Soil sodicity: Its influence on cane yield in the Burdekin

Soil sodicity is known to reduce cane yields, but little quantitative information is available, especially for areas depending on irrigation. The aim of this study was to determine the influence of sodicity on cane yield in the Burdekin district. Seventeen sites with variable sodicity were chosen throughout the district. At each site, cane yield was measured in plots 3 rows wide by 20 or 30 m long. Soil salinity was measured at all sites and sodicity was measured at six sites. Over all measured sites, cane yield was reduced by approximately 2.4 t/ha for every 1% increase in exchangeable sodium percentage (ESP) in the subsoil. There was also a significant negative correlation between yield and salinity. The effect of sodicity on yield was greater than that measured previously in Mackay, primarily because potential yield at low ESP was greater in the Burdekin.