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United States Department of Agriculture

Agricultural Research Service

Title: Soil Penetrometer Resistance and Corn Yield under Tilled and No-Till Soil Management

Authors
item Riedell, Walter
item Pikul Jr, Joseph
item Osborne, Shannon
item Schumacher, Thomas - SOUTH DAKOTA STATE UNIV

Submitted to: State University Ag Report
Publication Type: Experiment Station
Publication Acceptance Date: February 23, 2005
Publication Date: March 15, 2005
Citation: Riedell, W.E., Pikul Jr, J.L., Osborne, S.L., Schumacher, T. 2005. Soil penetrometer resistance and corn yield under tilled and no-till soil management. South Dakota State University Soil/Water Research Report, Soil PR 04-40. Available http://plantsci.sdstate.edu/soiltest/data2004/PR%2004-40%20FinalSDSU2004AnnualSWReport.pdf.

Interpretive Summary: No-till soil management is an excellent way to reduce soil erosion by wind and water. However, reports in the literature indicate that soil penetrometer resistance is initially higher in no-till soils than in tilled soils. Increased mechanical impedance can create unfavorable growing conditions for crop roots which in turn can cause crop yield reductions. We were interested in determining if no-till shows the same effect on soils common to eastern South Dakota. We also wanted to determine if grain yield is affected by differences in soil penetrometer resistance. We conducted experiments on long-term tillage/rotation plots at Eastern South Dakota Soil and Water Research Farm on a Barnes sandy clay loam soil. Soil penetrometer resistance was greatly affected by tillage, with no-till plots having greater penetrometer resistance values than tilled plots at all soil depths studied. Grain yield was negatively correlated with soil penetrometer resistance. These data reveal the importance of minimizing soil compaction, especially when using no-till soil management. One way to minimize soil compaction would be to control wheel traffic so all tire/track passes for field operations occur in the same path.

Technical Abstract: No-till soil management is an excellent way to reduce soil erosion by wind and water. However, reports in the literature indicate that soil penetrometer resistance is initially higher in no-till soils than in tilled soils. Increased mechanical impedance can create unfavorable growing conditions for crop roots which in turn can cause crop yield reductions. Because of this, we were interested in determining if no-till shows the same effect on soils common to eastern South Dakota. We also wanted to determine if grain yield is affected by differences in soil penetrometer resistance. We conducted experiments on long-term tillage/rotation plots at Eastern South Dakota Soil and Water Research Farm on a Barnes sandy clay loam soil. Soil penetrometer measurements were taken in non-wheel track rows at the corn sixth leaf development stage. Soil penetrometer resistance was greatly affected by tillage The fall chisel plow and spring disk operations conducted on the research plots were designed to mix and loosen the soil to a depth of about 15 cm (6 inches). Data from the tilled plots shows a relatively low penetration resistance in the top portion of the soil profile (1 to 3 cm depth) followed by a gradual increase in resistance with increasing depth to about 17 cm. This region of higher penetrometer resistance likely indicated the presence of a plow pan. These measurements from 1 to 15 cm depth were much lower than equivalent depths in no-till plots. Starting at about 20 cm depth in the tilled plots, the penetration resistance slightly decreased and then slightly increased as the depth approached 60 cm (24 inches). Only at the deepest depths did the penetration resistance exceed 1.4 megapascal. Thus root penetration in the tilled plots should have been un-impeded to a depth of about 50 cm. Contrary to the tilled plots, soil penetration resistance in the no-till plots was relatively uniform in the top 15 cm of the soil profile (Fig. 1). Starting at about 20 cm depth, the penetration force in no-till plots steadily increased to a depth of 60 cm. Soil bulk density and soil moisture measurements taken in tilled and no-till plots reveal higher bulk density and equal soil moisture at the 30 cm depths (data not shown). The penetration resistance in no-till plots was very close to 1.4 megapascal in the top 30 cm, while at deeper depths it approached 2.3 megapascal. Thus it appears that no-till plots had a greater level of deep soil compaction (below 30 cm soil depth) than tilled plots. The data presented in this report do not allow speculation as to the cause of this deep soil compaction. However, it is possible root penetration in no-till plots could have been impeded, especially at depths greater than 30 cm. Other measures of root growth at various soil depths would be needed to confirm this hypothesis. The relationships between soil penetrometer resistance at different soil depths and corn grain yield were investigated by calculating Pearson’s correlation coefficients. Our data, which show a negative correlation between soil penetrometer resistance and grain yield, reveal the importance of minimizing soil compaction, especially when using no-till soil management.

Last Modified: 12/21/2014