Key points of cultivation of POA pratensis

Kentucky bluegrass (Latin name: Poa annua L.), also known as: grass, chicken grass, cold grass, etc.; annual or winter grass. Culms erect or oblique, soft, 7-30 cm tall, all smooth glabrous. Leaf sheath slightly compressed, closed below middle; ligule 1-3 (- 5) mm long, rounded. Born in plain and hilly roadside grasslands, field ditches or shaded barren slope wetlands, 100-4800 meters above sea level, distributed in the north and south provinces of China, Europe, Asia and North America. It is a widespread weed in the world and needs strict management and control.

Morphological characteristics of POA pratensis

Annual or winter grasses. Culms erect or oblique, soft, 6-30 cm tall, all smooth glabrous. Leaf sheath slightly compressed, closed below middle; ligule 1-3 (- 5) mm long, round head; leaf blade flattened or folded, 2-12 cm long, 1-4 mm wide, soft texture, often with transverse veins, apex acutely boat-shaped, margin scabrous. Panicle broadly ovate, 3-7 cm long, spreading; branches 1-3 bearing nodes, smooth; spikelets ovate, containing 3-5 florets, 3-6 mm long, green; glumes thin, with broad membranous margins, apex obtuse, first glume lanceolate, 1.5-2 (- 3) mm long, with 1 vein, second glume 2-3 (- 4) mm long, with 3 veins Lemma ovoid, apical and margin broadly membranous, with conspicuous 5-veined, lower part of ridge and marginal veins pilose, interveins pilose near base, basal disc glabrous, first Lemma 3-4 mm long; Palea subequal to Lemma, two ridges densely filiform; anthers yellow, 0.6-0.8 mm long. Caryopsis fusiform, ca. 2 mm. The florescence is from April to May and the fruiting period is from June to July. Chromosome 2, chromosome 14, 14, 28 (Litardiere 1938, Tate0ka, 1985, a), Tutin 1954.

How to cultivate Kentucky bluegrass?

Grass can be sowed or sowed. Because the seeds are very small, it is necessary to prepare the land very carefully before sowing; after sowing, it is required to suppress the land and keep it moist. Seed 7.5-12.0kg per hectare. Control sowing depth, sowing depth 1~2cm to ensure the emergence rate. Line spacing 30cm. Mixed sowing with white clover and hundred vein root can improve the yield and quality of grass and adjust the grass supply season, because the hundred vein root grows vigorously in summer. The sowing date should be adapted to local conditions. Spring, summer and autumn can be sowed in warm areas, and autumn sowing is the most suitable; spring sowing should be early to prepare for summer and avoid competition with weeds; spring sowing from April to May and autumn sowing in July in high and cold areas. Lawn seedlings were sown with 105~120kg per hectare and seed direct seeding with 150-450kg per hectare. It is sensitive to nitrogen fertilizer. The application of nitrogen fertilizer in spring can enter the grazing period in advance, and generally graze 11 days in advance. Nitrogen application can increase the proportion of Kentucky bluegrass and control the proportion of legume grass. When it is mixed with leguminous forage, leguminous forage will degenerate and need to be replanted. However, Kentucky bluegrass can be used continuously, even after heavy grazing, it can be recovered quickly. If complete fertilizer is applied every year, the grass can be maintained indefinitely. Sowing attention in order to make the sowing uniform, separate the seeds according to the number of plots divided according to the predetermined sowing amount, sow the seeds according to the blocks, and rake the seeds into the soil gently with a rake after sowing. The covering soil should be shallow but not exposed, and do not go too deep. Gently press the soil with a ballast after sowing to ensure that the seed soil can be in close contact. The common diseases of this grass are leaf spot, root rot, rust, fungal powdery mildew, ergot, anthracnose and so on. The common pests are Japanese beetle, Kentucky bluegrass grain elephant, Chilo suppressalis and Swedish stem fly.