山东青石山区的障林

障林是在人为保护下形成的。它是人类自觉保护自然的一个范例。本文论述了它的一般特点,和四个群落类型,并对障林的保护与以展提出了建议。

Cultivation Techniques of Panax notoginseng F.H. Chen under Different Forests

To overcome the issues of high cost and continuous cropping obstacles in facility cultivation of Panax notoginseng_ F. H. Chen, satisfy the market demand, save the production cost, improve the utilization rate of forest land, increase the in-come of forest farmers and protect the ecological environment, the cultivation tech-niques of high-quality P. notoginseng seedlings from Wenshan, Yunnan under four kinds of forests （walnut forest, China fir forest, grape forest and kiwi forest） were in-vestigated in this study. The results showed that the height growth, crown diameter, survival rate and 3-year-old tuber weight of P. notoginseng_under walnut forest were higher than those under the other three kinds of forests; the height growth, crown diameter, survival rate and 3-year-old tuber weight of P. notoginseng under China fir forest were higher than those under grape forest and kiwi forest; and the crown di-ameter and survival rate under grape forest were higher, and the height growth and tuber weight under grape forest were lower than those under kiwi forest. Walnut is a broad-leaved deciduous tree species, so large-scale cultivation of P. notoginseng_should be conducted under broadleaf deciduous forest with canopy density around 0.8, taking advantage of the cool environment and rich humus layer under forest. This cultivation technology could save labor, shade, fertilizer and other costs, and accord with the ecological habit and the growth rules of P. notoginseng, thus im-proving yield and achieving high economic benefit.

Spin-Dependent Transport and Densities of States in Non-collinear Magnetic Barriers

The spin-dependent transport properties in the non-collinear pattern of series of δ-magnetic barriers are studied by using scattering theory and Green＇s function methods. The Green＇s function is obtained by using distorted wave approach and the scattering matrix is related by Fisher-Lee relationship. In addition to reproducing the results of Papp＇s and Xu＇s in parallel and antiparallel configurations, we also obtain further results, where arbitrary orientations of the magnetic barriers and arbitrary number of barriers are included. The main finding of our results is that the signs of polarizations can be switched around some ＂geometric unpolarized windows＂. The well-known antiparallel configuration has no such characteristics. Furthermore, we discuss spin-related partial densities of states in both polarized and unpolarized structures.

Agroforestry Initiatives for Capacity Building and Social Security through Captive Plantations on Degraded Lands of Farmers in State Karnataka, India

To meet the demand of raw material, i.e., wood, from the available sources always remained a big challenge for paper industries since the last two decades. For a sustainable supply of raw material in future, major plantation activities were undertaken by paper industries, like West Coast Paper Mills Limited （WCPM）, by constituting a society, i.e., Society for Afforestation, Research and Allied Works （SARA）, Dandeli in 2001. The main aim was to promote afforestation programme through major plantations activities on the degraded lands （under rainfed condition） and to generate employments and capacity building. The WCPM is a leading paper manufacturing industry of the country （under the flagship of Bangur group） located at the bank of Kali River in Dandeli of Uttar Kannada district in State Karnataka. To date, company through SARA has raised captive plantations on more than 50,000 acres of degraded land by farmers in different districts of Maharashtm, Karnataka, Andhra Pradesh and Tamilnadu States under Captive Plantation Project through Contract for Farming （CFF） since 2006 under a simple agreement period of only five years. After five years, society arranged to harvest the first rotation crop of the farmer of 2006, 2007, 2008, 2009 plantations and paid the amount of the crop directly to farmers. SARA has a mutual contract with WCPM for purchasing pulpwood. With this, farmers are getting full amount of their crop harvested after five years without any hurdle through SARA. SARA did all the expenditures, i.e., from land development, plantation and harvesting. Under its agroforestry plantation programme, superior planting material of various pulpwood species suited to particular area, i.e., Eucalyptus, Subabul, Casuarina and Acacia were planted on farmer＇s land. Farmers were also encouraged for intercropping, like maize, peanut （groundnut）, chilly, tomato and ginger with plantations. Apart from this, SARA is also providing free fodder to the livestock of farmers. Various types of fodder species such as Stylosanthes scabra, S. hamata are grown with plantation. SARA has also set up its own hi-tech clonal nursery developing around 5-6 millions of clonal ramets every year through clonal propagation technology. Till date, SARA has received 0.15 million ton （MT） of pulpwood from the plantations on farmer＇s land with a yield of 25-30 MT/acre. This type of activities will prove a boon for farmers as well as for industry, when raw material is going to be short in India. It will also conserve our natural resources, high conservative valued forests （HCVF） and will reduce the pressure on forest for wood. In addition, this will maintain the balance between environment and nature. To meet the requirement of pulpwood for industry, this type of plantation activities will open new ways for industry to secure raw material for future use. Also, this would be helpful to enhance productivity and generate employments for rural communities to improve their living standard and capacity building.