mapping the distribution and flora of summer weeds in citrus orchards of bandar-e-gaz township by geographic information system(gis)

in order to identify flora and distribution mapping of weeds in citrus orchards of bandar-e-gaz township, 101 orchards were selected during 2014, and the summer weed species were sampled and detected using a w method. with using specific formula of density, frequency, uniformity, abundance of each weed species was calculated. also, geographic coordinates of orchards (latitude, altitude and elevation) were determined by using gps. these data were used for producing weed maps using arcgis 10 software. the results showed that there are 28 summer weed species in citrus orchards of bandar-e-gaz township and these belong to 14 families. 25 percent of these species belong to astearceae and other families, respectively. in general, 68 and 32 percent of species were annual and perennial weeds, respectively. also, 71 percent of weeds belong to dicotyledonous and 59 percent to monocotyledonous. based on dominate index, the most important weeds in citrus orchards of bandar-e-gaz were included: cynodondactilon (42/2%), amaranthus .spp (36%), cyperusrotundus (32/6%) and portulacaoleracea (32/5%).