БОТАНІЧНИЙ СКЛАД І ВРОЖАЙНІСТЬ БОБОВО-ЗЛАКОВОГО ТРАВОСТОЮ ЗАЛЕЖНО ВІД СТРОКІВ СІВБИ

Abstract

Significant changes in climatic conditions require some correction in the technology of growing perennial grasses, in particular, setting the optimal sowing time. To investigate the influence of the sowing terms of the mixture of bird's-foot trefoil with timothy meadow on the botanical composition and grass yield.It is established, that the basis of the herbage created in early spring, summer and autumn sowing dates was made by sown crops. Their share in the first mowing was from 74.9 to 90.2 %, in the second mowing - 75.4-90.1 %. So, with early spring emergency sowing, the share of the bird's-foot trefoil in the botanical composition of the green mass of the first mowing was 50.6 %, in the second mowing - 64.0 %. At summer sowing, the proportion of the bean component in the first mowing was only 34-38.1%, in the second mowing - 41.4-47.2 %. The content of bird's-foot trefoil was even lower during the sowing in early September - 30.8% in the first and 37.6 % in the second mowing. The variant with autumn sowing turned out to be the least resistant to penetration into the phytocenosis of unplanted species, the share of forbs on which was 25.1 % in the first and 24.6 % in the second mowings. The legume-grass herbage was not formed at all during the late autumn sowing.On average, in three tabs, the highest dry mass yield (5.78 t/ha) was provided by the variant from early spring sowing times, where the share of the legume component was more than 50 %. Significantly lower productivity was provided by grass, created by summer post-crop or post-emergence seeding. With summer sowing time (post-mowing and post-harvest), the productivity of this grass mixture decreased to 4.80 and 4.16 t/ha of dry substance. Autumn sowing periods reduced this figure to 3.46 and 2.09 t/ha. Thus, the advantage of the early spring planting period is proved, during which lotus-cereal grass provides 0.98-3.69 t/ha higher yield of dry substance and higher content of the bean component in the green mass crop compared with the summer and autumn sowing terms.In the conditions of the southern part of the western forest-steppe on the slopes with acidic, low natural soil fertility, the best botanical composition of the grass was formed during the early spring-crop sowing of a mixture of bird's-foot trefoil and timothy meadow. In this variant, the proportion of the bean component in the crop of the green mass of the first mowing was 50.6 %, the second - 64 %. The grass, created by early spring sowing, was characterized by low level of clogging with herbs, the share of which in the first mowing was 9.8 %, in the second mowing - 9.9 %. The yield of dry substance in this variant was 5.78 t/ha, which exceeded the productivity of grass created by summer and autumn sowing by 0.98-3.69 t/ha.