The Associations of Soil Properties and Climatic Factors with Weed Distribution in Turfgrasses

A survey was conducted to study the effects of soil and climatic factors on distribution of weeds in 48 parks in 22 districts of Tehranin 2014. 52 weed species from 21 plant families were identified. Multivariate analyses with canonical correspondence analysis (CCA) showed that changes in the weed species distribution were due to soil traits (pH, Phosphorus, Nitrogen, Potassium, %Carbon, %Organic matter, EC) and environmental conditions during previous years. Green foxtail (Setaria viridis), hairy crabgrass (Digitaria sanguinalis), ragweed (Kochia scoparia) and knotweed (Polygonum patulum) had a wide distribution in the areas with high temperature. Where the soil nitrogen were high, Green foxtail (Setaria viridis), Ragweed (Kochia scoparia), Ladino clover (Trifolium repense), Knotweed (Polygonum patulum) and Sow thistle (Sonchus oleraceus ) density was found frequently. Besides, there was a correlation between soil potassium and the density of Broad leaf plantain (Plantago major L.), Little hogweed (Portulaca oleracea), Watter grass (Echinochloa crus-galli), Procumbent yellow-sorrel (Oxalis corniculata) and Common dandelion (Taraxacum officinale) in turfgrasses. Based on the results of this study, it would be possible to overcome these problems to some extent by predicting future problems of weeds and changing management plans.