Proceedings Volume 2010 (format .pdf) - SimpBTH

field research after the fertilization with mineral nitrogen and phosphorus fertilizersa positive change in reserves of substrates with assimilated forms of nutrients isreported.2. / The investigations conducted for gypsum use as a chemical meliorantshow that with introduction of increasing doses of gypsum the exchangeablesodium in meliorated arable layer 0-25 cm significantly reduced at the end of thestudy. The same trend is observed in its percentage from sorption capacity. In thelayer 0-25 cm the values of exchangeable Na before starting experience are 2,57meq/100g soil, and correspondingly decreased at the end of the experiment to 0,47- 0,06 meq/100g. In lying below horizon 25-50 cm exchangeable Na reduces from73,4 meq/100g soil to 8,21 -1,4 meq/100g soil. The data in Table 1 for the degreeof alkalescence show clearly that in a standard gypsum processing with a rate 3 t /dka gypsum the soil from deep alkaline is already weak alkaline, and by the landmelioration in with and 5 t / dka gypsum we can talk about non-alkaline soils .Therefore the best ameliorative effect was obtained in standards rates ofgypsum processing with 4 and 5 t / ha gypsum of SCI. In all variants the soilreaction in the arable horizon 0-25 cm is slightly alkaline to neutral, in the alkalineB horizon (25-50 cm) it is still high (8,9-9,6) and only in the variants with theaddition of 4 and 5 t / da gypsum pH decreased respectively to 7,6 and 7,2. At theend of 3-year experiment the positive ameliorative effect is reached, but to fullyimprovement the chemical properties of alkaline soils a longer period of time isrequired to respond to difficult soluble gypsum into the soil in order to replace theexchangeable sodium of the soil absorption complex with calcium.CONCLUSIONSThe investigations conducted for the evaluation of gypsum of SCI bychemical, agrochemical and physical-mechanical properties show that they do notcontain harmful substances which can have negative effects in using as acomponent of disturbed land reclamation and as a chemical meliorate of saltedsoils.The complex studies characterizing the anthropogenic "soils" created bymixed filling of waste from the power production of “Maritsa Iztok 2” TES withmine overburden indicate that the concentration of gypsum from SCI to 3% in thethree-component mixture for filling /disposal/ is no ecological risk is growing ofagricultural crops. For the implementation of successful biological reclamation thefilling of upper insulation layer of clean overburden / homogeneous mineralmaterials / is necessary, with layers thickness 2m after subsidence over thedeposited waste and the spreading of humus soil layer on the lined surface of theupper insulation layer with a thickness of the layer 30-35cm after the subsidence.On the basis the results obtained from the field studies conducted as theexisting environmental legislation documents the technology for reclamation202