ABSTRACT
Summary On degraded soils in hilly-mountain regions, natural grasslands are impoverished, low-yielding, and of low quality. While such grasslands yield 1,870 to 2,430 kg/ha dry matter without fertilization, and 6,040 to 2,430 kg/ha with N-P-K fertilization, cultivated grasslands are more productive by far. Experiments were conducted from 1971 to 1979 and from 1975 to 1980 in different ecological conditions of the hilly 435mountain part of the country. Sixteen grass and grass-leguminous mixtures were used in the establishment of cultivated grasslands. Yields of dry matter/ha varied from 10,184 to 12,670 kg in hilly regions, 9,433 to 10,933 kg in transitional hilly-mountain regions, and 7,940 to 11,720 kg in mountain regions. Differences in yields among the examined mixtures were not always statistically significant (P ≤ 0.05). It was found that cultivated grasslands with tall grasses and a limited number of components not including legumes were more vigorous and more productive. Fertilization had a pronounced effect on the examined mixtures, especially on their yields, which ranged from 6,794 to 12,670 kg dry matter/ha, or 72% to 225% higher than the nonfertilized control. Differences were highly significant (P ≤ 0.01). One kg of N-P-K nutrients produced from 10.8 to 20.0 kg of dry matter and in most cases ranged from 13.7 to 18.4 kg of dry matter/kg of N-P-K. Fertilization also affected the composition of grass cover, the distribution of plant species and groups, and the quality of herbage.
