Somayeh Dehnavi

The role of “Celtis siliquastrum” as NFTs Species on understory’s soil and criterion plant

Abstract

Nitrogen-fixing trees or trees that have the ability to sequestrate nitrogen in soil, they could increase the organic matter in understory’s soil. Hackberry tree species found abundantly in the northern and central regions of Iran. This Nitrogen-fixing trees are multipurpose by there ability in producing forage, timber, fuel, food, medicine. High growth rate, resistance to air pollution, salinity, cold, wind and storm, and nitrogen fixation activity of these two species, are characters that make them suitable for the restoration of the degraded rangelands and forests. Trees "Celtis australis" and "Celtis caucasica" are two Nitrogen-fixing tree species (NFTs) of hackberry genus where there are naturel or planting and able to improve the microclimate. The studied trees located in two county of Iran. C.caucasica growing in reserved area in Aedasteh-Dehaghan in Isfahan county and C.australis planted in Imamzadeh Abdollah-Amol in Mazandaran county. This study aimed to investigate the effects of “C.australis” and “C.caucasica” on the physical and chemical characteristics of understory soil. In this study, to achieve the goals, the understory soil of “C.australis” and “C.caucasica” and control at three depths 0-20, 20-40 and 40-60 cm with five replications were analyzed based on comletely randomized factorial experiment. The studied paramters include: Inorganic nitrogen, Total nitrogen, Organic carbon percentage, Lime, EC, pH, soil texture and critorion plant analyzsis to test the effect of trees on the amount of total nitrogen, protein and production of  ceritorion plant growing on the samples soils. In order to establish the equal condition in the test, a touchstone plant was chosen and planted in the areas dominate by "Celtis australis" and "Celtis caucasica" trees and also the pich up the testimonal sample. In order to study the rate of effectiveness of "Celtis australis" and "Celtis caucasica" trees on the associate plants, “Lepidium sativum” was selected as the touchstone plant. Lepidium sativum or “Garden cress” is a fast growing plant and has short groeth period. Nitrogen-fixing trees have the ability to fix nitrogen into inorganic nitrogen or nitrate that usable by plants. Therefore we can see that effects in two Celtis spicies in this study. Aproximately in all the studied parameters the two tree had a sighnificantly different effect on the soil and both respect to the controls. This show the high potential and positive effect of NFTs on soil quality compare to the uncovered areas. In order studies, in order studies, Lime, pH, EC and soil totel nitrogen in soil under C.caucasica tree was higher than C.caustralis tree and Organic carbon percentage, Inprganic nitrogen, critorion total nitrogen and protein production, in soil under C.australis tree was higher than C.caucasica tree. Overall, the highest amounts of Lime, Inorganic nitrogen, soil total nitrogen and Organic carbon percentage was gained in depth 0-20 cm understory of two hackberry species and then increasing with depth. In fact litter decomposition plays a great role in nutrient and physical quality improving of the soil. The effect of "Celtis australis" and "Celtis caucasica" on nitrogen content of soil shows the improving effect of this trees on soil microorganism’s condition