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Biomass Production and Relative Palatability of Possible Supplementary Forage Plants of the Northeastern Amazon

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Stefan Hohnwald at Georg-August-Universität Göttingen
Stefan Hohnwald
Julia Trautwein
Julia Trautwein
Julia Trautwein
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Ari Pinheiro Camarão
Ari Pinheiro Camarão
Ari Pinheiro Camarão
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Gerhard Gerold at Georg-August-Universität Göttingen
Gerhard Gerold
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Tropentag 2010
ETH Zurich, September 14 - 16, 2010
Conference on International Research on Food Security, Natural
Resource Management and Rural Development
Biomass Production and Relative Palatability of Possible Supplementary Forage Plants of
the Northeastern Amazon
Hohnwald, Stefan
a*
, Julia Trautwein
b
, Ari Pinheiro Camarão
c
, Gerhard Gerold
a
, Clemens B.A.
Wollny
b
a
Georg-August University, Department of Landscape Ecology, 37077 Göttingen, Germany
b
University of Applied Sciences Bingen, 55411 Bingen, Germany
c
Embrapa Amazônia Oriental, 66095-100, Belém-Pará, Brazil
Introduction
In the Bragantina region of north-eastern Pará, Brazil, the sustainability of extensive smallholder
pastures is constantly jeopardized by resprouting trees of the native resprouting secondary
vegetation, nationally called capoeira. In all, more than 825 plant species have been identified
within the Bragantinian capoeira, including numerous trees, shrubs, and forbs. However, not all
spontaneous capoeira species are just weeds but most of them play an important role in the
above-ground biomass accumulation of the fallow. Moreover, a recently conducted study showed
that on a grass-capoeira pasture, where the resprouting capoeira was partly tolerated on the plots,
many capoeira trees were intensively and regularly browsed by cattle (Hohnwald 2002). Thus, we
assumed that within this huge pool of capoeira species there is still a considerable pool of
promising underutilised forage supplement plants. To select these species, the following criteria
were chosen: plants should have a high palatability, leafy biomass production, fast recuperation
abilities after defoliation, free accessibility on smallholdings, good adaptations to environmental
conditions (climate, acid soils, frequent fires, slashings), and high nutrient contents in leaves.
Furthermore, species should be easy to handle with a minimum of management. Fitting the same
criteria, we also looked for other common introduced and domesticated tree species on
smallholdings. To evaluate the respective species we compared its leafy biomass production and
relative palatability against well-known multi-purpose forage legumes, hypothesizing that they
possess the same forage values.
Material and Methods
An on-farm buffet trial was therefore conducted on a 0.5 ha pasture in the centre of the
Bragantina region, at Igarapé-Açu (1°08’36”S/ 47°35’33”W). The region belongs to the per-
humid warm tropics with a mean annual temperature of 26.7°C, and 2469 mm rainfall. It is
furthermore characterized by acid Latosols, poor in P and N, with a low cation exchange
capacity. Six native species, namely Attalea maripa (Arecaceae), Cecropia palmata
(Cecropiaceae), Phenakospermum guyannense (Strelitziaceae), Abarema jupunba, Inga edulis
(both Fabaceae), and introduced Tithonia diversifolia (Asteraceae), Mangifera indica
(Anacardiaceae), and Racosperma mangium (Fabaceae) were tested against the forage legumes
Cratylia argentea (Desvaux) O. Kuntze cv. Veraniega and Flemingia macrophylla (Willd.) Merr.
(Figure 1). All species were joined in an on-farm experiment, where 25 saplings of each species
were planted on 25 m² plots, respectively, and repeated eight times in a randomized block design
Figure 1: Schematic design of the buffet trial: 1=Racosperma mangium, 2= Inga edulis, 3=Cratylia argentea,
4=Abarema jupunba, 5=Mangifera indica, 6=Tithonia diversifolia, 7=Flemingia macrophylla, 8=Phenakospermum
guyannense, 9=Attalea maripa, 0=Cecropia palmata.
(n=80 plots, n=2000 saplings). After 24 months of establishment time, the buffet trial was grazed
by four mixed-bred steers (mean liveweight: 506 kg; 2 AU/ha) for one week. The leafy biomass
of ten randomised mean individuals per species before and after cattle access was collected and
dried in an oven (65°C) until weight constancy was reached (n=200). The biomass values were
extrapolated to kg/ha and the consumed biomass calculated as percentage from the biomass
values before cattle access. Protein values were evaluated according to the Weende analysis.
Results
The results showed that many tested species had a comparable leafy biomass production, protein
values and palatability like the two reference legumes (Table 1). Especially R. mangium showed a
severe growth while other species, e.g. A. maripa and T. diversifolia suffered from the
transplantation on the slightly degraded pasture plot. The consumption of most tested species was
found mainly between the reference legumes. However, while C. palmata showed even higher
consumption values than C. argentea, I. edulis and P. guianensis were hardly browsed at all by
cattle, which can be explained by its small plant heights, hardly detectable in the overgrown
forage grasses. This was also true for A. maripa and T. diversifolia, where even not enough
biomass was found for evaluation. The protein contents were also mostly satisfactory besides the
relatively low values of P. guianensis, M. indica, and A. maripa.
Table 1: Leafy biomass, consumed percentages and protein contents of the 10 compared forage species.
Species name (plus family)
Leafy biomass in kg/
ha
(standard deviation)
Consumed
biomass
in %
Protein
contents in %
(standard deviation)
R. mangium (Fabaceae) 455 (429) 21 9.6 (0.33)
F. macrophylla (Fabaceae) 260 (89) 13 14.1 (0.11)
C. argentea (Fabaceae) 164 (87) 40 19.2 (0.41)
P. guianensis (Strelitziaceae) 156 (13) 1 8.1 (0.08)
M. indica (Anacardiaceae) 156 (19) 25 6.1 (0.03)
A. jupunba (Fabaceae) 140 (13) 29 13.9 (0.81)
I. edulis (Fabaceae) 94 (9) 8 13.3 (0.52)
C. palmata (Cecropiaceae) 88 (20) 60 15.1 (0.32)
A. maripa (Arecaceae) 60 (13) - 6.1 (0.31)
T. diversifolia (Asteraceae) 57 (62) - 20.4 (0.43)
Discussion
The results of the buffet trial elucidated that smallholders possess excellent free accessable forage
alternatives on their farms and even on their pasture plots. Thus, it is recommendable to farmers
not to eliminate all resprouting capoeira trees but just unpalatable species. This idea would also
fit into the improvement philosophy of smallholder agriculture: to invest more in knowledge-
intensive than into labour-intensive systems and to avoid monocultures in the humid tropics.
Therefore, the promising species should also not be taken into breeding consideration.
Establishment of the buffet trial was problematic and transplantation of saplings to a soil-
compacted and sun-exposed pasture cannot be recommended to farmers as mortality was high
and growth rates were low (Figure 2). Transplantation also means high-input activities on farms,
which would be hardly acceptable for farmers. However, frequent pruning of the trees into
accessable heights for cattle is advisable as the pioneer trees would grow quickly out of the
animal range. Furthermore, tolerating trees on pastures and invest into silvo-pastoral systems will
also counteract the foreseen climate change in the NE-Amazon.
Figure 2: View on the buffet trial, 16 months after capoeira transplantation on the pasture. In the foreground,
yellowish leaves of Phenakospermum
guianensis from block 5 can be seen (background block 7 and 8).
References
Hohnwald, S., 2002: A Grass-Capoeira Pasture Fits Better Than a Grass-Legume Pasture in the Agricultural System
of Smallholdings in the Humid Brazilian Tropics. Cuvillier Verlag Göttingen, Germany, ISBN 3-89873-614-8
... Under rising temperatures the forage quality of grass is predicted to decline, whilst simultaneously methane emissions from cattle are predicted to increase . In the Bragantina region of Northern Brazil, Hohnwald et al. (2010) demonstrated that in the humid tropics, the integration of woody components could enhance forage production, ecological stability and sustainability when compared to grass monocultures. Historically, shrubs and trees have been perceived as weeds that limit grass productivity and efforts have concentrated on their elimination (Scoones, 1995). ...
... The importance of locally adapted plants for the development of silvopastoral systems has been highlighted by many authors (including but not limited to Ibrahim et al., 2006;Guimarães-Beelen et al., 2006;Murgueitio et al., 2011;Nunes et al., 2016;Dechnik-Vázquez et al., 2019). However, research on the forage potential of trees that are adapted to Amazon pastures is scarce and to date has concentrated on the North Eastern Amazon in Brazil (Hohnwald et al., 2010;Hohnwald, 2016). The present study is in the South Western Amazon, Peru, 1700 miles from Hohnwald's (2016) study site. ...
... carbohydrates and 0.31 g/100g of condensable tannins in the foliage of I. edulis. Staver (1989) considered I. edulis in association with Desmodium ovalifolium as a "planted fallow suitable for grazing", and suggested I. edulis 'grew more vigorously' than Leucaena sp., Gliricidia sepium, and Calliandra calothyrsus when planted in observation plots.Hohnwald (2010) reported that I. edulis was palatable on a scale of very palatable, palatable or medium palatability. They report that in a browsing trial by cattle I. edulis plants may have been too small to be detected by the cattle among the tall adjacent grass.Hohnwald (2016) reported I. edulis as having 'poor palatability' for cattle. ...
Designing silvopastoral systems for the Amazon: a framework for the evaluation of native species
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  • Jul 2020
The integration of trees into pastures, termed silvopasture systems, could make livestock farming more economically and environmentally sustainable. A framework to assess the forage potential of native tree species would assist in developing regionally appropriate silvopasture for pastures in the Amazon. Five tree species of with reported silvopastoral potential, Senegalia loretensis, Ceiba pentandra, Erythrina berteroana, Inga edulis and Leucaena leucocephala, were selected to investigate their potential use in a silvopastoral system. A 26-month field experiment planted 900 trees of the five species to assess tree mortality, biomass production and palatability for cattle. Five monospecific replicates of each species and a control with no trees planted were installed on a Brachiaria brizantha pasture in Madre de Dios, Peru. After 18 months, S. loretensis and C. pentandra showed double the rate of mortality compared to the other species and were deemed inappropriate for continued consideration. Destructive harvests of the remaining three species showed that total biomass production and hence carbon storage was greater for I. edulis (7.2 Mg dry mass ha-1) than E. berteroana (4.4 Mg dry mass ha-1) or L. leucocephala (4.3 Mg dry mass ha-1) at 24 months. These biomass gains were not at the expense of grass: edible biomass within the reach of cattle was 1.5 Mg ha-1 in the no tree control, whereas E. berteroana produced 2.3 Mg ha-1, I. edulis 2.3 Mg ha-1 and L. leucocephala 2.2 Mg ha-1. Cattle were introduced into each treatment to assess palatability. Cattle consumed 99% of E. berteroana, 75% of I. edulis and 80% of L. leucocephala. E. berteroana had a mortality six times greater than other species, but all species have silvopastoral potential. This evaluation of tree species supports regionally appropriate silvopastoral systems and shows that silvopasture can increase productivity on existing cleared land and can contribute to mitigating climate change.
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Browse from Three Tree Legumes Increases Forage Production for Cattle in a Silvopastoral System in the Southwest Amazon
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  • Dec 2021
Assessing the palatability of forage from locally adapted trees could improve the sustainability of livestock production systems. However, grasses continue to dominate livestock feed across the Amazon. We established a silvopastoral cattle farming system in Peru, comparing three different forage tree species with grass monocultures using a randomised block design. Trees were arranged in alleys of 0.5 x 7.5 m, planted alongside grass, and were directly browsed by cattle. Browse removal was estimated by three methods: destructive sampling, canopy measurements and leaf counts. We found that all three tree species were palatable to cattle. Plots containing trees andg rass produced more available forage (mean > 2.2 Mg ha-1) for cattle than the grass monocultures (mean = 1.5 Mg ha-1). Destructive sampling below 1.6 m demonstrated that cattle consumed 99% of the available Erythrina berteroana forage, 75% of the available Inga edulis forage and 80% of the available Leucaena leucocephala forage in 8 days. This research demonstrates methodologies to estimate the intake of locally adapted browse species by cattle and highlights the potential benefits of silvopastoral systems in the Amazon. Planting trees could also benefit animal health and provide ecosystem services such as soil regeneration, enhanced nutrient cycling and carbon capture.
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A Grass-Capoeira Pasture Fits Better Than a Grass-Legume Pasture in the Traditional Agricultural System of Smallholdings in the Brazilian Humid Tropics
Book
Full-text available
  • Nov 2002
In the humid tropics of the Bragantina region (northeastern Pará, Brazil) traditional agriculture of smallholders is based on the exploitation of the regenerative potential of the secondary vegetation, locally called "Capoeira" : a 5 to 10 years old fallow is slashed and burned to fertilize the soil for a subsequent cropping phase, which normally consists of maize/ upland rice, beans, and cassava. In the last two decades cattle husbandry has become an important additional farming activity on smallholdings. Generally, unfertilized pastures in the Brazilian Amazon region are said to reach an advanced state of degradation after 7 to 10 years due to decreasing soil fertility, insect pests, and invading woody vegetation. After 10 to 15 years of use, pastures have to be abandoned because the stocking rate has to be gradually reduced until the costs do not longer justify further pasture maintenance. Eight years after abandonment moderately and heavily used pastures still show a disturbed or retarded fallow regeneration. Since cattle husbandry is often only a short-term engagement of smallholders, an integration of pastures into the slash-and-burn cycle could be more appropriate for the smallholder situation than keeping them on separated pastures. Thus, the purpose of this study was to test two different types of Brachiaria humidicola-pastures, which were able to prepare the area for a subsequent cropping phase and to keep cattle at least like on a traditional pasture, at the same time. First option was a Grass-Legume pasture, which included two woody legumes, Cratylia argentea and Chamaecrista rotundifolia, and the herbaceous legume Arachis pintoi. The restorative functions should mainly be achieved by nitrogen fixation. The second approach was to tolerate parts of the re-sprouting Capoeira on the pastures, so that the accumulated above ground biomass could enrich the soil fertility like a traditional fallow in a later stage (Grass-Capoeira pasture). Therefore, the hypothesis of this study was: " The inclusion of legumes or Capoeira in pastures restores the soil for a subsequent cropping phase and still allows the keeping of cattle. " This hypothesis was tested on a researcher-managed on-farm experiment, located in the municipality of Igarapé-Açu at 47°30' W and 1°2' S (Bragantina region). It was established on a 3.2 ha sized field, which had been cultivated with maize and cassava for 1.5 years, preceded by a 12-year old Capoeira. The two tested treatments were tested against two controls: a conventionally managed traditional pasture and an undisturbed re-growth of secondary vegetation. The three pasture types had an area of 3600 m² and were divided into three replications in a block design. In each of the nine pasture plots a 100 m² exclosure was fenced to allow the undisturbed Capoeira re-growth without B. humidicola. Three cross-bred steers were allocated on each pasture treatment and then rotated between the three replications. The stocking rate was 1.5 LU ha-1 year-1 in the rainy season and adjusted to 1.48 LU ha-1 year-1 during the dry season, by withdrawing the lightest animal from each treatment. For the comparison of chemical and physical soil restoration the contents of nitrogen, carbon and other important indicators (pH, P, K, Ca, Mg, Al, and Na) were compared between treatments, taking five soil samples at five points and four different depths (0-10, 10-20, 20-50, 50-100 cm) per plot. For the comparison of soil bulk-density six undisturbed samples were taken per plot, separated into three depths (0-10, 10-20, 20-30 cm). The vegetation was controlled in four fixed 100 m² subplots on each pasture plot by half-yearly estimating of the soil cover percentage of each Capoeira species every six months. The similarities between treatments were calculated with the aid of the Sørensen-Index and the Euclidian Distance. To have direct indicators for cattle impact (browsing, trampling) damage was measured after animals had access to the plants, and soil cover percentages were compared over the complete experimental time. Results after one year of pasture establishment and nearly two years of grazing showed that the legumes did not collect enough nitrogen and other elements to prepare the soil for a subsequent cropping phase. Differences in soil fertility and pH between treatments were not significant. This was due to establishment and development problems of the legumes. Thus, C. argentea and A. pintoi were almost grazed out and not able to produce enough nodules. C. rotundifolia was consumed very little but nitrogen fixation was also negligible as judged by the nodule mass produced after one year of grazing. The soil bulk-densities also did not differ significantly between treatments. On the Grass-Capoeira pasture even the high stocking rates did not significantly alter the botanical composition and phytodiversity of the vigorous re-growing Capoeira. The Capoeira re-growth was stronger than the cattle impact. Cattle were very selective and about 48 of the 285 detected plant species were frequently browsed. Of the most important Capoeira species, in respect of biomass production and as key species, only Myrciaria floribunda, Phenakospermum guyannense, Machaerium quinata, Cecropia palmata, Maximiliana maripa, Cordia exaltata and Cordia nodosa were in danger of being eliminated by cattle. Most Capoeira species like all Myrtaceae and Melastomataceae were not palatable and restored as in a natural Capoeira or slightly retarded. Cattle performance showed with averagely 466 kg ha-1 (Grass-Legume pasture = 417, Grass-Capoeira pasture = 483, Traditional Pasture =500) good results in the first year, but decreased drastically to 39 kg ha-1 (Grass-Legume pasture = -33, Grass-Capoeira pasture = -9, Traditional Pasture = 160) in the second year, which were mainly due to the bad values of –51 kg ha-1 (Grass-Legume pasture = -60, Grass-Capoeira pasture = -115, Traditional Pasture = 24) during the second dry season. It can be concluded that the establishment and management of a Grass-Legume pasture has yet to be improved while the Grass-Capoeira pasture is an interesting option for an integrated pasture. Furthermore, the Grass-Capoeira pasture is better adapted to the highly dynamic and flexible agricultural system of smallholders because farmers can finish their pasture engagement whenever they want, just allowing the unchanged Capoeira vegetation to take over. Thus it is possible to convert the pasture into another use much more quickly. The Grass-Legume pasture seems to have better options to be used by farmers, who intend to keep cattle for a longer time.
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