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Understanding Agriculture – Growing Soybeans

A few years ago, I ran a series of articles on understanding agriculture, designed for anyone in the general public who had an interest in understanding more about various agricultural crops and livestock. After receiving a few requests to revisit that project, I’m updating and redelivering that content for you today.

In Whitley County, as in most of northern Indiana, the predominant crops we grow include corn, soybeans, and wheat and hay. We’ll cover soybeans today. According to the most recent statistics available, Whitley County harvested 66,300 acres of soybeans in 2020, with an average yield of 50.4 bushels per acre. In 2020, Whitley County ranked 50th among Indiana counties in soybean production.

Soybeans are used for many things, including livestock feed, biodiesel, cooking oil, baby food, crayons, candles, printing ink, margarine, tofu and many other uses.

Farmers have to add nutrients to soybean crop fields in the form of fertilizer if nutrient levels are not sufficient (as determined by a soil test). However, as a legume, soybeans supply their own nitrogen through little structures that grow on the roots, called nodules. Bradyrhizobia japonicum bacteria in the soil infect roots and develop a symbiotic relationship with the soybean plant by “fixing” atmospheric nitrogen, and supplying that nitrogen to the plant. Soybeans can appear yellow (nitrogen deficient) until this nitrogen fixation kicks in. Corn does not have this ability, which is why farmers have to add a lot of nitrogen to corn. Other common legumes include peas, alfalfa, clover and green beans.

If you have a vegetable garden, soybeans look a lot like green beans. They typically get from waist- to chest-high in a farmer’s field. As soybeans mature in the field, passers-by will notice the green-to-yellow-to-brown color progression. Eventually soybeans end up as mainly stems with bean pods after leaves have fallen off.

Many inputs are required for a successful soybean crop. Examples include seed, fertilizer, herbicides, and other crop inputs. Different production systems (conventional, organic, no-till, etc.) will vary crop inputs used and how much they cost.

Crop rotation was discussed in my recent article on corn, and the practice is important for soybeans for the same reasons of fighting diseases and insects with a proven non-chemical cultural practice.

Purdue Extension experts construct annual average crop budgets for corn, soybeans and wheat. This information is available at Purdue Center for Commercial Agriculture: Search for “Purdue Crop Cost & Return Guide.”

To give you a feel for what farmers face in terms of costs per acre, let’s explore some of the costs outlined in Purdue’s guide (updated March 2022). For average productivity soil for soybeans in crop rotation, farmers could spend, on average for one acre: $100 for fertilizer, $71 for seed, $63 for pesticides, $20 for machinery fuel, $18 for machinery repairs, $6 for hauling, $10 for interest on borrowed money, and $41 for insurance and other miscellaneous expenses, for a total of $329 per acre.

Other costs include cash rent or land ownership costs, labor and management costs, machinery ownership costs, and risk.

At harvest, farmers combine soybeans and store the grain in a bin, or sell to the elevator or biodiesel plant. Some years, farmers may also have to dry soybeans or pay a discount at the elevator to dry it. This must be done so that soybeans can be stored safely without risk of spoilage.

We have just scratched the surface on what it means to grow soybeans. And, granted, there are a variety of management systems that farmers employ, from no-till to organic to conventional systems. Find Purdue Extension publications on a wide array of subjects at the Education Store:

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