Composition and diversity of weed communities in Al-Jouf province, northern Saudi Arabia

Abstract

The aim of this study was to identify the main weed communities in Al-Jouf province in northern Saudi Arabia. Moreover, the composition and diversity of these communities were studied in relation to soil variables and crop type. Some 54 stands representing olive orchards, date palm orchards, wheat crop and watermelon crop were studied, using ten quadrats (1 × 1 m) per stand. A total of 71 species belonging to 22 families and 61 genera were observed. The classification of vegetation using the Two Way Indicator Species Analysis (TWINSPAN) resulted in the recognition of four vegetation groups representing wheat crop, orchards in winter season, orchards in summer season and watermelon crop. These results suggested the importance of both crop and season for the formation of weed community. Detrended Correspondence Analysis (DCA) showed that these groups are clearly distinguished by the first two DCA axes. The species richness was higher in both olive and date palm orchards than in wheat and watermelon crops. This pattern of species richness could be related to farm management practices and habitat micro-heterogeneity. Soil electrical conductivity, organic carbon and soil texture showed significant correlations with species richness and the cover values of some dominant species, suggesting the significant role of soil characteristics in weed community structure and diversity.

Floristic diversity and vegetation structure of Al-Dissah area northwestern Saudi Arabia

“…Therophytes had the highest contribution (49.2%), followed by chamaephytes (17.5%), phanerphytes (14.3%), geophy tes (9.5%), while the least frequent life form class was hemicryptophytes (7.9%) ( Table 2). The dominance of therophytes in the study area is characteristic of arid deserts where they usually bloom and form luxurious growth in rawdhat, wadis and at the base of stable dunes (Gomaa, 2012). In the present study the ascendancy of therophytes and chamaephyts in the vegetation spectra of AlDissah area agrees with the spectra of vegetation in desert and semi -arid habitats in other parts of Saudi Arabia as descr ibed by some authors as Alatar et al (2012), Osman et al (2014), andAl-Mutairi et al (2016).…”

Spatial heterogeneity of soil and vegetation characteristics and soil-vegetation relationships along an ecotone in Southern Mu Us Sandy Land, China

“…Significantly positive correlations between plant species richness and EC were also reported in several relevant studies (Zuo et al 2009b;Fattahi and Ildoromi 2011;Gomaa 2012;Hájková and Hájek 2003). EC (along with SOC, TN, and pH) was identified as one of the main factors affecting most herbaceous plants in mobile dunes (Zuo et al 2009b).…”

Caucalido platycarpi-Vicietum michauxii — a new weed association from crop fields of Kyrgyzstan (Middle Asia)

“…Despite their location on the outskirts of a warm mediterranean climate zone, samples with more than 30 species have to be regarded as significantly rich in segetal species when compared to other crop cultivation areas in the world [e.g. 21,22,25,39,58,60,71,90].…”

“…Most studies investigate European agrocoenoses; however, several are focused on the weed vegetation of southwest Asia [21,22]. In last years several studies have been published, focusing on the problem of maintaining agrocoenoses biodiversity in relation to changes in intensification of crop cultivation.…”