Growing Soybeans: Best Planting & Cultivation Practices

Environmental Conditions Needed For Growing Soybeans

In the right soil and climate, soybean is a simple crop to grow. Although it doesn’t require much in the way of particular care while growing, there are environmental factors to look at before you plant.

Climatic Conditions

Cold-temperate areas like the United States and Canada, as well as tropical and sub-tropical areas like Indonesia, are suitable for growing the crop. As long as there is enough water, sunlight, and a warm growing season for soybeans, you can grow this crop practically anywhere. It needs between 20 and 26 inches (510 and 660 mm) of water per soybean growing season, depending particularly on the planting date and weather conditions. Throughout the middle to later plant stages of reproduction, water stress is the most detrimental for the growing crop.

The optimum temperature for soybean growth ranges between 72 and 95°F (22 and 35°C). Lower than this, and the crop’s chances of growing mature are hampered by a delay in development. Although soybeans are hardier than some other crops, they still can be affected by frost. With recent breeding efforts, new early-maturing cultivars are available, making it possible to reap before the onset of winter frosts in colder climates ^{Coleman, K. et al. (2021, May 1). The potential for soybean to diversify the production of plant-based protein in the UK. Science of the Total Environment, 767. https://doi.org/10.1016/j.scitotenv.2020.144903.}.

Soil And Nutrients

Growing high-yielding soybeans is best on well-drained, rich in organic matter, loamy soils with a pH of 6.0 to 7.5. This type of soil should be favored above others for a number of reasons. To begin, seeds have a tough time sprouting in saline or sodic soils. Very acidic soils (with a pH below 4.5) are not suitable for growing legumes due to the potential for aluminum and manganese toxicity. Finally, soils with a pH higher than 8 often lack the required micronutrients for growing soybeans, especially zinc and iron ^{Nimje, P. M. Soybean production technology. All India Society for Electronics and Computer Technology (AISECT).}.

The shallowness of their roots makes these plants unable to withstand dry growing conditions. So, soybeans do not grow well in soils with poor water retention, such as sand, gravel, or shallow soils. Waterlogging could also be to blame for crop damage. Hence, it is necessary to grow soybeans only in fields with well-drained soil that can still retain adequate moisture for plants to thrive.

How To Plant Soybeans

There are several steps and processes involved in planting soybeans. Below, we’ll break down the most crucial aspects of each so you can grow yield and economic return.

Pre-Planting Operations

Seed treatment with pesticides and fungicides is usually recommended. Before planting, make sure the seeds don’t contain any of these chemicals. It’s noteworthy that the tillage method has no bearing on crop harvest. No-till soybean planting is an efficient and cost-effective alternative to conventional tillage methods ^{Licht, M., Clemens, Z. (2020, September 1). Plan for No-till Soybean. Iowa State University Extension and Outreach.}.

Best Time To Plant Soybeans

They should be planted in the late winter or early spring, when the soil temperature grows to 60°F (15°C), in frost-free regions. The same soil temperature for planting soybeans two to three weeks following the last frost date is ideal in cooler climates. Delayed soybean planting dates might lead to shorter plants and lower pod formation, both of which hinder harvesting. Late-planted soybeans have a greater risk of being damaged by fall frost, further reducing crop output.

Soybean Planting Rates

The planting rate for soybeans should reflect the intended crop density. The number of plants you want to grow, the size of the seeds of each type, and the success rate of your seeds all play a role in determining seeding rates.

Planting Methods And Approaches

Until the middle of the twentieth century, commercial farmers frequently used broadcast seed planting. However, planters and drills with more capacity and improved technology have since replaced this technique. Direct seeding in the soil is the most effective method for planting the crop. Soybean plant spacing of no more than 6 inches (15 cm) apart allows plants to eventually grow a canopy that acts as a natural pest barrier.

How deep should soybeans be planted? A range of 0.75 to 1.5 inches (2 to 4 cm) would be ideal soybean planting depth. When seeds are planted too deeply, they may not germinate and could become susceptible to soil-borne diseases. After sowing the seeds, cover them lightly with soil and moisten thoroughly with warm water.

How Long Does It Take To Grow Soybeans?

They require anywhere from 100 to 130 days or more to complete their full growth cycle. Because day length affects plant development, longer days can delay flowering in short-day types and lead them to grow in height and node number. Meanwhile, shorter days accelerate flowering, even more so for late-maturing types.

There are more environmental conditions that influence soybean growing time. Insects, crop diseases, a lack of sunlight, and dry spells during the grain fill stage can all affect the plants’ health and thus the time it takes for them to grow mature.

Soybean Pests And Diseases And Ways To Combat Them

Pests and diseases still pose a threat to yields and farm profits, even though soybeans are more resistant than other legume crops. Some of the aspects affecting the prevalence of insects and pathogens in growing soybeans include hybrid selection, climate, past disease incidents, rotation crops, and agricultural strategies.

Common Soybean Pests

The most widespread pod-feeding pests are bean leaf beetles (BLB), stink bugs, and grasshoppers. They damage crop yields and can lower seed quality.

BLBs are a constant problem for growing soybeans from the time they emerge until harvest. Grasshopper populations tend to grow in crops during dry spells when natural predators are unable to keep them in check. Soybean leaves and pods are fair game for adult and immature forms of this pest. Shriveled, undersized, and discolored plants are a common outcome of pod feeding by stink bugs (particularly green stink bugs), which can sometimes impede germination.

Using integrated pest management techniques is the most sustainable approach for keeping pests away from your growing crops. Conventional insecticide treatment may be needed if 10–15% of the pods are damaged during the full seed soybean growth stage. There are a lot of effective pesticides, such as pyrethroids, organophosphates (OPs), and neonicotinoids, which can all be bought separately or in mixes. Nonetheless, while deciding when to apply pesticide, keep the pre-harvest interval in mind.

Common Soybean Diseases

There are more than a hundred different pathogens that can damage growing soybeans, but only a few cause significant losses (up to a 10%–30% drop in yield) ^{Diseases in soy production. (2020, April 7). ProTerra Foundation, Netherlands.}. Viruses, bacteria, fungi, and nematodes are all potential culprits in the spread of crop diseases. The most effective method of fighting them is integrated pest and disease management, which relies on a number of different yet complementary control strategies.

Knowing how to identify and treat these soybean diseases is good, but prevention is always better. Fortunately, modern technology offers solutions for proactive crop management. The Disease risk feature on our platform allows farmers to monitor the risk of prevalent soybean diseases remotely: a clear, easy-to-understand risk assessment (low, medium, high) for each disease, based on detailed weather forecasts up to two weeks in advance. This feature, with its field-by-field breakdown of potential threats, is invaluable for crop producers managing multiple fields across different regions.

Using Satellite Technologies To Address Challenges In Soybean Growing

Soybeans are fairly simple to grow and require little care. There are times, though, when even the most seasoned farmer makes oversights. One of the best ways to avoid this is to use satellite technology for early detection and addressing crucial issues in soybeans growing.

Overwatering Detection And Management

Farmers frequently overwater the seeds, which hinders them from germinating. Yet, overwatering remains an issue even if germination is a success. Growing soybeans that have been overwatered develop large, floppy leaves and are more prone to disease and lodging. Overwatering can also cause the flowers and pods to drop off the growing plant. Rapid drainage and removing crop residues may save such plants, though.

When you look at the NDMI index map in EOSDA Crop Monitoring, you can figure out what’s wrong without having to go to the field. High index values may be a sign of overwatering and the need for prompt intervention. Additionally, the platform has soil moisture monitoring feature that helps to assess the problem with watering underground.

Identification Of Weed Infestation

Growing soybeans have an advantage over many invasive plants due to their canopies’ ability to completely cover the ground. However, diligent weed management is required beforehand. Seedlings are most susceptible to damage from weeds between 4 and 7 weeks after planting.

Using MSAVI index maps, which are most effective when applied to young crops, allows growers to locate separate areas of a field where seeds are failing to germinate and dispatch scouts to investigate the presence of weeds. With the information you’ve gathered, you may rapidly eradicate unwanted plants and save your harvest.

Pest And Disease Infestations Management

The best disease and pest control programs are built on a solid foundation of scouting, accurate pest identification, and economic crop damage assessment. Regular scouting of soybean fields is essential, but it is especially important in the two weeks following emergence and from full flowering to full seed soybean growth stages. With EOSDA Crop Monitoring’s task-assignment tool and specialized mobile application, scouts can quickly explore areas of concern and report their findings, ensuring that your growing crops are protected from diseases and pests.

Fertilizing Rates

When soybeans are growing, they do not require any further nitrogen fertilizer. As a legume, they are capable of nitrogen fixation. Even though these plants don’t need supplemental nitrogen for growing, a boost of 9–18 lbs/ac (10–20 kg/ha) N fertilizer at planting could promote robust early soybeans growth.

Applying some aged compost midway through the summer can help your soybeans grow stronger, and you may not need to add any more fertilizer until harvest. Yet, never assume anything about soil fertility; instead, examine it periodically. There is no need to take samples for soil testing from the entire field every time because EOSDA Crop Monitoring can aid in a prior status evaluation off-site with its productivity maps.

Cold Or Heat Stress Detection

Soybeans are especially susceptible to cold stress from the chilly rain within the first 24 hours after planting, during their germination. They require warm weather, over 50°F (10°C), for at least 24 to 48 hours after sowing to ensure a successful harvest ^{Specht, J. et al. (2015, April 22). Chilling Injury in Corn and Soybeans. Institute of Agriculture and Natural Resources, University of Nebraska-Linkoln.}. Using the accurate weather forecasts in EOSDA Crop Monitoring, you can see if the upcoming days will be favorable for soybean germination.

Heat stress may occur when air temperatures grow over 85°F (30°C). When high temperatures and drought strike at once, growing soybeans suffer the most. Adjust irrigation and prevent plant stress by keeping an eye on weather reports (particularly temperature and precipitation), NDMI index maps, and soil moisture graphs for your fields, all of which are available in our precision agriculture platform.

Excessive heat can also hasten plant maturation. Thus it’s essential that you monitor what plant growth stage the crop is at so you don’t miss the moment when the soybean plant is ready to be harvested. If your crop grows too fast, you can see it in EOSDA Crop Monitoring and speed up harvesting.

Not only soybean farmers will find great value in these and many other capabilities of EOSDA Crop Monitoring. Get in touch with our sales team at sales@eosda.com for additional information on how to use satellite data to keep an eye on your growing crop.

When And How To Harvest Soybean Plant

Soybeans need to be harvested at just the right time; picking them too soon may bring about immature beans, whereas picking them too late when the pods have overdried can lead to shattering losses. There are three main criteria that will determine when to start harvesting:

• Crop maturity. Take into account how the crop’s maturity varies across your field.
• Moisture levels in seeds. When the beans grow fully ripe, they retain 45–55% moisture and need to be dried down to 13%–14% before being picked.
• Weed presence. To minimize the risk of unwanted residues in the harvest, it is advised to use pre-harvest herbicides when the bean water content is below 30% in the least mature area of the field.

Soybeans are typically harvested with combines. A combine harvester cuts the plants, extracts the beans from the pods, and then puts them in a holding tank. Finally, after the combine’s storage tank is filled, the operator transfers the beans to a special grain wagon or truck.

As not all of the soybeans growing in a field/fields may be ready for harvest at the same time, this process could take quite some time. To help with logistics and resource planning, retain consistent harvesting records, and reduce the time, money, and effort spent on in-field harvest monitoring, EOSDA provides a tailored solution for remote monitoring of harvest dynamics. Now, you’ll be able to track the harvesting progress of each of your fields from the convenience of your computer.

Soybean growing, as you can see, calls for relatively little input. The primary things that are expected of you are to time agricultural operations correctly, pay a bit more attention during the early phases of soybean growth and development, and periodically monitor the state of the growing crop. With just a little effort and adherence to these planting, maintenance, and harvesting guidelines, you can grow robust, healthy crops.