اثر آهك بر آزاد سازي پتاسيم و آهن از كاني فلوگوپيت در محيط هاي آزمايشگاهي و ريز سفري

چكيده انگليسي :

1 Effect of Lime on the Release of Potassium and Iron from Phlogopite under Laboratory and rhizospheric conditions Mohammad Amirmohammady Mohammad amir@ag iut ac ir September 2 2014 Department of Soil Science Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor H Khademi hkhademi@cc iut ac irAbstractCarbonates are common soil constituents in arid and semiarid areas and have significant impact onphysical and chemical properties of soils among which are the adsorption and release of cations andanions and the soil reaction Potassium and iron in clay minerals are an important source of potassium andiron for plants in many soils This study was conducted to investigate the effect of lime on potassium andiron release from phlogopite under laboratory and rhizospheric conditions Under laboratory conditions acompletely randomized design with factorial arrangement using five levels of lime 0 2 5 12 25 andeight time periods including 12 hours 1 2 4 8 16 32 and 64days was set up Ammonium acetatesolution 1N and DTPA were used to extract potassium and iron from phlogopite respectively Then theamount of released potassium and iron soluble from minerals were measured by flame photometry andatomic absorption spectrometry respectively The greenhouse experiment was run using a completelyrandomized design with factorial arrangement and three replications The treatments included four typesof nutrient complete iron free potassium free and iron and potassium free and five levels of lime 0 2 5 12 25 After 180 days alfalfa shoot and root were harvested and the amount of potassium iron calcium and magnesium was measured The results of the laboratory experiment showed that the rate ofpotassium and iron release from phlogopite mineral depends on the amount of lime and time of contactwith extractor Treatments without lime release more potassium as compared to other treatments Potassium release increased with time up to 32days and reached to plateau level after 64days In all thetime periods the amount of released potassium was higher in lime free treatments as compared to that incarbonates containing treatments Iron released from the beginning of the experiment followed anincreasing trend and then reached to a constant value at the end of the experiment The highest amount ofiron released from phlogopite in lime free treatments In general the rate of iron and potassium releasefrom phlogopite declined as the amount of lime increased Results of greenhouse experiment showed thatthe presence of lime in the growth media caused a great reduction in dry shoot and root biomass Thepresence of lime in the rhizosphere appears to increase the amount of available Ca which could in turn reduce the absorption of potassium and iron Amount of ammonium acetate extractable potassium andDTPA extractable iron in rhizosphere decreased as the level of carbonates increased The presence of limein the rhizosphere of plants could reduce the release of nutrients from soil minerals resulting in thereduction of plant yield The presence of lime could change the balance of potassium to calcium level ingrowth medium This imbalance may lead to the occupation of root surfaces by calcium interfering withthe uptake of potassium That is why the concentration of calcium in plant shoots increased in plantscontaining less It seems that the high concentration of calcium in soil solution compete swith iron tointeract with chelating ligands This would reduce the availability of iron to plants In general the rate ofK and Fe release from phlogopite is adversely influenced by the level of carbonates in medium Keywords Release of potassium and iron lime DTPA Phlogopite

امير محمدي پور دولت آباد، محمد

اثر آهك بر آزاد سازي پتاسيم و آهن از كاني فلوگوپيت در محيط هاي آزمايشگاهي و ريز سفري

DTPA