【摘要】 <正> 目前,陕北和整个黄土丘陵沟壑区植被稀少,水土流失严重,土壤干旱贫瘠,气候恶化,农业产量低而不稳,天然草场载畜量很低,极大地影响着农牧业的发展。 加速绿化大面积荒山荒坡是改变该地区落后面貌的重要途径和根本措施。在黄土高原地广人稀地区开展飞机播种造林种草是加快大面积荒山绿化的重要手段。更多还原

【Abstract】 Astragalus adsurgens with cold, drought resistance and resistance to poor or saline soil is a fine grass selected from a great many grasses. It has wide adaptability, fast-growth, high yield and many uses, and is suitable for aerial sowing. The experiment conducted on aerial sowing Astragalus adsargens has been successful on semiarid Wuqi County where annual rainfall is about 400 mm. Sown area was over twelve thousand mn in the period of 1976—1979. The results of the experiment show that we have success during the four years. 5,700—13,900 plants, i. e. 11.7—24.6 per cent of the total aerosown seeds, were obtained per mu at the seeding rate 0.3—0.4 jin/mu. Because about two fifth of each sown-region was missing, the established grassland occupy 47.8—67% of the effective area of sown-region. The plants are measured 50—150 cm in height from second to sixth year, and the production of fresh grass averages 1,800—3,800 jin/mu that is 5—20 times more than the natural vegetation.The results of the experiment indicate that optimum seed-time on the semiarid area of the loess Plateau is before the coming of the rainy-season, that is from the third decade of June to July. After sowing it is necessary for germination to rain continually about five days and to have rainfall 30—50Sowing Astragalus adsurgens by aeroplane is of great significance to the rapid recovery of vegetation of bareland, improvement of grassland, controlling soil erosion, providing feed, fuel, and manure crops, and then speeding up the development of agriculture and animal husbandry in the loess gully and hilly regions where there is a small population for so large an area.更多还原