نقش درختان تثبيت كننده نيتروژن ﴿كهور پاكستاني و كرت﴾ بر ويژگي هاي خاك زير اشكوب و گياه محك

چكيده انگليسي :

The Role of Nitrogen Fixing Trees on Soil Properties and Understory Plants Marziyeh Naiminiya m naiminia@gmail com Date of Submission May 12 2011 Department of Natural Resources Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language Farsi Supervisor Dr SayedHamid Matinkhah Email address matinkhah@cc iut ac irAbstractIn Arid and semiarid regions trees have noticeable effects on soil resources distribution and its biochemicalprocesses Organic materials are naturally much more in the understory than out of it Acacia nilotica and Prosopisjuliflora are two nitrogen fixing trees NFTs which mainly grew in arid and semiarid tropics and tropics In Aridand semiarid regions trees have noticeable effects on soil resources distribution and its biochemical processes Organic materials are naturally much more in the understory than out of it Acacia nilotica and Prosopis julifloraare two nitrogen fixing trees which mainly grew in arid and semiarid tropics and tropics These Nitrogen fixingtrees are multipurpose by their ability in producing fodder timber and fuel and since they are resistant to aridity they are suitable for rehabilitation of degraded lands in arid and semiarid tropics This study was done to reveal andcompare the effects of Acacia and Prosopis trees on the physical and chemical properties of the soil and theirresults on the growth of understory plants The studied trees were selected quiet randomly in a range of age about12 years old Considering the fact that the provender quality under the tree shadows is higher comparing with theopen areas the under study area is selected of those covered with the trees Regarding the works referred in thehistory section of the present work the Nitrogen stabilizer trees have the capability of stabilizing nitrogen andconverting it into the inorganic Nitrogen which is usable for the plants From this point of view there is deferencein the Nitrogen amount in the areas dominated by the Acacia nilotica and Prosopis juliflora trees in analogy withthe testimonial sample Nitrogen is one of the main components in the main plant compounds The properabsorption of Nitrogen stimulates growth and development of the roots and the absorption of other nutritionalelements by plants In order to establish the equal condition in the test a touchstone plant was chosen and plantedin the areas dominated by Prosopis juliflora and Acacia nilotica trees and also the pickup testimonial sample Inorder to study the rate of effectiveness of Prosopis juliflora and Acacia nilotica trees on the associated plants Lepidium Sativum Garden cress was selected as the touchstone plant Garden cress is a fast growing plant andhas short growth period The studied trees located in Armandkenar suburb of Abadan County and not expose toany fertilizer To achieve the goals the understory soil of Acacia Prosopis and control situated in an open area atabout one kilometer distance of the trees at three depths 0 20 20 40 and 40 60 cm with three replications wereanalyzed based on completely randomized factorial experiment The studied parameters include mineral nitrogen Dissolved organic nitrogen nitrogen mineralization potential total nitrogen organic carbon percentage lime EC pH soil texture and criterion plant analysis These variables show the potential of the trees in nitrogen absorptionand production of the criterion plant Approximately in all the studied parameters the two trees had a significantlydifferent effect on the soil and both respect to the control This shows the high potential and positive effect of NFTson soil quality compare to the uncovered areas In other studies carbon and other nutrients increase in theunderstory of these trees during biological rehabilitations projects were reported Most of mineral nitrogen Dissolved organic nitrogen nitrogen mineralization potential total nitrogen was observed in 0 20 cm depth of soiland they will reduce in deeper soils In fact litter decomposition plays a great roll in

نعيمي نيا، مرضيه

نقش درختان تثبيت كننده نيتروژن ﴿كهور پاكستاني و كرت﴾ بر ويژگي هاي خاك زير اشكوب و گياه محك

اثر تاج پوشش درخت , گياهان زير اشكوب , آبادان