Author
Morris, Dolen | |
GILBERT, ROBERT - EREC, BELLE GLADE, FL | |
Reicosky, Donald | |
Gesch, Russell - Russ |
Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 12/11/2003 Publication Date: 1/1/2004 Citation: Morris, D.R., Gilbert, R.A., D.C. Reicosky,and R.W. Gesch. 2004.Oxidation potentials of soil organic matter in histosols under different tillage methods. Soil Science Society of America Journal. 68:817-826. Interpretive Summary: Soils in the Everglades Agricultural Area (EAA) of south Florida, USA are decomposing at a rate of 1.3 cm ha per year due mostly to microbial activity. One way to reduce soil organic matter losses is through minimum tillage. An experiment was set up on an organic soil to determine the potentials for decomposition resulting from different tillage practices. Tillage treatments from lowest to highest soil disturbance consisted of: (1) no-till, (2) one surface scratching, (3) two surface scratchings, (4) one discing, and (5) one deep plowing. Two fields (bare fallow and plant residue covered) were utilized. Surface soil samples (0 to 15 cm) were taken on 0, 1, 4, 13, 28, and 42 days after tillage. The switchplow treatment had the greatest decomposition potential and soil microbial respiration averaged over the 42 day period compared to the other treatments. No-till tended to have the lowest decomposition potential and microbial activity. Other tillage treatment effects were intermediate depending on the field type. Influence of tillage on organic matter oxidation can persist for longer than 42 days. Adaptation of minimum tillage practices in organic soils could reduce potential for soil loss. Technical Abstract: Soils in the Everglades Agricultural Area (EAA) of south Florida, USA are subsiding due primarily to oxidation by aerobic microoganisms. One way to reduce oxidation of soil organic matter is through minimum tillage. An experiment was set up on a Histosol to determine the potentials for oxidation resulting from different tillage practices. Tillage treatments from lowest to highest soil disturbance consisted of: (1) no-till, (2) one tine implement scratching, (3) two tine implement scratchings, (4) one heavy harrow discing, and (5) one switchplowing. Two fields (bare fallow and plant residue covered) were utilized. Surface soil samples (0 to 15 cm) and all microbial measurements were taken on 0, 1, 4, 13, 28, and 42 d after tillage. The switchplow treatment had the greatest oxidation potential (C-14 oxidation of benzoate) (OP) and soil CO2 respiration (RESP) averaged over the 42-d period compared to the other treatments. No-till tended to have the lowest OP and RESP. Other tillage treatment effects were intermediate depending on the field type. Influence of tillage on organic matter oxidation can persist for longer than 42 d in some organic soils. Adaptation of minimum tillage practices in Histosols could reduce potential for C loss and thereby reduce soil subsidence. |