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2005 Annual Report: Effect of Changing from No-till to Chisel Disk Tillage System on Corn and Soybean Yields


A tillage pan existed at this plot site in 2004. Soybean yields at the site were less than 20 bushels per acre. Water management and compaction are always a concern of growers in the Missouri river bottom regarding heavy, clay soils. The demonstration was designed to show the impact of breaking up the tillage pan.

Materials and Methods

The plots were fall chiseled twice in the fall of 2004 and no-till plots remained unchanged. Both corn and soybean demonstrations were established.

Crop Management Info
Planting Date: May 5, & May 20, 2005
Herbicides: Dual + Atrazine for corn Roundup for soybeans
Hybrid: Golden Harvest H9359 corn Garst 120310 soybeans
Insecticides: Lorsban on corn
Population: 28,500 seeds/acre corn 162,000 seeds/acre soybeans
Row Width: 30-inch

Demonstration Design
Replications: 6
Design: Randomized Block
Size: 15 X 50
Statistics: Analysis of Variance


The effect of compaction on crop yields is difficult to predict. The low soybean yields of the previous season, in my opinion, were from compaction and low soil test pH. The plot area was very compacted. However, the results from corn and soybean plots indicate that compaction did not impact yield this season.

Crop yields are affected by compaction during planting by the placing and covering of the seed. Secondly, in very wet springs, water pools in the compacted area and we may have stand loss which can reduce yield. Thirdly, when the soils turn dry during the growing season, plant roots have a difficult time penetrating and passing through a compaction layer. Good soil moisture through the season generally lessens the effect of any tillage pan.

The results indicate a trend in both tillage systems of lower yields after tillage but the results were not significant. No-till creates better soil structure than tilled fields and once no-till is disturbed, the soil must go through the process of rebuilding the structure. The yield differences are typical of long-term tillage systems demonstration at Graves/Chapple Farm. Also, data in Nebraska and Iowa show a similar no-till yield advantage.

The soil pH of the area ranges from 5.2 to 5.4. An area next to this location has been devoted to a no-till liming demonstration.