How to propagate Magnolia denudata by air layering and improve the survival rate?
How to propagate Magnolia denudata by air layering and improve the survival rate?
In practice, several technical points should be handled well.
(1) Layering time: generally mostly from February to May. From trials, in years when winter temperatures are rather low and early spring warming is late, layering from April to May is more favorable for rooting. Conversely, layering can begin in February. Where the tree is vigorous in spring and the canopy is dense and leafy, layering can be done earlier; where the canopy is weak, it can be postponed by 1 to 2 months.
(2) Branch selection and branch treatment: one- and two-year-old branches distributed inside and outside the canopy with a diameter of 1 to 2 cm can all be used for layering. Trials show that when the canopy is not too dense, branches in the inner and lower parts have a higher rooting rate and should be fully used. The degree of lignification at the girdled site of the layered branch is directly related to rooting. Where the lignification at the girdled and soil-wrapped site is good, the rooting rate is high; where lignification is poor, the rooting rate is low.
The girdled site of the layered branch can be directly coated with 100 mg/kg ATB No. 1 rooting solution and then wrapped with a soil ball. It can also be wrapped with culture soil mixed with 20 to 50 mg/kg ATB No. 1 rooting solution. Treated by the above methods, layered branches have a high rooting rate and generally more roots.
(3) Heeling-in can increase the survival rate: 3 to 5 months after air layering, the branch can be cut from the canopy. The cut layered seedling has weak young roots, and if planted directly the survival rate is relatively low. Heeling-in is an important technical step for raising the survival rate of layered seedlings.
The specific method of heeling-in: first prune the cut layered branches according to their rooting condition. For layered branches with many roots, keep 50 to 60 cm, cut off the top and remove branches and excess leaves. Generally keep 5 to 6 leaves per layer. For layered branches with few roots, keep 20 to 30 cm, generally leaving no branches or 2 to 3 half-leaves. Second, choose a shady, fertile and loose garden plot. Make a 30 cm high bed and open furrows 15 to 20 cm deep for planting. Third, remove the plastic film wrapped outside the soil ball, trying not to break the soil ball. Fourth, soak the base of the layered branch in a water solution containing 50 mg/kg ATB No. 1 rooting powder for 1 to 2 hours, then plant it on the bed furrow at a spacing of 20 to 25 cm. The layered seedling should be planted 15 to 20 cm into the soil, and the root soil should be pressed firmly. If the temperature is high, build a shade frame 50 to 60 cm high over the bed surface. Strengthen fertilizer and water management, adjust the light on the bed surface, and after 3 to 5 months the strong layered seedlings can leave the nursery.
(1) Layering time: generally mostly from February to May. From trials, in years when winter temperatures are rather low and early spring warming is late, layering from April to May is more favorable for rooting. Conversely, layering can begin in February. Where the tree is vigorous in spring and the canopy is dense and leafy, layering can be done earlier; where the canopy is weak, it can be postponed by 1 to 2 months.
(2) Branch selection and branch treatment: one- and two-year-old branches distributed inside and outside the canopy with a diameter of 1 to 2 cm can all be used for layering. Trials show that when the canopy is not too dense, branches in the inner and lower parts have a higher rooting rate and should be fully used. The degree of lignification at the girdled site of the layered branch is directly related to rooting. Where the lignification at the girdled and soil-wrapped site is good, the rooting rate is high; where lignification is poor, the rooting rate is low.
The girdled site of the layered branch can be directly coated with 100 mg/kg ATB No. 1 rooting solution and then wrapped with a soil ball. It can also be wrapped with culture soil mixed with 20 to 50 mg/kg ATB No. 1 rooting solution. Treated by the above methods, layered branches have a high rooting rate and generally more roots.
(3) Heeling-in can increase the survival rate: 3 to 5 months after air layering, the branch can be cut from the canopy. The cut layered seedling has weak young roots, and if planted directly the survival rate is relatively low. Heeling-in is an important technical step for raising the survival rate of layered seedlings.
The specific method of heeling-in: first prune the cut layered branches according to their rooting condition. For layered branches with many roots, keep 50 to 60 cm, cut off the top and remove branches and excess leaves. Generally keep 5 to 6 leaves per layer. For layered branches with few roots, keep 20 to 30 cm, generally leaving no branches or 2 to 3 half-leaves. Second, choose a shady, fertile and loose garden plot. Make a 30 cm high bed and open furrows 15 to 20 cm deep for planting. Third, remove the plastic film wrapped outside the soil ball, trying not to break the soil ball. Fourth, soak the base of the layered branch in a water solution containing 50 mg/kg ATB No. 1 rooting powder for 1 to 2 hours, then plant it on the bed furrow at a spacing of 20 to 25 cm. The layered seedling should be planted 15 to 20 cm into the soil, and the root soil should be pressed firmly. If the temperature is high, build a shade frame 50 to 60 cm high over the bed surface. Strengthen fertilizer and water management, adjust the light on the bed surface, and after 3 to 5 months the strong layered seedlings can leave the nursery.