Sugarcane Photosynthesis, Transpiration, and Stomatal Conductance Due to Flooding and Water Table

Abstract

Sugarcane (Saccharum spp.) is the primary crop on the Histosols of the Everglades Agricultural Area (EAA), where periodic floods and undesirably high water tables are increasing in occurrence and duration. Improved understanding of the physiologic responses of sugarcane to these conditions could help develop strategies to sustain high yields. The purpose of this study was to evaluate the effects of periodic flooding followed by drainage to different depths on single‐leaf net photosynthetic rate (Ps), transpiration (Ts), and stomatal conductance (SC) of sugarcane. In 2000 and 2001, two sugarcane genotypes were planted as split plots in 12 lysimeters filled with Pahokee muck soil. Responses of Ps, Ts, and SC to four water‐table treatments were measured for four 21‐d cycles each year. Three treatments consisted of 7‐d flooding followed by 14‐d drainage to depths of 16, 33, or 50 cm. The fourth treatment was a continuous 50‐cm water table. Analyses of individual cycles and analyses repeated over cycles generally identified neutral or positive responses of Ps, Ts, or SC to flood. Drained water‐table depth did not consistently affect Ps, Ts, or SC, but when differences occurred, 16 cm was often a favorable drainage depth. These neutral and sometimes positive responses to short‐duration flood or long‐duration high water tables support previous reports of acceptable and sometimes enhanced yields from sugarcane exposed to high water tables. Previous findings were supported that time of formation of stalk aerenchyma in sugarcane may be a key factor for sustaining high yields after exposure to flood.