CHANGES IN PH VALUE AND NUTRIENT SOIL RESERVE IN DEPENDENCE ON THE FERTILIZING SYSTEM UNDER COCKS FOOT LEY

The effect of two fertilizing systems, based on the use of results of soit analyses for so-called available nutrients, for changes in agroch emical soil properties under Daetylis glomerata L. ley, was studied in a four-year micro-plot trial. Both the systems were distributed in tw o blocks differing by a rate and kind of time fertilizers. The calcula tion of fertilizer rates was based on an analysis of average soil samp le taken from the experimental plot. Data are shown in Tabs I and II. The block I was limed pursuant to the principles of complex methodolog y of plant nutrition - KMVR (N e u b e r g et al., 1985) and criteria for arable land treated with ground limestone (chemical composition - 32.9% of Ca, 0.49% of Mg). Block II was limed after the principles of cation exchangeable capacity - KVK (M a t u l a , 1984) with dolomitic limestone (chemical composition -21.4% of Ca, 11.4% of Mg) because of high need for magnesium fertilizing. Changes in agrochemical values i n soil were tested through the methods Mehlich 2 ( M e h l i c h , 197 8), KVK-UF (M a t u l a , P i r k l, 1988) pH/KCl, pH/H2O (J a v o r s k y et al., 1987). Nutrient concentration in soil solution was determ ined after M a t u l a (1985). Soil samples were collected in 1985 (on e average sample), 1987 (32 samples) and 1989 (32 samples). The trial has been established in the cadastre of the village Chlum (the Kutna H ora district) at the altitude 470 m with long time annual sum of preci pitation 615 mm and average daily temperature 7.4-degrees-C, texture i s loam soil, great soil group - Cambisol with a topsoil deep 0.18 m an d bulk weight 1.55 t.m-3. Four cut-system was applied in the experimen tal crop Dactylis glomerata L. (the Roznovski variety). Liming with th e total rate 13.71 t.ha-1 of ground limestone induced a notable change in exchangeable and active soil response (Fig. 1) in the block 1. The rise of changes in the calcium content recorded in the tests after Me hlich 2 and KVK-UF as well corresponded with pH changes to certain lev el of saturation. Further increment in the calcium content was not yet accompanied by such a marked change in pH value (Fig. 2). The was als o calcium mobility increase (the concentration in soil solution). No e xtreme values of calcium content were observed neither in soil, nor in soil solution in the block 2 when dolomitic limestone was applied at the rate 3.04 t.ha-1. An optimum rate corresponded to 70% of saturatio n of sorptive complex. The dependence of mentioned cation exchangeable soil capacity on pH values was confirmed.