39 research outputs found
Soil Carbon in Agroforestry Systems: An Unexplored Treasure?
Soil organic matter (SOM), which contains more reactive organic carbon (C) than any other single terrestrial pool, plays a major role in determining C storage in ecosystems and regulating atmospheric concentrations of carbon dioxide (CO2)^1^. Agroforestry, the practice of growing trees and crops in interacting combinations on the same unit of land^2^, primarily by resource-poor smallholder farmers in developing countries, is recognized as a strategy for soil carbon sequestration (SCS) under the Clean Development Mechanism (CDM) of the Kyoto Protocol^3^. The understanding about C storage and dynamics under agroforestry systems (AFS), however, is minimal. Our studies under various AFS in diverse ecological conditions in five countries showed that tree-based agricultural systems, compared to treeless systems, stored more C in deeper soil layers up to 1 m depth under comparable conditions. More C is stored in soil near the tree than away from the tree; higher SOC content is associated with higher species richness and tree density; and C3 plants (trees) contribute to more C in the silt- + clay-sized (<53 µm) fractions that constitute more stable C, than C4 plants, in deeper soil profiles4 - 8. These results provide clear indications of the possibilities for climate change mitigation through SCS in AFS, and opportunities for economic benefit - through carbon trading - to millions of smallholder farmers in developing countries
PRODUÇÃO DE SERAPILHEIRA EM FLORESTA ESTACIONAL SEMIDECIDUAL E EM PLANTIOS DE Pterogyne nitens Tull. e Eucalyptus urophylla S. T. Blake NO SUDOESTE DA BAHIA
Leaf litter is a major component responsible for maintaining the productive capacity of forests; thus, knowledge on their production and composition can provide information to adjust management techniques. The objective of this study was to evaluate the monthly litter fall in a Seasonal Semideciduous Forest and two pure forest plantations (Pterogyne nitens and e de Eucalyptus urophylla), located in city of Vitoria da Conquista, Bahia state, as well as to analyze the influence of climatic factors in this production. Leaf litter samples were collected during ten months, using 0.25 m2 square collectors. The materials collected were screened (fractions: leaves, branches, bark and reproductive structures) and dried in a dry kiln at 60° C. The monthly average litter productions were 544.6, 522.6 and 179.5 kg ha-1 in areas of Seasonal Semideciduous Forest, Eucalyptus urophylla and Pinus nitens, respectively. The leaves represented an increasing proportion of litter in three coverages (65% of the total). The average monthly production of leaves was higher in native forest, followed by Eucalyptus urophylla and Pinus nitens. The contribution of branches was significantly lower in the Pinus nitens and did not vary between Seasonal Semideciduous Forest and Eucalyptus urophylla. The production of reproductive materials varied in the order: Eucalyptus urophylla > Seasonal Semideciduous Forest > Pinus nitens. The bark fraction did not vary between Seasonal Semideciduous Forest and Pinus nitens, being higher in Eucalyptus urophylla. There was a significant negative correlation between total production and average air temperature in all studied coverage. Only on Pinus nitens were found significant associations with the litter production variables precipitation and wind speed. Eucalyptus urophylla forest and Seasonal Semideciduous Forest have similar aspects regarding leaf litter production, 67% higher than the production of Pinus nitens. The temporal variation of litter production of Pinus nitens shows up much more sensitive to the influence of climatic variables that Seasonal Semideciduous Forest and Eucalyptus urophylla. The contribution of litter fractions followed the same order in all coverage studied: leaves > branches > reproductive structures > bark.http://dx.doi.org/10.5902/1980509819614A serapilheira constitui um dos principais componentes responsáveis pela manutenção da capacidade produtiva de sítios florestais e, sendo assim, o conhecimento da sua produção e composição pode fornecer subsídios para adequação de técnicas de manejo. O objetivo deste trabalho foi avaliar mensalmente a serapilheira produzida em uma Floresta Estacional Semidecidual (mata de cipó) e dois plantios florestais puros (de Pterogyne nitens e de Eucalyptus urophylla), localizados no município de Vitória da Conquista - BA, assim como analisar a influência de fatores climáticos nessa produção. As amostras da serapilheira foram coletadas durante dez meses, por meio de coletores quadrados com 0,25 m2. Os materiais coletados foram triados (frações: folhas, galhos, casca e estruturas reprodutivas) e secos em estufa a 60oC. As produções mensais médias de serapilheira foram de 544,6, 522,6 e 179,5 kg ha-1 nas áreas de mata de cipó, Eucalyptus urophylla e Pinus nitens, respectivamente. As folhas representaram maior proporção da serapilheira produzida nas três coberturas (65% do total). A produção mensal média de folhas foi superior na mata nativa, seguida do Eucalyptus urophylla e Pinus nitens. O aporte de galhos foi significativamente menor no povoamento de Pinus nitens e não variou entre mata de cipó e Eucalyptus urophylla. A produção de materiais reprodutivos variou na ordem: Eucalyptus urophylla > mata de cipó > Pinus nitens. A fração casca não variou entre mata de cipó e Pinus nitens, sendo superior no Eucalyptus urophylla. Em todas as coberturas estudadas verificou-se correlação significativa negativa entre produção total e temperatura média do ar. Apenas no plantio de Pinus nitens foram verificadas associações significativas do aporte de serapilheira com as variáveis precipitação e velocidade do vento. O Eucalyptus urophylla e a mata de cipó apresentam similaridade quanto à produção média de serapilheira, sendo cerca de 67% superior a produção de Pinus nitens. A variação temporal do aporte de serapilheira de Pinus nitens mostra-se bem mais sensível à influência de variáveis climáticas que a mata de cipó e o Eucalyptus urophylla. A contribuição das frações da serapilheira obedeceu a uma mesma ordem em todas as coberturas estudadas: folhas > galhos > estruturas reprodutivas > cascas
LITTER PRODUCTION IN SEASONAL SEMIDECIDUOUS FOREST AND Pterogyne nitens Tul. AND Eucalyptus urophylla S. T. Blake PLANTATIONS IN SOUTHWESTERN BAHIA STATE, BRAZIL
A serapilheira constitui um dos principais componentes
respons\ue1veis pela manuten\ue7\ue3o da capacidade produtiva de
s\uedtios florestais e, sendo assim, o conhecimento da sua
produ\ue7\ue3o e composi\ue7\ue3o pode fornecer subs\ueddios
para adequa\ue7\ue3o de t\ue9cnicas de manejo. O objetivo deste
trabalho foi avaliar mensalmente a serapilheira produzida em uma
Floresta Estacional Semidecidual (mata de cip\uf3) e dois plantios
florestais puros (de Pterogyne nitens e de Eucalyptus urophylla ),
localizados no munic\uedpio de Vit\uf3ria da Conquista - BA, assim
como analisar a influ\ueancia de fatores clim\ue1ticos nessa
produ\ue7\ue3o. As amostras da serapilheira foram coletadas durante
dez meses, por meio de coletores quadrados com 0,25 m2. Os materiais
coletados foram triados (fra\ue7\uf5es: folhas, galhos, casca e
estruturas reprodutivas) e secos em estufa a 60oC. As
produ\ue7\uf5es mensais m\ue9dias de serapilheira foram de 544,6,
522,6 e 179,5 kg ha-1 nas \ue1reas de mata de cip\uf3, Eucalyptus
urophylla e Pinus nitens, respectivamente. As folhas representaram
maior propor\ue7\ue3o da serapilheira produzida nas tr\ueas
coberturas (65% do total). A produ\ue7\ue3o mensal m\ue9dia de
folhas foi superior na mata nativa, seguida do Eucalyptus urophylla e
Pinus nitens. O aporte de galhos foi significativamente menor no
povoamento de Pinus nitens e n\ue3o variou entre mata de cip\uf3 e
Eucalyptus urophylla. A produ\ue7\ue3o de materiais reprodutivos
variou na ordem: Eucalyptus urophylla > mata de cip\uf3 > Pinus
nitens. A fra\ue7\ue3o casca n\ue3o variou entre mata de
cip\uf3 e Pinus nitens, sendo superior no Eucalyptus urophylla. Em
todas as coberturas estudadas verificou-se correla\ue7\ue3o
significativa negativa entre produ\ue7\ue3o total e temperatura
m\ue9dia do ar. Apenas no plantio de Pinus nitens foram verificadas
associa\ue7\uf5es significativas do aporte de serapilheira com as
vari\ue1veis precipita\ue7\ue3o e velocidade do vento. O
Eucalyptus urophylla e a mata de cip\uf3 apresentam similaridade
quanto \ue0 produ\ue7\ue3o m\ue9dia de serapilheira, sendo
cerca de 67% superior a produ\ue7\ue3o de Pinus nitens. A
varia\ue7\ue3o temporal do aporte de serapilheira de Pinus nitens
mostra-se bem mais sens\uedvel \ue0 influ\ueancia de
vari\ue1veis clim\ue1ticas que a mata de cip\uf3 e o Eucalyptus
urophylla. A contribui\ue7\ue3o das fra\ue7\uf5es da
serapilheira obedeceu a uma mesma ordem em todas as coberturas
estudadas: folhas > galhos > estruturas reprodutivas > cascas.Leaf litter is a major component responsible for maintaining the
productive capacity of forests; thus, knowledge on their production and
composition can provide information to adjust management techniques.
The objective of this study was to evaluate the monthly litter fall in
a Seasonal Semideciduous Forest and two pure forest plantations (
Pterogyne nitens and e de Eucalyptus urophylla ), located in city of
Vitoria da Conquista, Bahia state, as well as to analyze the influence
of climatic factors in this production. Leaf litter samples were
collected during ten months, using 0.25 m2 square collectors. The
materials collected were screened (fractions: leaves, branches, bark
and reproductive structures) and dried in a dry kiln at 60\ub0 C. The
monthly average litter productions were 544.6, 522.6 and 179.5 kg ha-1
in areas of Seasonal Semideciduous Forest, Eucalyptus urophylla and
Pinus nitens, respectively. The leaves represented an increasing
proportion of litter in three coverages (65% of the total). The average
monthly production of leaves was higher in native forest, followed by
Eucalyptus urophylla and Pinus nitens. The contribution of branches was
significantly lower in the Pinus nitens and did not vary between
Seasonal Semideciduous Forest and Eucalyptus urophylla. The production
of reproductive materials varied in the order: Eucalyptus urophylla
> Seasonal Semideciduous Forest > Pinus nitens. The bark fraction
did not vary between Seasonal Semideciduous Forest and Pinus nitens,
being higher in Eucalyptus urophylla. There was a significant negative
correlation between total production and average air temperature in all
studied coverage. Only on Pinus nitens were found significant
associations with the litter production variables precipitation and
wind speed. Eucalyptus urophylla forest and Seasonal Semideciduous
Forest have similar aspects regarding leaf litter production, 67%
higher than the production of Pinus nitens. The temporal variation of
litter production of Pinus nitens shows up much more sensitive to the
influence of climatic variables that Seasonal Semideciduous Forest and
Eucalyptus urophylla. The contribution of litter fractions followed the
same order in all coverage studied: leaves > branches >
reproductive structures > bark
Decomposição de serapilheira foliar em três sistemas florestais no Sudoeste da Bahia
The decomposition process influences the functioning of forest ecosystems, because it regulates the accumulation of soil organic matter and nutrient cycling. The objective of this study was to evaluate the decomposition of leaf litter in a native forest fragment (semideciduous forest) and two forest plantations (native species planting: Tabebuia impetiginosa, Tabebuia serratifolia, Tabebuia roseo-alba, Alchornea triplinervia and Astronium urundeuva and jackfruit planting. The decomposition was evaluated from the use of nylon bags containing about 10 grams of leaf material. The bags were collected at 30, 60, 90, 120, 150 and 180 days after installation. Were estimated the percentage of the remaining mass, the rate of decomposition (k) and half-life time of the litter (t1/2). At the end of the experiment, in the jackfruit planting, over 50% of the leaf material was decomposed, while in the native forest and in the native planting native the decomposition occurred of 34 and 35%, respectively. The coefficient k was higher for jackfruit planting (0,0033 g g-1 day), followed by native forest (0,0023 g g-1 day) and the native planting (0,0019 g g-1 day). The half-life time was 210,04 days (jackfruit planting), 364,81 days (native planting) and 301,37 days (native forest). The leaf litter of jackfruit planting has more rapid decomposition in relation to native forest and native planting. The decomposition process is influenced not only by the quality of the litter, but also by quality of the microenvironment of a given forest stand.O processo de decomposição influencia o funcionamento de ecossistemas florestais, pois regula o acúmulo de matéria orgânica no solo e a ciclagem de nutrientes. O objetivo deste trabalho foi avaliar a decomposição da serapilheira foliar de um fragmento de floresta nativa (Floresta Estacional Semidecidual Montana) e dois plantios florestais, um plantio de espécies nativas [Ipê roxo (Tabebuia impetiginosa), Ipê amarelo (Tabebuia serratifolia), Ipê branco (Tabebuia roseo-alba), Sete-cascas (Alchornea triplinervia) e Aroeira (Astronium urundeuva)] e um plantio de jaqueira (Artocarpus heterophyllus). A decomposição foi avaliada a partir da utilização de bolsas de náilon contendo cerca de 10 g de material foliar. As coletas ocorreram aos 30, 60, 90, 120, 150 e 180 dias após a instalação. Foram estimados o percentual de massa remanescente, as taxas de decomposição (k) e o tempo de meia vida do folhedo (t1/2). Ao final do experimento, no plantio de jaqueira mais de 50% do material foliar foi decomposto, enquanto na floresta nativa e no plantio de nativas ocorreu decomposição de 34 e 35%, respectivamente. O coeficiente k foi maior para o plantio de jaqueira (0,0033 g·g-1·dia), seguido da floresta nativa (0,0023 g·g-1·dia) e do plantio de nativas (0,0019 g·g-1·dia). O tempo de meia vida foi de 210,04 dias (plantio jaqueira), 364,81 dias (plantio de nativas) e 301,37 dias (floresta nativa). A serapilheira foliar do plantio de jaqueira apresenta decomposição mais acelerada, em relação ao plantio de espécies florestais nativas e a floresta nativa. O processo de decomposição é influenciado não apenas pela qualidade do folhedo, mas também pela qualidade do microambiente de determinado povoamento florestal
DECOMPOSIÇÃO DA SERAPILHEIRA FOLIAR DE FLORESTA NATIVA E PLANTIOS DE Pterogyne nitens E Eucalyptus urophylla NO SUDOESTE DA BAHIA
The decomposition process regulates the accumulation of litter and nutrient cycling in forest ecosystems, being central to its maintenance. The objective of this study was to evaluate the dynamics of leaf litter decomposition in three forest ecosystems (semideciduous forest Montana and homogeneous stands of Pterogyne nitens Tul. and Eucalyptus urophylla ST Blake), located in Vitória da Conquista, Bahia, Brazil. To evaluate the decomposition, newly fallen leaves on the ground of trees and shrubs in each of the studied toppings were collected. The sheets were dried at 65 °C, and thereafter, 10 g portions were weighed and placed in litter bags, which were randomly distributed on the surface of the forest floor in each of the areas studied. Five litter bags at random were collected after 30, 60, 90, 120, 150 and 180 days of installation. After collection, the material contained in each litter bag was subjected to drying in an oven at 65 °C and weighed. Based on the obtained masses were estimated the percentage of the remaining mass, the rate of decomposition (k) and half-life time of the litter (t1/2). For chemical characterization three subsamples were separated from the dried leaf litter, which were ground and analyzed by determination of the total nitrogen, carbon, polyphenols, lignin and cellulose. The decomposition was related to environmental variables (precipitation, temperature and humidity) and the microenvironment (temperature and soil moisture).The total accumulated litter varied significantly between the settlements studied, the highest value was observed in the area of Eucalyptus urophylla (12,7 Mg ha-1), followed by native forest (6,9 Mg ha-1) and Pterogyne nitens (1,1 Mg ha-1). At the end of the six months of the experiment, Eucalyptus urophylla showed the greatest remaining mass (73,6%), followed by native forest (67,8%) and Pterogyne nitens (46,3%). The decomposition constant (k) was higher in litter of Pterogyne nitens (0,0054 g g-1 day), with lower values for native forest (0,0016 g g-1 day) and Eucalyptus urophylla (0,0015 g g-1day). The rate of decomposition of leaf litter of the peopling of Pterogyne nitens is in a superior position in relation to rates of native forest and stand of Eucalyptus urophylla, which provides the largest species ability to recycle organic matter and nutrients. The decomposition process in the studied ecosystems is influenced not only by the quality of the litter but also by the quality of their microenvironment.O processo de decomposição regula o acúmulo de serapilheira e a ciclagem de nutrientes em ecossistemas florestais, sendo fundamental para sua manutenção. O objetivo deste trabalho foi avaliar a dinâmica de decomposição foliar em uma Floresta Estacional Semidecidual Montana e em plantios homogêneos de Pterogyne nitens Tul. e de Eucalyptus urophylla S. T. Blake, localizados no município de Vitória da Conquista, Bahia, Brasil. Para avaliação da decomposição, foram coletadas folhas recém-caídas sobre o solo de árvores e arbustos em cada uma das coberturas estudadas. As folhas foram secas em estufa a 65oC e, após isso, porções de 10 g foram pesadas e colocadas em litter bags, que foram distribuídos aleatoriamente na superfície do piso florestal em cada uma das áreas estudadas. Realizaram-se coletas de cinco litter bags de forma aleatória após 30, 60, 90, 120, 150 e 180 dias da instalação. Com base nas massas obtidas, foram estimados o percentual de massa remanescente, as taxas de decomposição (k) e o tempo de meia-vida do folhedo (t1/2). Para caracterização química, foram separadas três subamostras do material foliar seco, que foram moídas e analisadas, determinando-se os teores de nitrogênio total, carbono, polifenóis, lignina e celulose. Os dados de decomposição foram relacionados com variáveis ambientais (precipitação, temperatura e umidade do ar) e microambientais (temperatura e umidade do solo) referentes ao mês de coleta. O acúmulo total de serapilheira variou entre as áreas estudadas, o maior valor foi observado no plantio de Eucalyptus urophylla (12,7 Mg ha-1), seguido pela floresta nativa (6,9 Mg ha-1) e plantio de Pterogyne nitens (1,1 Mg ha-1). Ao final dos seis meses de avaliação, o Eucalyptus urophylla apresentou a maior massa remanescente (73,6%), seguido da floresta nativa (67,8%) e Pterogyne nitens (46,3%). A constante de decomposição (k) foi maior para a Pterogyne nitens (0,0054 g g-1dia), com menores valores para floresta nativa (0,0016 g g-1dia) e Eucalyptus urophylla (0,0015 g g-1dia). A taxa de decomposição da serapilheira foliar do povoamento de Pterogyne nitens situa-se em uma posição superior em relação às taxas da floresta nativa e do povoamento de Eucalyptus urophylla, o que proporciona à espécie maior capacidade de reciclar matéria orgânica e nutrientes. O processo de decomposição nos ecossistemas estudados é influenciado não apenas pela qualidade do folhedo, mas também pela qualidade do seu microambiente
Atividade microbiana, carbono e nitrogênio da biomassa microbiana em plantações de eucalipto, em seqüência de idades
Atributos químicos e microbianos de solos sob diferentes coberturas vegetais no norte do Estado do Rio de Janeiro
LEAF LITTER DECOMPOSITION IN NATIVE FOREST, PLANTATION OF Pterogyne nitens AND Eucalyptus urophylla IN SOUTHWESTERN BAHIA
O processo de decomposi\ue7\ue3o regula o ac\ufamulo de
serapilheira e a ciclagem de nutrientes em ecossistemas florestais,
sendo fundamental para sua manuten\ue7\ue3o. O objetivo deste
trabalho foi avaliar a din\ue2mica de decomposi\ue7\ue3o foliar
em uma Floresta Estacional Semidecidual Montana e em plantios
homog\ueaneos de Pterogyne nitens Tul. e de Eucalyptus urophylla
S. T. Blake, localizados no munic\uedpio de Vit\uf3ria da
Conquista, Bahia, Brasil. Para avalia\ue7\ue3o da
decomposi\ue7\ue3o, folhas rec\ue9m-ca\ueddas foram coletadas,
secas em estufa a 65oC, pesadas e colocadas em litter bags, que foram
distribu\ueddos aleatoriamente na superf\uedcie do piso florestal
de cada uma das \ue1reas estudadas. Realizaram-se coletas de cinco
litter bags de forma aleat\uf3ria ap\uf3s 30, 60, 90, 120, 150 e
180 dias da instala\ue7\ue3o. Com base nas massas obtidas, foram
estimados o percentual de massa remanescente, as taxas de
decomposi\ue7\ue3o (k) e o tempo de meia-vida do folhedo (t1/2).
Para caracteriza\ue7\ue3o qu\uedmica, foram separadas tr\ueas
subamostras do material foliar seco, que foram mo\ueddas e
analisadas, determinando-se os teores de nitrog\ueanio total,
carbono, polifen\uf3is, lignina e celulose. Os dados de
decomposi\ue7\ue3o foram relacionados com vari\ue1veis ambientais
(precipita\ue7\ue3o, temperatura e umidade do ar) e microambientais
(temperatura e umidade do solo) referentes ao m\ueas de coleta. O
ac\ufamulo total de serapilheira variou entre as \ue1reas
estudadas, o maior valor foi observado no plantio de Eucalyptus
urophylla (12,7 Mg ha-1), seguido pela floresta nativa (6,9 Mg ha-1) e
plantio de Pterogyne nitens (1,1 Mg ha-1). Ao final dos seis meses de
avalia\ue7\ue3o, o Eucalyptus urophylla apresentou a maior massa
remanescente (73,6%), seguido da floresta nativa (67,8%) e Pterogyne
nitens (46,3%). A constante de decomposi\ue7\ue3o (k) foi maior
para a Pterogyne nitens (0,0054 g g-1dia), com menores valores para
floresta nativa (0,0016 g g-1dia) e Eucalyptus urophylla (0,0015 g
g-1dia). A taxa de decomposi\ue7\ue3o da serapilheira foliar do
povoamento de Pterogyne nitens situa-se em uma posi\ue7\ue3o
superior em rela\ue7\ue3o \ue0s taxas da floresta nativa e do
povoamento de Eucalyptus urophylla, o que proporciona \ue0
esp\ue9cie maior capacidade de reciclar mat\ue9ria org\ue2nica e
nutrientes. O processo de decomposi\ue7\ue3o nos ecossistemas
estudados foi influenciado n\ue3o apenas pela qualidade do folhedo,
mas tamb\ue9m pela qualidade do seu microambiente.The decomposition process regulates the accumulation of litter and
nutrient cycling in forest ecosystems, being central to its
maintenance. The objective of this study was to evaluate the dynamics
of leaf litter decomposition in three forest ecosystems (semideciduous
forest Montana and homogeneous stands of Pterogyne nitens Tul. and
Eucalyptus urophylla ST Blake), located in Vit\uf3ria da Conquista,
Bahia, Brazil. To evaluate the decomposition, newly fallen leaves on
the ground of trees and shrubs in each of the studied toppings were
collected. The sheets were dried at 65 \ub0C, and thereafter, 10 g
portions were weighed and placed in litter bags, which were randomly
distributed on the surface of the forest floor in each of the areas
studied. Five litter bags at random were collected after 30, 60, 90,
120, 150 and 180 days of installation. After collection, the material
contained in each litter bag was subjected to drying in an oven at 65
\ub0C and weighed. Based on the obtained masses were estimated the
percentage of the remaining mass, the rate of decomposition (k) and
half-life time of the litter (t1/2). For chemical characterization
three subsamples were separated from the dried leaf litter, which were
ground and analyzed by determination of the total nitrogen, carbon,
polyphenols, lignin and cellulose. The decomposition was related to
environmental variables (precipitation, temperature and humidity) and
the microenvironment (temperature and soil moisture).The total
accumulated litter varied significantly between the settlements
studied, the highest value was observed in the area of Eucalyptus
urophylla (12,7 Mg ha-1), followed by native forest (6,9 Mg ha-1) and
Pterogyne nitens (1,1 Mg ha-1). At the end of the six months of the
experiment, Eucalyptus urophylla showed the greatest remaining mass
(73,6%), followed by native forest (67,8%) and Pterogyne nitens
(46,3%). The decomposition constant (k) was higher in litter of
Pterogyne nitens (0,0054 g g-1 day), with lower values for native
forest (0,0016 g g-1 day) and Eucalyptus urophylla (0,0015 g g-1day).
The rate of decomposition of leaf litter of the peopling of Pterogyne
nitens is in a superior position in relation to rates of native forest
and stand of Eucalyptus urophylla, which provides the largest species
ability to recycle organic matter and nutrients. The decomposition
process in the studied ecosystems is influenced not only by the quality
of the litter but also by the quality of their microenvironment