The observations were conducted on chernozem soil in a sugar-beet production region in . Six variants of organic amendment were examined: l -straw harvest, 2 -straw harvest + green manuring, 3 -straw incorporation, 4 -straw incorporation + green manuring, 5 -straw burning, 6 -straw burning till 1977 + intercrop, incorporation of farmyard manure at 10 t/ha since 1978. The effect of organic amendment on winter wheat continuous cropping was statistically significant. On average of the whole period (32 years), the highest yields were produced in variants with straw burning (var. 5) -6.04 t/ha and with green manuring (var. 2) -6.03 t/ha, and lower yields in variants with straw incorporation into soil (var. 3) -5.65 t/ha, (var. 4) -5.67 t/ha. The smallest differences between variants were found in the first decade of the experiment. Over time (in the second and third decades), the differences increased and positive effects of green manuring and straw burning and adverse effects of straw incorporation into soil increased. The yield level of winter wheat continuous cropping was high under the given conditions. The yield for the whole period of the experiment averaged 5.85 t/ha, the yields 5.19, 6.54 and 5.76 t/ha were obtained in the first, second and third decade, respectively.

Field experiments were conducted in the maize-growing region on heavy gleic fluvisol from 1974 to 2000. Three variants of straw management (straw harvested, incorporated into soil and burned), two variants of soil tillage (conventional plough tillage to 0.22 m, shallow disc tillage to 0.12-0.15 m) and three variants of fertilization (30, 60 and 90 kg N.ha -1 ) were studied. After conventional tillage, the highest yield was obtained in the variant with burned straw (5.50 t.ha -1 ), followed by the variant with straw incorporated into soil (5.40 t.ha -1 ) and the lowest after harvested straw (5.01 t.ha -1). At shallow tillage, lower yields were assessed in all variants of straw management in comparison with conventional tillage (after straw burning 5.07 t.ha -1 , incorporation into soil 4.66 t.ha -1 and harvest 4.54 t.ha -1 ). The ranking of variants was identical to that in inversion tillage; however, the yield increased more after straw burning in comparison with its incorporation into soil. Yields increased regularly along with increasing rates of nitrogen. If long-term effects of straw incorporation on yields and yield trends were evaluated (in comparison with straw harvest), statistically significant decrease in yields was assessed after shallow in contrast with increase in yields after deeper straw incorporation.

DUBEC, J., KŘEN, J., PROCHÁZKOVÁ, B., DRYŠLOVÁ, T., DOVRTĚL, J.: Comparison of humus balance methods in relation with yields of monoculture spring barley. Acta univ. agric. et silvic. Mendel. Brun., 2004, LII, No. 5, pp. 29-40 Long term stationary field experiments with continuous spring barley were conducted in the maizegrowing region on heavy gleic fluvisol from 1974 to 2002. Two variants of straw management (straw harvested and incorporated into soil), two variants of soil tillage (conventional plough tillage to 0.22 m, shallow disc tillage to 0.12-0.15 m) and three variants of fertilization (30, 60 and 90 kg. N ha -1 ) were studied. The results of organic matter balance in the examinated period according to particular methods were related to trends of real humus content which is presented in C ox in particular experiment variants. The examinated method by LEITHOLD et al. (1997), used in model Repro, answers most accurate in given conditions according to hypothesys defined in scientific literature. On the base of this result we can confirm significancy of the result. Other verification of method is appropriate for its using in real conditions in context of agricultural sustainability assesment. Změny ekonomických podmínek jsou úzce spjaty se změnami struktury rostlinné a živočišné produkce. Počet zemědělských podniků bez živočišné produkce nebo podniků s živočišnou produkcí, ale bez potřeby slámy v České republice vzrůstá. Rovněž dochází ke zúžení spektra pěstovaných kulturních plodin a k vý-znamnému nárůstu podílu obilnin. Nedostatek statkových hnojiv a nezbytnost udržení půdní úrodnosti dodávkou organických látek vede k potřebě hnojení slámou.Problematikou vlivu hospodaření se slámou a zpracování půdy na výnosy jarního ječmene a aspekty půdní úrodnosti se zabývala celá řada autorů (ELEN,