An article in the July 2015 issue of Agronomy Journal entitled “A comparison of soil properties after five years of no-till and strip-till” by Fernández, Sorensen, and Villamil presents some interesting results that are pertinent to conservation tillage methods that are used for crop production.

No-till (NT) has been adopted by many producers of major row crops in the US. Increased residues that lead to increased soil organic matter (SOM), lowered labor and input costs, and less erosion are major benefits that have led to the increased adoption of NT crop production systems.

An alternative to strict NT is the use of a strip-till (ST) system, where tillage is performed in the crop row without disturbing the soil and residue in the between-row areas. This minimum tillage system improves seedbed conditions in the row while lowering the risk of erosion from a field as a whole because the soil and residue in the between-row areas are not disturbed.

The study described in the above article was conducted at Urbana, IL on a site that was mostly silt loam, with a smaller area of silty clay loam soil. Data were collected in 2012 and 2013 following 5 years of NT and ST treatments being in place.

In the NT treatment, no soil disturbance occurred before planting operations. In the ST treatment, tilled strips were placed in the same location each year using an RTK guidance system.

Appropriate fertilizer amounts were applied to the surface of the NT plots, and in a 4-in.-wide, 6-in.-deep tilled band directly beneath the crop row in the ST treatment. The planting operation in the ST treatment disturbed a band of soil about 6.5 in. deep and about 1.5 in. wide at the bottom and about 10 in. wide on the soil surface. Row spacing was 30 in.

A summary of results follows.

• Corn grain yield in the ST treatment (152.6 bu/acre) was 9% greater than yield in the NT treatment (140 bu/acre) over the 2007-2013 period of the study.


• Soil organic matter in the ST treatment (3.8%) was 8.6% greater than in the NT treatment (3.5%) at the end of the 7 years. The greater amount of residue from the higher ST yield likely contributed to this higher SOM content in the ST treatment.


• Penetration resistance (PR) in the tilled zone in ST was reduced 45% in the 0-2 in. soil depth and 27% in the 2-4 in. soil depth compared to the NT treatment. This indicates an improved rooting environment in ST compared to NT in the soil zone where most roots are present and where a majority of nutrient uptake occurs.


• There was no difference in PR between ST and NT in the 4-12 in. depth, which indicates that the tillage operations in the ST treatment did not create a compaction layer.


• Soil bulk density (BD) was lower in the ST (1.35 g/cm³) than in the NT treatment (1.4 g/cm³). This is likely related to the lower PR and higher SOM in the ST treatment.

The authors conclude that these results demonstrate that ST can be used as an alternative to NT as a conservation tillage system to improve soil properties.

These results are especially cogent when coupled with the ability to plant in the same row position or in consistent repeated planting patterns in the same field from year to year as allowed by present and improving precision guidance technologies.

It is likely that these results are not directly transferrable to Midsouth conditions, but for different reasons that may offset each other. First, SOM in Midsouth soils will have neither the magnitude nor response of SOM in this study. Second, ST in Midsouth soils likely will have a greater effect on BD in the tilled zone than in the above study because of the much lower inherent SOM that is present. Therefore, it is probably safe to say that ST in Midsouth soils should be considered as an alternative to NT until Midsouth research dictates otherwise. This is especially so since ST apparently does not negate the major benefits that are associated with NT; i.e., ST is considered an acceptable conservation tillage system.

Composed by Larry G. Heatherly, Aug. 2015, larryheatherly@bellsouth.net