四川盆地丘陵区坡地农林复合系统内部结构和系统综合效能的研究

针对四川盆地丘陵区农林生产特点和坡地农林复合系统特征,对其内部结构进行综合研究。分析了林带对农作物的正,负效应,依据林带间散射辐射分布规律、农地水土流失特征和农作物产量分布格局等方面与林带间距离的相互关系,提出了坡地林带间距离应不小于３倍林带平均高,才能保证农作物不至于减产;同时,对建成的坡地农林复合系统模式进行综合效能分析,表明,与农地系统对比,坡地农林复合系统提高了土地生产力、能量转化率、营养     

水分亏缺条件下农林复合模式的生物生产力分析

本文针对１９９７ 年度四川盆北山丘区遭遇的严重旱情,探讨了阆中市岳家沟流域农林复合系统内的水分亏缺及其与农经作物生物生产力的关系,分析了不同林带距离对林带＋ 水稻复合模式作物产量的影响,结果表明：土壤有效持水量和土壤相对含水量（ＲＷ ）是土壤抗旱性能的重要指标,土壤一定的肥效性有利于土壤抗旱性能的提高;在连续干旱４０天后,系统内各农林复合模式土壤水分亏缺极为严重,并对花椒成活和生长、大春作物产量及产品的经济性状构成了严重的影响,其中花椒成活率为６０．７％ ～７５．０％ ,各大春作物相对减产幅度为玉米３０．９％ ,花生４６．０％ ,水稻２８．９％ ～６２．２％ ,棉花２３．６％ ～５９．３％ ,表现出整个系统综合抗旱能力较差;在水分亏缺之下,不同林带距离水稻生物生产力差异显著,并表现出林带对农作物的光胁地在一定范围内并不表现为负效益而相对具有增产的作用。     

农田林网胁地发生规律及防治措施

平原绿化是我国十大林业生态工程之一 ,在平原地区林网对农田的保护作用与农作物的明显增产是人所共知 ,但林带对农作物影响也是很大的 ,林带边缘两侧的农作物因发育不良而减产。这种现象老百姓叫做胁地 ,胁地是平原林区普遍存在而又难于解决的问题。林网造成胁地的主要原因是 ,由于林带树冠遮荫蔽光 ,影响了农作物的光合作用和正常生长 ;林带树木的根系侵入林带两侧农田 ,与农作物争水争肥而使农作物发育不良减产。为了防止和减轻农田林网胁地 ,从 1978年鲁北平原马西会战就开始关注 ,并围绕着林网胁地做了些试验探讨性的工作。经 2 0多年…     

农田防护林胁地效应及其解决对策

论述了防护林带胁地原因及胁地范围与树种和林带宽度的关系,在防护效益不减的情况下,通过物理、化学和生物学措施,提出了解决林带胁地的几种途径,从而减少了林带的副效应,起到了减少林带占地、减轻林带胁地的作用,从而提高了整个防护林体系的效益。     

如何预防林网胁地

随着我区各地农田林网化水平的提高,农林矛盾日益突出。许多农民朋友反映:“树胁地影响农作物产量。”针对这一问题,我们通过几年的探索,观测查证,摸索出一些规律:树胁地一般是对秋田农作物影响重,对夏田农作物影响轻;对干旱土地上生长的农作物影响重,对湿润土地上的农作物影响轻;对贫瘠土地上生长的农作物影响重,对肥沃土地上生长的农作物影响轻;树大胁地重,树小胁地轻;栽高不胁低,栽低不胁高。依据此规律,提出预防措施,以供农林朋友参考。合理规划“网格”:林带网格过大,防护效益差,过小则胁地重。在内蒙中西部区,一般宜在100～300亩。地…     

杨树农林复合经营研究进展

摘要：杨树农林复合经营是杨树产业的一个重要发展方向,在全球范围逐步受到重视。本文整理了杨树农林复合经营模式、并综述了农林复合经营效益、胁地效应及他感作用等方面的研究进展。在此基础上分析了杨树农林复合经营研究中存在的问题及展望。     

四川盆地低山丘陵区农林复合模式分类与优化选择

针对四川盆地长江防护林体系建成后区内农林复合特征，提出了农田林网型、坡地林带型、山地林药型、林农间作型和庭园复合型计5个类型30个农林复合模式的分类系统，运用动态经济分析方法优选出了适于四川盆地低山区和丘陵区生产发展的10个优良农林复合模式。     

农田防护林带胁地原因及控制措施

农田防护林在防风固土、增温保墒和提高农作物产量等方面的效益,已在生产实践中得到了证实。但近年来,由于国家调整土地及一系列富农政策的出台和实施,农林争地矛盾尤显突出,农田防护林也存在着胁地的不利一面。因此,分析林带胁地的原因,探索减免胁地的技术措施,对扩大营造农田     

如何减轻林带胁地

在淮北平原地区。营造农田防护林时，群众对林带树冠的遮荫和地下根系争水，争肥造成林缘附近的农田生长不良而显著减产，即“林带胁地”现象，不能够充分认识，心存疑虑。采取以下方法和措施，可减轻林带胁地。     

单项承包“林胁地”

农田防护林带在林网中存在着“近胁地,远受益”的客观现实。林带树木根系吸收大量水分、养分,树冠遮荫,使林带近缘的土壤变得瘠薄。人们把这种影响叫做“胁地”,造成农作物减产。而那些离林带较远处,由于林带防风、固沙,调节小气候,较好地维持了生态平衡,又不受林带树木争水、争肥、争阳光的危害,农作物能大面积增产。在大包干生产责任制实行以前,大部分农田林网属于一个经济核算单位,对于一个生产队来说,林网内的受益面积远远超过林胁地面积,一般为九与一之比,增产效益仍是显著的,但是,农业实行大包干责     

四川盆地丘陵区坡地农林复合系统林带类型、农作物复种方式的选择

针对四川盆地丘陵区农、林业生产特点和坡地农林复合系统特征，运用层次分析法（ＡＨＰ），从结构、功能，效益方面设置评价指标，分别对系统中的６种林带类型和１０种农作物复种方式进行综合评价，结果提出了３种较好的林带类型（即桤、柏混交和栎，柏混交－灌－草结构的林分以及桤木－草结构的林分）和４种较好的农作物复种方式（即小麦－花生、小麦／西瓜／蔬菜，蚕豆／玉米／红薯和蚕豆／西瓜／红薯等）；为该区坡地农林复合系统     

Indigenous market-oriented agroforestry: dissecting local diversity in western Amazonia

This paper reports on a study of local diversity and variation in indigenous agroforestry practices among Amazonian peasants in a traditional community near Iquitos, Peru. Data were gathered through in-depth interviews with agroforestry-reliant households n = 36) on farming practices, demographic characteristics, income-expenditures and household wealth. Visits to crop fields and forest fallows n = 329) allowed the reconstruction of extensive cropping histories. More in-depth assessments of crop occurrence, density and diversity were conducted on 83 fields. Our results indicate considerable variation in field characteristics, agroforestry-cycles, and household agroforestry portfolios. Agroforestry practice is found to be strongly related to access to land within the community: households holding more land use both potentially more sustainable and more lucrative swidden-fallow agroforestry systems. Our results question the view of indigenous agroforestry systems as intrinsically ‘stable, equitable, and sustainable’, and underscore the importance of studying local variation in indigenous agroforestry practices. Promising avenues are discussed for future research on the factors related to the successful adoption of sustainable agroforestry systems. This revised version was published online in June 2006 with corrections to the Cover Date.     

Comparisons of Mayan forest management, restoration, and conservation

Numerous communities associated with at least five distinct ethnic Mayan groups in southern Mexico and Central America continue to rely upon forested areas as integral components of their agricultural systems. They carefully manage these areas so that forests provide food, raw materials, and animals. Management practices include removing and planting of woody and herbaceous species, apiculture, and seed harvest. Mayan agroforestry systems in geographically and ecologically distinct areas of Mesoamerica were evaluated to better understand traditional agroforestry system components and how indigenous Mayan agroforestry could be a part of regional forest conservation and restoration. Systems were within Mexican land grant areas (ejidos) or on contested land. Although these systems rely upon different woody species and management techniques, common among them are: (1) the use of multi-stage and successional pathways with forest as a part of the larger system, (2) species that are believed by traditional ecological knowledge (TEK) to accelerate forest regeneration - more than 30 tree species are recognized and managed as potential facilitators of forest regeneration and (3) direct human consumption of forest products at all stages of regeneration.     

韩国山林农业概况与类型

"山林复合经营项目"是韩国在1999年为了增加林业从业者的收入而正式实施的,主要包括短期收入、木材生产和复合山地管理3种类型。截至2005年,该项目在韩国国内的168个市(区)都得到了推广。文中主要介绍韩国山林农业系统,分析该系统存在的问题并探讨与之相应的解决方案,提出应在开发更可行的复合农林经营模式的基础上加大对林业从业者的培训和奖励力度并改善对复合农林业的支持制度。     

The role of complex agroforestry systems in the conservation of forest tree diversity and structure in southeastern Ghana

The role of different agroforestry systems in the conservation of plant diversity and forest structure has not been directly compared in many agricultural dominated landscapes. In this study, we investigated tree diversity and forest structure in a complex agroforestry landscape traditionally grown for cocoa and mixed food crops and compared these to the natural forest in southeastern Ghana. The study was carried out using 36 25 m × 25 m plots. There was significant difference [95% Confidence Interval (95% CI)] in the native forest/non-crop tree species richness between the natural forest and the agroforest farmlands but species richness was similar between the cocoa and mixed food crops agroforests. The density of native forest/non-crop trees was significantly higher (P < 0.05) in the natural forest but similar between cocoa and mixed food crops agroforest. Similarly, the basal area of native forest/non-crop trees was significantly higher (P < 0.05) in the natural forest but comparable between cocoa and food crops agroforest. Of the 20 most abundant native forest/non-crop trees recorded, 12 of them showed significant responses (P < 0.05) to land use change with nine of the species significantly abundant in the natural forest relative to the agroforest systems. Eighteen native forest/non-crop trees species in the agroforestry systems were commonly recorded as being used; 100% of them being used as fuel wood with 83.3 and 77.8%, respectively, used as medicines and materials. The findings of this study suggests that although complex agroforestry systems are a poor substitute for the natural forest the heterogeneous mosaic landscape in which complex agroforestry forms part can be strategically managed to maximize the benefits of both sustainable agriculture production and conservation of plant diversity by acting as buffer between protected areas and intensively managed areas.     

Seasonal variation of soil respiration rates in a secondary forest and agroforestry systems

Agroforestry systems are widely practiced in tropical forests to recover degraded and deforested areas and also to balance the global carbon budget. However, our understanding of difference in soil respiration rates between agroforestry and natural forest systems is very limited. This study compared the seasonal variations in soil respiration rates in relation to fine root biomass, microbial biomass, and soil organic carbon between a secondary forest and two agroforestry systems dominated by Gmelina arborea and Dipterocarps in the Philippines during the dry and the wet seasons. The secondary forest had significantly higher (p < 0.05) soil respiration rate, fine root biomass and soil organic matter than the agroforestry systems in the dry season. However, in the wet season, soil respiration and soil organic matter in the G. arborea dominated agroforestry system were as high as in the secondary forest. Whereas soil respiration was generally higher in the wet than in the dry season, there were no differences in fine root biomass, microbial biomass and soil organic matter between the two seasons. Soil respiration rate correlated positively and significantly with fine root biomass, microbial biomass, and soil organic C in all three sites. The results of this study indicate, to some degree, that different land use management practices have different effects on fine root biomass, microbial biomass and soil organic C which may affect soil respiration as well. Therefore, when introducing agroforestry system, a proper choice of species and management techniques which are similar to natural forest is recommended.     

Analysis of existing agroforestry practices in Madhupur Sal forest: an assessment based on ecological and economic perspectives

A study was conducted in Madhupur sal forest of Tangail, Bangladesh to identify the suitable agroforestry practices of the area. Considering the ecological aspects of different agroforestry practices 10 sample plots (10 m × 10 m) from each land uses were taken, including natural forest to get a comparative scenario. The study showed that among the different agroforestry practices, Margalef and Shannon-Weiner index values are the maximum for pineapple agroforestry and lower for banana agroforestry, and Evenness index value is the maximum for lemon agroforestry. Determination of tree biomass in different land uses revealed that it is highest (3 078.6 kg/100 m²) in natural forest followed by pineapple agroforestry, lemon agroforestry and banana agroforestry. Soil pH, moisture content, organic matter, organic carbon, phosphorus and total nitrogen showed statistically significant variation while bulk density, particle density, sulphur and potassium did not show any statistically significant variation among the land uses. Soil fertility status showed that pineapple agroforestry is more fertile than rest of other land uses. The Net Present Value (NPV) indicated that banana agroforestry is financially more profitable than other two systems, while the Benefit-Cost ratio (BCR) is higher in pineapple agroforestry (4.21 in participatory agroforestry and 3.35 in privately managed land). Even though banana agroforestry gives higher NPV, capital required for this practice is much higher. The findings suggest that pineapple agroforestry has a tendency towards becoming ecologically and economically more sound than other two practices as it has better ecological attributes and required comparatively low investment.     

Alternate cycle agroforestry

Agroforestry research and design has heavily favored intergrated production of annuals and perennials, that is production of tree crops on the same parcel of land and at the same time as production of food crop annuals. For areas having high population densities and intensive modes of agricultural production, integral agroforestry may be appropriate, but for areas of sparse population where extensive agriculture is practiced or marginal hill lands, alternate cycle agroforestry may prove more suitable. Alternate cycle agroforestry, in the form of modified forest swidden systems, is discussed and compared to integral agroforestry systems. Advantages and disadvantages of each system are discussed relative to their use on marginal hill and forest lands.The author wishes to thank N.T. Vergara, L.S. Hamilton, A.T. Rambo and K.F.Wiersum at the Environment and Policy Institute of the East-West Center for their comments.