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1.
Marisa Nordenstahl Pedro E. Gundel M. Pilar Clavijo Esteban G. Jobbágy 《Agroforestry Systems》2011,83(2):201-211
In managed rangelands periods of low primary productivity determine troughs of forage availability, constraining animal production
year-round. Although alternative tools to increase forage availability during critical seasons exists, most of them are unaffordable
and short-lived in marginal areas. We explore the potential benefits of deciduous tree plantations favoring winter forage
productivity by comparing aboveground net primary productivity (ANPP) patterns in herbaceous understory to tree plantations
and natural grasslands in the Pampas (Argentina). These temperate subhumid grasslands are characterized by the coexistence
of winter species, mainly C3 grasses of the native genera Stipa, Piptochaetium, and Bromus and the exotic genera Lolium and Festuca) and summer species (mainly C4 grasses of the native genera Paspalum, Bothriochloa, and Stenotaphrum) that replace each other throughout the seasons, with domination of the latter. We hypothesize that the natural decoupling
of growing seasons between winter deciduous trees and winter grasses could provide the basis for the sustainable promotion
of winter forage. We measured ANPP on two 23-year-old Populus deltoides plantations and their understory and compared them with adjacent open grasslands. Afforested stands had 55–75% higher annual
ANPP than their non-afforested neighbors, with trees contributing ~70% to total ANPP. Herbaceous canopies beneath plantations
achieved about half of the ANPP observed in non-afforested situations with a contrasting seasonal distribution associated
with shifts from C4 to C3 grass dominance. Winter ANPP, the most critical source of forage in these grazing systems, was similar
or higher in the herbaceous understory of tree plantations to that on their non-afforested counterparts, suggesting that mixed
systems involving deciduous trees and understory pastures are a valid and viable option in the region. 相似文献
2.
Trees and shrubs as sources of fodder in Australia 总被引：2，自引：0，他引：2
E. C. Lefroy P. R. Dann J. H. Wildin R. N. Wesley-Smith A. A. McGowan 《Agroforestry Systems》1992,20(1-2):117-139
Experience with browse plants in Australia is briefly reviewed in terms of their forage value to animals, their economic value to the landholder and their ecological contribution to landscape stability. Of the cultivated species only two have achieved any degree of commercial acceptance (Leucaena leucocephala and Chamaecytisus palmensis). Both of these are of sufficiently high forage value to be used as the sole source of feed during seasonal periods of nutritional shortage. Both are also leguminous shrubs that establish readily from seed. It is suggested that a limitation in their present use is the reliance on stands of single species which leaves these grazing systems vulnerable to disease and insects. Grazing systems so far developed for high production and persistence of cultivated species involve short periods of intense grazing followed by long periods of recovery. Similar management may be necessary in the arid and semi-arid rangelands where palatable browse species are in decline. 相似文献
3.
4.
Stewart A.W. Diemont Jessica L. BohnDonald D. Rayome Sarah J. KelsenKaity Cheng 《Forest Ecology and Management》2011,261(10):1696-1705
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. 相似文献
5.
Impact of communal land use and conservation on woody vegetation structure in the Lowveld savannas of South Africa 总被引：2，自引：0，他引：2
K.J. Wessels R. MathieuB.F.N. Erasmus G.P. AsnerI.P.J. Smit J.A.N. van AardtR. Main J. Fisher W. MaraisT. Kennedy-Bowdoin D.E. KnappR. Emerson J. Jacobson 《Forest Ecology and Management》2011,261(1):19-29
Millions of people rely on savannas for ecosystem services, such as the provision of grazing and fuel wood, so it is important to determine the extent to which utilization affects woody vegetation resources. Using airborne LiDAR from the Carnegie Airborne Observatory (CAO), we quantified and compared tree canopy cover and height distributions between areas of contrasting management in the Lowveld savanna region of South Africa - a region connecting communal landscapes with heavy utilization (especially fuel wood harvesting) to fully protected public (Kruger National Park - KNP) and private reserves (SabiSand Game Reserve - SSGR) that conserve biodiversity. Differences in total woody vegetation cover and cover within functional height classes (1-2 m, 2-3 m, 3-5 m, 5-7 m and >7 m) were investigated between 7 sites located within (i) conservation areas (in KNP, SSGR), (ii) communal rangelands or (iii) cultivated fields in communal areas. The impact of human utilization on wood resources in the communal areas varied widely between sites. Heavy utilization on gabbro substrate greatly reduced total woody cover of the rangelands, while two other communal rangelands that were presumably less intensively utilised had double the total woody cover of conservation areas. Rangelands and fields in most of the communal sites had more vegetation cover in the 5-7 m and >7 m classes than most of the conservation sites, presumably due to the absence of elephants in communal rangelands and the active preservation of large fruiting trees. On granite substrates, which account for the majority of the study area, there was a 50% reduction in woody cover below 5 m in communal rangelands. Although large trees were clearly being conserved in communal rangelands and fields, there was a relatively low cover of vegetation below 5 m, which raise doubts about recruitment and long-term sustainability of the tree resources. These results in conjunction with other studies based on the CAO LiDAR data for experimental burn plots and large mammal exclosures in KNP, suggest that communal land use on granite substrates have a higher impact on the woody cover below 5 m than both elephants and fire. 相似文献
6.
Reduction in forage production (FP) under trees in the humid tropics is well known, but information on how different levels
of nitrogen (N) fertilizer influence FP under trees is meager. The present study reports effects of four N fertilizer levels
(0, 60, 80 and 120 kg ha−1 N) on net soil N mineralization rate (NMR) and soil moisture (SM), FP, shoot biomass/root biomass ratio (SB/RB), N concentration
in SB, N uptake and nitrogen use efficiency (NUE) of three grasses [guinea (Panicum maximum Jacq.), para (Brachiaria mutica (Forssk) Stapf) and hybrid-napier (Pennisetum purpureum Schumach.)] under three canopy positions [under canopy (UC, representing high shade), between canopy (BC, representing low
shade) and open] of coconut trees (Cocos nucifera L.) in a coconut based silvopastoral system in the humid tropical climate of South Andaman Island of India. The study was
performed for two annual cycles (2005–2006 and 2006–2007). The hypotheses tested were: (1) FP would decline under tree shades,
both in N fertilized as well as no N fertilized conditions, when SM was not growth limiting in the open. However, amount of
decline in the FP would depend on grass species and intensity of shades i.e., higher was the shade greater would be the decline;
(2) N fertilizer would increase FP under tree shades, but the increase depended on grass species, intensity of shades and
amount of N applied. Amount of N applied, however, would not annul the shades effects when SM was not growth limiting in the
open. The study revealed that the tree reduced light 59% under UC and 32% under BC positions, but the N fertilizer levels
increased NMR by 11–51% under UC and 3–44% under BC positions compared to the open. SM did not differ across the canopy positions.
Under all situations, FP of all grasses declined under UC (47–78%) and BC (18–32%) positions compared to the open; the decline
was greater in Hybrid-napier than Guinea and Para grasses. Forage production of all grasses increased with N fertilizer increments
under all canopy positions reaching 32 t ha−1 dry matters for hybrid-napier at 120 kg ha−1 N in the open. Both guinea and para grasses outyielded hybrid-napier grass under UC but not under BC or in the open. N concentration
in the forage (SB) also increased as N fertilizer level increased. These observations support our hypotheses and suggest that
forage production under coconut palms can be increased by the application of N fertilizer with both guinea and para grasses
being more productive than hybrid-napier grass under the high shade. Where light conditions are better, hybrid-napier would
produce more forage than the other species. 相似文献
7.
以草业为纽带的桔园生态系统及其生态效益研究 总被引：5，自引：0，他引：5
在浙西红壤桔园套种牧草,建立以草业为纽带的"桔－草－畜（渔）"复合生态系统,对调节园地小气候、减少水土流失、改良红壤、促进畜渔业发展,具有良好的作用,生态、经济、社会效益明显。 相似文献
8.
Forage production of woody fodder species and herbaceous vegetation in a silvopastoral system in northern Greece 总被引：5，自引：0，他引：5
Introduction of woody plants in silvopastoral systems could be an appropriate land-use for the poor sandy soils of the Mediterranean
semiarid zone. Forage production of four woody fodder species and herbaceous vegetation in relation to plant spacing and animal
(sheep) grazing was studied in a silvopastoral system on such a site in Macedonia, northern Greece. The woody fodder species
tested were Robinia pseudoacacia L., Gleditsia triacanthos L., Amorpha fruticosa L. and Morus alba L. They were planted at
the spacings 1.5 × 1.5 m,2.5 × 2.5 m and 3.5 × 3.5 m and kept in a shrubby form by topping. They were grazed by sheep (stocking
rate of 1.1 sheep/ha/year) in early July and late August of 1992, 1993 and 1994. Among the species Robinia yielded the highest
forage production (394 kg/ha). The spacing 1.5 × 1.5 m had the highest (P ≥ 0.05) forage production per area unit (280 kg/ha)
while the spacing 3.5 × 3.5 m had the highest forage production per plant (91.8 g/plant). No competition was observed between
the woody and the herbaceous plants in the various spacings probably due to topping of the woody species every winter. Percent
utilisation of the native herbage dropped as forage of the woody species increased.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
9.
10.
The effects of leucaena hedgerows, mulching with leucaena foliage (0,50 and 100% of harvested foliage), cowpea intercropping and adition of dairy cattle slurry (55 t ha–1 per maize crop) on the yield of maize from a sandy soil were assessed. The four-year results from five maize crops are reported.Except in the first year, yields of maize grain and stover were significantly reduced by 30% in the presence of leucaena hedgerows. Use of leucaena mulch eliminated this effect; application of all the harvested leucaena mulch (100%) increased the total maize grain yield of the five crops by 44% over sole maize. Hedgerow and mulching management required an additional 36 mandays labour ha–1 which was more than compensated by the increased maize yields. Furthermore leucaena hedgerows substantially depressed the growth of weeds between cropping seasons.Intercropping with cowpea significantly depressed yields of maize grain and stover when both crops were sown together, but not in later seasons when cowpea was sown four weeks after the maize. Application of slurry increased the total yields of maize grain and stover by 35 and 37%, respectively. The grain yield of maize in leucaena hedgerow treatments fertilized with slurry did not respond to application of more than 50% of leucaena foliage, which suggested that half of the foliage could be spared for feeding to livestock. The cumulative yield of maize grain from the highest yielding organic system was 85% of the yield from the fertilizer treatment.The study, which is continuing, demonstrates that large increases in agricultural productivity are possible through the intercropping of maize with woody forage and grain legumes and the integration of dairy cattle production into the system. It thus shows the importance of exploiting crop/livestock interactions. 相似文献
11.
12.
Temperate short-rotation agroforestry systems are promising solutions for environmentally and economically sound production of crops and woody biomass. Accurate estimates of microclimatic conditions and tree-crop interactions in these systems are clearly needed to improve their adoption and management, especially in northeastern North America. The objective of this study was to determine the effects of a windbreak and an alley cropping system that were planted with strips of short-rotation willow on microclimate and forage crop yields. Microclimatic conditions (wind speed, air temperature, air relative humidity, light availability, soil moisture, snow depth) and forage yields were measured at different distances from the willow strips in these two agroforestry systems and in agricultural control plots between the third (2020) and fourth years (2021) after experiment establishment. Willow strips significantly reduced wind speed in both experiments, despite their relatively short stature (260 cm, June 2021). Wind speed reduction was greatest (50 and 58% in alley cropping and windbreak systems, respectively) close to the willow strips (5 m), intermediate at 20 m (22% in both systems), and negligible at 50 m (windbreak system). A significant increase in daytime air temperature that reached almost 1 °C was measured close to the willow strips in the agroforestry systems, compared to control plots. Higher soil moisture was measured close to the windbreak. In both agroforestry systems, snow depth was significantly greater near the willow strips. In both systems, forage yield close to the willow strips was not different from that at any other measured distances and in the control plots, which suggests that no competition for resources occurred between the willows and the forage crop during the study. In July 2021, forage yield within the windbreak (0–50 m from the willow strip) was 44% greater than that in the control plots. The alley cropping system had significant negative (-12%, June 2020) and positive (+?13%, September 2021) effects on forage yield, possibly as a result of temporal variation in climatic conditions. Results of this study stress the importance of better understanding of intra- and inter-annual forage crop variability within agroforestry systems.
相似文献13.
Frederick Cubbage Gustavo Balmelli Adriana Bussoni Elke Noellemeyer Anibal N. Pachas Hugo Fassola Luis Colcombet Belén Rossner Gregory Frey Francis Dube Marcio Lopes de Silva Hayley Stevenson James Hamilton William Hubbard 《Agroforestry Systems》2012,86(3):303-314
Silvopasture systems combine trees, forage, and livestock in a variety of different species and management regimes, depending on the biophysical, economic, cultural, and market factors in a region. We describe and compare actual farm practices and current research trials of silvopastoral systems in eight regions within seven countries of the world: Misiones and Corrientes provinces, Argentina; La Pampa province, Argentina; northwestern Minas Gerais, Brazil; the Aysén region of Patagonia, Chile; the North Island of New Zealand; the Southeast United States; Paraguay; and Uruguay. Some countries use native trees and existing forests; some use plantations, particularly of exotic species. Natural forest silvopasture systems generally add livestock in extensive systems, to capture the benefits of shade, forage, and income diversification without much added inputs. Plantation forest systems are more purposive and intensive, with more focus on joint production and profits, for small owners, large ranches, and timber companies. Trends suggest that more active management of both natural and planted silvopastoral systems will be required to enhance joint production of timber and livestock, achieve income diversification and reduce financial risk, make more profit, improve environmental benefits, and realize more resilience to adapt to climate change. 相似文献
14.
Tree legumes play a vital role in many agroforestry systems currently in use throughout the world. Because of their multipurpose nature they can be used to provide high quality fodder for livestock, nutrient rich mulch for crops, fuelwood and timber, microenvironment amelioration, ecosystem stability, and human food.Tree legumes are increasingly being used to provide fodder for livestock, as they have a number of unique characteristics which make them attractive for both smallholder and largescale livestock enterprises. Research and development efforts have concentrated on broadening the resource base by evaluating a greater range of tree legume genera, defining optimum management strategies, and developing appropriate systems which capitalize on the advantages of these species.This paper reviews the role of tree legumes in agroforestry, especially for fodder purposes, outlines the areas of current research focus, and endeavors to highlight some gaps in our knowledge which require further research effort. 相似文献
15.
Land use systems in the Northeast Region of Brazil are dominated by large holdings and extensive cultivation of perennial crops such as cashew, coconut, carnauba wax palm, babaçu palm and so on. The common feature which links these crops is the silvopastoral system of livestock (chiefly cattle, sheep and donkeys) grazing under them. Agrosilvicultural systems involving cultivation of annual subsistence crops, and in some instances other perennials, in the stands of these perennial crops is also common. The paper presents the available information on the management, production, rate of growth, economic importance, etc. of these agroforestry systems involving cashew, coconut and carnauba palm. These systems are of considerable merit in the environmental, agricultural and socio-economic conditions of Northeast Brazil. However, practically no research nor even systematic data collection has been done on these so that there is an almost total lack of information on them. In order to improve the systems, they should be studied in detail and research undertaken on various components (crops, trees and livestock) individually as well as the system as a whole. Selection of suitable species of grass and other herbaceous crops, appropriate management techniques for both overstorey and understorey species in relation to the age of the overstorey species, optimal stocking rates of animals, etc. have to be determined so as to enable plantation owners and operators to realize the full potential of these systems. 相似文献
16.
Berta Caballero-López José M. Blanco-Moreno Nicolás Pérez-Hidalgo José M. Michelena-Saval Juli Pujade-Villar Emilio Guerrieri José A. Sánchez-Espigares F. Xavier Sans 《Journal of pest science》2012,85(1):81-88
The aphid–natural enemy interaction in winter wheat fields constitutes a complex system that has been frequently studied because
of its implication for biological control. However, not all of the aphids living in cereal fields are crop pests, as there
are also aphids living on weeds that may serve as alternative hosts or prey for aphid parasitoids or predators. In this context,
a concomitant survey of the plant and insect communities was conducted to understand how different plant communities affect
the abundance and richness of aphids and the interactions with their natural enemies. The plant community was split into functional
groups (grasses, legumes and forbs), and the aphid community was divided into feeding groups according to their host preferences
(specialists in grasses or forbs). The grass aphids, which dominated the total aphid catches, responded positively to grass
cover, which was particularly enhanced in the conventional fields. Conversely, the forb aphids, which mainly conditioned the
total species richness of the aphids, were closely correlated with the local abundance of legumes. The system of cereal aphid-parasitoids
was enhanced in the conventional fields, where the abundance of grasses was higher, whereas the legumes of the organic fields
indirectly played a key role in enhancing the richness of the parasitoids and the abundance of predators. Our findings indicate
that a bottom-up effect exists throughout the plant community, aphids, and aphidophagous insects and that plant community
characteristics should be considered to better understand cereal aphid control. 相似文献
17.
Conservation of forest biodiversity and ecosystem properties in a pastoral landscape of the Ecuadorian Andes 总被引：1，自引：0，他引：1
High Andean cloud forests are home to a diversity of unique wildlife and are important providers of ecosystem services to people in the Andean regions. The extent of these cloud forests has been widely reduced through conversion to pasture for livestock, which threatens the forests’ ability to support biodiversity and provide ecosystem services. This paper explores whether impacts on woody plant biodiversity and four ecosystem properties (woody plant species richness, juvenile timber tree abundance, soil organic matter content and soil moisture) from converting forest to pasture can be mitigated if some woody forest vegetation is maintained within pastures. Woody vegetation in pastures was found to conserve those woody plant species that are more tolerant to exposure and grazing, but conservation of the high montane cloud forest community required areas of forest from which livestock were restricted. The sampled sites clustered according to woody plant species cover; these clusters represented a gradient from pasture with patches of shrubs to mature forest. Clusters differed in both woody plant species richness and number of juvenile timber trees whereas soil organic matter and soil moisture were observed to be similar among all clusters. This suggests that the different habitats may have some equivalent ecosystem properties. We conclude that the presence of woody vegetation in pastures may reduce some of the impacts of converting forest to pasture, but should not be considered a substitute for protecting large areas of forest, which are essential for maintaining woody plant species diversity in high Andean cloud forest. 相似文献
18.
Traditional agroforestry systems and biodiversity conservation in Benin (West Africa) 总被引：1，自引：1，他引：0
Vodouhe G. Fifanou Coulibaly Ousmane Biaou Gauthier Sinsin Brice 《Agroforestry Systems》2011,82(1):1-13
In the past, the conservation of biodiversity has been mostly understood in terms of the management of protected areas and
natural forests, ignoring the possible role of farm areas and the ways through which rural communities have promoted biodiversity
in their subsistence agricultural production systems. The present study focused on the floristic diversity within traditional
agroforestry parkland systems around the Pendjari Biosphere Reserve in Benin and showed the diversity of tree species in the
area as well as socio-economic factors which affect the practice of this farming system. We used questionnaires and interviewed
a total of 118 households to collect data. Respondents were interviewed on their farms and during the interview; we inventoried
the number of tree on the farm and determined the farm size. Twenty-one tree species belonging to 14 botanical families were
recorded during the surveys and the average stand density of the woody component of farmlands was 7.97 ± 5.43 stems/ha. A
number of both native and exotic tree species occurred in the parkland agroforestry systems with dominance of indigenous tree
species. Species richness varied with the size of household where households with small land holding conserve more tree species
in their field than households with large land holdings. 64% of households surveyed were making deliberate efforts to plant
tree species on their farmlands. The most important reasons which determined household ambitions to conserve woody species
on farmland were tree products contribution to food and medicine. Results also showed that respondents who noticed that trees
were decreasing in the wild conserve more tree species on their farmlands. This research highlights the role of traditional
agroforestry practices to support tree species richness and provides evidence of the farms’ role as biodiversity reservoirs. 相似文献
19.
Nick F. Emtage 《Small-Scale Forestry》2004,3(3):319-336
This paper reviews the existing social and community forestry programs in the Philippines, these being the leading programs
for natural resource management and rural development in the country. The paper takes the form of a stakeholder analysis of
those involved in the Community-Based Forest Management Program, drawing on literature discussing the roles of and challenges
faced by the various stakeholder groups and on interviews with participants in the program. Challenges to the success of the
program come from a variety of sources, in particular from the economically and socially marginalised position of the target
communities, lack of resources available to support them, deficiencies in physical and social infrastructure in the Philippines,
and the difficulties caused by the continual revision of forestry policies and regulations. It is concluded that in order
for CBFM to be successful, greater efforts are needed to ‘empower’ the communities, provide adequate budgetary support to
agencies administering the program, and provide a stable policy and regulatory framework. 相似文献
20.
Luciano Fernandes Sousa Rogério Martins Maurício Guilherme Rocha Moreira Lúcio Carlos Gonçalves Iran Borges Luiz Gustavo Ribeiro Pereira 《Agroforestry Systems》2010,79(2):189-199
This study aimed at evaluating the influence of a silvopastoral system (SPS) composed of “Aroeira” trees (Myracrodruon urundeuva) on the nutritional value of Brachiaria brizantha cv. Marandu forage grass over the rainy season. The experiment was conducted in the SPS located in the “Cerrado” biome in
Lagoa Santa County, Minas Gerais state, Brazil, in the agricultural year of 2004–2005. It was evaluated the influence of “Aroeira”,
whose density in the area was 140 trees/ha, on the following parameters of the B. brizantha cv. Marandu forage grass: forage mass harvest above stubble height, morphogenic attributes, bromatological composition and
nutritional value. The effects of “Aroeira” trees on the micro-climatic conditions were also evaluated. The experiment adopted
a randomized block design with five blocks (cutting seasons), two treatments (a shaded pasture—B. brizantha cv. Marandu shaded by M. urundeuva—and a pasture in full sun—B. brizantha cv. Marandu in full sun), and three replicates. The tree component, composed of the tree species M. urundeuva in the experimental density adopted, increased dry matter and crude protein of the forage mass harvest above stubble height,
without affecting the concentration of neutral detergent fibre or acid detergent fibre, thus causing dry matter and organic
matter in vitro degradability as well as effective degradability of the forage grass to remain the same as those obtained
in full sun. Therefore, the results of this study show the possibility of using trees and grass to increase both animal production
and environmental services. 相似文献