This paper presents the effect of zeolitic volcanic tuff on soil fertility as a consequence oftreating soil with zeolitic tuff supplies (clinoptilolite rich tuff). This high silicon tuff type and the essentialfeatures of the clinoptilolite has generated in time changes in soil properties like soil reaction, aneffective pH buffering, increase of water absorption and cation exchange properties. The effect of usingthree different doses of zeolitic volcanic tuff, with and without ammonium nitrate addition as fertilizer, onacid soils was assessed by means of physical and chemical soil parameters, biomass and grain yields.The pH increase of soil treated by volcanic tuff alone or mixed with ammonium nitrate confirmed thebuffering effect and suggested the opportunity of using volcanic tuff for conditioning and remedying acidsoils. An increase of soil humidity and the enrich of calcium, magnesium and potassium content in soilwas also observed. The analysis of extractable mineral content showed the contribution of the zeolitic tuffon increasing soil mineral content and fertility. Global soil fertility enhance, particularly in theneighborhood of the rizosphere, was reflected also by biomass and grain yields increase. The obtainedresults showed the benefit of using the zeolitic volcanic tuff in conjunction with ammonium nitrate torestore the fertility of low fertile soils. The usefulness of the paper is to inform about the zeolitic volcanictuff features and its action as soil treatment on soil quality. The importance of this research lies inpresenting a technology to restore soils with low fertility using a rather cheap natural resource of ourland. In Romania, major deposits of clinoptilolite rich tuff can be found near Mirsid, Salaj County andBarsana, Maramures County. The use of zeolitic volcanic tuff in agriculture might be an alternative forfertilizing and amending low fertile soils as part of practicing an ecological agriculture.

zeolitic volcanic tuff, soil fertility, pH, humidity, cation content, crop yield;

Presentation: oral