From Seed to Harvest

Crop Production

Related Education Resources

“Here on our farm, we'd rather grow what you want. Crop diversity is a big deal.”
—Roric Paulman

To protect the health of the soils, Roric plants a diversity of crops at Paulman Farms. “We grow less corn now than we did ten years ago, he explains. “We're growing more and more crops that are more the farm-to-table variety. Popcorn is one of those, it comes out of our field, it's cleaned and bagged, and it goes to the grocery shelf. We're growing potatoes. Same thing there. They come right out of the field, they're washed and bagged, and go right to the warehouse. We're growing dry edible beans—a lot of black turtle beans (a small, shiny variety of the common bean especially popular in Latin American cuisine) and pinto beans (A medium-sized speckled variety of kidney bean.). We grow confection sunflowers (non-oil seed). Everybody likes those big sunflower seeds!” Growing a rotation of diverse crops improves the soil ecosystem making it possible for beneficial organisms to thrive, and in turn discouraging pests. Fewer pest problems reduces the need for the application of insecticides, which is good for the environment and saves Roric money.

Ears of corn on a mature corn plant.
Ears of corn on a mature corn plant.

But, most farmers in Nebraska grow mainly corn, soybeans, wheat, hay, grain sorghum, beans, and sugar beets. Corn and soybeans are by far the dominant crops. The United States grows more than 85 million acres of corn and soybeans on the Great Plains. Nebraska grows about 1.5 billion bushels of corn and 319 million bushels of soybeans each year. King Corn has transformed agriculture worldwide—from its original use as a traditional food source in the Americas to its modern transformation into plastics and biofuels (derived directly from living matter). Soybeans, native to East Asia, became a rotation crop companion to corn and is today a major U.S. crop.

CornProduction_PageBreak_Image

Corn Production


Corn, or maize (Zea mays), is a tropical grass native to Mexico and Central America. Maize (a Central American cereal plant that yields large grains set in rows on a cob; corn.) descended from teosinte, a wild grass from southern Mexico, more than 6,000 years ago. Teosinte (A Mexican grass that is grown as fodder and is considered to be one of the parent plants of modern corn.) looks nothing like corn. It has no ear and bears only a handful of tiny, naked seeds. A few thousand years ago, teosinte underwent dramatic mutations that turned it into corn. Mesoamerican (A historical region of Central America that flourished before the Spanish colonialists invaded in the sixteenth century.) Indian cultures collected wild teosinte plants and selected seeds with certain favorable characteristics, such as large, soft kernels. The wild plant slowly became domesticated. The earliest archaeological evidence of corn dates to about 5000 B.C. and was found in Tehuacan Valley of Mexico. Maize was easily stored and could be eaten whole or ground into flour that was used to make tortillas. For many Mesoamerican civilizations, including the Aztecs, Incans, and Mayans, maize was not only a food source, but was of spiritual and religious importance. Through trade routes on land and at sea, corn quickly spread throughout the world and is today one of our most important grains.

Dent corn, still on the cob.
Dent corn, still on the cob.

There are four major types of domesticated corn grown in the United States: sweet corn, popcorn, dent corn (small indentation ("dent") at the crown of each kernel on a ripe ear of corn.), and flint corn (corn of a variety that has hard, slightly translucent grains). Sweet corn is what you find on your dinner plate in the summer months. Yet, it makes up less than one percent of the corn grown in the U.S. Popcorn is a familiar snack food. It has a hard, outer shell that pops when the moisture inside the kernel turns to steam. Nebraska grows more popcorn than any other state, producing in 2012 45 percent of all popcorn grown in the U.S. Dent corn is the most common type of grain corn grown in the U.S. It is primarily used in livestock feed, but it is also milled into corn flour, used to make foods such as corn chips and taco and tortilla shells. Dent corn may also be turned into cornstarch, which is used to make high fructose corn syrup (HFCS), a sweetener found in many processed food products, such as bread, cereal, yogurt, salad dressing, soda, and candy. Dent corn can also be transformed into a biofuel called ethanol (a colorless volatile flammable liquid which is produced by the natural fermentation of sugars; alcohol), which is blended with gasoline and used in motor vehicles.

In the spring, usually in April—when soil temperature and moisture levels are optimal—Roric plants corn seeds in the residue of soybean plants harvested the previous fall. Once the seeds are in the soil, they begin to absorb water and nutrients, which will burst the pericarp or protective outer covering. The corn seed or embryo (a rudimentary stage that shows potential for development) then begins to germinate (begin to grow and put out shoots after a period of dormancy). About ten days after planting, the seed sends a primary root or radicle (The primary root of a germinated seed.) to anchor it in the soil and sends up a mesocotyl (The stem of a germinating seedling, also known as a hypocotyl.) or stem. As the mesocotyl breaks through the soil surface, the coleoptile (A sheath protecting a young shoot tip in a grass or cereal.) or young grass shoot tip emerges. As the corn stalk matures it forms 15 to 20 broad leaves. The leaves, through the process of photosynthesis (The process by which plants and other organisms convert light energy into food.), absorb sunlight and carbon dioxide and convert that energy to carbohydrates to feed the growing plant.

As the corn plant begin to mature ear shoots will begin to form on the plant. Once tassels are visible, silks begin to emerge within two to three days. The silks capture pollen from the tassels transferred by the wind, bees, or birds. Pollen grains move down the silk to the ovule in a 24-hour period. Once pollinated, small, white kernels begin to develop on the ear. At this stage, the plants are vulnerable to environmental conditions that may interrupt the pollination process (the transfer of pollen to a stigma, ovule, flower, or plant to allow fertilization.). Hail and drought are of particular concern as the entire crop may be destroyed. It is a tense time for farmers as they wait for this critical period to pass. After about five days the ear will begin to form kernels.

Parts of a corn plant (Courtesy North Dakota Studies Program, State Historical Society of North Dakota).
Parts of a corn plant (Courtesy North Dakota Studies Program, State Historical Society of North Dakota).

Timelapse video of a corn plant recovering from hail damage.

As the silks dry out and turn reddish-brown in color, the kernels continue to mature until they are bright yellow in color. Once the plant has reached peak maturity, it begins to lose moisture content. The characteristic dent forms on the kernels in dent corn. After the entire plant loses moisture and the leaves turn brown, it is ready for harvest.

A view of the sunset through the corn crops.
A view of the sunset through the corn crops.
A closeup of soybean plants.
A closeup of soybean plants.

Roric, like many farmers grows corn and soybeans in rotation each season. Planting corn and soybeans in rotation helps to maintain a healthy balance of nutrients in the soil. Soybeans are legumes or members of the pea family, which include alfalfa, clover, peas, dry beans, lentils, chickpeas, and peanuts. During the development of the soybean plant’s root system, millions of mutualistic Rhizobium japonicum (A type of mutualistic soil bacteria that improves nutrients for crops.) bacteria in the soil environment infect the roots of the host plant. The roots form nodules or small round sacs around the mutualistic bacteria (Bacteria that forms a relationship with a host plant that is mutually beneficial to both organisms.). The bacteria do not harm the host plant. Instead, they share a mutually beneficial relationship with the soybean plants. They provide soybean plants with nitrogen (the chemical element of atomic number 7, a colorless, odorless unreactive gas that forms about 78 percent of the earth's atmosphere.) through a process known as nitrogen fixation. The bacteria convert nitrogen (N2) from the air into a form of nitrogen that the plant can use, and in return the host plant provides the bacteria with carbohydrate.

Soybean_PageBreak_Image

Soybean Production


In the spring, after the last frost, Roric plants soybean seeds through the corn residue of the previous harvest. Depending on soil temperature, moisture level, and planting depth, the seed begins to absorb water—up to 50 percent of its weight. As it swells, the seed begins to germinate by first sending a primary root to anchor it in the soil. Lateral roots begin to grow just before emergence. The seed then sends up its hypocotyl (The stem of a germinating seedling, also known as a mesocotyl.) or stem to the surface of the soil. As the stem grows, it carries with it two cotyledons that store the leaves. The cotyledons usually emerge from the soil surface in about one to two weeks after planting. As the plant grows, its primary root may reach a depth of up to six feet and its lateral roots may spread 10-12 inches into the top six inches of the soil. At this stage, soybean roots become infected with millions of mutualistic Rhizobium japonicum bacteria that will be beneficial to the plant and the surrounding soil. At full maturity, soybean plants can grow over four feet tall. After flowering, the plants produce bean pods (fruit), which contain seeds about 3 inches long. Soybeans are ready for harvest, once the leaves dry out and turn from green to brown and the seeds reach the optimal harvest moisture level of 13 to 15 percent.

At any stage after the leaves have developed, soybean plants are vulnerable to unexpected weather events, like hail, and pests that can significantly affect yield. A pest called the soybean aphid—small, winged or wingless, yellow-bodied insects. The species was accidentally introduced in the Midwestern United States from Asia in 2000. From late May to August across the Midwest, soybean aphids invade soybean crops, feeding on the new growth of plants with needle-like mouthparts that extract nutrient-rich juices.

A unique aspect of this animal’s lifecycle is that females can produce live female offspring, or clones. This leads to a rapid increase in their population size, making them difficult to control. There are however, several beneficial organisms that can be used to control the aphids, such as Asian ladybird beetles or ladybugs.

While corn has been a staple of the Great Plains for centuries, soybeans are a relatively new crop. In the early twentieth century, Henry Ford helped usher in a new modern farming age with technological advancements that included gas-powered tractors, combines, and farm trucks. As a result, grain production soared. The surplus of grain quickly overwhelmed the markets, decreasing prices. In order to protect the family farmer and seek out alternative uses for crop surpluses, Ford oversaw chemical research at his agricultural laboratory and “chemical plant” at the Ford Motor Company’s Greenfield Village in Dearborn, Michigan. In 1929, the USDA sent researchers around the world in search of crops that might have an industrial application. They returned with 10,000 varieties of soybeans. Researchers at Ford’s “chemical plant” soon determined that soybeans could be turned into industrial oil that could be used in the production of biofuel and plastics.

By 1935, the soybean harvest surpassed both barley and rye. And today, here in Nebraska, farmers continue to grow industrial soybean and corn crops for use in the production of ethanol, biodiesel, and plastics. Soybeans are primarily processed into a high-protein feed for livestock. Soybean oil, which is refined for cooking and margarine, is used in salad dressing, mayonnaise. and other foods. Soy milk, tofu (A curd made from mashed soybeans, used chiefly in Asian and vegetarian cooking.), and soy flour are also produced.

Cattle eating from long feed troughs.
Cattle eating from long feed troughs.
CropstoMarket_PageBreak_Image

Crops to Market


Planting diverse crops also helps Roric weather uncertain grain markets. When farmers grow the same crops, they must compete against each other to receive the best price per bushel when they bring their grain to market. Farmers compete with one another, not just from different regions, but neighbors compete with neighbors. “When I'm growing corn and soybeans, or popcorn, I'm competing against my neighbor,” says Roric, “That's another tough thing to reconcile. When you get to that fence line, what you do and how you do it, there's nothing shared.” It’s a difficult reality for farmers to accept, because they value their neighbors and pride themselves on helping each other. An added benefit of diversifying his crops is that Roric also reduces the amount of direct competition with his neighbors.

Grainbins for crop storage.
Grainbins for crop storage.

After crops are harvested, the grain can be sold on the global grain market or stored in grain bins. Farmers may elect to use grain bins to store grain on their farms and wait, “We're waiting for that demand to pick back up,” says Roric. These bins are equipped with heating and drying systems to keep the grain (usually corn) at the appropriate moisture content. There are many advantages to using grain bins, which includes storing corn during harvest and drying corn to avoid paying a drying fee at the co-op ( A way of agricultural organization where farmers pool their resources together to help all members achieve more productivity.). Storing grain is a way for farmers to obtain the best price for their grain. As supplies diminish later in the season, they sell their grain stores at a higher price than they would have received earlier in the season. Grain pricing is complicated and varies from year to year. There are also disadvantages to storage, such as the cost to build and maintain grain bins and the cost of electricity for drying.

Farmers eventually bring their grain to a co-op facility where, for a fee, grain elevators provide large-scale grain storage and drying. Grain is usually shipped from the farm to the co-op in a semi-truck. At the grain elevator, the grain is weighed, inspected, stored, and eventually shipped by rail to both domestic and international markets as far away as China where it is mostly used for livestock feed.

Harvest is a time of great anticipation for farmers. This is the moment when they learn if their hard work will earn them a profit. Roric’s concerns at this time of year turn to “production costs, taxes, and the market” as he calculates profits and plans for a new season.

Trucks filling with crops during harvest.
Trucks filling with crops during harvest.

Watch the Paulman Farms corn harvest in 360° below: