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Soy Decisions and Best Practices

You’ve all heard the saying, “April showers bring May flowers.” Well, it looks like the April showers will also bring some anxiety to local farmers.

The forecast may not look good for getting a lot of field work done, but it’s not nearly as bad as the spring blizzard in North Dakota and Montana. They have been in severe drought for several months and now the only moisture they get is measured in feet of snow and blizzard.

One of my biggest concerns for these people is livestock. There are several beef producers in this region and many are in the midst of calving season. Keep these farming families in your thoughts as we enjoy our Easter weekend locally.

Soy Decisions

Given that field work is currently limited, consideration could be given to making decisions prior to planting soybeans. These decisions can be extremely important to the success of the culture.

Laura Lindsey, soybean specialists from Ohio State University, as well as soybean extension specialists from across the United States, worked together on the Science for Success initiative (funded by the United Soybean Board) focused on the harnessing local expertise to provide national best practices for soy management.

Recently, this group of experts has focused on soybean planting date, row spacing and seeding rate.

Lindsey shares the following information from this national effort as it relates to Ohio soybean production.

Planting date

Planting date of soybeans has a significant effect on yield. In Ohio, the yield reduction due to late planting ranges from 0.25 to 1.0 bushel/acre/day. In our small-plot research in Clark County, Ohio, soybean yield reduction in 2013 and 2014 was approximately 0.6 bushels/acre/day for each day planted from early to mid -may (Figure 1).

Although early planting is important to maximize soybean yield, the timing of planting should be based on field suitability and soil temperature at and after planting and frost forecast. Soybeans can germinate and emerge when the soil temperature is at or just below 50°F. At soil temperatures between 50-60°F, soybean plants typically take about 15-20 days to emerge after soybean planting.

Planting in a wet seedbed or after excessive tillage can result in soil compaction and crusting which could reduce stand establishment.

At the same time, planting in extremely dry soil can also adversely affect stand establishment due to insufficient soil moisture for germination and/or emergence.

For Ohio, in general, we recommend that soybeans be planted anytime after April 15th in the southern part of the state and anytime after the last days of April in the northern part of the state SI soil conditions are satisfactory.

Row spacing

In Ohio, soybeans are generally grown in narrow rows (7.5 to 15 inch row width). Soybeans grown in narrow rows generally produce more grain than soybeans grown in wide rows (30 inch row width) because they capture more solar energy, which drives photosynthesis.

In the United States, soybeans grown at a row width ≤ 15 inches have a yield advantage of 1 to 4 bu./acre over a row width > 15 inches. However, these yield advantages are generally greater with later planting dates, early maturing varieties and high temperatures, all of which reduce the time between VE (emergence) and R3 (initial pod set).

Seeding rate

Soybean plants are incredibly flexible in adapting to a wide range of plant populations. Sparsely populated soybean plants will produce more branches, more pods, and more seeds per plant.

Soybeans at higher populations will grow taller, produce fewer branches, pods and seeds per plant. Because of this flexibility, soybeans can often produce a similar number of seeds per acre and similar yields across a wide range of plant populations.

In Ohio, for a crop planted in May, a final plant population of 100,000 to 120,000 plants/acre is generally adequate for maximum yield.

The final population is a function of the seeding rate, the quality of the planting operation and the percentage of seed germination and depends on factors such as soil moisture conditions, seed-soil contact, disease pressure , fungicide seed treatments, etc. at rates above the minimum plant population required.

As a general rule, sow about 25% more than the target plant population. For example, for a target plant population of 100,000 to 120,000 plants/acre, you can plant 125,000 to 150,000 seeds/acre.

For more information on “The Best Soybean Planting Date”, please see this Science for Success article: https://soybeanresearchinfo.com/wp-content/uploads/2022/01/2700-002-20-Planting- Date_Science-for-Success22_TRV2_12-22-21.pdf.

For more information on “How to Choose the Right Soybean Row Spacing”, please see this Science for Success article: https://soybeanresearchinfo.com/wp-content/uploads/2022/01/2700-002-20- Row-Spacing_Science-for-Success-copy_updated12-22-21.pdf.

For more information on “Soybean Plant Population Density”, please see: https://soybeanresearchinfo.com/wp-content/uploads/2022/01/2700-002-20-Seeding-Rate_Science-for -Success_updated12-22-21. pdf.

Tony Nye is the state coordinator of The Ohio State University’s Small Farm Extension Program and has been an OSU extension educator for agriculture and natural resources for more than 30 years, currently serving Clinton County and Miami Valley EERA.