Successful Biological Methods for Combating Desertification at Degraded Areas of China - Combating Desertification in Asia, Africa and the Middle East - page 53

• Air Seeding:

Aerial seeding is a mechanized afforestation method that plants seeds that are
spread by plane in a suitable space and timetodevelopthevegetationsoastofix
the shifting sands on a large scale. Aerial sowing has achieved success on Mu Us
Sandy lands in Inner Mongolia. The vegetation coverage reached 50-60 % after
4-5 years after sowing. This is of important practical significance to improve the
sand control work in the semiarid area of China.

The advantages of air seeding for afforestation

• Rapid afforestation

• Plane can fly into the remote sand regions to work

• The cost is relatively low

The selection of plant species

(a) In the desert steppe area
Hedysarum laeve, Amorpha fruticosa, Lespedeza bicolor, Caragana micro-
phylla, Artemisia halodendron, Astragalus adsurgens, Ulmus pumila.
(b) In the steppe and desertfied steppe areas
Hedysarum laeve, Hedysarum scoparium, Artemisia sphaerocephala, Astra-
galus adsurgens, Caragana korshinskii, Hippophae rhamnoides.
(c) In the arid areas
Haloxylon ammodendron,Calligonum mongolicum, Hedysarum scoparium,
Artemisia sphaerocephala .

The calculation of air-seeding seed rate

(a) The principles of determining rational seed rate are firstly, the seed rate per unit
area of the air seeding for afforestation should be determined by the survival
plant density in the air-seeding regions in the first year and next year. Secondly,
the determination of the seed rate should consider the sand fixing efficiency.
Thirdly, the inevitable losses of seeds and seedlings by the rodents, insects,
birds and other animals should be taken into consideration.
(b) The empirical formula of the seed rate of the air seeding for afforestation

10 6 p 1 p2 p3 p4 /

N D n g =. 1

where:

N is the seed rate (kg/ha) of the air seeding for afforestation,
n is the planned survival seedlings numbers per hectare,
g is the weight of a thousand seeds,
p1 is the purity rate of seeds (%),
p2 is the germination percentage of seeds (%),
p3 is the residual rate of seeds after losses to rodents and insects (%) and
p4 is the survival rate of seedlings in the first year (%).