Author
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Morris, Dolen |
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Glaz, Barry |
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DAROUB, S.H. |
Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 12/15/2003 Publication Date: 7/1/2004 Citation: Morris, D.R., Glaz, B.S., Daroub, S. Organic matter oxidation potential determination in a periodically flooded histosol under sugarcane. Soil Science Society of America Journal. Vol. 68. P. 994-1001. Interpretive Summary: Histosols in the Everglades Agricultural Area are degrading at a rate of about 1.4 cm per year, primarily from microbial activity; flooding reduces microbial activity. An experiment was set up in field lysimeters with sugarcane growing in soil to determine the best method to detect potential for reduced soil degradation under varying water table levels after flood. Treatments were: continuously drained to 50 cm water table depth, and flood for 7 days followed by drainage to 16, 33, and 50 cm water table depths for 14 days. Methods tested were radioistope C (RC), microbial respiration (RESP), and microbial biomass (MB). Increasing the water-table depth tended to decrease RC and increase MBC. Soil respiration increased sharply within 1 day after drainage, but all treatments had similar RESP within 7 days of the drain cycle. There was no relationship between RC, RESP, and MBC. Since RC was the only parameter that responded according to expected potentials based on long-term field measurements reported in the literature, RC appears to be the most useful method for short term monitoring of soil degradation potential. Technical Abstract: Histosols of the Everglades Agricultural Area (EAA) are subsiding primarily from aerobic microbial oxidation. An experiment was set up in field lysimeters with sugarcane (interspecific hybrids of Saccharum species) growing in a Histosol to determine the best method (C14 benzoate oxidation (RC), closed chamber respiration (CO2 evolution) (RESP), and microbial biomass (MBC)) to indicate short term organic matter oxidation potential and to determine the relationship between those parameter due to water table management. Treatments were: continuously drained to a 50 cm water table depth, and flooded for 7 days followed by drainage to 16, 33, and 50 cm water table depths for 14 days. Soil samples were taken from the upper 16 cm of soil during the summer growing season. Increasing the water-table depth tended to decrease RC and increase MBC. Soil respiration increased sharply within 1 day after drainage, but all treatments had similar RESP within 7 days of the drain cycle. There was no intercorrelation between RC, RESP, and MBC. Since RC was the only parameter that responded according to expected potentials based on long term field measurements reported in the literature, RC appears to be the most useful method for short term monitoring of soil organic matter oxidation potential. |