Weeds flora of the Agricultural University Peshawar Research Farm.
Weeds intrusion cause negative impacts on biodiversity in the wild and crop productivity in the fields. Weeds have greater phenotypic plasticity and hence are more pliable to changing climate. They establish easily into new areas and, become invasive over the native vegetation. To study the adaptability of invasive weeds and their status among the native plant community, a field survey was carried out from July - September 2017 at New Developmental Farm (NDF), Malakandher, The University of Agriculture, Peshawar (UAP). Data were recorded from three sites i.e. field crop area, non-field, and orchards with a quadrate randomly thrown 50 times at different locations. A total of 39 weeds species from 16 families (14 dicots and 2 monocots) and 36 genera were identified. The major monocot family Poaceae contributed 10 species while among dicots, Asteraceae took the lead with 6 species. Among the weed species, 27 were annual and the rest 12 were perennial. Annuals were reported from all three sites, while perennials were found in the non-field area i.e. irrigation canals, field ridges, orchards, and undisturbed waste areas. Data regarding absolute and relative density, frequency and relative frequency and importance valve were recorded by the quadrate method. Cynodon dactylon had the highest relative density (27.21%), followed by Digiteria sanguinalis (14.87), Cyperus rotundus (12.96) and Euphorbia prostrata (5.12). Parthenium hysterophorus L. an invasive alien weed was recorded in almost all the sites with a density of (2.6 m-2) in the non-field areas particularly, followed by (0.85 m-2) in field crop and (0.8 m-2) in orchards and with a mean density of (1.42 m2) and a relative density of (1.52%) across all locations. Similarly, another invasive weed Broussonetia papyrifera was recorded in the non-field area only with the lowest mean relative density of (0.07%). Mean distribution data showed the highest relative frequency for Cynodon dactylon (13.66%), followed by D. sangunalis (10.22), C. rotundus (7.86) and S. halepense (7.23), respectively. Alhaji maurorum, Eclipta alba, Cucumis callosus, B. papyrifera, Withania somnifera and Boerhavia diffusa showed the smallest relative frequency at all locations studied thereby indicating them as insignificant among the weed flora of the study area. Importance value data revealed that C. dactylon, D. sangunalis, C. rotundus and S. halepense having IV % of 34.03, 19.99, 16.89, and 10.17, respectively. Looking at the overall distribution of weeds flora in NDF-Malakandher, UAP during the summer season C. dactylon is distributed on roadsides, field ridges, irrigation channels, agricultural fields, orchards and wastelands, while P. hysterophorus being an invasive weed showed an increasing trend compared to its earlier status evident from the previous study.