高台整地和苗木截干对水曲柳次生林下水曲柳栽植苗成活及生长的影响

【目的】研究高台整地和苗木截干对水曲柳次生林下水曲柳栽植苗成活及生长的影响,以期解释低洼地带水曲柳次生纯林林下水曲柳天然更新不良的原因,为同样立地的水曲柳人工造林提供参考依据。【方法】在水曲柳典型分布区内选择生长在低洼且有季节性积水地段上的水曲柳次生纯林,采用两因素随机区组试验设计,在其林下进行高台整地(配合地被物去除处理,并设置未整地对照),人工栽植水曲柳1年生苗(栽植后立即截干至8cm高和未截干保持原15.8 cm平均高2种处理),对苗木栽植后3个生长季内的成活和成长情况及栽植后第3年的地表水分与温度变化动态进行观察分析。【结果】1)配合死、活地被物去除处理的高台整地可以有效降低表层土壤含水量,且变化幅度明显降低;高台整地可增加生长季初期(5月)地表温度升幅、降低生长季末期(9月)地表温度降幅和生长季地表温度变幅,使地表温度趋于匀质化;2)高台整地可提高栽植苗木的成活率和保存率(未截干情况下,3个生长季分别比未整地高出7.17%,13.37%和15.56%),降低栽植苗木的生长季死亡率(未截干情况下,3个生长季分别比未整地低100%,64.73%和20.89%),提高栽植苗木的地径和苗高生长量(未截干情况下,3个生长季内地径和苗高生长量分别比未整地高出19.37%,27.13%和35.80%及100.53%,50.00%和64.17%),增加苗木生物量和茎根生物量比值,增加苗木叶片的叶面积和数量;3)在高台整地情况下,截干处理对水曲柳苗成活没有显著影响,但截干处理成活率和高生长量小于未截干处理;未整地情况下,截干处理水曲柳苗成活率和保存率显著低于未截干处理,但对苗高生长量和地径生长量无显著影响;截干处理可增加水曲柳苗叶片的面积与数量,提高苗木根和叶生物量积累。【结论】土壤水热状况不良和地被物竞争是中下坡低洼地带水曲柳次生纯林林下水曲柳更新幼苗存活和生长差的重要原因,通过高台整地改善土壤水热状况、削弱地被物竞争,可以促进水曲柳栽植苗的存活和成长。

Study on Improvement of Walnut Bud Grafting Technology in the North

[Objective] This study was conducted to change the situation of high cost in walnut grafting by reducing seedling cost through technical means.[Method] Effects of different rootstock processing methods and rootstock pruning time on walnut growth and cost were studied by the square bud grafting method.[Result] The survival rate and cost under stumping were higher than those under no stumping,and the proportion of grafting-capable rootstocks under stumping was lower than that under no stumping by 9%.The cost differences between different rootstock time were remarkable.The cost for the stock pruning 15 d after grafting was 5 times as much as 1 d after grafting.[Conclusion] Direct grafting could achieve the effect of easy and convenient management,and the overall cost was lower though the survival rate was reduced to a limited extent.Sooner rootstock pruning resulted in a better effect.Pruning the rootstocks within 5 d after grafting not only could improve the quality of seedlings,but also could reduce the cost for seedling management.