نوع مقاله : مقالات پژوهشی
نویسندگان
1 گروه اگروتکنولوژی، دانشکده کشاورزی، دانشگاه فردوسی مشهد، مشهد، ایران
2 بخش تحقیقات علف‌های هرز، موسسه تحقیقات گیاهپزشکی کشور، سازمان تحقیقات، آموزش و ترویج کشاورزی، تهران، ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Introduction
Tehran, in terms of extent, is the 26th megacity of the world. Tehran’s urban green landscape per capita is 15.5 square meters per person. Weeds annually financially damage green landscapes in Tehran, the cost of weed management in a lawn is 1500 rials per square meter. One of the tools and methods that can improve weed management is to map their distribution. These map help researchers. 1- Areas affected by the population of different species. 2- Identify areas of the invasive weed infested areas. So far, the study of community structure and species diversity in weeds in the green space of Mashhad, Khorshid park Mashhad, and grass fields of Shiraz University have been done, but a similar research has not been done in Tehran. A research was conducted in parks of 22 districts of Tehran in order to assess, specify diversity, density, dominance and distribution map of weeds in Tehran.
Materials and Methods
This study was conducted in years 2014-2015 in 48 parks of 22 districts of Tehran. Sampling was conducted in summer using W systematic method. The parks in each area were chosen according to the extent of green area, the location of the park in the twon (whether the park was in the suburbs of Tehran or other parts of the area) and according to the three following scales. In the 5 hectare parks, 10 samples, 6 to 15 hectare parks, 15 samples and in 16 and more than 16 hectare parks 25 samples were taken. In the 5 hectare parks, 25 meters, 6 to 15 hectare parks, 40 meters and in 60 and more than 60 hectare parks 70 meters of margin was considered for each park. Latitude, longitude and altitude were recorded. Weeds of each quadrat were identified and counted according to their species and finally, using Thomas equations (1985), their frequency, uniformity, average aggregation and dominance index were calculated. In order to create distribution map of weeds Arcgis and Arcmap soft-wares were used for determine the distribution of dominant species of weeds and other species in the city of Tehran. Shannon-Wiener and uniformity indexes were calculated for all parks. For comparing and grouping 22 districts, cluster analysis was performed using SPSS software.
Results and Discussion
A total of 52 weed species from 21 families were observed. Maximum weed densities respectively were found in the Region 17 and Region 16 with 34.38 and 36.25 plant/m2. The 28 species of 52 species belonging to four families, Asteraceae,Poaceae, Fabaceae, and Chenopodiaceae, with 10, 7, 6 and 4 species, respectively. Based on a abundance index (AI). Lion′s tooth (Taraxacum officinale), knotweed (Polygonum patulum), greaet plantain (Plantago major), bermuda grass (Cynodon dactylon) and Sow thistle (Sonchus oleraceus) were dominant species. Parks in district 2 with 3.30 had maximum diversity in weed community and parks in districts 15, 21, 11, 18, 12, 14, 3 with 2.25, 2.25, 2.25, 2.19, 2.31, 2.33, 2.12, respectively had minimum diversity. Also presence of Beggarticks (Bidens parviflora Willd), garden anchusa (Anchusa italic Retz), garden orache (Atriple hortensisL.), common reed ((Phragmmites austrialis (Cav.) Trinexsteud), ribwort plantain (Plantago lanceoleta L.), nappola minor (Xanthium brasilicum), yellow sweet clover (Mellilotus officnalis L. Desr), common mallow (Malva sylvestrisL.) weeds in some specific areas makes it necessary to control these weeds to stop their reproduction in these specific area and expansion of infected seeds from these areas to other areas of Tehran. Lion′s tooth distribution maps, as the most dominant broad leaf weed showed that the highest plant density above regions 21, 18, 16, 17, 19 and the lowest density in regions 4, 1, 5, 22, 3 there. Bermuda grass distribution maps, as the most dominant weed of slim leaf showed that the highest plant density above regions 2, 4, 5, 8, 9, 10, 16, 21 and the lowest density in regions 12, 13 there.
Conclusion
Determination of density, type, species and life cycle of weeds in Tehran parks, allows to manage and reduce weeds damages and also by using integrated weed management system it is possible for better management and reduce weeds population and stop spreading of them from one area to another. Also close monitoring and precise management of other parameters such as soil and manure is effective in reducing the population of weeds in all areas.
کلیدواژه‌ها [English]
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