Distribution of the weed communities in the North East Nile Delta, Egypt

Abstract

AbstractThe weed flora associated with field crops and orchards in Dakahleya Province, NE Nile Delta, were classified using TWINSPAN technique into nine weed groups dominated by nine weed species. These groups comprised 73 weed species related to 27 families. These species included 56 annuals (75.7%) and 18 perennials (24.3%). The recorded species were formed of 22 monocots and 52 dicots, with Poaceae as the most represented family (23.0%).The application of the DECORANA technique resulted in a clear separation of the weed groups according to the seasonality of the host crops. Evironmental variables used in this study accounted for 84.3% of the variability of the weed groups composition.Chorological analysis of the recorded species indicated that the study area comprises 24.6% of its species as all the year active species, 32.9% as summer active and 42.5% as winter active species. The Mediterranean elements (mono, bi & pluriregional) presented 44.4%, while, cosmopolitan elements attained 23.6%. The Mediterranen weed species extending into the Euro‐Siberian territory attained higher presentation in the study area as compared to those species with Saharo‐Sindian extension.The ordination axis 1 showed significant relationships with soil clay, pH, water holding capacity, calcium carbonate and bicarbonate. Stepwise regression analysis selected clay, soil pH, water holding capacity, calcium carbonate and soil bicarbonate as the best set of predict – or variables of the weed species distribution in the study area. In the meantime, herbicide application and rate of hoeing were selected also as the best set of predictor variables of weed richness in the study area while calcium carbonate and silt were selected as the best set of predictor variables for weed diversity as measured by Shannon index.