Tillage – Yield Booster Or Penalty? South Dakota Adds To Debate.

Tillage, pre-plant land preparation. ©Debra L Ferguson Stock Photography

The discussion of grain yields and different tillage practices needs to start in producers’ fields. Grain yield comparisons and results from un-biased research are very important for making agronomic decisions that include tillage; however, producers need to put these practices to work in everyday situations across large acres to consider a practice worthy in modern agriculture.

Today, many producers are concerned with soil health. Experts in soil health have identified that it should first start with one big change, i.e. very reduced tillage or better yet, ceasing tillage, ultimately no-till. No-till is used on 45% of South Dakota croplands (The 2017 South Dakota Cropping Systems Inventory, USDA-NRCS/SD). The Eastern 25% of South Dakota has not fully adopted no-till (less than 25% of the area under no-till), despite growers in these areas that have demonstrated its success.

2017 Yield Contest Findings

The 2017 corn and soybean yield contest results show that no-till and conservation farming practices do bring successes. In 2017, both the corn and soybean yield contests offered specific categories based on tillage practices.

CLICK IMAGE TO ENLARGE: Figure 1. 2017 Corn and Soybean Yield Contest Winners.
Top-3 place winners in each non-irrigated classes.

In the Soybean contest sponsored by the South Dakota Soybean Association and the South Dakota Soybean Research and Promotion Council, overall average no-till soybean yield was only 1.93 bushels less than the tilled category (Table 1). The tilled entries gave more yield in the maturity group 0 and I categories while the no-till entries had more yield in the maturity group II and III.

In the 2017 corn yield contest sponsored by SDCORN and the National Corn Growers Association, the overall average for the no-till category was 8.9 bushels greater than the tilled category (Table 2).

Winner Demographics
The demographics for the yield contest winners were very interesting. All but two no-till entries for both corn and soybeans were from the Eastern 25% of South Dakota, which has the lowest rate of no-till adoption (Figure 1). The last year’s yield contest winners showed strong evidence that when managed properly, no-till and conservation cropping systems are very successful in the Eastern Regions of South Dakota.

Table 1. Average yield of top three winners from each maturity group (non-irrigated) in 2017 South Dakota Soybean Yield contest.
Tillage Method
Soybean Maturity Group
Tilled 75.21 77.28 74.62 69.30 74.10
No-Till 70.60 71.80 74.82 71.45 72.17
Table 2. Average yield of top three winners from each tillage group (non-irrigated) from the 2017 South Dakota Corn Yield contest.
Tillage Method Overall Average
—- bu/a —-
Tilled 266.5
No-till/Strip Till 275.4

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