Crops

Soybean Planting in Warm Spring Weather

AUBURN, Ala.—Producers understand the risks associated with planting crops where irrigation is not available and rain is not forecast. Soil moisture is one of the major concerns for farmers as they head into planting season.

The late-season drought of 2016 caused issues for producers harvesting fall crops. Dry field conditions led to lower test weights and dustier harvests than normal. Now, producers are battling low soil moisture as they prepare to plant the cash crops of 2017. Field conditions have been dry in recent weeks, with scattered rainfall.

After a week with a handful of April showers, farmers are headed to the field to plant soybeans, cotton and peanuts—hoping the soil will hold moisture long enough for the seeds to germinate.

Alabama Extension professionals developed guidelines for soybean planting in a warm, dry spring. These guidelines can also be found in the free, downloadable Climate and Crops iBook.

Planting Risks

In wheat/soybean double-cropping systems, the wheat is typically harvested earlier, allowing early planting of soybeans.

The lack of soil moisture associated with warmer and drier spring planting conditions can delay emergence.

Vegetative growth under these conditions is also affected. The plants that emerge tend to be too small for sunlight interception.

Planting Strategies

  • Under anticipated warmer and drier spring conditions, planting should occur earlier. Also, growers should consider using cover crops and conservation tillage to preserve soil moisture.
  • Irrigation, if available, is another important safeguard.
  • Row spacing of soybean plants should be reduced and irrigation increased. Growers should also select taller varieties.

Insect Risks

Several insects typically migrate into soybean fields faster during drier spring conditions.

Under these conditions, growers should anticipate higher populations of grasshoppers. Grasshoppers lay their eggs in the soil; however, these eggs aren’t as likely to fall prey to disease as they are under wet conditions.

Stinkbug populations also tend to increase in warmer spring conditions. Conversely, colder weather suppresses southern green stinkbugs and red-banded stinkbugs, which are more significant pests in the Southeast.

Dry springs also promote the spread of three-cornered alfalfa hoppers, which are more likely to migrate onto soybeans as wild host plants dry out earlier.

Thrips are another problematic insect pest in warmer springs. Wet springtime weather, on the other hand, typically contributes to higher mortality rates of immature thrips.

Insect Management Strategies

  • Under drier spring conditions, growers should be aware that these pests will likely move into fields from host plants much sooner than usual.
  • Scouting is an essential safeguard, though many of these pests are difficult to detect given the small size of the emerging soybean plants.
  • Insecticides can be simultaneously applied with herbicide treatments that are sprayed on small beans as part of an early season weed control regimen.

Disease Risks

During warmer and drier springs, especially those preceded by warm, dry winters, growers should monitor for soybean rust. Rust is a fungal pathogen that can survive on kudzu leaves along the Gulf Coast during years when temperatures are consistently above normal for this region. During mild winters, it’s likely that soybean rust will build up on kudzu in the spring and could potentially move into soybean production areas later in the spring and summer.

Disease Management Strategies

  • Growers should follow the spread of soybean rust through the IPM Pest Information Platform for Extension and Education at http://sbr.ipmpipe.org/cgi-bin/sbr/public.cgi or through soybean rust alerts provided by their state’s extension system.
  • Growers may need to apply fungicides earlier in the season based on increased risk from this disease. Failure to deal with this disease early could trigger an epidemic later in the season.

Climate and Crops iBook

Climate and Crops is intended to be a comprehensive resource not only for farmers, crop consultants and Cooperative Extension professionals but also for school teachers who want to introduce their students to how farming practices are increasingly being adapted to new findings about climate variability.

Each chapter includes basic considerations associated with crop production. Additionally, each chapter covers potential climatic conditions that may occur during the growing season and how these affect each of the principal crops in terms of planting, crop growth and development, insect, weed and disease pressure and harvesting. Along with the risks, farmers are provided with the most effective management strategies to deal with each of these climate scenarios.

Learn more about Climate and Crops at http://www.aces.edu/climateandcrops.

 

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