Paratilling frequency effects on runoff and soil loss for no-till systems in TN Valley region of AL.

Authors: Truman, Clinton; Schwab, Eric; Raper, Randy; Balkcom, Kipling

Submitted to: Annual Southern Conservation Tillage Conference for Sustainable Agriculture
Publication Type: Abstract Only
Publication Acceptance Date: 7/15/2005
Publication Date: 7/20/2005
Citation: Truman, C.C., Schwab, E.B., Raper, R.L., Balkcom, K.S. 2005. Paratilling frequency effects on runoff and soil loss for no-till systems in TN Valley region of AL. IN: Southern Conservation Tillage System Conference. Clemson University, Florence, South Carolina, 06/27-29/2005. P213.

Interpretive Summary: Erodible soils of the Tennessee River Valley in northern Alabama are susceptible to soil consolidation and compaction, especially under conservation tillage systems. Paratilling, a non-inversion deep tillage technique, eliminates soil consolidation and compaction in conservation tillage systems, yet is expensive and time-consuming. We quantified runoff and sediment yields associated with time since paratilling in no-till (NT) systems on a Dewey silt loam. Five NT treatments representing paratilling (P) frequency were evaluated: NT without paratilling (NT-P), NT with paratilling 6 months previous (NT+P6), NT with paratilling 18 months previous (NT+P18), NT with paratilling 36 months previous (NT+P36), and NT with paratilling 42 months previous (NT+P42). Infiltration and runoff decreased and increased respectively with decreased paratilling frequency. Differences between infiltration and runoff percentages for a given treatment ranged from 55% (NT+P6) to 0% (NT-P). Maximum runoff rate steadily increased with decreased paratilling frequency, ranging from 19 (NT+P6) to 40 mm/h (NT+P42), and significantly increased with decreased partilling frequency for the first 36 months. No significant trends were found between paratilling frequency and soil loss, however, the NT-P treatment had the greatest soil loss, soil loss rate, and shortest time to maximum soil loss rate compared to other paratilled NT treatments. Paratilling soils in the Tennessee valley is a beneficial practice for farmers of this region because paratilling increases infiltration and decreases runoff, thus promoting efficient water utilization.

Technical Abstract: Erodible soils of the Tennessee River Valley in northern Alabama are susceptible to soil consolidation and compaction, especially under conservation tillage systems. Paratilling, a non-inversion deep tillage technique, eliminates soil consolidation and compaction in conservation tillage systems, yet is expensive and time-consuming. Our objective was to quantify runoff and sediment yields associated with time since paratilling in no-till (NT) systems on a Dewey silt loam. Five NT treatments representing paratilling (P) frequency were evaluated: NT without paratilling (NT-P), NT with paratilling 6 months previous (NT+P6), NT with paratilling 18 months previous (NT+P18), NT with paratilling 36 months previous (NT+P36), and NT with paratilling 42 months previous (NT+P42). NT plots had winter fallow (no cover crops) which was burned down with Roundup prior to simulating rainfall. Rainfall simulation plots (6-m2, 2 m wide x 3 m long) were established on three (of four) NT treatments, and exposed to simulated rainfall (50 mm h-1 for 60 min). Infiltration and runoff, each expressed as a percent of rainfall, decreased and increased respectively with decreased paratilling frequency. Differences between infiltration and runoff percentages for a given treatment ranged from 55% (NT+P6) to 0% (NT-P). Maximum runoff rate (Rmax) steadily increased with decreased paratilling frequency, ranging from 19 (NT+P6) to 40 mm/h (NT+P42). Rmax values significantly increased with decreased partilling frequency for the first 36 months. No significant trends were found between paratilling frequency and soil loss, however, the NT-P treatment had the greatest soil loss, soil loss rate, and shortest time to maximum soil loss rate compared to other paratilled NT treatments. Paratilling soils in the Tennessee valley is a beneficial practice for farmers of this region because paratilling increases infiltration and decreases runoff, thus promoting efficient water utilization.