杉木采穗圃的树体管理和插条选择
Cultivation of Young stock Plants and Selection of Cuttings in Chinese Fir Scion-plucking Garden
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摘要: 杉木采穗圃建立初期,树体管理方式对单株产条量有显着影响。在12种不同处理中,生长季节(8月)进行压干和生长初期(4月)进行截顶两种处理的效果最好,有效产条量为17~18根/株,总产条量为47~51根/株,4月和8月进行全截干处理,产条极少,甚至引起植株死亡。单株产条量的高低顺序是:压干≈截顶>埋干>半截干>全截干。树体管理的关键在于维持足够的树冠营养面积和及时抑制主干高生长优势。对两种采穗圃连续3a观测表明,栽植密度为1.66万株/hm2的压干式采穗圃的产条量,超过密度为2.66万株/hm2的换干式采穗圃产条量的40%~50%.但压干式采穗圃适宜稀植,而换干式采穗圃可实行高密度圃地栽培,从而实现早期丰产。两者各具优点,可因地制宜地选用。在采穗圃中采集树干基部20cm以下部位、带有顶芽、长度10cm左右、粗细均匀和较为粗壮的穗条,用于扦插育苗,能够显着提高苗木生长量、整齐度和成活率。Abstract: In the first year after one-year-old superior seedlings were planted in Chinese fir cutting collecting garden,a trial involved in 12 treatments(5 ways×2 or 3 seasons)to stimulate sprouts at the bottom of the stocks was established. The numbers of both total sprouts and available cuttings per tree in the spring of the following year varied significantly among the treatments. MSA(make stem with an angle of 20~30°against ground)CST(cut off stem top)CMS(cover up middle of stem with earth)CHS(cut off half stem)CSG(cut off stem at ground level). MSA and CST were carried out separately in August and in April,and the best results obtained.The worst were found in CSG in both April and August,but the CSG in December was better than the former's both. Though it is really important to maintain enough canopy but to timely limit its terminal growth in the young stock's management.The numbers of available cuttings per ha of both the MSA with spacing of 0.5 m×0.8m,and the CSG with 0.5m×0.5 m were observed for three years. The result showed that the cutting yield of MSA was 40%~50% higher than that of the CSG. Howerver,thining of stock plants should be done in the fourth year after planting for the MSA garden. But the CSG was suitable for dense planting,where the higher numbers of cutting could be obtained in early stage. Some experiment indicated that position and size of cutting materials showed significant influence on height growth,uniformity,and survival of rooted cuttings. It is suggested that stout cuttings of 10 cm long,with a well developed terminal bud should be collected from the lower part of a stem,20 cm above ground.