Defoliation time and intensity of wall barley in the Mediterranean rangeland

Abstract

Wall barley (Hordeum murinum L.) is the dominant species in northeastern rangeland of Jordan that decreases under grazing. We investigated the responses of wall barley to clipping time and height during 2 growing seasons in the semiarid rangeland of Jordan. A natural stand was utilized to conduct the experiments that were arranged in a randomized complete block design during 1994/95 and 1995/1996 growing season. Treatments were combinations of clipping heights (5 or 10 cm above soil surface) and plant growth stages (tillering, jointing, or booting), in addition to unclipped check. Results showed that clipping to 5 and 10 cm stubble height at tillering produced 1,167 and 1,349 kg ha(-1) dry matter, respectively, compared to 1,122 kg ha(-1) for unclipped check. Clipping to 5 and 10 cm stubble height reduced shoot weight by 28 and 21% at jointing stage and 52 and 38% at booting stage. Defoliation during tillering stage did not impact plant height of regrowth nor seed yield. Weed biomass were higher when plant defoliation was delayed to the jointing and booting stages. Therefore, it is recommended to defoliate wall barley early at tillering stage but before plants reach jointing or reproductive stages.