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1.
A preliminary nutrient cycling study quantified total and temporal nutrient inputs via litterfall and pruning residues in two agroforestry systems: (1) Coffea arabica (perennial crop)-Erythrina poeppigiana (leguminous shade tree); and (2) C. arabica-E. poeppigiana-Cordia alliodora with emphasis on the effect of the timber tree C. alliodora. The total annual input of litterfall plus pruning residues was similar in both associations. Total annual input from E. poeppigiana was less than half in the association with C. alliodora than without, but the litterfall from this latter species compensated for the loss. Large differences in the total annual nutrient input of K, Ca and Mg was found between associations, but not for N or P. The amount of nutrients recycled by the associated trees reached the recommended level of fertilizer required for coffee production. The inclusion of C. alliodora within the C. arabica-E. poeppigiana association resulted in a more evenly distributed annual nutrient input. 相似文献
2.
Coffee agroforestry is a conservation strategy that has shown promise to support the diversity of bird, bat, and insect communities, but few studies have focused on non-volant mammals in coffee farms. We assessed mammal diversity within coffee agroforestry systems in Kodagu, India and investigated the impacts of the non-native shade tree species, Grevillea robusta, on mammal diversity. Twenty farms, with varying amounts of G. robusta planted within the coffee farm, were sampled throughout three rainfall zones during the 4-month study period. We captured six species of small mammals, with indirect methods yielding an additional five species, totaling 11 mammal species. Contrary to current ecological thought, we found that increased amounts of G. robusta did not have a negative impact on either abundance or richness of mammals. Small mammal abundances were higher at farms with greater amounts of herbaceous ground cover and larger, mature shade trees, while small mammal species richness was found to increase with an increase in tree species richness as well as greater amounts of herbaceous ground cover. Additionally, small mammal abundance was higher at coffee farms closer to forested areas. Based on these findings, we suggest the maintenance or cultivation of shade tree richness, mature shade trees, and herbaceous ground cover within coffee farms and preservation of forested areas within the landscape to enhance coffee agroforestry habitat for non-volant mammals. We hope that these habitat requirements will be incorporated into conservation strategies for the promotion of biodiversity within coffee agroforestry systems. 相似文献
3.
Allometric models for estimating aboveground biomass
of shade trees and coffee bushes grown together
Allometric models for dominant shade tree species and coffee plants (Coffea arabica) were developed for coffee agroforestry systems in Matagalpa, Nicaragua. The studied shade tree species were Cordia alliodora, Juglans olanchana, Inga tonduzzi and I. punctata. The models predict aboveground biomass based on diameter at breast height (for trees), and the stem diameter at a height of 15 cm and plant height (for coffee plants). In addition, the specific gravity of the studied species was determined.The total aboveground biomass of the shade trees varied between 3.5 and 386 kg per tree, and between 0.005 and 2.8 kg per plant for coffee. The aboveground biomass components (foliage, branch, and stem) are closely related with diameter at breast height (r > 0.75). The best-fit models for aboveground biomass of the shade trees were logarithmic, with adjusted R
2 between 0.71 and 0.97. In coffee plants, a high correlation was found (r = 0.84) with the stem diameter at 15 cm height, and the best-fit model was logarithmic, as well. The mean specific gravity was 0.52 (± 0.11) for trees and 0.82 (± 0.06) for coffee plants. 相似文献
4.
E. Somarriba 《Agroforestry Systems》1992,18(1):69-82
Both model and field estimations were made of the damage inflicted to coffee plants due to the harvest of timber shade trees (Cordia alliodora) in coffee plantations. Economic analyses were made for different coffee planting densities, yields, and both coffee and timber prices.Damage due to tree felling and log skidding should not be a major limitation to the use of timber shade trees in coffee plantations. The timber price that would balance all discounted losses and benefits to zero, for scenarios with and without trees ranged between 8–20 US $/m3 (current overbark log volume at the saw mill yard is US$ 66/m3). There will be lower margins for coffee damage in high yielding plantations, specially in years of good coffee prices. Nevertheless, the use of timber shade trees is recommended even in these scenarios. 相似文献
5.
R. G. Muschler 《Agroforestry Systems》2001,51(2):131-139
Quality is an important attribute of coffee. Therefore it is important to understand the effect of overstory trees not only on the environment and long-term coffee production, but also on the quality of coffee grown underneath the trees. This study compared coffee quality of Coffea arabica L. vars. Caturra and Catimor 5175 under different levels of shade in a low-elevation, sub-optimal environment for coffee in Costa Rica. Fruit weight and bean size increased significantly when shade intensity was increased from 0% to more than 80% under unpruned Erythrina poeppigiana. While large beans (diameter > 6.7 mm) accounted for 49 and 43% of the coffee from unshaded Caturra and Catimor, respectively, these proportions increased to 69 and 72% under dense permanent shade. This suggested a stronger shade benefit for Catimor than for Caturra. The conversion percentages from fresh-weight coffee fruits to dry-weight green coffee for export were not affected by the treatments. A blind tasting experiment showed consistent shade-induced improvements in appearance of green and roasted coffee as well as in acidity and body of the brew for both varieties. The effect of shade on aroma of the brew was neutral for Caturra and slightly negative for Catimor. It is hypothesized that, in the sub-optimal (low-altitude) coffee-zone studied, shade promotes slower and more balanced filling and uniform ripening of berries, thus yielding a better-quality product than unshaded coffee plants. Shade experiments along environmental gradients should help to validate this conjecture and its relative importance in different coffee-zones. 相似文献
6.
Anne Richter Alexandra-Maria Klein Teja Tscharntke Jason M. Tylianakis 《Agroforestry Systems》2007,69(3):175-182
Shade coffee including many tree species is known to support generally high biodiversity. Due to low coffee prices on the
world market, many farmers have abandoned their farms, thereby creating a new ecosystem type, which has attracted increasing
interest for biodiversity conservation. Here we used pyrethrum knockdown samples to compare the arthropod community on coffee
plants of six traditionally managed coffee agroforests with those of six abandoned coffee agroforests in coastal Ecuador.
We investigated eight randomly selected coffee shrubs per site, six of them inside and two at the edge. All arthropods were
identified to orders and beetles to morphospecies. We additionally sampled the vegetation to test for vegetation-mediated
effects on the arthropod community. The number of arthropod individuals was higher in abandoned than managed coffee, driven
by the abundance of Arachnida, Blattaria, and Heteroptera, and higher in the edge than in the centre of the abandoned agroforests.
Higher arthropod abundance appeared to be closely related to arthropod diversity, as shown for beetles (r = 0.79, n = 96). Contrary to expectations, predator-prey ratios in managed agroforests was as high as in the abandoned ones. In conclusion,
abandonment of coffee agroforests greatly encourages arthropod communities, in particular in the habitat edges, and therefore,
should be considered in landscape management for conservation. 相似文献
7.
Coffee (Coffea canephora var robusta) is grown in Southwestern Togo under shade of native Albizia adianthifolia as a low input cropping system. However, there is no information on carbon and nutrient cycling in these shaded coffee systems.
Hence, a study was conducted in a mature coffee plantation in Southwestern Togo to determine carbon and nutrient stocks in
shaded versus open-grown coffee systems. Biomass of Albizia trees was predicted by allometry, whereas biomass of coffee bushes was estimated through destructive sampling. Above- and
belowground biomass estimates were respectively, 140 Mg ha−1 and 32 Mg ha−1 in the coffee–Albizia association, and 29.7 Mg ha−1 and 18.7 Mg ha−1 in the open-grown system. Albizia trees contributed 87% of total aboveground biomass and 55% of total root biomass in the shaded coffee system. Individual
coffee bushes consistently had higher biomass in the open-grown than in the shaded coffee system. Total C stock was 81 Mg ha−1 in the shaded coffee system and only 22.9 Mg ha−1 for coffee grown in the open. Apart from P and Mg, considerable amounts of major nutrients were stored in the shade tree
biomass in non-easily recyclable fractions. Plant tissues in the shaded coffee system had higher N concentration, suggesting
possible N fixation. Given the potential for competition between the shade trees and coffee for nutrients, particularly in
low soil fertility conditions, it is suggested that the shade trees be periodically pruned in order to increase organic matter
addition and nutrient return to the soil.
An erratum to this article can be found at 相似文献
8.
The advantages of associating shade trees in coffee agroforestry systems (AFS) are generally thought to be restricted mostly
to poor soil and sub-optimal ecological conditions for coffee cultivation whereas their role in optimal conditions remains
controversial. Thus, the objective of this study was to investigate, under the optimal coffee cultivation conditions of the
Central Valley of Costa Rica, the impact of Inga densiflora, a very common shade tree in Central America, on the microclimate, yield and vegetative development of shaded coffee in comparison
to coffee monoculture (MC). Maximum temperature of shaded coffee leaves was reduced by up to 5°C relative to coffee leaf temperature
in MC. The minimum air temperature at night was 0.5°C higher in AFS than air temperature in MC demonstrating the buffering
effects of shade trees. As judged by the lower relative extractable water (REW) in the deep soil layers during the dry season,
water use in AFS was higher than in MC. Nevertheless, competition for water between coffee and associated trees was assumed
to be limited as REW in the 0–150 cm soil layer was always higher than 0.3 in shaded coffee compared to 0.4 in monoculture.
Coffee production was quite similar in both systems during the establishment of shade trees, however a yield decrease of 30%
was observed in AFS compared to MC with a decrease in radiation transmittance to less than 40% during the latter years in
the absence of an adequate shade tree pruning. As a result of the high contribution (60%) of shade trees to overall biomass,
permanent aerial biomass accumulation in AFS amounted to two times the biomass accumulated in MC after 7 years. Thus provided
an adequate pruning, Inga-shaded plantations appeared more advantageous than MC in optimal conditions, especially considering the fact that coffee
AFS provides high quality coffee, farmers’ revenue diversification and environmental benefits. 相似文献
9.
A preliminary survey of seven coffee producing Awrajas (Provinces) in eastern Ethiopia revealed that there is a traditional tree crop based agroforestry system being practised by the farmers. Coffee (C. arabica) was found to grow under the shade of several trees, 16 species, usually intercropped by one or several, a total of 15, important grain, fruit, vegetable, stimulant, oil-seed and spice crops. The majority of the trees, 69%, is leguminous and Ficus spp. The system is characterized by the integration of crops, livestock and sometimes apiculture. Recommendations are made for future studies. 相似文献
10.
Water use efficiency and uptake patterns in a runoff agroforestry system in an arid environment 总被引：3，自引：0，他引：3
Water is the most limiting factor for plant production in arid to semiarid regions. In order to overcome this limitation surface runoff water can be used to supplement seasonal rainfall. During 1996 we conducted a runoff irrigated agroforestry field trial in the Turkana district of Northern Kenya. The effects of two different Acacia saligna (Labill.) H. Wendl. tree planting densities (2500 and 833 trees per ha), tree pruning (no pruning vs. pruning) and annual intercrops (no intercrop vs. intercrop: Sorghum bicolor (L.) Moench during the first season and Vigna unguiculata (L.) Walp. during the second season) on water use were investigated. The annual crops were also grown as monocrops. Water consumption ranged from 585 to 840 mm during the first season (only treatments including trees). During the second season, which was shorter and the plants relied solely on stored water in the soil profile, water consumption was less than half of that during the first season. Highest water consumptions were found for non-pruned trees at high density and the lowest were found for the annual crops grown as monocrops. Tree pruning decreased water uptake compared to non-pruned trees but soil moisture depletion pattern showed complementarity in water uptake between pruned trees and annual intercrops. The highest values of water use efficiency for an individual treatment were achieved when the pruned trees at high density were intercropped with sorghum (1.59 kg m–3) and cowpea (1.21 kg m–3). Intercropping and high tree density increased water use efficiency in our runoff agroforestry trial. We ascribe the observed improvement in water use efficiency to the reduction of unproductive water loss from the bare soil.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
11.
The effects of crown pruning of mature indigenous fruit trees of Vitellaria paradoxa C. F Gaertn (commonly known as karité) and Parkia biglobosa (Jacq.) R. Br. ex G. Don (commonly known as néré) on recovery of crown size and fruit yield were assessed during 6 years
in an agroforestry parkland system in Burkina Faso. Three treatments of crown pruning (total-pruning, half-pruning and a control
of no-pruning) were applied to karité and néré. Each treatment comprised ten individuals of each species or a total of 60
trees of both species. Six years after pruning, higher recovery (81%) of crown diameter was achieved in total-pruned trees
of néré as opposed to karité which recovered by only 73%. On the contrary, fruit production in total-pruned trees of karité
recovered by 83% 5 years after pruning and fully (100%) 6 years after pruning as opposed to néré which recovered by only 57%
5 years after pruning but declined to 16% on the sixth year probably due to interannual variability. Fruit yields did not
differ significantly between unpruned and half-pruned trees of both species throughout the experiment period. Total pruning
may, therefore, be recommended to farmers to rejuvenate old trees of karité in parklands on the basis of fast recovery of
fruit and slow recovery of crown in the species. Slow recovery of crown in pruned trees is the most desirable characteristic
in parklands in order to avoid the negative effect of tree shade on adjacent crop. 相似文献
12.
Céline Leroy Sylvie Sabatier Novi Sari Wahyuni Jean-François Barczi Jean Dauzat Marilyne Laurans Daniel Auclair 《Agroforestry Systems》2009,77(1):37-47
In agroforestry systems, the distribution of light transmitted under tree canopies can be a limiting factor for the development
of intercrops. The light available for intercrops depends on the quantity of light intercepted by tree canopies and, consequently,
on the architecture of the tree species present. The influence of tree architecture on light transmission was analysed using
dynamic 3D architectural models. The architectural analysis of Acacia mangium and Tectona grandis was performed in Indonesian agroforestry systems with trees aged from 1 to 3 years. 3D virtual trees were then generated
with the AmapSim simulation software and 3D virtual experiments in which tree age, planting density, planting pattern and
pruning intensity varied were reconstructed in order to simulate light available for the crop. Canopy closure of trees was
more rapid in A. mangium than in T. grandis agroforestry systems; after 3 years the quantity of light available for A. mangium intercrops was three times lower than under T. grandis. Simulations with A. mangium showed that practices such as pruning and widening tree spacing enable to increase the total transmitted light within the
stand. On T. grandis, modification of the tree row azimuth resulted in changes in the spatial and seasonal distribution of light available for
the intercrops. These results are discussed in terms of agroforestry system management.
相似文献
| Sylvie SabatierEmail: |
13.
Mônica Matoso Campanha Ricardo Henrique Silva Santos Gilberto Bernardo de Freitas Hermínia Emília Prieto Martinez Silvana Lages Ribeiro Garcia Fernando Luiz Finger 《Agroforestry Systems》2004,63(1):75-82
This research compared coffee plants (Coffea arabica L.) grown in an agroforestry and monoculture systems. Data were collected during two years, on vegetative growth, reproductive
development, nutritional status and yield of coffee, besides monitoring air temperature and the tree growth. All trees in
agroforestry system increased in growth, resulting in a reduction in the magnitude of the diurnal temperature variation and
also maximum temperature. Coffee plants in agroforestry system had less branch growth and leaf production, more persistent
and larger leaves, and presented earlier flowering, with a smaller number of productive nodes and flower buds, leading to
smaller berry yield than plants in monoculture system. In both systems, the coffee plants showed adequate leaf nutrient levels,
except for P and K. The yield of 2443 kg ha-1 of coffee from the monoculture was greater than 515 kg ha-1 of coffee from the agroforestry system. 相似文献
14.
Shade management in coffee and cacao plantations 总被引：1，自引：0，他引：1
Shade trees reduce the stress of coffee (Coffea spp.) and cacao (Theobroma cacao) by ameliorating adverse climatic conditions
and nutritional imbalances, but they may also compete for growth resources. For example, shade trees buffer high and low temperature
extremes by as much as 5 °C and can produce up to 14 Mg ha-1 yr-1 of litterfall and pruning residues, containing up to 340 kg N ha-1 yr-1. However, N2 fixation by leguminous shade trees grown at a density of 100 to 300 trees ha-1 may not exceed 60 kg N ha-1 yr-1. Shade tree selection and management are potentially important tools for integrated pest management because increased shade
may increase the incidence of some commercially important pests and diseases (such as Phythphora palmivora and Mycena citricolor)
and decrease the incidence of others (such as Colletotrichum gloeosporioides and Cercospora coffeicola). In Central America,
merchantable timber production from commercially important shade tree species, such as Cordia alliodora, is in the range of
4–6m3 ha-1 yr-1.
The relative importance and overall effect of the different interactions between shade trees and coffee/cacao are dependent
upon site conditions (soil/climate), component selection (species/varieties/provenances), belowground and aboveground characteristics
of the trees and crops, and management practices. On optimal sites, coffee can be grown without shade using high agrochemical
inputs. However, economic evaluations, which include off-site impacts such as ground water contamination, are needed to judge
the desirability of this approach. Moreover, standard silvicultural practices for closed plantations need to be adapted for
open-grown trees within coffee/cacao plantations.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
15.
Fine-root dynamics (diameter < 2.0 mm) were studied on-farm in associations of Coffea arabica with Eucalyptus deglupta or Terminalia ivorensis and in a pseudo-chronosequence of C. arabica-E. deglupta associations (two, three, four and five years old). Coffee plants were submitted to two fertilisation types. Cores were taken
in the 0–40 cm soil profile two years after out-planting and subsequently in the following year in depth layers 0–10 and 10–20
cm, during and at the end of the rainy season, and during the dry season. Fine root density of coffee and timber shade trees
was greater in the coffee fertilisation strip as compared to unfertilised areas close to the plants or in the inter-rows.
Coffee fine roots were more evenly distributed in the topsoil (0–20 cm) whereas tree fine roots were mostly found in the first
10 cm. Although the two tree species had approximately the same fine root length density, lower coffee / tree fine root length
density ratios in T. ivorensis suggest that this shade tree is potentially a stronger competitor with coffee than E. deglupta. Coffee and tree fine root length density for 0–10 cm measured during the rainy season increased progressively from two to
five-year-aged associations and coffee fine root length density increased relatively more than E. deglupta fine root length density in the four and five-year-aged plantations suggesting that contrary to expectations, coffee fine
roots were displacing tree fine roots. 相似文献
16.
Transpiration of Arabica Coffee and Associated Shade Tree Species in Sub-optimal, Low-altitude Conditions of Costa Rica 总被引：3，自引：0，他引：3
Sap flows of coffee (Coffea arabica L. cv ‘Costa Rica 95’) and associated timber trees (Eucalyptus deglupta or Terminalia ivorensis) or leguminous tree (Erythrina poeppigiana) were measured simultaneously during 12 months in 4-year-old coffee agroforestry systems in sub-optimal ecological conditions
of Costa Rica. In the wet period, coffee and shade tree transpiration followed the daily patterns of photosynthetic photon
flux density (PPFD) and reference evapotranspiration (ETo) while their transpiration was restricted at higher air VPD values
(>1.5 kPa) registered during the dry period. Coffee transpired more per unit leaf area in full sun than under shade, an indication
of higher environmental coffee stress in non shaded conditions. Nonetheless, coffee daily water consumption per hectare was
generally higher under shade than in full sun due higher vegetative growth of shade-grown coffee plants. Minimum and maximum
daily transpiration were 0.74 and 4.08 mm for coffee, 0.35 and 1.06 mm for E. deglupta, 0.70 and 2.10 mm for T. ivorensis and 0.13 and 0.79 mm for E. poeppigiana. Estimation of the annual combined water transpiration by coffee and shade trees was 20–250% higher than that of coffee grown
in full sun. Nevertheless, there was no evidence that water use by associated trees decreased soil water availability for
coffee and hence limited coffee transpiration in the dry season due to its relatively short length (3 months) and the high
annual rainfall (over 3100 mm). In the sub-optimal, low altitude conditions of this experiment, E. deglupta was the optimum shade species as it maintained a more constant shade level throughout the year and ensured a better protection
to coffee underneath than T. ivorensis and E. poeppigiana which underwent a complete defoliation during the adverse meteorological conditions of the dry period. 相似文献
17.
Tree/crop complementarity in an arid zone runoff agroforestry system in northern Kenya 总被引：5，自引：0，他引：5
We tested the hypothesis that shallow-rooted crops and deep-rooted trees will share the available water in a complementary manner, when grown together, in a field trail in the Turkana district of northern Kenya during 1994 to 1996. Such studies have been few in dryland agroforestry. The effects of two different Acacia saligna (Labill.) H. Wendl. tree planting densities (2500 and 833 trees per ha), tree pruning (no pruning vs. pruning) and annual intercrops (no intercrop vs. intercrop) on total biomass production and their interactions were tested. In 1996 Sorghum bicolor (L.) Moench was used during the first vegetation period and Vigna unguiculata (L.) Walp. during the second. We used naturally generated runoff water for irrigation to supplement low rainfall amounts typical for the area. High biomass production (> 13 t ha–1 over a two year period) was observed irrespective of intercropping of pruned trees or sole tree stands. Although the pruning treatment reduced total tree biomass yields by a quarter, the introduction of annual intercrops after the pruning of trees outweighed this loss. The yields of the intercrops in the pruned tree treatments were similar to their yields when grown as monocrops. The calculation of land equivalent ratios showed overyielding for intercropped, pruned systems. The high values for LER (1.36 at low and 1.47 at high density of trees) indicate that there is complementarity in resource use between the different species.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
18.
As a tree management tool, three treatments of crown pruning (total-pruning, half-pruning and no-pruning) were applied to
Vitellaria paradoxa (karité) and Parkia biglobosa (néré) in agroforestry parkland systems in Burkina Faso. The area under each tree was divided into four concentric tree influence
zones (Zones A: up to 2 m from the tree trunk, B: up to half of the radius of the tree crown, C: up to the edge of the tree
crown and D: up to 2 m away from the edge of the tree crown). Millet production under these zones and outside was assessed
during two cropping seasons over the study period of three years and the results showed that tree crown pruning had significant
effect on millet production and the highest millet grain yield and total dry matter were produced under total-pruned trees
(507 ± 49 and 2033 ± 236 kg ha−1 year−1, respectively). Light transmission, transpiration and soil nutrient status under the trees were also analysed in relation
to millet production. The results of the analysis showed that total-pruned trees gave the highest millet production due to
the reduction by crown pruning of the effects of large tree crowns on PAR transmission below crowns and rates of transpiration
by trees. Soil was more fertile closer to the tree trunks than outside tree crowns. This may also be one of the reasons why
millet overall performed better under Zone B than outside tree crowns. The higher production of millet under Zone B than under
Zone A, the zone closer to the tree trunk, may be due to lower light intensity and more intense competition for water between
trees and crops under Zone A. It was concluded that at least in the short term millet production could be improved by crown
pruning of both karité and néré, but long term effects may depend on the ability of the trees to maintain the amelioration
of soil fertility and on how quickly the trees recover from pruning.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
19.
John Beer 《Agroforestry Systems》1988,7(2):103-114
The relative importance of N fixation, organic material inputs and nutrient inputs in litterfall, as justifications for including shade trees in plantations of coffee or cacao, is discussed. According to existing data, N fixation by leguminous shade trees does not exceed 60 kg.N/ha/a. However, these trees contribute 5,000–10,000 kg. organic material/ha/a.Comparisons are made between the leguminous shade tree Erythrina poeppigiana and the non-leguminous timber tree Cordia alliodora. The former, when pruned 2 or 3 times/a., can return to the litter layer the same amount of nutrients that are applied to coffee plantations via inorganic fertilizers, even at the highest recommended rates for Costa Rica of 270 kg.N, 60 kg.P, 150 kg.K/ha/a. The annual nutrient return in this litterfall represents 90–100 percent of the nutrient store in above-ground biomass of E. poeppigiana, and hence the consequences of competition with the crop should not be a serious limitation. In the case of C. alliodora, which is not pruned, nutrient storage in the tree stems, especially of K, is a potential limiting factor to both crop and tree productivity.It is concluded that, in fertilized plantations of cacao and coffee, litter productivity is a more important shade tree characteristic than N fixation.An early version of this review was presented at the CATIE-IUFRO meeting Los Arboles de Uso Multiple en Sistemas Agroforestales, June 1985, Turrialba, Costa Rica. 相似文献
20.
Marcel van Oijen Jean Dauzat Jean-Michel Harmand Gerry Lawson Philippe Vaast 《Agroforestry Systems》2010,80(3):341-359
Research on coffee agroforestry systems in Central America has identified various environmental factors, management strategies
and plant characteristics that affect growth, yield and the impact of the systems on the environment. Much of this literature
is not quantitative, and it remains difficult to optimise growing area selection, shade tree use and management. To assist
in this optimisation we developed a simple dynamic model of coffee agroforestry systems. The model includes the physiology
of vegetative and reproductive growth of coffee plants, and its response to different growing conditions. This is integrated
into a plot-scale model of coffee and shade tree growth which includes competition for light, water and nutrients and allows
for management treatments such as spacing, thinning, pruning and fertilising. Because of the limited availability of quantitative
information, model parameterisation remains fraught with uncertainty, but model behaviour seems consistent with observations.
We show examples of how the model can be used to examine trade-offs between increasing coffee and tree productivity, and between
maximising productivity and limiting the impact of the system on the environment. 相似文献