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1.
Heidi C. Zimmer Hanh Le Thi Duc Lo Jack Baynes J. Doland Nichols 《Agroforestry Systems》2018,92(6):1721-1735
Intense cultivation of annual crops on steep slopes in northwest Vietnam has resulted in widespread and severe erosion. This has led to myriad problems including siltation of dams critical for hydroelectricity generation, and increasing levels of rural poverty due to declining crop yields. The solution to these problems is sustainable land management, in particular sloping land agricultural technologies. Our study focuses on defining, and finding solutions to, a second-order problem: that farmers are reluctant to adopt sustainable land management practices, despite numerous projects demonstrating their effectiveness. Interviews with farmers in northwest Vietnam confirmed that intense corn cultivation on steep slopes provided the majority of income for most households. The financial security associated with growing corn (compared to alternative crops) was the deciding factor in land management choices. However, interviews also revealed that farmers were dissatisfied with growing corn because of low income and high input costs. Farmers’ replies indicated that they thought they had no alternative to growing corn. However, farmers were aware of alternative crops, and were particularly interested in growing grass, fruit trees and timber trees, although few farmers were keen to be first to adopt these alternative species extensively. Further research is required on development of production-to-commercialization chains for alternative crops, and more generally, to find ways to increase farmer financial security during transition to sustainable land management. 相似文献
2.
Socioeconomic factors affecting the adoption potential of improved tree fallows in Africa 总被引：2，自引：1，他引：1
S. Franzel 《Agroforestry Systems》1999,47(1-3):305-321
In many parts of Africa, farmers periodically fallow their land, which is allowing land to lie idle for one or more seasons primarily to restore its fertility. This paper assesses the feasibility, profitability, and acceptability of improved tree fallows, which are the deliberate planting of trees or shrubs in rotation with crops to improve soil fertility. Improved tree fallows are assessed at different stages of intensification, drawing on farmers' experiences in three different settings. In extensive systems where land is plentiful and existing fallows with natural regeneration of vegetation restore soil fertility (southern Cameroon), farmers have little incentive to invest labor in establishing improved fallows. Where population density is higher and fallow periods are decreasing and farmers perceive a decline in soil fertility (eastern Zambia), improved fallows have great potential. In intensive systems where land is unavailable and cropping is often continuous (western Kenya), many farmers find it difficult to fallow land. Even here, there is scope for introducing improved fallows, especially among farmers who have off-farm income. Labor constraints and institutional support were found to greatly influence the feasibility of improved fallows. In intensive systems, low returns to cropping, low base yields, and a high opportunity cost of labor increase the returns to improved fallows. Principal factors associated with acceptability include past perception of soil fertility problems, past use of measures for improving soil fertility, current fallowing, economic importance of annual cropping, and wealth level. Adoption potential may be increased by reducing fallow periods, intercropping trees and crops during the first season, reducing establishment costs, producing higher value by-products, and by encouraging farmers to test improved fallows on high-value crops.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
3.
G. Moreno Marcos J. J. Obrador E. García E. Cubera M. J. Montero F. Pulido C. Dupraz 《Agroforestry Systems》2007,70(1):25-40
Dehesas are extant multi-purpose agroforestry systems that consist of a mosaic of widely-spaced scattered oaks (Quercus ilex L.) combined with crops, pasture or shrubs. We aimed to clarify the role of trees in dehesas of CW Spain focussed on the
analysis of tree-understorey interactions. Spatial variability of resources (light, soil moisture and fertility), microclimate,
fine roots of both herbaceous plants and trees and forage yield was measured. Additionally, we compared the nutritional and
physiological status, growth and acorn production of oaks in cropped (fodder crop), grazed (native grasses) and encroached
(woody understorey) dehesa plots. Significant light interception by trees was limited to the close vicinity of the trees,
with very low reduction away from them. Both microclimate and soil fertility improved significantly in the trees vicinity,
irrespective of soil management. Soil moisture varied very few with distance from the trees, as a result of the extended root
system of oaks. Root systems of trees and herbs did not overlap to a great extent. Crop production was higher beneath trees
than beyond the trees in unfertilised plots and foliar nutrient content of oaks did not increase significantly with crop fertilisation,
indicating that trees and crops hardly compete for nutrients. Moreover, trees benefited from the crop or pasture management:
trees featured a significantly improved nutritional and physiological status, a faster growth and a higher fruit productivity
than trees growing in encroached or forest plots. 相似文献
4.
重金属铅和镉对土壤与作物的危害及防治 总被引：14，自引：0，他引：14
重金属污染环境对人类的危害很大,对作物产量和质量也影响极大。在受重金属污染的土壤上,如果种农作物或其它植物,可采用排土客土法,也可施用化学改良剂或调整种植结构,发迹耕作制度,减少生金属进入食物链,在垦复绿化时要造反估大气污染和土壤污染的极端条件下能良好地生长。 相似文献
5.
Lloyd J Bird MI Vellen L Miranda AC Veenendaal EM Djagbletey G Miranda HS Cook G Farquhar GD 《Tree physiology》2008,28(3):451-468
To estimate the relative contributions of woody and herbaceous vegetation to savanna productivity, we measured the 13C/12C isotopic ratios of leaves from trees, shrubs, grasses and the surface soil carbon pool for 22 savannas in Australia, Brazil and Ghana covering the full savanna spectrum ranging from almost pure grassland to closed woodlands on all three continents. All trees and shrubs sampled were of the C3 pathway and all grasses of the C4 pathway with the exception of Echinolaena inflexa (Poir.) Chase, a common C3 grass of the Brazilian cerrado. By comparing the carbon isotopic compositions of the plant and carbon pools, a simple model relating soil delta 13C to the relative abundances of trees + shrubs (woody plants) and grasses was developed. The model suggests that the relative proportions of a savanna ecosystem's total foliar projected cover attributable to grasses versus woody plants is a simple and reliable index of the relative contributions of grasses and woody plants to savanna net productivity. Model calibrations against woody tree canopy cover made it possible to estimate the proportion of savanna productivity in the major regions of the world attributable to trees + shrubs and grasses from ground-based observational maps of savanna woodiness. Overall, it was estimated that 59% of the net primary productivity (Np) of tropical savannas is attributable to C4 grasses, but that this proportion varies significantly within and between regions. The C4 grasses make their greatest relative contribution to savanna Np in the Neotropics, whereas in African regions, a greater proportion of savanna Np is attributable to woody plants. The relative contribution of C4 grasses in Australian savannas is intermediate between those in the Neotropics and Africa. These differences can be broadly ascribed to large scale differences in soil fertility and rainfall. 相似文献
6.
The homegardens are characterised by an intensive integration of numerous multipurpose trees and shrubs with food crops and animals, simultaneously on the same unit of land.The Chagga are skilled farmers with an intimate knowledge of the crops and their ecological requirements. They have a good idea of functions/uses of the plant species on their farms. The large species diversity provides both subsistence and cash crops. It enables the farmer to keep his management options open and provides insurance against drought, pest and economic risks. 相似文献
7.
David P. Shelton Rodney A. Wilke Thomas G. Franti Scott J. Josiah 《Agroforestry Systems》2009,75(1):83-89
Farmer-to-farmer outreach was used within a targeted watershed to promote the installation of conservation buffers. In this
program called “FarmLink”, four farmers/landowners were employed part-time as “advisors” and trained by University of Nebraska-Lincoln
Extension, Natural Resources Conservation Service, and Natural Resources District personnel. Topics included basic buffer
design and benefits, availability of incentive programs, and sales techniques. These individuals then contacted their neighbors
to explain the need for and benefits of buffers and other conservation practices. In early 2003, 42 landowners were contacted,
leading to contracts for the establishment of 16 separate conservation practices on 24.8 ha (61.3 acres) of farmland. These
included just over 8 ha (20 acres) of grassed waterways or similar plantings and 14 ha (35 acres) of streamside buffers. In
addition, because of information received in the training sessions, one of the advisors installed 1.7 ha (4.3 acres) of streamside
buffers, 0.45 ha (1.1 acres) of grassed waterways, and 2.0 ha (5.0 acres) of grasses and forbs on his own land. During these
contacts, it became apparent that: (1) many farmers and landowners were not familiar with the multitude of programs available
to assist with the installation and maintenance of conservation practices; and (2) landowners generally appreciated the personal
touch of someone coming out to talk directly to them, pointing out specific areas on their land where conservation practices
could best be implemented, discussing available compensation programs, and describing management needed to help ensure practice
success. Although one-to-one contacts cannot be used in all cases, it was demonstrated to be effective in this watershed. 相似文献
8.
E. T. Craswell A. Sajjapongse D. J. B. Howlett A. J. Dowling 《Agroforestry Systems》1997,38(1-3):121-137
Steeply sloping lands are widespread in the tropics. An estimated 500 million people practice subsistence agriculture in these
marginal areas. Continued population growth has led to the intensified cultivation of large areas of the sloping lands, exacerbating
the problem of soil erosion. Although research shows that alley cropping and other contour agroforestry systems can stabilize
the sloping lands, these systems have not been widely adopted by farmers.
The Framework for Evaluating Sustainable Land Management (FESLM) has been tested in sloping land areas in the Philippines.
Sustainable land management must be productive, stable, viable, and acceptable to farmers, while protecting soil and water
resources. Farms on which contour hedgerow intercropping has been adopted meet the multifaceted requirements of FESLM, whereas
the farmers' current practice does not. Appropriate land management measures for particular locations depend on a complex
suite of social, economic, and biophysical factors, and need to be developed in participation with farmers.
The role of agroforestry in sustainable management of sloping lands is the subject of networks coordinated by the International
Board for Soil Research and Management (IBSRAM) in seven countries in Asia (ASIALAND) and four countries in the Pacific (PACIFICLAND).
We review selected outcomes from a wealth of network data. From these results the following conclusions about the sustainability
of various agroforestry systems for sloping lands can be drawn:
• In the Pacific, soil loss from sloping lands due to water erosion under farmers' current practices is episodic, unpredictable,
and possibly not severe;
• Agroforestry systems that utilize legume shrubs, fruit trees, coffee (Coffea spp.) or rubber (Hevea brasiliensis) provide
useful economic returns, but are not an essential component in terms of soil protection because grass or pineapple (Ananas
comosus) planted on the contour are equally effective in reducing erosion;
• Agricultural intensification will lead to nutrient mining, reduction of aboveground biomass, declining yields, and less
soil protection unless external sources of nutrients are used;
• nitrogen can be effectively supplied using legumes;
• Cash derived from hedgerow trees and/or shrubs may providean incentive for their adoption by farmers, as well as funds to
purchase external inputs such as fertilizers;
• Labor may be a major constraint to the adoption of complex agroforestry systems.
We also discuss the information management systems required to effectively manage and utilize the extensive sets of experimental
and indigenous data being accumulated. We believe such information systems can facilitate technology transfer across and between
regions, and improve the efficiency of research into agroforestry and other land-management approaches.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
9.
Information about traditional and unreported agroforestry systems could be useful as a basis for developing adoptable innovations.
The Quezungual System, found in the department of Lempira in western Honduras near the border with El Salvador, is one such
indigenous system. The distinctive feature of the system is the existence of various naturally-regenerated trees and shrubs
that are pollared to a height of approximately 1.5 metres. Farmers also leave taller trees in the fields and these include
Cordia alliodora (laurel) and various fruit trees such as Psidium guajava (guayabo). A variety of crops is grown within the
System including Zea mays (maize), Sorghum bicolor (sorghum) and Phaseolus vulgaris (beans). Advantages of the System, identified
by farmers, include retention of soil moisture, production of fruits and timber, and the fact that plots can be cultivated
for longer periods than is normal practice before being left in fallow. One of the prerequisites for the establishment of
the System is that farmers abandon the practice of burning their fields prior to the beginning of the rains in April. Those
practising the Quezungual System are smallholder farmers living in areas with a scarcity of land. Farmers have customary but
not legally- recognised title to their land and many of them have fewer than 2.5 ha of land, much of it on slopes from 5%
to 50%. There is growing adoption of the System because of the direct benefits to the smallholder farmer.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
10.
Reforestation is one of the most important and efficient measures of water and soil conservation. Based on field investigations
in the Shangyang Soil Conservation and Reforestation Station in Huizhou, Guangdong Province, China, we studied the variation
in vegetation development, vegetation succession processes and soil erosion. The regional vegetation consists mainly of monsoon
evergreen broad-leaved forests (MEBF). The area was deforested and became a denuded hill area with extremely high soil erosion
in the 1960s and 1970s. Then, the area was closed in order to allow recovery of the vegetation. Under natural conditions the
vegetation development and succession processes were slow during which soil erosion and strong sunshine and evaporation slowed
down the development of the vegetation. About 25 years later, the vegetation cover was still merely 35% or so. The dominant
vegetation types were heliophilous herbage and shrubs which formed a poorly developed shrub-herbage community and erosion
remained high. In contrast, reforestation with selected tree species dramatically speeded up the vegetation succession process.
About 12 years after reforestation, vegetation cover of the Acacia auriculiformis plantations in the Shangyang Station was 90% and erosion was under control. After 23 years, understory vegetation, consisting
of indigenous species, had developed in the plantations. The planted trees and naturally developing herbage, shrubs, bamboo,
local trees and liana formed a complex vegetation community in three layers. It will take 60 years for the vegetation to succeed
from bare land to a secondary growth forest under natural conditions. Reforestation may speed up the vegetation succession
process. The time may be reduced to 20 years. Reforestation is the most effective measure of vegetation restoration and erosion
control in this area.
__________
Translated from Acta Ecologica Sinica, 2006, 26(8): 2558–2565 [译自: 生态学报] 相似文献
11.
Sai Leung Ng Qiang Guo Cai Shu Wan Ding Kwai Cheong Chau Jie Qin 《Agroforestry Systems》2008,74(3):279-291
Soil erosion has long been recognized as a major environmental problem in the Three Gorges Region (TGR) where slope farming
is commonly practiced but the local topography is hilly. In consideration of the poor socioeconomic position of local farmers,
low cost hedgerows had been introduced as a soil conservation measure to the TGR in the late 1980s. A collaborative research
programme was initiated by the Chinese University of Hong Kong, the Chinese Academy of Science, the Huazhong Agricultural
University, and the Bureau of Soil and Water Conservation of Zigui County to study the potential of adopting hedgerows in
the TGR. Six experimental plots (10 m × 2 m, gradient = 25°) were constructed at Zigui County, Hubei Province to study effects
of hedgerows on erosion, nutrient loss and crop productivity. Results indicated that there were significant relationships
between rainfall and runoff, and rainfall and soil loss, respectively. Conventional slope farming could not be considered
a sustainable agricultural practice because it resulted in severe erosion and low crop yield. Hedgerows per se seemed not
to be effective in reducing soil loss and boosting crop productivity, but performances could be greatly improved when they
combined with the use of fertilizers. Current farming and fertilization practices, however, generally did not meet N demands
of crops. Results and findings of this paper will contribute towards a technical reference for the promotion and adoption
of hedgerows in the TGR. 相似文献
12.
In the água de Gato Watershed on the island of Santiago, Cape Verde Islands, 51 farmers were surveyed regarding their attitudes
and knowledge of agroforestry. The farmers identified eight constraints to agroforestry implementation, with virtually all
indicating that a source of loan funds was the major concern. Space or land constraints and availability of tree seedlings
were identified as constraints by 94% and 88%, respectively. Despite these concerns, 92% of the farmers expressed a willingness
to adopt or improve agroforestry practices in the watershed, with 73% expressing a willingness to establish fruit trees, 53%
willing to establish trees or shrubs for fuelwood, and 16% willing to plant trees for shade. 相似文献
13.
退耕还林地造林树种选择的探讨 总被引：10，自引：3，他引：10
退耕还林，是我国当前为改善生态环境、治理国土的一项重大决策。为使退耕还林农户获取较高经济收益，“稳得住”退耕还林土地，其关键在于退耕还林地造林树种的正确选择。为获得发展山区经济、改善生态环境的双重效益，退耕还林地的造林树种选择，应遵循适地适树、乡土树种优先、经济效益与生态效益相统一、按不同效益区划选择树种、多种乔灌草植物相结合、为野生动物提供食物和庇护场所的6项原则。从利用花、果实、种子、芽、枝叶为主获取经济效益，而不以砍伐树干，取根获得效益出发，提出了青剌尖等30余种树种供云南的退耕还林地作造林树种选择用。 相似文献
14.
Productivity, sustainability and economics of agriculture, forestry and agroforestry land use practices were compared over
a six year period in a split plot experiment on a moderately alkali soil of the Central Soil Salinity Research Institute,
Karnal, India. Three commercial trees of the area formed the main plot treatments and four crop sequences were the sub-plots.
The trees were: poplar (Populus deltoides), Acacia (Acacia nilotica) and Eucalyptus (Eucalyptus tereticornis), and the crop
sequences were (1) rice (Oryza sativa)-wheat (Triticum aestivum) for four years followed by guinea grass (Panicum maximum)-oats
(Avena sativa) for two years; (2) rice-Berseem (Trifolium alexandrium) for four years followed by cowpea (Vigna unquiculata)-Berseem
for two years; (3) pigeonpea (Cajanus cajan)/sorghum (Sorghum bicolor)-mustard (Brassica juncea) for three years followed
by turmeric (Curcuma longa) for three years and (4) no intercrops (only trees). Eucalyptus and poplar gained maximum height,
girth and woody biomass in six years when they were intercropped with rice crops in sequences 1 and 2. Acacia attained maximum
growth in the absence of intercrops. Protein content in guinea grass was more under tree canopies than in the open. Soil amelioration
during five years followed the order: Acacia based system > poplar > Eucalyptus > sole crops. The benefit-cost ratio was heighest
(2.88) in poplar based system and minimum (1.86) in Acacia based system. The study indicated that growing trees and agricultural
crops together is a better land use option in terms of productivity, maintenance of soil conditions and economics.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
15.
In Pakistan, particularly in Punjab Province, it is difficult for agrofarmers to combine their indigenous knowledge and modern scientific methods to evaluate existing traditional farming systems and forestry practices. This requires an evaluation of indigenous soil classification in simple terms along with knowledge of the local flora, especially trees. This study focuses on land suitability classification for trees in the Attock District of Punjab, Pakistan. A survey was conducted which included interviews of local agrofarmers as well as standard soil analyses including both chemical and physical determinations of local soil types. An evalu- ation of soil types for cultivation of various crops was carried out given its total extent, component soil series and their proportions, spotting characteristics of each soil series and their major limitations/hazards for trees/crops. These would lead to the identification of various tree species according to soil characteristics. Then, according to the soil types and species, a land suitability map was obtained for the choice of tree species by using geographic information system (GIS) software. Land suitability classification will help local agroforesters/agrofarmers in matching suitable agricultural trees/crops properly for different soils in the area. 相似文献
16.
P. B. Dharmasena 《Agroforestry Systems》1994,28(3):203-212
Traditional agricultural villages in the dry zone of Sri Lanka are minor watersheds where small earth bank reservoirs provide water for irrigation and domestic purposes. The farmers practise rainfed farming on a shifting basis called chena in the reservoir catchments, which are being degraded due to soil erosion. The consequent sedimentation in reservoirs has reduced the extent of irrigation, and the total farming system has lost its ecological balance and economic sustenance. The present study aimed at identifying suitable farming methods for reservoir catchments in order to prevent further deterioration.The investigation was carried out on plot basis to assess soil loss and runoff from forest, scrub and cultivated lands as well as from four other types of farming lands namely plough-farming, bund-farming and two conservation farming practices: strip mulch and graded hedgerow farming. In graded hedgerow farming hedgerow trees are planted across the slope with a mild gradient of 0.4–0.5%. The study was carried out in a reservoir watershed at Maha Illuppallama, Sri Lanka during 1989/90 major rainy season.Results indicated that the two conservation farming practices generate 33–34% annual runoff while replenishing soil moisture of the watershed. Soil loss data showed that the conservation farming practices provide more than 80% protection against soil erosion while bunding can provide only 40% protection compared to existing shifting cultivation practices. 相似文献
17.
Anthony Young 《Agroforestry Systems》1987,5(3):277-291
ICRAF's main contributions to research related to soils have been a symposium, Soils Research in Agroforestry; a review of soil productivity aspects of agroforestry; a further review of the potential of agroforestry for soil conservation, covering both erosion control and maintenance of fertility; the construction of a computerized model to predict soil changes under agroforestry systems; and a handbook of practical methods of agroforestry for soil and water conservation in dryland Africa. In research on land evaluation, an environmental data base has been established, leading to a capacity to obtain information, for environmental conditions similar to those of a given site or area, on publications, multipurpose trees, crops, existing agroforestry systems and current experimental work. Land evaluation for agroforestry cannot be achieved merely by synthesis of methods from agriculture and forestry, but will require more data on the performance of agroforestry land utilization types. Recognition of problems of environmental degradation has become an integral part of planning for agroforestry research. By means of a partial synthesis between land evaluation and diagnosis and design, a procedure of site selection for agroforestry research and development has been established.Principal Scientist, ICRAF 相似文献
18.
Abebe Mekoya Simon J. Oosting Salvador Fernandez-Rivera Akke J. Van der Zijpp 《Agroforestry Systems》2008,73(2):141-153
Many organizations in Ethiopia have for many years promoted exotic multipurpose fodder trees (EMPFT) for livestock feed and
soil improvement. Despite the apparent benefits, the number of farmers planting these trees was low. The objectives were to
elucidate farmers’ perceptions about their use value, management practices and constraints to adoption in three districts
representing annual (one wheat-based and one teff-based) and perennial (coffee-based) crop-livestock systems in the Ethiopian
highlands. Data were collected from 235 farm households. Most farmers (95.3%) had awareness of EMPFTs and the principal information
sources were development agents (75.3%). Over half of the farmers were motivated to plant EMPFTs for feed value. Motivation
for other purposes depended on cropping system, vegetation cover and availability of alternative local fodder trees in the
area. Farmers had positive perceptions about EMPFTs for their feed value and contribution to soil conservation. Current adopters
had a mean number of 587 (SE ± 84) EMPFTs per farm. Major constraints to adoption of EMPFTs were agronomic problems, low multipurpose
value, and land shortage. Majority of farmers (89.8%) were interested to either continue or begin fodder tree development.
Of the interested respondents, 44.5% preferred local fodder trees whereas 55.5% preferred EMPFTs. We conclude that farmers
are aware of use values of EMPFTs while perceived constraints suggest that introduction of EMPFTs need consideration of farmers
multiple criteria, but also awareness of feeding fodder trees and resource availability. Moreover, current development approaches
have to recognize the importance of involving the end-users at all stages through participatory approaches to enhance adoption. 相似文献
19.
M. Van Noordwijk K. Hairiah S. Partoharjono R. V. Labios D. P. Garrity 《Agroforestry Systems》1996,36(1-3):55-82
Purely annual crop-based production systems have limited scope to be sustainable under upland conditions prone to infestation by Imperata cylindrica if animal or mechanical tillage is not available. Farmers who must rely on manual cultivation of grassland soils can achieve some success in suppressing Imperata for a number of years using intensive relay and intercropping systems that maintain a dense soil cover throughout the year, especially where leguminous cover crops are included in the crop cycle. However, labour investment increases and returns to labour tend to decrease in successive years as weed pressure intensifies and soil quality declines.Continuous crop production has been sustained in many Imperata-infested areas where farmers have access to animal or tractor draft power. Imperata control is not a major problem in such situations. Draft power drastically reduces the labour requirements in weed control. Sustained crop production is then dependent more solely upon soil fertility management. Mixed farming systems that include cattle may also benefit from manure application to the cropped area, and the use of non-cropped fallow areas for grazing. In extensive systems where Imperata infestation is tolerated, cassava or sugarcane are often the crops with the longest period of viable production as the land degrades.On sloping Imperata lands, conservation farming practices are necessary to sustain annual cropping. Pruned tree hedgerows have often been recommended for these situations. On soils that are not strongly acidic they may consistently improve yields. But labour is the scarcest resource on small farms and tree-pruning is usually too labour-intensive to be practical. Buffer strip systems that provide excellent soil conservation but minimize labour have proven much more popular with farmers. Prominent among these are natural vegetative strips, or strips of introduced fodder grasses.The value of Imperata to restore soil fertility is low, particularly compared with woody secondary growth or Compositae species such as Chromolaena odorata or Tithonia diversifolia. Therefore, fallow-rotation systems where farmers can intervene to shift the fallow vegetation toward such naturally-occurring species, or can manage introduced cover crop species such as Mucuna utilis cv. cochinchinensis, enable substantial gains in yields and sustainability. Tree fallows are used successfully to achieve sustained cropping by some upland communities. A variation of this is rotational hedgerow intercropping, where a period of cropping is followed by one or more years of tree growth to generate nutrient-rich biomass, rehabilitate the soil, and suppress Imperata. These options, which suit farmers in quite resource-poor situations, should receive more attention. 相似文献
20.
Compound farms are a homegarden-type of agroforestry system involving the deliberate management of multipurpose trees and shrubs in a multistoried association with agricultural crops and small livestock within the compounds of individual houses. In addition to the advantages of diversified production, risk minimization, improved labour and nutrient use efficiences and soil conservation, compound farms represent germplasm banks containing many of the useful tree/ shrub species currently disappearing due to indiscriminate clearing of fore and woodlands. 相似文献