Abstract:

Alxa Plateau is located in Western Inner Mongolia with widely distributed desert and gobi， which is one of the main sand and dust sources of North China. Air seeding is one of the main measures to control land desertification in this area. Generally， germination of plants was influenced by many natural factors after air seeding， e.g. climate and habitat. Ammopiptanthus mongolicus， Corethrodendron scoparium， Caragana korshinskii and Prunus mongolica are four dominant shrubs in desert region of Alxa Plateau. In this study， the effects of precipitation， seeding depth and soil type on germination of four shrubs were investigated by pot experiment in the greenhouse. Our aims were to improve air seeding technology and to give theoretical support for precisely sand control. Three precipitation were 10， 15 and 20 mm first irrigation， then irrigated 5 mm once every two days for 10 times. Four seeding depths were 0.5， 1， 2 and 3 cm， respectively. Four soil types were micro-fine sand， fine sand， medium sand and coarse sand. The results showed that the favorable condition of germination was 15-20 mm first irrigation for A. mongolicus， whereas were 10， 15 and 20 mm first irrigation for other three shrubs. Germination were higher in 0.5 and 1cm seeding depth for A. mongolicus， but were higher in 0.5， 1 and 2 cm for other three shrubs. There were only few germination of C.scoparium in 3 cm seeding depth. Germination of A. mogolicus was higher in micro-fine sand， fine sand and medium sand， but was lower in course sand. However， germination of other three shrubs was higher in all four soil types. Thus， it is suggested that in air seeding on east Alxa Plateau， A. mongolicus seed should be used after 15 mm rain on moving， semi-moving and semi-fixed sand dune， but not on gobi. However， C. korshinskii， C. scoparium and P. mongolica seed should be applied in air seeding after rain exceeds 10 mm on moving， semi-moving， semi-fixed sand dune and gobi.

Key words: air seeding, precipitation, seeding depth, soil type