Animal manure applications can increase soil organic matter in both medium- and long-term application periods. Consequently, manure contributes to reducing soil bulk density and compaction as well as increases soil aggregate stability, water infiltration and retention.

Cornell Cooperative Extension recently sponsored the presentation “The Value of Manure in Five Stories” to present farmers with examples of how prudent application of manure can benefit their operations.

Presentation of the seminar was conducted jointly by Dr. Quirine Ketterings, professor of nutrient management, Kirsten Workman, nutrient management and environmental sustainability specialist, and Juan Carlos Ramos, an on-farm research coordinator for the nutrient management program at Cornell.

“Manure contains all 17 essential nutrients,” said Workman. “It is incredibly important to our cropping systems.”

Injection of Manure in Alfalfa/Grass Fields

According to Ketterings, this research project came about to answer two practical questions: “Will application of manure increase alfalfa and grass yields? And does injection reduce yields due to mechanical damage of the root system?”

Ketterings described the four treatments of this research: no manure addition (no slicing, no manure), “disk down, no manure” (slicing of the soil only), injection of liquid dairy manure and surface application of manure.

“We found that the application of manure resulted in increased yield, often doubling or more than doubling the yield,” she reported. She also noted that there was no difference in yields between plantings that sliced the soil and those that did not.

Chisel vs. Shallow Mixing for Corn

“More and more we talk about injection,” said Workman. “But we also want to share that you don’t have to be high tech to get your manure incorporated.”

This study compared the application of manure using both a deeper chisel toolbar and a more shallow aeration toolbar as well as a simple surface application.

“Both aeration and chisel applications gave us a yield benefit over a surface application,” Workman said.

Direct Seeding of Corn After Manure Injection

Ketterings explained, “This research was based on the questions ‘Can I just seed directly after manure injection, or do I need another tillage pass to prepare the seedbed?’”

Ketterings and her team found no difference between treatments, suggesting that farmers could plant directly after manure injection.

“This can sustain yields and conserve nitrogen while reducing soil disturbance, risk of phosphorus runoff and tillage-associated fuel, equipment and labor costs,” she added.

The value of manure in five stories

(L – R) Researchers Dr. Quirine Ketterings, Juan Carlos Ramos and Kirsten Workman

Sidedressing of Standing Corn

This trial sought to answer whether there is a net benefit to applying manure to corn crops once the plants have begun growing. According to Workman, “Trials showed that sidedressing of liquid manure increased yield beyond what could be achieved with nitrogen fertilizer.”

Furthermore, Ramos noted that “there was no yield increase due to inorganic fertilizer application” – indicating that the practice of sidedressing crops with manure might actually eliminate the need for nitrogen fertilizer in this instance.

Carryover of Yield Benefits from Corn to Alfalfa

This final study tracked five years of plantings of alfalfa directly after five years of corn plantings on the same land. The variable in this trial was that some of the corn plantings had received manure treatments while others had not.

Ketterings detailed her findings. “All of the fields [that had manure applications during their corn growing years] out-yielded the fields that had not received any manure during their corn years,” she said.

These results support the position that the benefits of manure use are not just realized in the year it is applied, but also for a number of years afterward.

“These are tremendous yield benefits,” Ketterings stated. “There were several tons of difference in the yields between the fields with manure applications versus the use of inorganic fertilizers.”

“This really shows the value of manure!” added Workman.

by Enrico Villamaino