Farm Progress

Do you really need to do fall tillage?

November 5, 2018

4 Min Read
PROTECTION: A no-till field after corn harvest shows lots of crop residue protecting the soil from erosion and adding organic matter to regenerate soil health.

This fall’s late harvest and the rush to get crops out of the fields presents an opportunity to rethink the need for tilling fields in the fall. The question is, “Do I need to till this fall?”

Given the economic and environmental challenges farmers are facing, the answer in most cases is no, says Mahdi Al-Kaisi, an Iowa State University professor of agronomy, and Extension soil and water management specialist.

Consider your specific situation, and whether tillage will provide economic and environmental benefits. Consider the costs associated with tillage and the impact tillage has on soil health and water quality. “Even though you may think tillage may be needed in certain situations and field conditions, a well-managed field and proper crop rotation may not call for tillage,” he adds.

2 main considerations
There are two key factors to consider for making any tillage decisions, says Al-Kaisi:

• Soil conditions. It’s important to evaluate your field’s natural drainage, topsoil depth, soil slope, organic matter and soil texture. These factors have significant effects on how tillage affects soil health, productivity and water quality.

• Management. This includes crop residue management, crop rotation, equipment availability and efficiency (planter suitability for different tillage systems, calibration of combine to ensure uniform residue distribution, etc.). Also, drainage tiles for managing excess soil water, soil test results and fertilizer management, suitable crop varieties for your area, and insect and disease control. These management decisions are equally important to determine the success of crop production.

Think long-term evaluating tillage results
Over the past 16 years, long-term tillage and crop rotation studies were conducted across Iowa. The studies document the most effective tillage and crop rotation combination for each region of the state. Results showed a wide range of yield responses in corn and soybeans for different regions, which reflect the various soil and climate conditions across the state, notes Al-Kaisi.

Also, the research shows that tillage systems did not affect soybean yields after corn. Soybeans in no-till performed as good as or better than in conventional tillage systems. And it shows a reduction of $15 to $30 per acre in input costs with no-till compared to conventional tillage systems (chisel plow, deep rip and moldboard plow).

The choice of tillage for corn is more complex. “Careful consideration should be given to the soil’s long-term health and productivity as decisions are made,” Al-Kaisi says. The research demonstrated that no-till and strip till are as competitive as any conventional tillage system in well-drained soils or where field drainage is available to remove excess water in poorly drained soils with corn-soybean or continuous-corn rotation.

Benefits of no-till add up
Conservation tillage systems such as no-till have a positive impact on soil health, productivity and profitability under extreme weather events of wet or dry conditions. These systems protect soil, conserve energy and improve soil health by improving soil organic matter, Al-Kaisi says. You can get a 0.17- to 0.23-ton increase in carbon per acre per year with no-till. In addition, conservation tillage reduces costs associated with tillage operations by almost 17%.

Row cropping systems place significant stress on soil functions through tillage, chemical applications and mono-cropping systems (continuous corn). Conservation practices, including no-till, cover crops and extended crop rotations, can mitigate the negative effects on soil health and productivity. A no-till system can restore soil health over time by improving soil infiltration, organic matter, microbial diversity and soil structure.

Extended crop rotations that include small grains, legumes and cover crops will equally increase soil biodiversity, protect the soil surface physically during the off season and provide organic carbon input.

Other ways to manage corn residue
“There may be some challenges in managing corn residue, but tillage is not the answer,” Al-Kaisi says. “Modification of the planter to include residue cleaners, heavier down-pressure springs or other residue management attachments are far more cost-effective given the environmental cost and economic expense associated with conventional tillage.”

He adds, “The extended time period when the soil has no living cover or residue in Iowa presents a major environmental challenge that needs consideration when deciding on a tillage practice for fall. Tillage can contribute to the acceleration of soil and nutrient loss given the uncertainty of weather events and their variability, as demonstrated yearly and most particularly this year from an early wet season last spring to a late wet fall.”

Source: Iowa State University




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