The effect of soil applications of zeolite,agrisorb and lignite on the chemical composition of clover-grass mixtures grown in arid conditions of south moravia

The two-year field trial was established in May 2008 on light soil in the cadastre of Ratíškovice near Hodonín in an arid maize-growing production area. Prior to sowing selected soil conditioners were applied in experimental plots of an area of 864 m2 as follows: zeolite (a mineral of high sorption capacity),lignite (the youngest coal containing humus substances) and the supplementary soil substance agrisorb (polymer organic compound capable of holding in its structure and subsequently releasing water) and they were incorporated into a profile of 0.15 m. Including the untreated control the experiment involved 4 treatments. The rates of the conditioners were as follows: zeolite - 3l.m-2,fraction used 1-2 mm; agrisorb - 20g.m-2; lignite -1000 g.m-2. Three types of clover-grass mixtures were sown: landscape mixture with an addition of leguminous plants (seeding rate 200kg.ha-1),regional mixture (100kg.ha-1) and annual mixture (70kg.ha-1). The aboveground biomass taken from an area of 0.05 m2 was sampled in the stage of bud setting with three repetitions to each treatment. In 2008 and 2009 the respective treatments did not significantly change the contents of N,P,K,Ca and Mg in the aboveground biomass of the clover-grass mixtures. The differences in the contents of the macro elements were significant only between the individual types of mixtures and were due to their different botanical composition. Between the years 2008 and 2009 no significant differences were discovered among treatments in terms of the contents of P and K in none of the mixtures,but the Mg content decreased in the second year in most treatments by 50 relative % and more. The contents of N and Ca increased significantly in the second year in the regional and landscape mixtures; in the annual mixture also the Ca content. The year-on-year differences however were seen also in the untreated control showing the apparent effect of the year. A longer period of monitoring is necessary if we are to achieve an objective evaluation of the effect of the applied preparations on the chemical composition of the aboveground biomass.