Aims Dead plant material(i.e.litter)is the major source of soil organic matter and thus plays a fundamental role in regulating soil carbon cycling in global forest ecosystems.The storage of litter is jointly determine...Aims Dead plant material(i.e.litter)is the major source of soil organic matter and thus plays a fundamental role in regulating soil carbon cycling in global forest ecosystems.The storage of litter is jointly determined by its production from plants and decomposition in a given environment.However,only few studies have explored the relative importance of en-vironmental(i.e.abiotic)and plant(i.e.biotic)factors in driving the spa-tial variation of litter mass.The objective of this study is to quantify the relative contributions of biotic and abiotic factors in affecting the spatial variation of aboveground litter stock in a mature subtropical forest.Methods The aboveground litter mass was sampled in 187 grids of a 20-hm forest dynamics plot in a subtropical broad-leave forest in eastern China.The contributions of environmental variables,topographical and species variables on litter stocks were quantified by the boosted regression tree analysis.Important Findings The mean aboveground litter stock was 367.5 g m^(−2) in the Tiantong dynamics forest plot across all the 187 grids.The litter stock ranged from 109.2 to 831.3 g m^(−2) and showed a large spatial variation with the coefficient of variance as 40.8%.The boosted regression tree analysis showed that slope elevation and soil moisture were the most influential variables on the spatial variation of litter stock.The relatively influence of abiotic factors(environmental and topographical factors)was 71.4%,which is larger than biotic factors(28.6%).Overall,these findings sug-gest that abiotic factors play a more important role than plants in driving the spatial variation of aboveground litter stock in the subtropical forest.Given that the global carbon-cycle models have been aiming to refine from the hundred kilometers to sub-kilometer scale,this study highlights the urgency of a better understanding of the spatial variation of litter stock on the fine scale.展开更多
Two experiments were conducted to evaluate the effect of alum on ammonia emission,live performance,and health of broilers.In experiment 1,the effect of alum （0,2,and 4%） supplementation on the emission of ammonia wa...Two experiments were conducted to evaluate the effect of alum on ammonia emission,live performance,and health of broilers.In experiment 1,the effect of alum （0,2,and 4%） supplementation on the emission of ammonia was measured.The effects of alum-treated litter and stocking density （12,16,and 20 birds m-2） on the live performance and incidence of footpad and hock dermatitis were investigated in experiment 2.Alum supplementation in chicken excreta significantly decreased pH from 8.06 to 5.27 and 3.62 by 2 and 4% alum treatments,respectively.Ammonia emission rate was reduced 73.0 and 75.8% by 2 and 4% alum treatments,respectively.The suppressed litter urease activity was detected in 4% alum treatment.Alum-amended litter （1 kg m-2） decreased atmosphere ammonia concentrations by 30% in broiler house.Alum-amended litter maintained a lower pH until 35 d of age.Body weight （BW） gain was decreased by alum treatment in the period of 4-7 wk of age.Higher stocking density （20 birds m-2） increased BW gain in the first 3 wk of age but decreased BW gain during the period of 4-7 wk of age.Neither alum nor stocking density treatments had a significant effect on feed intake and feed efficiency.Alum-treated litter had no detrimental effect on the development of footpad and hock burns.In contrast,high stocking density （20 bird m-2） increased the incidence of footpad and hock lesion.The result suggests that the decreased litter pH and suppressed bacterial urease activity by alum treatment is responsible for the decreased ammonia emission.At high stocking density,the increased litter moisture content should be responsible,at least partially,for the development of footpad and hock lesions.展开更多
Litter production, components and dynamics were investigated and forest floor litter was quantified throughout awhole year in three subalpine forests, dominated by tree species of spruce (SF), fir (FF) and birch (BF),...Litter production, components and dynamics were investigated and forest floor litter was quantified throughout awhole year in three subalpine forests, dominated by tree species of spruce (SF), fir (FF) and birch (BF), in WesternSichuan, China, in order to understand the key factors that influenced litter production and dynamics. Litterfall in thethree forests consisted mainly of leaves, woody litter, reproductive organs and moss. Contribution of leaf litter to thetotal litterfall was significantly (P < 0.05) greater than that of woody litter, reproductive organs or moss. Regardlessof the stands, litterfall exhibited a marked monthly variation with the maximum litterfall peaks occurring in October,with smaller peaks occurring in February for SF and FF, and May for BF. The analysis indicated that tree species,stand density, leaf area index (LAI), stand basal area and stand age were the key factors determining litter production.Meanwhile tree species and phenology controlled the litter dynamics, with wind and snow modifying the litter componentsand dynamics.展开更多
The aim of this study is to determine the influence of tree litters on soil nutrients in a managed forest in southwestern Nigeria.Mono species tree clusters consisted of indigenous species:Gmelina arborea,Tectona gran...The aim of this study is to determine the influence of tree litters on soil nutrients in a managed forest in southwestern Nigeria.Mono species tree clusters consisted of indigenous species:Gmelina arborea,Tectona grandis,Leucaena leucocephala,Bambusa vulgaris,Treculia africana,Anogeissus leiocarpus were selected and analyzed for their litter and soil chemical properties at 0–5 and 15–30 cm.T.africana and T.grandis litters have the highest nutrients,while L.leucocephala and A.leiocarpus are the lowest.Soils under G.arborea,T.africana,and A.leiocarpus are more acidic due to lower calcium and magnesium contents but have higher manganese and sulphur levels.Tree litters improved soil nitrogen,phosphorous,and micro-nutrients but depleted potassium.Litter lignin and carbon appeared to hinder the release of some nutrients.Nitrogen,potassium and copper are concentrated in the topsoil while others nutrients are not differentiated with soil depth.There is a positive correlation between litter chemistry and soil chemical properties.It was concluded that tree litter chemistry differs according to species but determines soil reaction and nutrient content.The magnitude of the effect on soil properties is related to the quality of the organic litters.展开更多
Several studies have been conducted in the past on carbon stock measurements in the tropical forests of Indonesia. This study is the first related research conducted in the New Guinea Island. In a degraded logged-over...Several studies have been conducted in the past on carbon stock measurements in the tropical forests of Indonesia. This study is the first related research conducted in the New Guinea Island. In a degraded logged-over secondary forest in Manokwari Regency （West Papua, Indonesia）, carbon stocks were measured for seven parts, i.e., above-ground biomass （AGB）, below-ground biomass （BGB）, under-storey biomass （B）, necromass of dead leaves （N~）, necromass of dead trees （Art）, litter （L） and soil （S） using appropriate equations and laboratory analysis. Total carbon stocks were measured at 642.8 tC.h~~ in the low disturbance area, 536.9 tC＇ha-~ in the moderate disturbance area and 490.4 tC＇ha ~ in the high disturbance area. Bu, N1 and N were not significant in the carbon stock and were collectively categorized as a total biomass complex. The carbon stock of litter was nearly equal to that of the total biomass complex, while the total carbon stock in the soil was eight times larger than the total biomass complex or the carbon stock of the litter. We confirmed that the average ratio of AGB and BGB to the total biomass （TB） was about 84.7% and 15.3%, respectively. Improvements were made to the equations in the low disturbance logged-over secondary forest area, applying corrections to the amounts ofbiomass of sample trees, based on representative commercial trees of category one. TB stocks before and after correction were estimated to be 84.4 and 106.7 tC.ha-~, indicating that these corrections added significant amounts of tree biomass （26.4%） dur- ing the sampling procedure. In conclusion, the equations for tree biomass developed in this study, will be useful for evaluating total carbon stocks, especially TB stocks in logged-over secondary forests throughout the Papua region.展开更多
Understanding how soil fertility changes due to environmental conditions and stand-age-dependent forest attributes is important for local-scale forest restoration.We evaluated the effects of stand-age-dependent forest...Understanding how soil fertility changes due to environmental conditions and stand-age-dependent forest attributes is important for local-scale forest restoration.We evaluated the effects of stand-age-dependent forest attributes(plant community composition and litter stock)on soil and technosol fertility across two second-growth Atlantic forests(SGF)after the deposition of mining tailings in Mariana,southeastern Brazil.We hypothesized that technosol fertility in the SGF tailings is positively affected by plant community composition variability,stand age,and litter stock.We used total exchangeable bases and organic matter as fertility indicators for technosol and soil,and species composition and litter stock as stand-age-dependent forest attributes.Our results showed significant differences in the stand-age-dependent forest attributes and soil chemical properties between the two forest patches(SGF tailing and SGF non-tailing)evaluated.Thus,there was a marked gradient of litter storage and fertility between soil and technosol that can be important forest recovery indicators for the affected plant communities.Furthermore,according to the tested models,we corroborated the hypothesis that technosol fertility is positively affected by stand age,plant community composition variability,and litter stock,which may contribute considerably to forest recovery on tailings.Our results demonstrate that the fertility predictors analyzed to explain the forest recovery on tailings can also be considered as ecological indicators for assessing forest restoration in areas impacted by mining tailings in Mariana.展开更多
基金National Natural Science Foundation(31722009,41630528)Fok Ying-Tong Education Foundation for Young Teachers in the Higher Education Institutions of China(161016)the National 1000 Young Talents Program of China.
文摘Aims Dead plant material(i.e.litter)is the major source of soil organic matter and thus plays a fundamental role in regulating soil carbon cycling in global forest ecosystems.The storage of litter is jointly determined by its production from plants and decomposition in a given environment.However,only few studies have explored the relative importance of en-vironmental(i.e.abiotic)and plant(i.e.biotic)factors in driving the spa-tial variation of litter mass.The objective of this study is to quantify the relative contributions of biotic and abiotic factors in affecting the spatial variation of aboveground litter stock in a mature subtropical forest.Methods The aboveground litter mass was sampled in 187 grids of a 20-hm forest dynamics plot in a subtropical broad-leave forest in eastern China.The contributions of environmental variables,topographical and species variables on litter stocks were quantified by the boosted regression tree analysis.Important Findings The mean aboveground litter stock was 367.5 g m^(−2) in the Tiantong dynamics forest plot across all the 187 grids.The litter stock ranged from 109.2 to 831.3 g m^(−2) and showed a large spatial variation with the coefficient of variance as 40.8%.The boosted regression tree analysis showed that slope elevation and soil moisture were the most influential variables on the spatial variation of litter stock.The relatively influence of abiotic factors(environmental and topographical factors)was 71.4%,which is larger than biotic factors(28.6%).Overall,these findings sug-gest that abiotic factors play a more important role than plants in driving the spatial variation of aboveground litter stock in the subtropical forest.Given that the global carbon-cycle models have been aiming to refine from the hundred kilometers to sub-kilometer scale,this study highlights the urgency of a better understanding of the spatial variation of litter stock on the fine scale.
基金supported by the National Natural Science Foundation of China (30771573)the Natural Science Fund for Distinguished Young Scholars of Shandong,China (2008JQB01001)
文摘Two experiments were conducted to evaluate the effect of alum on ammonia emission,live performance,and health of broilers.In experiment 1,the effect of alum （0,2,and 4%） supplementation on the emission of ammonia was measured.The effects of alum-treated litter and stocking density （12,16,and 20 birds m-2） on the live performance and incidence of footpad and hock dermatitis were investigated in experiment 2.Alum supplementation in chicken excreta significantly decreased pH from 8.06 to 5.27 and 3.62 by 2 and 4% alum treatments,respectively.Ammonia emission rate was reduced 73.0 and 75.8% by 2 and 4% alum treatments,respectively.The suppressed litter urease activity was detected in 4% alum treatment.Alum-amended litter （1 kg m-2） decreased atmosphere ammonia concentrations by 30% in broiler house.Alum-amended litter maintained a lower pH until 35 d of age.Body weight （BW） gain was decreased by alum treatment in the period of 4-7 wk of age.Higher stocking density （20 birds m-2） increased BW gain in the first 3 wk of age but decreased BW gain during the period of 4-7 wk of age.Neither alum nor stocking density treatments had a significant effect on feed intake and feed efficiency.Alum-treated litter had no detrimental effect on the development of footpad and hock burns.In contrast,high stocking density （20 bird m-2） increased the incidence of footpad and hock lesion.The result suggests that the decreased litter pH and suppressed bacterial urease activity by alum treatment is responsible for the decreased ammonia emission.At high stocking density,the increased litter moisture content should be responsible,at least partially,for the development of footpad and hock lesions.
基金the National Natural Science Foundation of China (Nos. 30471378, 90202010 and 30211130504),and the Program of 100 Distinguished Young Scientists of the Chinese Academy of Sciences.
文摘Litter production, components and dynamics were investigated and forest floor litter was quantified throughout awhole year in three subalpine forests, dominated by tree species of spruce (SF), fir (FF) and birch (BF), in WesternSichuan, China, in order to understand the key factors that influenced litter production and dynamics. Litterfall in thethree forests consisted mainly of leaves, woody litter, reproductive organs and moss. Contribution of leaf litter to thetotal litterfall was significantly (P < 0.05) greater than that of woody litter, reproductive organs or moss. Regardlessof the stands, litterfall exhibited a marked monthly variation with the maximum litterfall peaks occurring in October,with smaller peaks occurring in February for SF and FF, and May for BF. The analysis indicated that tree species,stand density, leaf area index (LAI), stand basal area and stand age were the key factors determining litter production.Meanwhile tree species and phenology controlled the litter dynamics, with wind and snow modifying the litter componentsand dynamics.
文摘The aim of this study is to determine the influence of tree litters on soil nutrients in a managed forest in southwestern Nigeria.Mono species tree clusters consisted of indigenous species:Gmelina arborea,Tectona grandis,Leucaena leucocephala,Bambusa vulgaris,Treculia africana,Anogeissus leiocarpus were selected and analyzed for their litter and soil chemical properties at 0–5 and 15–30 cm.T.africana and T.grandis litters have the highest nutrients,while L.leucocephala and A.leiocarpus are the lowest.Soils under G.arborea,T.africana,and A.leiocarpus are more acidic due to lower calcium and magnesium contents but have higher manganese and sulphur levels.Tree litters improved soil nitrogen,phosphorous,and micro-nutrients but depleted potassium.Litter lignin and carbon appeared to hinder the release of some nutrients.Nitrogen,potassium and copper are concentrated in the topsoil while others nutrients are not differentiated with soil depth.There is a positive correlation between litter chemistry and soil chemical properties.It was concluded that tree litter chemistry differs according to species but determines soil reaction and nutrient content.The magnitude of the effect on soil properties is related to the quality of the organic litters.
文摘Several studies have been conducted in the past on carbon stock measurements in the tropical forests of Indonesia. This study is the first related research conducted in the New Guinea Island. In a degraded logged-over secondary forest in Manokwari Regency （West Papua, Indonesia）, carbon stocks were measured for seven parts, i.e., above-ground biomass （AGB）, below-ground biomass （BGB）, under-storey biomass （B）, necromass of dead leaves （N~）, necromass of dead trees （Art）, litter （L） and soil （S） using appropriate equations and laboratory analysis. Total carbon stocks were measured at 642.8 tC.h~~ in the low disturbance area, 536.9 tC＇ha-~ in the moderate disturbance area and 490.4 tC＇ha ~ in the high disturbance area. Bu, N1 and N were not significant in the carbon stock and were collectively categorized as a total biomass complex. The carbon stock of litter was nearly equal to that of the total biomass complex, while the total carbon stock in the soil was eight times larger than the total biomass complex or the carbon stock of the litter. We confirmed that the average ratio of AGB and BGB to the total biomass （TB） was about 84.7% and 15.3%, respectively. Improvements were made to the equations in the low disturbance logged-over secondary forest area, applying corrections to the amounts ofbiomass of sample trees, based on representative commercial trees of category one. TB stocks before and after correction were estimated to be 84.4 and 106.7 tC.ha-~, indicating that these corrections added significant amounts of tree biomass （26.4%） dur- ing the sampling procedure. In conclusion, the equations for tree biomass developed in this study, will be useful for evaluating total carbon stocks, especially TB stocks in logged-over secondary forests throughout the Papua region.
文摘Understanding how soil fertility changes due to environmental conditions and stand-age-dependent forest attributes is important for local-scale forest restoration.We evaluated the effects of stand-age-dependent forest attributes(plant community composition and litter stock)on soil and technosol fertility across two second-growth Atlantic forests(SGF)after the deposition of mining tailings in Mariana,southeastern Brazil.We hypothesized that technosol fertility in the SGF tailings is positively affected by plant community composition variability,stand age,and litter stock.We used total exchangeable bases and organic matter as fertility indicators for technosol and soil,and species composition and litter stock as stand-age-dependent forest attributes.Our results showed significant differences in the stand-age-dependent forest attributes and soil chemical properties between the two forest patches(SGF tailing and SGF non-tailing)evaluated.Thus,there was a marked gradient of litter storage and fertility between soil and technosol that can be important forest recovery indicators for the affected plant communities.Furthermore,according to the tested models,we corroborated the hypothesis that technosol fertility is positively affected by stand age,plant community composition variability,and litter stock,which may contribute considerably to forest recovery on tailings.Our results demonstrate that the fertility predictors analyzed to explain the forest recovery on tailings can also be considered as ecological indicators for assessing forest restoration in areas impacted by mining tailings in Mariana.
