تاثير ماده آلي بر قابليت جذب پتاسيم از كاني هاي ميكايي توسط يونجه و امكان تبديل كاني ها

چكيده انگليسي :

Effect of Organic Matter on Potassium Uptake from Micaceous Minerals by Alfalfa and the Consequent Mineralogical Transformations Zeinab Naderizadeh z naderizadeh@ag iut ac ir January 26 2010 Department of Soil Science College of Agriculture Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Hossein Khademi hkhademi@cc iut ac ir Abstract Many studies have been carried out on the effect of organic matter on soil physical chemical biological and nutritional properties including the effect of organic matter on the availability of such elements as P N and heavy metals However there is no information on the effect of organic matter on potassium release from micaceous minerals and their mineralogical changes The objective of this study was to investigate the effect of organic matter on potassium uptake from micaceous minerals by alfalfa and the mineralogical changes A pot experiment was carried out in a completely randomized design with factorial combination and three replicates The growth medium was a mixture of Hamadan quartz sand micaceous mineral Hamadan phlogopite Amlash biotite and Hamadan muscovite and organic matter 0 0 5 and 1 cocopeat During 120 days of cultivation plants were irrigated with either complete or K free nutrient solution and distilled water as needed At the end of cultivation plant shoots and roots were separately harvested The dry matters of plants were determined and their K concentration was measured by flame photometer following dry ash extraction Also the mica particles and their weathering products in each pot were separated from the quartz sand and their clay fraction analyzed using X ray diffraction XRD Under the K free nutrient solution a significant increase in shoot and root biomass occurred in pots containing trioctahedral micas phlogopite or biotite and organic matter as compared to those with no organic matter amendment Also under K free condition potassium concentration in shoot was above the threshold value only in phlogopite amended pots There was no significant difference in shoot K concentration and uptake among different levels of organic matter in control treatment as well as in muscovite added treatment Under both nutrient solutions treatments significant increase of shoot and root K uptake occurred in pots containing trioctahedral micas phlogopite or biotite and organic matter as compared to those without it XRD data showed the transformation of phlogopite and biotite under both nutrient solution treatments but no XRD detectable transformation of muscovite was detected Organic matter amendment seems to have created considerable mineralogical changes in clay sized phlogopite and induced the transformation of phlogopite to vermiculite and a minor quantity of smectite and chlorite Under complete nutrient solution the addition of organic matter did not influence the transformation of biotite But under K free nutrient solution the addition of organic matter resulted in great mineralogical changes Root activities and organic matter decomposition appear to have increased the acidity of rhizosphere which in turn facilitated the K release from trioctahedral micas phlogopite and biotite in K deficient medium So K release from K bearing minerals can be enhanced by addition of organic matter The quantity of organic matter addition is important The high rate of organic matter addition may lead to K deficiency in soils containing trioctahedral micas Under such conditions K fertilitization might be needed Keywords K release phlogopite biotite muscovite mineralogical changes organic matter

نادري زاده، زينب

تاثير ماده آلي بر قابليت جذب پتاسيم از كاني هاي ميكايي توسط يونجه و امكان تبديل كاني ها

فلوگوبيت , بيوتيت , موسكويت , تغييرات كاني شناسي