Investigation on relation between Physico-Chemical properties of soil with Vegetal cover on Marl formations in Sabzevar area

Marl formations in Sabzevar region have 100000 ha areas. Marls vegetation is very poor due to their unsuitable physicochemical properties. In this research relationship between marl vegetation and their physicochemical properties studied. Studies localized in establishment area of Salsola, Ephedra and Artemisia vegetation types. In 0-20 and 20-40 % deeps on northern slopes were dug soil profiles. Soil sampeles were taken from two first layers of marl soils. Vegetation properties of all slopes that contain soil profills studied. Soil sampeles in laboratory analyzed and all physical and chemical soil properties determined. Data analyzed by SAS method and relationship between marl vegetations and their physicochemical properties determined. Relation between independent factors (soil factors) and dependent factor (vegetation cover) in all vegetation Types studied by Step wise regression model. In comparison of each average soil factors among three vegetation types revealed that there was significant different in EC, Na, Cl, Sum Cations and Anions, SAR and ESP. In all vegetation types, by increasing in vegetation percent some soil factors such as Ec, Cl, Sum Cations and Anions, SAR and ESP decreased and factors of C, N and P increased. Variation analysis of datas showed that there are significant differences (p0.01) in interaction of plant cover percent with some soil factors such as EC, sand, silt ,Caco3 and gypsum percent, FC, P.W.P, Na, Ca, Cl, Sum Cations and Anions, SAR, CEC and ESP. Furthermore, there are significant differences (p0.05) in interaction of plant cover percent with K, porosity percent and bulk density. Analitical calculation using step wise regression method showed that : 1)- In Salsola Type, correlation between vegetation percent (dependent factors) with FC and EC (independent factors) is meaningful with probability of %99 and with T.N.V and CL is meaningful with probability of %95. 2)- In Ephedra Type, correlation between vegetation percent with EC, K and CEC is meaningful with probability of %95. 3)- In Artemisia Type, correlation between vegetation percent with ESP is meaningful with probability of %99.9 and with T.N.V and SAR with probability of 99 and 95, respectively. So concluded that in Salsola Type FC, EC, T.N.V and Cl and in Ephedra Type EC, CEC and K and in Artemisia Type ESP, T.N.V and SAR have greatest effects on vegetation cover percent, respectively