太行山区连翘雨季直播造林技术研究

Rainy season direct seeding afforestation technology of Forsythia suspensa(Thunb.)Vahl.in Taihang Mountain area

在太行山区开展了连翘雨季直播造林试验,通过出苗率、越冬越夏存活率、留苗率、生长量等指标的测定,探讨连翘在无灌溉条件下的种植方法,包括种子处理、保水剂应用、雨季播种时机选择、造林地选择、有无地面覆盖物等。结果表明,在7月4日、7月9日、7月13日、7月20日,将经包衣剂或保水剂处理的种子播种于半阴坡、半阳坡或阳坡上,其出苗率、留苗率和生长量显著高于对照(CK)和其他处理;6月下旬进行直播,由于降水量相对少、雨期间隔时间久,不利于种子萌发。7月下旬至8月降水量充足,此时播种持续降雨会使种子被冲失,同时高温易抑制种子萌发。9月初播种幼苗生长期短,越冬难度大,留存率逐渐下降;在土层厚度≥12.5 cm,有地面覆盖物的阴坡、半阴坡,连翘幼苗越夏越冬存活率均在80%左右,株高在90.81 cm以上。故认为连翘在无灌溉条件下雨季直播造林,最适宜时期为7月上中旬,且在土层厚度大于12.5 cm的半阴坡或有植被覆盖的阳坡直播造林较好。

A trial of direct seeding afforestation of Forsythia suspensa(Thunb.)Vahl.during the rainy season was conducted in the Taihang Mountain area.The planting methods under non irrigated conditions were probed by measuring such indicators as emergence rate,survival rate during winter and summer,retention rate and growth.The method induded seed treatment,application of water retaining agents,selection of sowing time during the rainy season,selection of afforestation site,and presence or absence of ground cover.On the 4th,9th,13th,and 20th of July,seeds treated with composite coating agents were sown on semi-shaded or sunny slopes,the emergence rate,retention rate,and growth were significantly higher than those of the control(CK)and other treatments.Direct seeding in late June was not conducive to seed germination due to relatively low precipitation and long rain intervals.Although there was sufficient rainfall from late July to August,continuous rainfall could wash away seeds,and high temperatures could inhibit seed germination.In early September,the suitable growth period for seedlings became shorter,making seedlings wintering more difficult and the retention rate decrease gradually.On shaded and semi-shaded slopes with a soil layer thickness more than 12.5 cm and ground cover,the survival of seedlings during summer and winter was 80%,and the plant height got above 90.81 cm.It was concluded that direct seeding afforestation of F.suspensa(Thunb.)Vahl.in the rainy season without irrigation was most suitable for implementation in early and middle of July,and better to do on semi-shaded slopes with soil thickness over 12.5 cm or sunny slopes with vegetation coverage.