固氮植物在林业上的应用

本文概述了豆科和非豆科固氮植物在林业上应用的状况,综合评论林业上应用固氮植物的四种基本途径:1)固氮植物与非固氮树木轮作,2)固氮树木与非固氮树木混交,3)固氮树木为目的经营树种的纯林,4)固氮植物作为林下植物与非固氮树木伴生,最后提出林业上应用固氮植物需考虑的技术关键。     

我国结瘤固氮树种资源及利用现状

我国结瘤固氮树木资源十分丰富，现已发现的豆科结瘤固氮树木有１８３种，非豆科结瘤固氮树木有４４种。目前，不少固氮树种在土壤氮素输入、荒山绿化、能源提供、发展经济和保持生态环境等方面起着十分重要的作用。     

固氮薪炭树种氮素营养及其应用

通过分析黄土高原主要薪炭树种叶片的氮素营养，表明在这１４种树木中固氮树种的氮素营养一般高于非固氮树种。经数理检验，两类树木的氮素营养差异达显著水平。在分析和检验的基础上，进一步探讨了固氮树种在黄土高原的应用问题。     

间种固氮树种──促进林木速生

间种固氮树种──促进林木速生一些树木的菌根能固氮，但目前还极少被人们所利用。我们已知能够固氮的树木有苏铁、苏木、桦木、蔷薇、合欢、紫穗槐、刺槐、黄檀、相思树、赤杨、胡知子、杨梅、荔枝、柑桔、木麻黄等。还有山毛榉科、鼠李秆树木的菌根能积累磷酸盐，并能释...     

我国结瘤固氮树种资源及利用现状

我国结瘤固氮树木资源十分丰富，现已发现的豆科结瘤固氮树木有１８３种，非豆科结大对木有４４种，目前，不同固氮树种在土壤氮素输入，荒山绿化，能源提供，发展经济和保持生态环境等方面起着十分重要的作用。     

沙枣的耐盐力与固氮研究

通过野外栽植试验和室内水培实验，证明沙枣抗逆性强、生长快、固氮活性强、固氮量高。沙枣固氮与耐盐特性之间关系密切，由于固氮增加了土壤肥力，提高了土壤养分，改变了土壤质地，降低了盐分，保证了树木成林及良好生长。沙枣可作为泥质海岸防护林体系建设中的主要造林树种。     

固氮树种与非固氮树种混交林研究现状

本文概述了国内外固氮树种和非固氮树种混交林的研究现状。指出在贫瘠缺氮立地上,固氮树种可改善林地小气候,提高林分稳定性,改良土壤,改善非固氮树种氮素营养状况,促进其生长,增加林地产量;而在肥沃富氮立地上,混交效益不能充分体现,树木生长不变或反而下降。同时,对混交林树种间存在的复杂关系（特别是特殊的营养关系）及其造林技术进行了讨论。最后指出这种类型的混交林由于在贫瘠地造林及在林业中部分代替无机氮肥方面的巨大潜力,必将在世界范围内得到长足的发展。     

木麻黄根瘤内生菌分离回接成功初报

<正> 非豆科固氮树木和豆科植物一样,同属于共生固氮体系,它们的固氮量远远高于自生固氮微生物。因此,历来受到人们的重视。然而,非豆科固氮树种根瘤内生菌的分离和纯培养一直未能得到解决,严重地阻碍了这个领域的基础理论研究和在林业生产上的应用。经过近70年的努力,1978年美国才首次从香蕨木根瘤中分离得固氮放线菌Frankia菌株。但到目前为止,仅从香蕨木、赤杨、胡颓子、沙棘、杨梅等属的根瘤中分离得内生菌,还有许多属宿主植物的根瘤内生菌至今还未能分离出来。最近(1982)H. G Diem等在加拿大微生物学杂志发表了分离木麻黄根瘤内生菌的报告,尽管他们实验证明分离菌确实属于弗     

树木庄稼也有相生相克

树木之间、庄稼之间、树木和庄稼之间,即有“亲朋好友”而相生,也有“冤家对头”而相克。人类就是要顺其相生,避其相克而种。 樱桃和苹果相生,若种在一起,各自都可放出一种挥发性气体,彼此互相吸收、促进生长发育,结出的果实格外香甜。刺槐和杨树是“好友”,刺槐是浅根性树种,杨树是深根性树种,互不争水肥,且刺槐的根瘤菌可固氮供给杨树,促进其生长。大豆、花生地内若种玉米,则大豆、花生的根瘤菌可固氮供给玉米,而玉米则可反哺碳水化合物给大豆、花生。黄瓜     

马尾松针叶中营养元素的分析和幼林施肥效益

<正> 一、引言树木是由许多有机物质和无机物质构成的。树体所贮藏的营养元素,除由空气中获取氧、二氧化碳和有些树木具有固氮能力外,大多数树木所需要的养分,都是从土壤和水中吸取的。因此,树木生育状况和生长环境有着密切的关系。早在1840年,德国农业化学家李比希(Liebig)就肯定地指出,矿物质是一切绿色植物唯一的养料,他还提出矿质营养学说和养分归还学说。近年来,国内外育种学家,生理、生化学家已将叶片营养分析,广泛地应用于诊断林木营养状况和育林措施的一种手段。因树木中营养物质含量的变化,受树体的内、     

Advances in European agroforestry: results from the AGFORWARD project

In global terms, European farms produce high yields of safe and high quality food but this depends on the use of many off-farm inputs and the associated greenhouse gas emissions, loss of soil nutrients and other negative environmental impacts incur substantial societal costs. Farmers in the European Union receive support through a Common Agricultural Policy (CAP) that comprises direct payments to farmers (Pillar I) and payments related to rural development measures (Pillar II). This paper examines the ways in which agroforestry can support European agriculture and rural development drawing on the conclusions of 23 papers presented in this Special Issue of Agroforestry Systems which have been produced during a 4-year research project called AGFORWARD. The project had the goal of promoting agroforestry in Europe and focused on four types of agroforestry: (1) existing systems of high nature and cultural value, and agroforestry for (2) high value tree, (3) arable, and (4) livestock systems. The project has advanced our understanding of the extent of agroforestry in Europe and of farmers’ perceptions of agroforestry, including the reasons for adoption or non-adoption. A participatory approach was used with over 40 stakeholder groups across Europe to test selected agroforestry innovations through field trials and experiments. Innovations included improved grazing management in agroforestry systems of high nature and cultural value and the introduction of nitrogen fixing plants in high value timber plantations and olive groves. Other innovations included shelter benefits for arable crops, and disease-control, nutrient-retention, and food diversification benefits from integrating trees in livestock enterprises. Biophysical and economic models have also been developed to predict the effect of different agroforestry designs on crop and tree production, and on carbon sequestration, nutrient loss and ecosystems services in general. These models help us to quantify the potential environmental benefits of agroforestry, relative to agriculture without trees. In view of the substantial area of European agroforestry and its wider societal and environmental benefits, the final policy papers in this Special Issue argue that agroforestry should play a more significant role in future versions of the CAP than it does at present.     

Agroforestry Tree Seed Production and Supply Systems in Malawi

A sustainable agroforestry tree germplasm supply system is vital to resource-constrained smallholder farmers who depend on agroforestry to improve the productivity of their farm enterprises. Successful adoption of agroforestry hinges on the development of a sustainable agroforestry tree germplasm supply system. This paper reviews the agroforestry tree seed supply system in Malawi, with a view to determining its sustainability and quality. Currently, more than 90% of the documented agroforestry tree seed distributed to farmers is produced by smallholder farmers collected mainly from scattered farmland trees, the remainder being produced from seed orchards and seed stands owned or controlled by research organizations. Three organizations—namely the Land Resources Centre (LRC), National Tree Seed Centre (NTSC) of the Forestry Research Institute of Malawi (FRIM) and the World Agroforestry Centre (ICRAF)—were identified as major procurers of agroforestry tree seed produced by smallholder farmers. Agroforestry germplasm is distributed to farmers by non-governmental organizations (NGOs) and government agricultural and forestry extension departments. The procurement and distribution of germplasm to farmers is in general effective. The major challenge to sustainability of agroforestry tree germplasm distribution in Malawi is dependence on donor funding. The agroforestry tree seed system is, to some extent, sustainable with regards to production, although the genetic quality of the germplasm is low. Germplasm storage facilities at national level are available and possibly adequate, but knowledge and information on effective low-cost tree germplasm storage systems at household level are limited. Sustainability could be enhanced by strengthening of grass-root organizations involved in tree seed production to institutionalize the distribution through farmer–farmer exchange. There is also a need to support the development, promotion and adoption of low-cost tree germplasm storage facilities by smallholder farmers.     

Large cardamom (Amomum subulatum Roxb.) plantation — An age old agroforestry system in Eastern Himalayas

Large cardamom (Amomum subulatum Roxb.) is a shade loving plant grown in the Indian hill states of Sikkim and Dargeeling district of West Bengal. About 30 important tree species are used to provide shade to the cardamom plants. Alnus nepalensis, a deciduous, nitrogen fixing and fast growing tree, is the species most commonly underplanted with cardamom. In addition to providing shade, it is also used for fuelwood. The old trees are cut and young plants coming up are allowed to grow in cyclic order. The quick decomposing leaf litter of A. nepalensis also fertilises the cardamom plants. The nitrogen added to the soil in this way has been found to be as high as 249 kg/ha. Large cardamom thrives well in a moist soil, which is maintained by water diverted from seasonal springs on the upper slopes. The system is well suited to conserving soil, water and tree cover of the characteristically steep slopes of the region. Moreover, the management inputs required for growing cardamom are low but the crop gives a higher financial return than rice or maize. The shade trees used in the system are also a major source of fuel, fodder and timber, especially as access to state owned forests is restricted by legislation. However, increasing incidence of viral chirkey and foorkey disease, panicle rot and capsule borer are reducing the cardamom productivity. It has been observed that integrating dairying and apiculture will further augment profitability from large cardamom agroforestry system.     

Evolution of agroforestry based farming systems: a study of Dhanusha District, Nepal

This paper examines how agroforestry-based farming systems evolved in the Dhanusha district of Nepal following the conversion of forest into agriculture during the early 1950s. Some data are from two focus group discussions with agroforestry farmers and one meeting with agroforestry experts. The farmers?? discussion traced the development of farming practices from 1950 to 2010 to identify the drivers of land use change. The experts?? discussion resulted in a scale to differentiate the prevailing farming systems in the study area considering five key components of agroforestry: agricultural crops, livestock, forest tree crops, fruit tree crops and vegetable crops. Data related to the system components were collected from the randomly selected households. The study reveals that land use had generally changed from very simple agriculture to agroforestry, triggered by infrastructure development, technological innovations, institutional support (subsidies and buy-back guarantees) and extension programs. A range of farming systems with varying degrees of integration was evident in the study area: simple agriculture; less integrated agroforestry; semi-integrated agroforestry and highly integrated agroforestry. The three types of agroforestry systems, which are the focus of this study, varied significantly in terms of farm size, cropping intensity, use of farm inputs, tree species diversity, tree density, home to forest distance and agricultural labour force.     

Agroforestry in the South Pacific region — an overview

The developing countries of the Pacific Region consist of 27 countries and territories with a total nd area of 542 000 km² and over 5 million inhabitants. Though highly variable in physical characteristics and land-use pattern, these countries, in general, give a higher priority for production of export crops over other agricultural crops, so that they are net importers of food. Natural forests of the region are luxuriant and floristically rich, but the level of their commercial exploitation is low. Swidden cultivation is the mainstay of subsistence livelihood, but with the increase in population, the system is now causing severe environmental and land-use problems.The major agroforestry systems and practices in the region include various forms of combination of tree crops such as coffee, coconut and cacao with nitrogen fixing trees such as Casuarina, Gliricidia and Leucaena, and food crops (mostly tubers) such as cassava, taro, sweet potato and yams. Additionally, some improvements to swidden (shifting) cultivation are also being tried in several places, the most common being the u use of Casuarina oligodon before abandoning the swidden as in PNG highlands, and intercropping food crops in tree crop stands.Land tenure system in most of the countries is the traditional clan of extended family control over land. This can have either positive or negative influence on the adoption of agroforestry practices depending on the extent and duration of tenancy tenure enjoyed by the assignees of land.Several governments of the region are now promoting the agroforestry approach. In hilly areas with poor access, farmers are forced to produce most of their basic necessities locally. On the other hand, the lack of roads and communication facilities can pose a problem in marketing any surplus products they have.The immediate opportunity in agroforestry in the region lies in making better use of the unexplored potential of a large number of locally available trees and agricultural crops. Intercropping in tree crop stands and the taungya system seem to propromising m methods for the Pacific region.Researh Fellow, July–September, 1984     

Tree Culture of Smallholder Farmers Practicing Agroforestry in Gunung Salak Valley,West Java,Indonesia

This paper investigates the types of agroforestry system that exist in Gunung Salak Valley, West Java, Indonesia in order to characterize the differences in their basic structure and associated crop plant diversity. Data were collected through rapid rural appraisal, field observation and focus groups, followed by household survey of a sample of 20 agroforestry farmers. Five main agroforestry systems (homegardens, fruit tree system, timber tree system, mixed fruit–timber system, and cropping in the forest understory) exist in the study area, and all of them exhibit a noticeable diversity in terms of both species composition and utilization. Products from farming accounted for an average 24 % of household income. They comprised agroforestry products which contributed IDR 3.25 million/year and other agricultural products contributing IDR 1.66 million/year. The observed agroforestry systems include not only a form of forest dominated by ‘cultivated trees’, but also an anthropogenic vegetation formation derived from agricultural antecedents. In land-use classifications agroforestry systems are not recognized as forestry, but like forests they provide tree products and services. Classification will always be disfunctional if a binary system is applied, thus a more sophisticated approach should be adopted that incorporates the economic and environmental characteristics of a wider range of systems.     

Establishment of Prosopis cineraria (L.) druce in the hot deserts of India

Prosopis cineraria (L.) Druce, commonly known as Jandi, is a deep rooted, nitrogen fixing, multipurpose tree endemic to the hot deserts of India. These trees are the essential component of the agroforestry land use system in these parts of India. The shade-intolerant tree reproduces poorly in nature and is difficult to propagate vegetatively. Germination up to 86.6% was observed after 15 days in seeds soaked in water at room temperature for 72 h. In another treatment, pouring of boiling water twice (at 0 and 6 h) over seeds and germinating after 12 h produced germination rates of 92.6%. Field establishment of containerized transplants in polythene bags (22×10 cm; 150 gauge) gave 90.3% survival after 6 months and 75.4% survival after 24 months. Seedlings were irrigated once during transplanting with 15 1 water. Bare root transplants and manual direct seeding after 6 months had a survival of 30.8 and 45.0%, respectively. Increased levels of nutrients (N, P and K), moisture content and organic carbon were observed under plantations as compared to open areas.     

Poplar agroforestry in India

The development of poplar agroforestry and associated research in India is reviewed. The model of agroforestry development involving a partnership between farmers, the private sector and the government is worthy of further investigation for application in other areas of India and to other countries. A number of suggestions are given for further research in the context of optimising the system for resource-poor farmers. These include changes in tree and crop varieties, tree spacing, and utilisation of small diameter logs, and other poplar products.     

现代遗传育种技术在农林复合系统中的应用

分子标记、辐射育种、基因工程等现代育种技术及其发展将对农林复合系统发挥重要作用.文中分析农林复合系统种间关系中存在的诸如林木品种选育周期长,冠幅影响林下作物光合效应,与林下作物争夺资源导致林下生物量减少等问题,从遗传育种对农林复合系统中林木的作用,生物技术限制林木高生长和冠幅长势,选育优质高产林下作物等方面阐述遗传育种...     

Role of social aspects in extent of on-farm tree growing in subsistence agroforestry systems of Western Himalaya

Many so-called society-oriented agroforestry programs, mainly in developing countries, fail because they do not take account of the social structure in their design. This study provides empirical evidence of the impact of social structure on the extent of on-farm tree growing. The study has been carried out in Mandi district of Himachal Pradesh, in Indian Western Himalaya. Analysis of survey data reveals significant relationships between extent of on-farm tree growing and caste, education of the head of household, family literacy, primary occupation, government employment, mobility of the household head, importance of tree growing for future generations, and holy tree worship practices. Households with concrete houses had more trees than households with mixed, mud and wooden houses. The study implies a need to consider social factors to encourage the level of on-farm tree growing and to design socially acceptable agroforestry programs. The study also emphasises the need for a holistic approach to agroforestry development by integrating other continuing rural development programs with that of agroforestry to increase the level of on-farm tree growing.