Submitted to: American Society of Agricultural Engineers
Publication Type: Proceedings
Publication Acceptance Date: 8/1/2004
Publication Date: 8/1/2004
Citation: Raper, R.L., Schwab, E.B., Balkcom, K.S., Burmester, C.H., Reeves, D.W. 2004. Frequency of in-row subsoiling required for southeastern u.s. silt loam soils. American Society of Agricultural Engineers. ASAE Paper No. 041083. (Technical handout) August 1-4, 2004, St. Joseph, Minnesota. p. 12.
Interpretive Summary: Deep tillage, often referred to as subsoiling, is sometimes required to remove compacted soil layers and allow roots to grow unimpeded to depths sufficient to acquire soil moisture. However, subsoiling is expensive and only needs to be performed when the soil is sufficiently compacted to restrict root growth. New conservation tillage practices which restrict subsoiling to zones beneath the row could result in longer-lasting benefits for crops. An experiment was conducted in a silt loam soil in the Tennessee Valley region of north Alabama to determine how frequently the soil needs to be subsoiled when used in a conservation tillage system. Maximum soil loosening was maintained when subsoiling was conducted on an annual basis. Reduced tillage forces were also found with annual subsoiling. Crop yields, however, did not respond to subsoiling and were equivalent to those obtained with no-till systems with a cover crop. In this soil condition, plant roots weren't restricted significantly to reduce yields, partly due to the positive benefits of a cover crop and restricting wheel traffic to row middles.
Technical Abstract: For those soils that require deep tillage to alleviate soil compaction, subsoiling can be an expensive and time-consuming tillage event. Alternative tillage methods are needed which conserve natural resources without sacrificing cotton yields. An experiment was conducted in the Tennessee Valley region of north Alabama to determine how frequently deep tillage is needed to alleviate soil compaction problems in these soils. Annual subsoiling resulted in reduced bulk density compared to biennial subsoiling, triennial subsoiling, or no subsoiling. Reductions in draft force were also found for annual subsoiling. However, cotton yield results over a two-year period from tillage three-years previous, two- years previous, and one year previous found no differences in seed cotton yield.