In Europe the views on the demand of magnesium by agricultural plants as well as on the need for magnesium fertilization are different. In European countries uses different methods for determining the available magnesium content in soil. Different assessment of soil characteristics in different countries as well as very unequal magnesium fertilization rates for crops have encouraged us to review the methods of determining available magnesium in soil and the effect of magnesium fertilizer on plants. The appropriateness of applying the magnesium determination methods commonly used in different soils in Europe was established and scientifically based as well as their relationship, recalculation algorithms for the values of available magnesium obtained by applying different determination methods were prepared. The effect of the plant available magnesium content in predominant soils of Lithuania determined by different methods and that of magnesium fertilizer on the yield of Italian ryegrass and spring barley were investigated. Summarizing the research developed the most suitable determination of available magnesium in Lithuanian soil and crop fertilization magnesium fertilizer recommendations. Different solubility of magnesium in different soils and magnesium fertilizers on agricultural plants in Lithuania was studied for the first time. / Požiūris į magnio poreikį žemės ūkio augalams, o tuo pačiu tręšimą magnio trąšomis, įvairiose šalyse nėra vienodas. Europos šalyse judrusis magnis dirvožemyje nustatomas labai įvairiais metodais. Skirtingas dirvožemio savybių vertinimas įvairiose šalyse, o taip pat labai nevienodos magnio trąšų normos augalams mus paskatino naujai peržiūrėti judriojo magnio nustatymo metodus dirvožemyje ir magnio trąšų įtaką augalams. Nustatytas ir moksliškai įvertintas dažniausiai Europoje naudojamų judriojo magnio nustatymo metodų taikymo tinkamumas įvairiuose dirvožemiuose, jų tarpusavio priklausomumas, parengti perskaičiavimo algoritmai tarp įvairiais metodais nustatytų judriojo magnio reikšmių. Vyraujančiuose Lietuvos dirvožemiuose ištirta įvairiais metodais nustatyto judriojo magnio kiekio ir magnio trąšų įtaka gausiažiedžių svidrių bei vasarinių miežių derliui ir kokybei. Apibendrinus atliktus tyrimus parengtos tinkamiausių judriojo magnio nustatymo Lietuvos dirvožemiuose metodų ir žemės ūkio augalų tręšimo magnio trąšomis rekomendacijos. Lietuvoje įvairaus tirpumo magnio kiekiai įvairiuose dirvožemiuose ir magnio trąšų įtaka žemės ūkio augalams tirta pirmą kartą.

A total of 12 multicomponent solutions of various compositions were developed in which we attempted to blend calcium and phosphoric salts, which usually precipitate and form sediments. Among the medicines of similar composition and purpose registered in Lithuania, there is none containing all three important macroelements: Ca, Mg, and P. After the tests, one of the solutions tested – C2 – was registered in Lithuania and was manufactured by AB Ukmergės Biofabrikas (Lithuania) for several years. Production technology of the developed preparation – Kamavetas – is patented (patent No. LT 4509 B. 1999 05 25). Kamavetas is the first preparation created and manufactured in Lithuania, which contains Ca, Mg, and P salts and glucose. It is convenient to use, because the animal receives several mineral substances within a single infusion.