ARS | Publication request: Organic Soil Oxidation Potential Due to Periodic Flood and Drainage Depth under Sugarcane

Submitted to: Soil Science
Publication Acceptance Date: May 7, 2004
Publication Date: August 5, 2004
Citation: Morris, D.R., Glaz, B.S., Daroub, S. 2004. Organic Soil Oxidation Potential Due To Periodic Flood And Drainage Depth Under Sugarcane. Soil Science. 169:600-608.

Interpretive Summary: High organic matter soils in the Everglades Agricultural Area are decomposing due to microbial activity resulting in soil subsidence. Flooding helps control decomposition but may reduce crop yields. The purpose of this study was to determine organic matter decomposition potential in the upper 15 cm of soil that results from intermittent flooding in combination with different water-table depths. A 2-year study was conducted by growing sugarcane in large plastic containers located outside that were filled with an organic soil. Treatments consisted of flood for 7 days followed by drainage for 14 days to 16-, 33-, and 50-cm water-table levels below the soil surface. A continuous drain treatment to a 50-cm water table was included as a control. A radioactive carbon method was used to determine degradation potential. In the flood followed by drainage to 33- and 50-cm depths, soil organic matter degradation increased immediately upon drainage and reached a maximum after 3 to 6 days. However, degradation in the 16-cm water table depth declined during the drainage cycle. Organic soils in the Everglades may not need to be flooded to substantially reduce degradation potential.

Technical Abstract: Organic soils in the Everglades Agricultural Area (EAA) are oxidizing due to aerobic microbial activity resulting in soil subsidence. Flooding helps control oxidation but may reduce crop yields. The purpose of this study was to determine organic matter oxidation potential in the upper 15 cm of soil that results from intermittent flooding in combination with different water-table depths. A 2-year study was conducted in field lysimeters filled with Pahokee muck soil. Sugarcane (Saccharum spp.) was grown and treatments were flood for 7 days followed by drainage for 14 days to 16-, 33-, and 50-cm water-table levels below the soil surface. A continuous drain treatment to a 50-cm water table was included as a control. A substrate induced respiration method was used to estimate oxidation potential using benzoate with a 14C-carboxyl label. In the flood followed by drainage to 33- and 50-cm depths, soil organic matter oxidation potential decreased to levels similar to flood, but increased immediately upon drainage and reached a maximum after 3 to 6 days. However, oxidation potential in the 16-cm water table declined during the drainage cycle. Histosols in the EAA may not need to be submerged continuously to substantially reduce oxidation potential.