构树截顶与留顶栽植的生长量及持水量差异

Effects of Topping and Branch-cutting Cultivation Patterns on Increment and Water Holding Capacity of Broussonetia papyrifera

为喀斯特地区水土保持构树造林提供理论依据,对3个地径组(A1:0.5cm≤d<1.0cm;A2:1.0cm≤d<1.5cm;A3:d≥1.5cm)的构树苗木进行截顶(离地面高30cm)留侧枝、留顶除侧枝处理,用简易吸水法测定标准株生长情况和地上部分枝、干、叶及林冠的持水量。结果表明:造林成活率和保存率都在85%以上,造林后第1年,≥1.5cm地径组截顶处理的标准株树高、地径、平均冠幅、平均根幅均最高,分别达197.37cm、24.70mm、106.45cm和101.61cm;枝、干和叶的持水量均最高,分别为11.94g/株、14.9g/株和227.92g/株;冠层的最大持水量为27.93kg/667m2。造林后第2年,3个地径组截顶处理的树高、地径、根长、平均根幅均优于留顶处理,其中≥1.5cm地径组截顶处理的树高、地径、根长、平均根幅均最高,分别达243.44cm、40.73cm、134.89cm和104.22cm;枝的持水量最高,为49.09g/株;叶的持水量达514.3g/株;冠层的最大持水量为61.10kg/667m2。地径≥1.5cm的构树进行截顶造林有利于植株的生长和握持水分。

The growth status and water holding capacity of branches, stem, leaf and canopy of B.papyrifera with three different stem diameters （A1∶0.5 cm≤d〈1.0 cm,A2∶1.0 cm≤d〈1.5 cm and A3∶d≥1 .5 cm）under topping and branch-cutting cultivation patterns were determined by the simple water absorption method to provide the theoretical basis for conservation of water and soil by B. papyrifera afforestation in Karst area.The survival and preserving rate of B.papyrifera both over 85%.The height,ground diameter,average canopy and average root width,and water holding capacity of branch,stem and leaf of the treatment with ≥1 .5 cm stem diameter under the topping cultivation pattern after one year were 197.37 cm,24.70 mm,106.45 cm and 101.61 cm,and 11.94 g/tree,14.9 g/tree and 227.92 g/tree respectively and the maximum backwater capacity was up to 27.93 kg/667m2 .The height, ground diameter,root length and average root width of the treatments with three different stem diameters under the topping cultivation pattern after two years all were higher than the treatments under the branch-cutting cultivation pattern.Of which,the height,ground diameter,root length and average root width, and water holding capacity of branch,stem and leaf of the treatment with ≥1 .5 cm stem diameter under the topping cultivation pattern were 243.44 cm,40.73 cm,134.89 cm and 104.22 cm,49.09 g/tree, 31.1 g/tree and 514.3 g/tree and the maximum backwater capacity reached 61.10 kg/667m2.The topping cultivation pattern of B.papyrifera with ≥1 .5 cm stem diameter was beneficial to growth and water holding of B.papyrifera.