Assessment of soil and vegetation cover charachtristics on marl formations, case study: Sabzevar marls

Marl formations due to their unsuitable physico-chemical properties have low vegetation cover and so are highly erodible. These formations make up about 2000 km2 of lands in Sabzevar and Davarzan areas. In this research, geology, pedology and vegetation cover of marl formations were studied. Geologically, there are two kinds of marl formations consisting salty and red gypsiferous marls. Marly lands in southern aspects usually have no vegetation but in northern aspects the vegetation varies between 0 to 27 percent. Three vegetation communities consisting of Salsola aucheri, Artemisia seiberi and Ephedra intermedia are stablished on marly soils. For recognizing soil factors of each vegetation community, studies localized in establishment area of Salsola, Ephedra and Artemisia vegetation types. Many soil profils were dug. Soil samples were taken from depth between zero and 40 cm of marly soils and were analyzed. Results showed that in all plant types with increasing of percent of plant cover from 0-10 to 10-24 percent, the main soil factors such as EC, pH, gypsum, silt an clay, Na+, K+, Mg2+, Cl-, So42-, total Cations and Anions and SAR were decreased and factors such as Organic carbon, N, P. T.N.V, Co3-1 and sand percent were increased. The statistical analysis of data was conducted with the SPSS software. This study showed that Artemisia and Ephedra had the highest and lowest vegetation percentages, respectively. Analyzing of data acording to Duncan Test showed that the differences between plant cover percent in three vegetation communities are very obvious (P<0.05). Meanwhile, the amount of EC and gypsum of  marly soils were important soil factors that had the most roles in establishment of  vegetation.