Study On Effects Of Direct Seeding In Rocky Hills In Shandong Province

Direct seeding is the process of sowing tree seed by hand or machine directly into a seedbed in the final growing position for the woodland. Although in the early phases of establishment direct seeded sites can appear abandoned and unmanaged compared to neatly planted, well-maintained rows of trees, direct seeding has a number of potential advantages over conventional planting of intact root system, a good suitability of planting site, simple construction and being cheaper (Willough et al. 2007). With further developing of afforestation and greening efforts, remote and barren mountainous areas have become the emphases and difficulties in the regard. So in future, direct seeding, which is cheaper, easier to conduct, lower in cost and easy to spread in large area, will be the pivot technology for afforestation and greening in China.1 In recent years, direct seeding has been adopted in Shandong Province,which can help improve forest coverage in Shandong. After several years, plenty of technologies and experiences of direct seeding have been used. In order to summarize successful technologies and formulate a systemaic standard, investigation of direct seeding afforestration in Shandong was studied. Some of technologies are successful, we adopt them. Other questions are also existed, which need to found better way to settle.2 After investigion, the water provision and animal harm in spring are so far the key questions in direct seeding afforestration. With them, effects of different treating ways, including mulching film1, mulching film2(see method), grass cover, block cover, water retaining agent, rooting powder and open field (control), on soil micro-environment and emergence rage of direct seeding afforestration of several tree species, including Robinia pseudoacacia Linn., Amorpha fruticosa L., Sophora Japonica L., Gleditsia sinensis Lam., Platycladus orientalis (L.) Franco, Ailanthus altissima (Mill.) Swingle and Diospyros lotus L., was studied. The results show that: (1) Mulching film1 increases every day average temperature and vertical profile of soil temperature, which supplies suitable temperature to the generation of seeds, and that the surface temperature of mulching film2 is lower than that of the soil, which is suitable to sow in later spring; grass cover and block cover decreasing soil temperature. (2) Mulching film, grass cover and block cover can improved soil water content and supplied a feasible water environment to seed growth, but water retaining agent cannot. (3) The enmergence rate and seedling height of four species forest tree seeds with Film mulching methods are significantly higher than those with open field way. And for litter seeds, the enmergence rate and seedling height with film mulching 1 are higher, while those are greater with film mulching 2 for big seeds. Those big seeds should be choosen in direct seeding afforestation in barren field. If little seeds, more grains in each hole are needed to keep high enmergence rate.3 Using species diversity indices,including species abundance, Simpson diversity index, Shannon-wiener index and Pielou evenness index, the characteristics of species diversity in forest community afforested by direct seeding in 1993, and wasteland in rocky hill in Zouwu town, Xuecheng county was studied ,and soil chemical property of both areas was also measured.The results showed that:(1) In forest community, dominance species is Melia azedarach in tree layer and is Rhus typhina in shrub layer, while dominance species is Vitex negundo in shrub layer in wasteland. No tree species was found except Melia azedarach, Ailanthus altissima, Platycladus orientalis, all of which were introduced by artificial factor. (2) In forest community, species diversity indices and evenness index of tree layer are significant increase, compared with wasteland, while those indices of shrub layer are significant decrease. (3) In forest community, the soil nutrients, including organic matter, total N, available P, available K, are significant higher than those of wasteland.