is limited throughout the growing season. The available amount of the sun is lowest at planting, increases until the summer solstice, and then slowly decreases until harvest. One of the best strategies to maximize yield is matching the growth cycles of our crops to the availability of sunlight.
Since crops harvest sunlight primarily through their leaves, we want to optimize ground cover by the crop leaves. Our goal is to achieve 100% canopy closure and 100% light interception by the start of summer.
There are four tools we use to ensure we hit our goal of 100% light interception: planting date, row spacing, seeding rate, and crop maturity (relative maturity or maturity group).
The optimal planting window for each crop type (corn, soybeans, cotton, etc.) varies by region. Planting too early may lead to problems with slow germination and emergence due to cold/wet conditions, resulting in poor early-season development and can limit stands and yield. Planting too late decreases the available sunlight the crop can harvest and shifts the reproductive growth stage into sub-optimal climatic conditions.
Row spacing directly affects the amount of time it takes a crop to reach full canopy closure and light interception. Wider rows mean individual plants must grow and develop longer before achieving full canopy closure. Narrower rows allow for better overall plant spacing, and the crop takes less time to reach canopy closure, resulting in an increased light interception.
Seeding rate and row spacing determine overall plant spacing within a field. Higher seeding rates generally result in more plants per acre, which decreases the amount of space each plant must fill to achieve canopy closure and maximum light interception.
Each crop type has an optimal seeding rate range. Seeding at too low a rate can result in low plant population and limit canopy closure. However, seeding above the optimal range doesn’t result in increased canopy closure and isn’t agronomically or economically justified.
Different varieties of crops can be genetically designed to grow and develop at different rates, allowing farmers to select a crop variety that can go through its entire life cycle in the growing season of their region.
For example, the growing season is much shorter in northern states than in southern states. Crops such as corn and soybeans grown in northern states need a shorter maturity/life cycle compared to the same crops grown in the south where the growing season is much longer.
To ensure maximum yield potential, plant a crop with the proper maturity rating for the region within the optimal planting date range. The crop can then reach flowering and reproductive growth when sunlight is most abundant.
How to know how much sunlight your crops are harvesting?
Now that summer is officially here; it’s time to look at the impact sunlight could make on your crops. Head out to the fields, peek under the canopy, and see how much sunlight is hitting the ground. If there isn’t much sun shining through, and the crop is advancing in early reproductive growth (ear and pod development), you’re headed in the right direction.
Of course, other environmental conditions, such as heat and rainfall (especially this year), also affect crop canopy development and light interception, so keep that in mind when assessing your crop.
Sunlight and the agronomic factors that affect light interception are important when making decisions for this year and planning for next year. When you focus on sunlight, you might bring around your best crop yet. Want more tips to increase crop production? Schedule a free consultation call to learn how Growers can help.