Soil compaction management in the southeastern USA typically relies heavily on the practice of annual deep tillage. Strip tillage systems have shown considerable promise for reducing energy and labor requirements, equipment costs, soil erosion, and cotton plant damage from blowing sand. Replicated field trials were conducted for three years in South Carolina, to compare the performance of three different strip tillage systems to conventional tillage and no-till methods. A second objective was to investigate whether the frequency of deep tillage can be reduced by planting cotton directly using controlled wheel traffic into the previous year’s subsoiler furrow. Tillage treatments included: conventional tillage (disk-subsoil-bed), straight shank strip-till, bent-leg shank strip-till (Paratill), bent-leg shank strip till (Terra Max), and no-till. Deep tillage was performed in all plots the first year. In years two and three, the plots were split and half received annual deep tillage and the other half were not deep tilled either year. Tillage methods were compared side by side with and without irrigation. Deep tillage reduced soil compaction and increased taproot length and cotton yields than the no-till system. There was no difference in cotton lint yield between the strip-till systems and conventional tillage in either dry land or irrigated plots. Deep tillage increased cotton lint yields compared to no-till. There was no difference in lint yield between plots which were deep-tilled in all three years with those which had tillage operation only in first year of the test. Dry matter partitioning at first bloom was reduced in plant height, total dry weight, and leaf area in strip-till and no-till production systems compared to the conventional tillage system. The results suggest that all three strip tillage systems are equally effective for cotton production and that annual deep tillage is not necessary if controlled traffic is employed.
Nationwide farmers across the U.S. lose over $1 billion in crop revenues every year due to the effects of soil compaction [
Conventional cotton production systems in the Southeastern U.S. typically involve three to five field operations at a cost of approximately $90 per hectare [
Deep tillage on these soils can be accomplished with implements that have either straight or bent-leg shanks. Bent-leg implements, such as Paratill and Terra Max, are commercially available for crop production. Previous research in South Carolina has shown that bent-leg shanks loosened a greater volume of the compacted layer compared to the straight-legged shanks [
There is a great interest in reducing the frequency of deep tillage to reduce horsepower requirements and fuel costs associated with tillage operations. Research in selected sandy soils in South Carolina has shown reconsolidation of the hardpan layer from one season to another [
Therefore, research is needed to evaluate and compare the effects of bent-leg strip, straight shank strip, conventional, and no tillage systems on cotton production under irrigated and dryland regimes. The residual effects of these tillage methods under a controlled traffic scenario on cotton production also need to be determined.
The objectives of this study were: 1) To evaluate the performance of three different strip tillage systems compared to conventional and no-till methods in terms of effects on soil parameters, crop growth and development, and tractor energy requirements; and 2) To investigate whether the frequency of deep tillage can be reduced by planting cotton directly into the previous year’s subsoiler furrow using controlled traffic.
Four units of the Unverferth strip attachment (Unverferth Manufacturing Co, Inc., Kalida, OH) were installed on a special toolbar which could be mounted behind 4-row tillage equipment (
wide compared to 38 cm wide disrupted zone for the Terra Max.
Field studies were conducted for three years (2002-2004) at the Edisto Research & Education Center (Edisto REC), located in Barnwell County, SC. The soil type was Varina loamy sand (Fine, kaolinitic, thermic Plinthic Paleudults), a typical Coastal Plain soil. The experimental design was a split-plot design with main plots being tillage and subplots being subsoiling frequency, with four replications.
The main plots consisted of:
1) Conventional tillage (2 × disk + subsoil-bed + crop planting)
2) Straight shank strip-till system (KMC, 0 degree orientation to vertical)
3) Bent-leg shank strip-till system (Bingham Paratill, 45 degree orientation to vertical)
4) Bent-leg shank strip-till system (Worksaver Terra Max, 15 degree orientation to vertical)
5) No surface or deep tillage (no-till).
The subplots consisted of deep tillage every year or deep tillage during the first year only. Subplot size was four 1-m wide rows that were 30 m long. To determine the effects of irrigation on reconsolidation of the hardpan layer, identical experiments, one with and one without irrigation, were conducted adjacent to each other. However, in 2003 and 2004, sufficient precipitation occurred so that no irrigation events occurred in those years.
Cotton was planted and grown each year and managed according to recommended Extension practices for seeding, fertilization, insect, and weed control. Tillage operations were done in early May each year. Cotton variety DP 458 BG/RR (Delta Pine and Land Co., St. Louis, MO) was planted on May 8th in 2002. Cotton variety DP 555BG/RR (Delta Pine and Land Co., St. Louis, MO) was planted on May 7th, 2003 and May 14th, 2004, respectively. These two cotton varieties contained in-seed protection against bollworm (Helicoverpa zea) damage (Bollgard [BG]) and tolerance to topical applications of glyphosate herbicide (Roundup Ready [RR]). All plots were planted using a 4-row John Deere MaxEmerge 2 planter (John Deere Co., Moline, IL).
Soil compaction was measured in each plot to a depth of 46 cm using a microcomputer-based, tractor-mounted, recording penetrometer [
Cotton height, taproot length, root dry weight, seedling population, total dry weight, leaf area index were collected during the growing season, around first bloom. Yield was collected around mid-October every year, using a cotton spindle picker equipped with sacking attachment and weighing system. Seed cotton samples were collected from each plot and ginned (seeds and plant residue removed) to determine percent lint content.
An instrumented John Deere tractor [
Cotton taproots measured six weeks after planting were longer in all plots receiving subsoiling than in the no-till plots. This occurred in both the irrigated and the dry land experiments (
No differences in plant stand were observed among the tillage treatments, with all plots ranging between 12 and 16 plants/m2. First bloom dry matter
partitioning data showed a reduction in the growth and development of cotton grown in strip-till and no-till production systems compared to the conventional system. Total plant dry weight was reduced 19% to 43%, stem dry weight was reduced 21% to 47%, leaf dry weight was reduced 18% to 38%, and leaf area index was reduced 19% to 37% at first bloom. Reproductive development was also affected by tillage system. Plants grown with conventional tillage had more
Cotton | ||||
---|---|---|---|---|
Water Regime | Tillage Treatments | Plant Height (cm) | Taproot length (cm) | Root Dry weight (g) |
Irrigated | Conventional Tillage | 99 a* | 40 a | 32.8 a |
Straight Shank Strip-till | 109 a | 40 a | 35.5 a | |
Paratill, Bent-leg Shank Strip-till | 104 a | 40 a | 33.9 a | |
Terra Max, Bent-leg Strip-till | 99 a | 39 a | 32.8 a | |
No-Till | 71 b | 18 b | 25.4 b | |
Dry Land | Conventional Tillage | 88 a | 34 a | 30.1 a |
Straight Shank Strip-till | 85 a | 34 a | 28.6 a | |
Paratill, Bent-leg Shank Strip-till | 83 a | 35 a | 28.3 a | |
Terra Max, Bent-leg Strip-till | 85 a | 35 a | 28.1 a | |
No-Till | 71 b | 14 b | 14.8 b |
*Values in a column, within a water regime, followed with the same letter are not significantly different (LSD, α = 0.05).
squares (17% to 38%) and partitioned more of their dry weight into squares compared to plants grown in strip-till or no-till systems. However, these differences in early-season growth and development did not result in differences in yield. Tillage systems had no effect on fiber quality in 2002 (
There was no difference in cotton lint yield between the strip-till systems and conventional tillage in either dry land or irrigated plots in 2002 (
Treatments | Gin Turnout (%) | Micronaire | Length (cm) | Strength (g/tex) | Uniformity | Elongation |
---|---|---|---|---|---|---|
Conventional | 39.8 a* | 5.1 a | 2.69 a | 29.6 a | 81.3 b | 8.3 a |
Straight Shank | 39.8 a | 5.0 a | 2.74 a | 30.1 a | 81.9 b | 8.6 a |
Paratill | 39.6 a | 5.2 a | 2.64 a | 28.9 a | 81.6 b | 8.4 a |
Terra Max | 39.0 a | 5.2 a | 2.64 a | 28.7 a | 81.4 b | 8.2 a |
No-Till | 40.9 a | 5.1 a | 2.72 a | 30.6 a | 82.8 a | 8.5 a |
*Values in a column, followed with the same letter are not significantly different (LSD, α = 0.05).
compared to deep tillage only in 2002.
In 2003, we had about 75 cm of rain during growing season compared to average rainfall of 51 cm for the same period. Therefore, irrigation was not applied to “irrigated” plots at the Edisto REC. Since there was no difference in lint yield between dry land and irrigated plots the yield data were averaged over 8 replications. There was no difference in lint yield between cotton planted back into the previous year’s subsoil furrows compared to an annual deep tillage operation (
Cotton taproots measured six weeks after planting were longer in all plots receiving subsoiling than in the no-till plots. This occurred in both experiments, which received tillage operations either in 2002 only or in both 2002 and 2003. Similar results were obtained with total root dry weight for plots, which was tilled only in 2002 (
Tillage Frequency | Treatments | Micronaire | Length (cm) | Strength (g/tex) | Uniformity | Elongation |
---|---|---|---|---|---|---|
Tillage in 2002 only | Conventional | 4.3 a | 2.77 a | 27.3 a | 82.7a | 8.4 a |
Straight Shank | 4.3 a | 2.78 a | 27.3 a | 81.8 a | 8.5 a | |
Paratill | 4.6 a | 2.74 a | 26.8 a | 81.7a | 8.3 a | |
Terra Max | 4.4 a | 2.77 a | 27.2 a | 80.8a | 8.3 a | |
No-Till | 4.4 a | 2.71 a | 26.4 a | 80.8 a | 8.3 a | |
Tillage in both 2002 and 2003 | Conventional | 4.4 a | 2.77 a | 27.6 a | 81.9 b | 8.3 a |
Straight Shank | 4.3 a | 2.73 a | 27.1 a | 81.3 b | 8.0 a | |
Paratill | 4.4 a | 2.78 a | 27.9 a | 82.1 b | 8.0 a | |
Terra Max | 4.3 a | 2.76 a | 28.0 a | 82.2 b | 8.2 a | |
No-Till | 4.5 a | 2.74 a | 27.5 a | 80.7 a | 8.2 a |
*Values in a column, within a tillage frequency, followed with the same letter are not significantly different (LSD, α = 0.05).
Treatments | Tillage Frequency | ||||
---|---|---|---|---|---|
Tillage in 2002 only | Tillage in both 2002 and 2003 | ||||
Length (cm) | Weight (g) | Length (cm) | Weight (g) | ||
Conventional | 38.9 a | 22.7 a | 41.6 a | 26.5 b | |
Straight Shank | 38.4 a | 21.7 a | 40.2 a | 27.2 b | |
Paratill | 39.2 a | 25.9 a | 41.0 a | 33.9 a | |
Terra Max | 38.8 a | 25.9 a | 40.3 a | 32.7 a | |
No-Till | 18.6 b | 14.1 b | 19.9 b | 8.3 c | |
*Values in a column, followed with the same letter are not significantly different (LSD, α = 0.05).
100 kg/ha compared to tillage every three years. This is due to the lower soil compaction values (20% lower) in the crop rows for the annual tillage treatments. In 2004, we had about 61 cm of rain during growing season (10 cm above the average rainfall). Therefore, irrigation was not applied to “irrigated” plots at the Edisto REC. Since there was no difference in lint yield between dry land and irrigated plots the yield data were averaged over 8 replications. Again, deep tillage increased lint yield compared to no-till plots. The average yield increase was 45%.
An instrumented John Deere tractor was used to make in field measurements of tractor fuel consumption, ground speed, wheel slip, and draft requirements of different tillage treatments. All energy measurements were collected at 7.6 km/h ground speed and 38-cm tillage depth.
Similar to 2003 results, cotton taproots measured six weeks after planting were longer in all plots receiving subsoiling (subsoiled either only in 2002 or in every year) than in the no-till plots. Similar results were obtained with total root dry weight for plots which were tilled only in 2002 (
Deep tillage systems reduced soil compaction and increased taproots length and
Treatments | Tillage Frequency | ||||
---|---|---|---|---|---|
Tillage in 2002 only | Tillage in 2002, 2003, and 2004 | ||||
Length (cm) | Weight (g) | Length (cm) | Weight (g) | ||
Conventional | 37.6 a | 33.1 a | 42.9 a | 32.2 b | |
Straight Shank | 37.2 a | 34.9 a | 42.7 a | 32.8 b | |
Paratill | 37.9 a | 34.6 a | 44.1 a | 39.8 a | |
Terra Max | 37.5 a | 32.3 a | 43.5 a | 39.1 a | |
No-Till | 17.3 b | 25.1 b | 20.4 b | 25.2 c | |
*Values in a column, followed with the same letter are not significantly different (LSD, α = 0.05).
cotton yields compared to no-till system. There was no difference in cotton yield between the strip-till systems and conventional tillage in either dry land or irrigated plots. Deep tillage increased lint yields compared to no-till. Averaged over all treatments, irrigation increased lint yields by 77% compared to dry land in a dry year (2002). There was no difference in lint yield between plots which had deep tillage operation in all three years with those which had tillage operation only in first year of the test. Therefore, with controlled traffic and planting directly into the previous year’s subsoiler furrow, the residual effect of deep tillage operations could extend for one or two additional years in coastal plain soils without causing farmers a loss of crop yield. Dry matter partitioning data collected at first bloom showed a reduction in the growth and development of plants grown in strip-till and no-till production systems compared to the conventional system.
Technical Contribution No. 6577 of the Clemson University Experiment Station. This material is based upon work supported by NIFA/USDA, under project number SC-1700540. The authors also acknowledge the funding support of the SC Cotton Board and the Clemson Public Service Activities.
Mention of a trade name does not imply endorsement of the product by Clemson University or the USDA to the exclusion of others that might be suitable.
Khalilian, A., Jones, M.A., Bauer, P.J. and Marshall, M.W. (2017) Comparison of Five Tillage Systems in Coastal Plain Soils for Cotton Production. Open Journal of Soil Science, 7, 245-258. https://doi.org/10.4236/ojss.2017.710018