Dickinson Research Extension Center in southwestern North Dakota has consistently found no-till to be a clear advantage for producers who use it in their rotational cropping systems.
Pat Carr, NDSU agronomist at DREC, said they have been researching tillage for a long time at the center. In fact, their numerous studies on the impact of tillage in rotations have been ongoing since a year after he arrived at the center in 1993.
In one study conducted from 2000 to 2005, the center looked at the impact of different types of tillage systems “in a very simple rotation” on wheat performance, Carr said. The three tillage systems they used were clean-till (conventional till), reduced-till, and no-till. The rotation was either a wheat-pea or a wheat-wheat rotation.
The tillage systems were actually put in place in the early ’90s, and different studies grew out of those established systems.
“We found a huge impact on wheat performance when you eliminated tillage from the rotation,” Carr said.
Carr pointed out that over the years of the study, the more tillage was removed from the rotation, the higher the yields were. “We always saw a positive impact as we eliminated tillage,” he said.
The year 2005 was the one exception.
For the most part, Carr said they saw a 12 bushel-per-acre increase in yield when going from reduced or clean-till to no-till.
Working with soil scientists at the ARS Northern Great Plains Laboratory in Mandan, N.D., Carr said they discovered that the benefits of soil biology occurred when producers used no-till systems. Even in dry years, they were finding soil biological activities increasing under no-till systems.
“We saw from a 20 percent to a 70 percent yield increase just because of no-till,” Carr said.
While they didn’t have a soil microbiologist working with them in the early 2000s, they attributed yield increases in the dry years to the better crop stand establishment that occurred in a no-till system.
“From 2000 to 2004, we had some dry years, but we had much better crop stands with the no-till,” he said.
Soil moisture was also impacted with no-till. They were able to reduce evaporation, particularly evaporation closer to the surface, with the no-till system.
“But we definitely saw a reduced grain protein with wheat in the no-till plots compared with the clean-till plots,” he said, adding that was more than likely because they had not corrected their fertilizer strategy to function in a no-till system.
Beginning in 1910, hard red spring wheat yields began increasing at the center from 17.2 bushels per acre to 48.6 bushels per acre in 2010.
Carr said the center has kept 100 years worth of HRSW trial data and has studied the differences through the decades. The introduction of fertilizer and herbicides in the ’80s saw a large jump in yields and there was an even bigger yield increase in the ’90s when the center went from a clean tillage system to no-till, Carr added.
“When we moved to no-till, yields significantly increased from 36 to 49 bushels per acre,” Carr said. “That is due to management, and maybe, a little to genetics.”