اثر تيمارهاي حرارتي بر آزاد شدن پتاسيم از ميكاهاي دي و تري اكتاهدرال

چكيده انگليسي :

The Effect of Heat Treatments on Potassium Release from Di and Trioctahedral Micas Asieh HadineZhad as hadinejad@gmail com March 6 2011 Department of Soil Science Isfahan University of Technology Isfahan 84156 8311 IranH Khademi hkhademi@cc iut ac irShamsollah Ayoubi ayuobi@ cc ac ir Soil Science Department Collage of Agriculture Isfahan University of Technology Isfahan Iran AbstractHeated micaceous minerals are used as culture medium in greenhouses under different commercial brandnames including vermiculite Heating minerals affects the release of elements such as potassium bychanging their structure The aim of this study was to investigate the effect of heating on potassiumrelease from muscovite and phlogopite as a di and a tri ochtahedral mica respectively undergreenhouse conditions and also during laboratory extraction Particles of muscovite and phlogopite witha diameter of less than 60 were heated at 100 to 900 0C for 5 hours In order to study the heat inducedmorphological changes mineral surfaces were studied by a scanning electron microscope SEM Theamount of extractable K from blank and heated minerals was then determined using two differentsolutions including ammonium acetate and sodium tetraphenyl boron for 3 time periods of 1 5 and 15minutes To simultaneously study the effects of heat treatments and rhizospheric conditions on potassiumrelease a pot experiment was carried out as a completely randomized design with factorial combinationsand three replications Heated minerals were mixed with quartz sand to fill the pots as the culture mediumfor alfalfa as a test plant The blank culture medium contained pure quartz sand and unheated minerals Pots were irrigated with two different nutrient solutions K and K and distilled water for 5 months After harvesting dry matter of shoot and root samples was measured separately The K uptake by plantwas then measured by flame photometer following the dry ash extraction Results revealed differentresponses of micaceous minerals to heat treatments SEM micrographs showed the exfoliation of mineralsat lower and their flaking at higher temperatures Heating from 200 to 350 0C also caused the mineralstructure to fold The pot experiment indicated the significant influence of the heat type of mineral andnutrient solution treatments on the plant dry matter K uptake and concentration parameters In K freetreatments the plant K uptake was significantly influenced by culture medium In phlogopite treatments the shoot K concentration of the K free pots was evaluated as sufficient except for the 700 and 900 0Ctemperatures whereas the sufficient shoot K concentration in muscovite treatments was only detected forplants supplied with the complete nutrient solusion The highest plant available K was released at 100 and200 0C for muscovite and phlogopite treated plants respectively The structural changes causing aconsiderable decrease in potassium release also took place at above 700 0C for phlogopite and 500 to700 0C for muscovite The amount of total K uptake by plants from phlogopite under the K free nutrientsolution was considerably higher than that extracted by both extractants Nonetheless the plant uptakewas more correlated with the sodium tetraphenyl boron extraction for 1 minute and the correlationdecreased as extraction time increased In phlogopite treated plants the extracted K by sodiumtetraphenyl boron in 1 and 15 minutes time periodss was very much similar to the K uptake of the firstand second cuts In the contrary the K uptake in the muscovite treated plants was more highly correlatedwith the K extracted by ammonium acetate solution Keywords Potassium Sodium tetraphenyl boron Phlogopite Muscovite Alfalfa Heat treatments

هادي نژاد، آسيه

اثر تيمارهاي حرارتي بر آزاد شدن پتاسيم از ميكاهاي دي و تري اكتاهدرال

سديم تترافنيل بران , فلوگوپيت , موسكويت , يونجه