ABSTRACT
The study aims at evaluating cyanobacterial diversity along altitudinal gradient with respect to various edaphic factors at western Saudi Arabia. Thirty-one cyanobacteria species belonging to 17 genera were isolated and identified along the different sites of the study area. Nostoc and Spirulina had the highest number of species in the study area (four species each), followed by Chroococcus and Oscillatoria (two species each). The number of colonies had positive correlation with organic matter and phosphates. The application of the two-way indicator species analysis to the data set of the percentage presence of 31 cyanobacteria species in 40 stands resulted in agglomerating of 6 groups (communities) at 4th level of classification. The application of the detrended correspondence analysis (DCA) indicates reasonable segregation between these groups .The application of CCA on the cyanobacteria communities and environmental variables indicated that some cyanobacteria species are correlated positively with total number of associated plants, TSS and phosphates such as Woella saccata Wolle, Chroococcus minor Lemm, Chroococcus majore Lemm, Microcystis areuginosa, Smith Anabaena spiroides Lemm and Nostoc muscorum Agard, while others are negatively correlated with organic matter, chlorides, pH, EC, clay and silt such as Oscillatoria limosa Bory, Synchococcus sp., Spirulina major Kutz and Lyngbya borgertii Lemm. It is worthy to mentioned that, the soil samples dominated by Commicarpus sinaicus Meikle, Verbesina encelioides (Cav.) Benth &Hook. f. ex A. Gray, Argemone ochroleuca Sweet, Haloxylon salicornicum (Moq.) Boiss., Acacia tortolis (Forssk.) Galasso & Banfi and Morettia parviflora Boiss. had no cyanobacteria species.
ABSTRACT
Application of biochar to soil additionally restores soil Carbon and nutrients lost from bioenergy cropping systems as a result of biomass harvesting. This study was carried out to investigate the effect of biochar amended saline soil on plant growth, leaf chlorophyll, soil mineral contents and some physiological parameters of two Soybean cultivars in Saudi Arabia. The obtained results showed that plant height, fresh and dry weight, chlorophyll a and b content of both varieties (Giza-111 and Clark) were inhibited in saline soil while enhanced in biochar one which derived from Pomegranate trees or biochar two which obtained from acacia trees. The highest value of carbohydrate and protein contents observed in Giza-111 with the compare to Clark cultivars under salinity conditions. It was concluded that soybean is a sensitive plant to salinity stress, but the extent of this sensitivity varies among cultivars. As a result, Giza-111 cultivar showed more capability to survive under salinity condition compared with another variety regarding of almost all plant parameter examined. Considering, biochar one was found more appropriate under salinity condition.