|Daroub, S - UNIV OF FL EREC|
Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 9, 2002
Publication Date: November 13, 2002
Citation: Morris, D.R., Glaz, B.S., Daroub, S. 2002. Soil organic matter oxidation potential with fluctuating water table under sugarcane. Agronomy Abstracts. CDR S05-morris084233-O. Technical Abstract: Histosols in the Everglades Agricultural Area are subsiding primarily from aerobic microbial oxidation. Flooding reduces soil subsidence. An experiment was set up in lysimeters with sugarcane growing in muck soil to determine oxidation potential 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. Parameters measured were organic matter oxidation potential (OP) using benzoate with a C14 carboxyl label, soil respiration (CO2 evolution) (RESP), microbial biomass C (MBC), and soluble organic carbon (SOC) in the 0 to 16 cm surface horizon. With flood followed by drainage to 16 or 33 cm water table there was little affect on OP. Apparently soils were saturated sufficiently to inhibit OP. RESP was similar for all drained treatments. There was a large flux in CO2 within 24 hrs after drainage likely due to air drawn into soil voids as water was being drained. MBC increased in all drainage treatments up to 7 d after drainage, with a tendency to be more MBC with higher water table levels even though SOC decreased after flooding for the drained treatments. Correlation analysis indicated the OP was negatively correlated with SOC. RESP and MBC were neither intercorrelated nor correlated with OP or SOC. It appears that soils do not have to be flooded to obtain oxidation potentials similar to flood, and that the C14 method appears best for monitoring oxidation potential in organic soils.