Long-term research finds no-till most cost-effective for corn and soybean farmers

While no-till may not always deliver the highest yields for corn and soybeans, it excels in terms of overall profitability. – Photo: Skitterphoto/Pixabay

While no-till may not always deliver the highest yields for corn and soybeans, it excels in terms of overall profitability, a new study reveals. The key benefit of no-till is its reduced labour and equipment costs, which makes it the most cost-effective option in the long run.

Decades-long research on corn and soybean plots at the University of Missouri in the U.S. shows how tillage systems have affected yields. Extensive research conducted at the University of Missouri Graves-Chapple Extension and Education Center in northwestern Missouri analysed the impact of various tillage methods on both crop yields and financial returns. The study compared four common tillage systems: fall and spring disk, spring disk, no-till, and fall chisel with spring disk.

Last year marked the 34th year of research into corn tillage systems at Graves-Chapple. According to the center’s 2023 annual report, each experimental plot featured eight rows, each 30 inches (76 cm) wide and extending 250 feet (76.2 meters) in length. The corn was planted on April 18, 2023, with a seeding rate of 32,000 seeds per acre in a field that had previously grown soybeans in 2022. The harvest took place on October 10, 2023.

The growing season of 2022 was notably dry, and the weather conditions in 2023 did not improve significantly, with rainfall remaining sparse and below average, coupled with considerable temperature fluctuations.

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The long-term data from the study reveal that the spring disk system has historically achieved the highest average corn yield of 188.2 bushels per acre, closely followed by no-till with an average of 187.6 bushels per acre. – Image: Graves-Chapple Extension and Education Center

Better water infiltration

Among the various tillage systems, the no-till corn plot achieved the highest yield, producing 218.8 bushels per acre. In contrast, the fall chisel and spring disk plot had the lowest yield, at 206.7 bushels per acre.

“Historical data indicates that during such weather patterns, no-till usually results in the highest yield because it allows better water infiltration”, explains Jim Crawford, director of the Graves-Chapple Center. “Allowing the roots to chase water deep into the profile benefits the plants when the hot and dry summers arrive. Additionally, no-till conditions help stabilise soil temperatures.”

Despite the high yield in 2023, the long-term data from the study, spanning 34 years, reveals that the spring disk system has historically achieved the highest average corn yield of 188.2 bushels per acre, closely followed by no-till with an average of 187.6 bushels per acre.

Conducted for 23 years

The soybean tillage research at Graves-Chapple has been conducted for 23 years. Over that time, the no-till treatment had the highest average yield for any tillage method, averaging 59.8 bushels per acre per year, followed closely by spring disk at 58.3 bushels per acre per year.

With 23 years of data, trends in the yields for each tillage method become evident. This longer term collection of data allows the weather variable to be minimised since the researchers have had varying weather patterns during this time period.

Comparing the data obtained during the life of the study, the no-till treatment has had the highest average yield for any of the tillage methods averaging 59.8 bushels per acre per year. The fall chisel/spring disk treatment has had the lowest average yield for any of the treatments, with an average of 55.2 bushels per acre per year.

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Over a time frame of 23 years, there is no significant difference between the yields for the four systems in soybeans. – Photo: Missouri Soybeans

Key points

Cost-effectiveness: No-till farming is the most cost-effective option in the long run due to its reduced labour and equipment costs, despite not always providing the highest yields for corn and soybeans.
Historical data: Over 34 years of research, the spring disk system historically achieved the highest average corn yield of 188.2 bushels per acre, followed closely by no-till with an average of 187.6 bushels per acre.
Weather impact: No-till helps improve water infiltration and stabilise soil temperatures, benefiting crops during adverse weather.
Soybean yields: For soybeans, no-till consistently had the highest average yield over 23 years, averaging 59.8 bushels per acre per year.
Environmental benefits: No-till farming significantly reduces soil erosion caused by wind and water runoff, which helps prevent water contamination and environmental degradation.

Financial savings

In 2023, no-till plots also had the highest yield at 63 bushels per acre. The fall chisel and spring disk was the lowest-yielding system, yielding 55.9 bushels per acre. Each plot consisted of eight 30-inch rows that were 250 feet long. The plots were planted on May 10, 2023, with a population of 138,500 seeds per acre into corn residue. Harvest was conducted Nov. 13, 2023. Yield results were taken from the centre four rows of each plot in both corn and soybeans.

“The biggest aspect of no-till over the years is the financial savings since there are no tillage costs,” Crawford points out. “The application of fertilizer, herbicides, seed, planting and harvesting were the same for each of the tillage systems used.”

Over this time frame there is no significant difference between the yields for the four systems. The real advantage is the lower labour and equipment costs for no-till, making it the most profitable over this time frame, Crawford emphasizes. “We used the average cost people charge for each tillage operation to account for labour and equipment costs. These numbers came from MU Extension publication G302, ‘Custom Rates for Farm Services in Missouri.”

Additionally, Crawford concludes, no-till practices offer considerable environmental benefits by significantly reducing soil erosion caused by wind and water runoff. Soil particles are the primary contaminants in rivers and streams in northwest Missouri. They not only cloud the water but may also carry other pollutants such as herbicides, insecticides, and fertilizers, potentially contaminating the water supply.

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Comparing the data obtained during the life of the study, the no-till treatment has had the highest average yield for any of the tillage methods averaging 59.8 bushels per acre per year. Image: – Graves-Chapple Extension and Education Center

Study: Biological seed treatments fail to boost corn yields in trial

The marketplace has actively promoted the use of biological products as seed treatments and in-furrow applications with the promise of reducing the need for nitrogen fertilizers. However, a recent study reveals that biological seed treatments did not perform as effectively as advertised.

In response to local growers’ requests for research into these products, a test was initiated at the Graves-Chapple Extension and Education Center in 2023. The research team, known for its annual corn nitrogen rate demonstrations, incorporated a split-plot design into the study. This design involved planting each replication of nitrogen rates with and without the application of a biological seed treatment. To maintain objectivity and avoid any bias, the specific name of the biological product was withheld.

For the study, a hybrid corn variety was selected, with one set treated with a popular biological seed treatment and another set left untreated. The demonstration was conducted using a planting population of 34,500 seeds per acre, although the specific hybrid used was not disclosed.

The effect on corn yield in response to different rates of nitrogen fertilizer and the addition of a biological seed treatment in 2023. The graph with the orange line shows the non-treated seed across nitrogen rates and blue line is biological seed treatment. The statistical analysis and graph were prepared by Dr. Rob Kallenbach, Associate Dean of CAFNR Extension and Senior Program Director Agriculture and Extension. Image: University of Missouri

Urea with Agrotain was applied at varying rates of 0, 60, 120, 180, 240, and 300 pounds of actual nitrogen per acre. Each replication of nitrogen rate was planted with both the treated and untreated hybrids in a randomized manner. Nitrogen application was top-dressed one day after planting.

The statistical analysis of the study showed no significant increase in corn yield attributable to the use of the biological seed treatment. However, a significant difference in corn yields was observed with varying nitrogen rates, with a least significant difference (LSD) of 11.5 bushels.