Optimizing Plant Establishment

A smile at harvest starts with the good decisions you made before and at planting. Like many row crops, soybeans yields will start to diminish once the bag is opened and seed is placed in the ground. Almost all management practices are implemented to preserve soybean top end yield, not necessarily to increase yield. When implementing a soybean game plan there are several areas to consider during planting; at the end of the day producers must ask these two important questions:

1. How will this decision impact soybean Stand Establishment?
2. How will this decision impact the soybeans ability to Maximizing Sunlight/Photosynthesis?

How will this decision impact soybean Stand Establishment?

When evaluating a planter for stand establishment needs, it’s important to keep in mind the importance of seed-to-soil contact. Good contact allows proper heat and moisture exchange to initiate germination and promote consistent emergence and final stand. This can be established by making sure that the planter is properly equipped with trash wheels to remove any residue or larger soil particles from the seed zone. It’s important the seed firmers are working correctly to make sure the soil is properly firmed around the seed. Also, consider using a spiked firmer to help reduce packing the soil surface too tightly in case of rain soon after planting that could cause a crusting issue.

Planters today are larger and heavier, and how that could potentially impact a soybean seedling must be taken into consideration when planting. That means planting when the soil is in the right condition for planting. There are several studies showing the impact to vegetative growth from poor root development due to soil compaction leading to rooting restriction. In the past decade producers have started to equip their planters with air bag systems that will regulate the down and up pressure of the machine as it travels throughout the field.

Treating soybeans has become very common. Currently, most soybeans are treated upstream before they come to the field and once treated they can’t be returned or delivered to a local elevator. It would be advantageous if producers could plant a non-treated bean and have an in-furrow injection system deliver the proper volume of treatment such as insecticide, fungicide, nematodes or rhizobia inoculant. This will allow a grower the ability to utilize these yield-saving products, while not having the non-return risk.

Variable rate soybean seeding, unlike corn, doesn’t generally increase soybean yield as population is altered. However, seed rates can be reduced in race horse zones while being increased in marginal zones. Today many planters are equipped with the ability to vary the population rate across a field based off a pre-established plan. This could be beneficial for typically wetter areas of fields where higher population would be more beneficial because it allows for a potentially higher percent of beans to emerge and establish an ideal population. Or in zones of the field that historically yield less than the field average and need a bigger plant count. This technology is a great concept that matches the population to the soil need and the dollars invested per acre on seed cost with the soils ability to provide a profitable return on investment.

How will this decision impact the soybeans ability to Maximize Sunlight/Photosynthesis?

A 2011 planting date study conducted by the University of Illinois indicated that vegetative yield (plant biomass) can be improved by simply planting early during April instead of May. This study also showed that the canopy closed over the row sooner. More vegetative plant mass exposed to sunlight equals more photosynthesis ability per plant per acre.

Maybe the time for soybean production has come that producers need to be planting soybeans at the same time they are planting corn. In this situation, a soybean-only planter could be equipped to handle early planting field condition (trash wheels, coulters, narrower row spacing, in-furrow delivery systems).

Row spacing continues to be a topic for debate throughout Illinois; several trials suggest that 30-inch row beans still yield as well, if not better, as 15inch rows. However, with increasing issues of battling weed resistance, there’s no doubt that 15-inch row beans will canopy much sooner than 30-inch rows, which could be an effective method to reduce additional weed flushes during the growing season. Another side benefit to an early fully closed row is that less sunlight is entering the soil layer, which can help reduce moisture lost.

Variable rate seeding can be helpful if a field has transitional soils (clays, sands or timber soils). These soils may need a higher population to help close over the rows and to ensure there are enough plants and nodes to optimize production of pods per acre. Beans in these environments tend to grow smaller and shorter with less yield potential.

CCA Todd Steinacher is an agronomist at AgriGold. He works with growers to better manage their Nitrogen and weed control needs, along with understanding the best way to understand cost in order to generate strong ROI.