Root growth of sugarcane irrigated with wastewater through subsurface drip system

Abstract

The use of wastewater in agriculture is an alternative to provide water and nutrients for plants.  However, root system development can be affected by water quality and depth of wastewater applied.  The objective of this study was to evaluate the sugarcane root system growth using a minirhizotron in a field irrigated with treated sewage effluent and freshwater by subsurface drip irrigation.  The treatments tested were two drip line installation depths (0.2 and 0.4 m); two water sources (treated sewage effluent and freshwater) and non-irrigated plots as control.  The experiment was a randomized block design with a 2×2 + 1 factorial, with three replications.  The root system evaluation (root length and spatial distribution) was performed using a minirhizotron with an access tube buried in the soil profile and installed on a 45 degree angle.  The soil moisture was determined using the time-domain reflectometry technique.  The lowest moisture on the soil surface resulted in the highest root length density (0.18 cm cm^-2) at the non-irrigated plots (p>0.05).  The application of treated sewage effluent and the installation depth of drip line did not change the root length of sugarcane in first ratoon (p>0.05).  Eighty percent of the root system was accumulated from the soil surface to 0.45 m.