Effects of Treflan injection on winter wheat growth and root clogging of subsurface drippers

Abstract

Abstract The clogging of drippers caused by crop root intrusion has been a great concern of subsurface drip irrigation (SDI) systems. To attempt to solve the problem of root clogging of drippers, a series of field experiments were conducted in the growing seasons of 2006–2008. The goal was to investigate the effects of Treflan injection on dripper clogging by roots, and on root distribution, yield, and the quality of winter wheat (Triticum aestivum L.) under SDI. For each growing season, two Treflan injection dates (March 6 and April 15 for the 2006–2007 growing season, and March 6 and April 15 for the 2007–2008 growing season) and three injection concentrations of 0, 3, and 7 mg/l were arranged in a randomized block experimental design. During harvest, root length density (RLD) and Treflan concentration at different soil layers were measured using the auger-sampling method. Thirty-five drippers from each treatment were randomly chosen to observe evidence of root intrusion into the dripper flow passage in order to estimate root clogging. The experimental results showed that Treflan injection could effectively reduce root density in areas adjacent to drippers, thereby significantly decreasing the potential of root clogging. In 2007, 4 out of the 35 drippers were found with root intrusion problems in the control (without Treflan injection), while no root clogging existed any dripper in Treflan application treatments. In 2008, 6 drippers from the control but only 1 dripper from those treated with Treflan application showed root clogging. In addition, within the range of concentration used by the current experiment, Treflan concentrations had no significant effects on winter wheat root distribution, yield, and quality. Injection date, however, influenced the vertical root distribution significantly. Injection of Treflan late in the growing season influenced the root distribution only in the areas close to the drippers; the influenced areas increased if Treflan was injected early in the growing season.