Litter Storage Research Articles

Carbon storage in evergreen broad-leaf forests in mid-subtropical region of China at four succession stages

To better understand the effect of forest succession on carbon sequestration, we investigated carbon stock and allocation of evergreen broadleaf forest, a major zonal forest in subtropical China. We sought to quantify the carbon sequestration potential. We sampled four forest types, shrub (SR), pine (Pinus massoniana) forest (PF), pine and broadleaf mixed forest (MF) and evergreen broadleaf forest (BF). A regression equation was constructed using tree height and diameter at breast height (DBH) and elements of total tree biomass. The equation was subsequently utilized to estimate tree carbon storage. The carbon storage of understory, litter, and soil was also estimated. Carbon storage in biomass increased significantly from the early succession stage SR (6.21 t·ha−1) to the late stage BF (134.87 t·ha−1). The biomass carbon stock of forest layers generally increased with succession except for the understory. The soil organic carbon storage for the total profile increased with forest succession, from 51.16 to 90.49 t·ha−1, but the contribution of SOC to the carbon stock of the forest ecosystem declined from 89.18% to 40.15%. The carbon stock at ecosystem scale increased significantly with succession from SR (57.37 t·ha−1), to PF (154.20 t·ha−1), to MF (170.96 t·ha−1) and to BF (225.36 t·ha−1), with carbon stock of BF 3.93 times that of SR. The forests in our study have great potential for increasing carbon sequestration, and large areas of secondary or degraded evergreen broadleaf forests in the subtropical zone of China could be a great carbon sink in future.

Carbon storage capacity of monoculture and mixed-species plantations in subtropical China

Mixed-tree plantations can be a good silvicultural alternative to large-scale monoculture coniferous plantations for climate change mitigation, which is facilitated by the sequestration of atmospheric carbon dioxide. To evaluate the impacts of tree species compositions on the carbon storage capacity of plantation ecosystems, we measured the above and belowground biomass, as well as the carbon content, in three 27-year old forest plantations of monoculture Castanopsis hystrix (CH stand), monoculture Pinus massoniana (PM stand), and mixed C. hystrix and P. massoniana (mixed CH/PM stand) stands. We developed an allometric equation to estimate tree carbon storage. The carbon storage levels of understory, litter, and soil components were also estimated. Results show that biomass is positively correlated with carbon storage. The ecosystem carbon storage of the mixed CH/PM stand (327.03Mgha−1) was higher than those of the CH (314.59Mgha−1) and PM (293.60Mgha−1) stands. The majority of carbon storage was found in the soil pool (84.73%, 63.54%, and 75.80% in the CH, PM and mixed CH/PM stands, respectively). Almost 40% of soil carbon at a depth of 0–60cm was stored in the upper 20cm of the soil pool. Except for the vegetation layer, each layer of the CH and mixed CH/PM stands consisted of a higher amount of carbon than did the layers of the PM stand. These findings suggest that mixed CH/PM plantation stands or valuable indigenous CH plantation stands more substantially improve carbon storage in litter, soil, and ecosystems than do monoculture PM plantation stands. The results also imply that developing valuable indigenous tree species is a good silvicultural option for enhancing carbon sequestration and valuable timber cultivation in subtropical China.

Bacterial Community Structure and Composition in Soils under Industrial Poultry Production Activities: An Observational study

Confinement is the predominant method of producing poultry and eggs for consumption in the US. Because of its high-density approach, the potential health threats regarding pathogenesis in animals and humans have raised concerns. Although there best management practices exist to control the persistence and proliferation of pathogenic bacteria in poultry houses, very little is known about the bacterial communities, and poultry houses are potential pathogen sinks. We assessed the contribution of industrial poultry production to the structure and composition of bacterial communities in the soils at a poultry production site. Soil samples were collected from under poultry housing areas, litter storage areas, and an accompanying pasture adjacent to the production area; and environmental DNA was extracted from the samples. Following validation and amplification, DNA was sequenced using bacterial-tag encoded pyrosequencing. Bioinformatics analysis showed that the bacterial communities in the soils showed no significant differences in species richness according to observed and estimated operational taxonomic units (Chao1 and rarefaction). Proteobacteria were the major phyla present in all samples ranging from 37.1% in the soils under poultry houses to 53.4% of the sequences identified under pasture soils. Significant shifts in specific taxa were observed, including drops in the abundance of Acidobacteria observed from the poultry house to litter storage soils ( P < 0.05) α-Proteobacteria increased from poultry house soil (10.9%) to pasture soils (32.8%, P < 0.01) and soils under litter storage (22.3%, P < 0.05). The phyla Bacteroidetes, which were observed between poultry house and pasture soils, dropped significantly from 21.8% to 7.2% ( P < 0.05). Clustering exhibited a closer relationship between the soils under pasture and litter storage, while those under the poultry houses were unique. Pathogenic genera were also found in greater abundance under the poultry houses, which raises the question of persistence and re-colonization of bedding material even in the presence of mitigation attempts.

Quantification of ionophores in aged poultry litter using liquid chromatography tandem mass spectrometry

Veterinary anticoccidials, biochemically known as ionophores, are widely used in poultry feed at therapeutic levels to treat Coccidiosis and at sub-therapeutic levels for growth- promotion. Commonly used ionophores in the US poultry industry are monensin, salinomycin, lasalocid and narasin. There is an increasing concern regarding the persistence of these anticoccidials in the environment. However, little attention has been directed to methods development for quantitatively measuring ionophores in complex environmental matrices such as poultry litters that are land applied. Here, we describe a rapid and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS)-based method developed for simultaneous quantification of monensin, lasalocid, salinomycin, and narasin in aged poultry litter samples. Results show significant level of monensin (97.8 ± 3.2 μg kg−1), lasalocid (19.2 ± 6.6 μg kg−1), salinomycin (70 ± 2.7 μg kg−1) and narasin (57.3 ± 2.6 μg kg−1) in poultry litter stored for over three years at < 5°C. Our findings indicate that even after several years of unmanaged storage of poultry litter, ionophores may continue to persist in this matrix, raising the possibility of prolonged release into the environment.

Soil respiration is stimulated by elevated CO2 and reduced by summer drought: three years of measurements in a multifactor ecosystem manipulation experiment in a temperate heathland (CLIMAITE)

AbstractThis study investigated the impact of predicted future climatic and atmospheric conditions on soil respiration (RS) in a Danish Calluna‐Deschampsia‐heathland. A fully factorial in situ experiment with treatments of elevated atmospheric CO2 (+130 ppm), raised soil temperature (+0.4 °C) and extended summer drought (5–8% precipitation exclusion) was established in 2005. The average RS, observed in the control over 3 years of measurements (1.7 μmol CO2 m−2 sec−1), increased 38% under elevated CO2, irrespective of combination with the drought or temperature treatments. In contrast, extended summer drought decreased RS by 14%, while elevated soil temperature did not affect RS overall. A significant interaction between elevated temperature and drought resulted in further reduction of RS when these treatments were combined. A detailed analysis of short‐term RS dynamics associated with drought periods showed that RS was reduced by ~50% and was strongly correlated with soil moisture during these events. Recovery of RS to pre‐drought levels occurred within 2 weeks of rewetting; however, unexpected drought effects were observed several months after summer drought treatment in 2 of the 3 years, possibly due to reduced plant growth or changes in soil water holding capacity. An empirical model that predicts RS from soil temperature, soil moisture and plant biomass was developed and accounted for 55% of the observed variability in RS. The model predicted annual sums of RS in 2006 and 2007, in the control, were 672 and 719 g C m−2 y−1, respectively. For the full treatment combination, i.e. the future climate scenario, the model predicted that soil respiratory C losses would increase by ~21% (140–150 g C m−2 y−1). Therefore, in the future climate, stimulation of C storage in plant biomass and litter must be in excess of 21% for this ecosystem to not suffer a reduction in net ecosystem exchange.

川中丘陵区人工柏木防护林适宜林分结构及水文效应

The study area is situated in the central Sichuan hilly region.Due to the long-term deforestation of natural ever-green broad-leaf vegetation,this area had been suffered from soil erosion over time and was regarded as one of the most serious eroded region in the upper reach of the Yangtze River.In order to mitigate soil erosion,a large area of cypress(Cuppressus funebris)protection forests was established starting early 1970s.However,the current cypress forests were in a quite poor state in terms of stand structure,natural regeneration,stand stability,product supply and ecological functions.The objective of the study was to identify optimum stand structure aiming to improve soil conservation functions of the cypress monoculture.Through the survey of 48 sample plots and analysis of the relationship between canopy closure and the coverage and biomass of shrubs,grasses and litter,the canopy closures of 0.6—0.7 was regarded as the most suitable one,and 5 stand types of cypress monoculture was categorized,that is,low density type,medium-low density type,suitable density type,medium-high density type and over-dense type.The following results were found through a comparative study of the hydrological effects of the 5 stand types.(1) The maximal water-holding capacity of the litter in the 5 stand types depended on the total litter storage,and it ranked from higher to lower as: suitable density type(4.038 ± 0.497) t/hm2 medium-low density type(3.583 ± 0.521) t/hm2 medium-high density type(3.243 ± 0.455) t/hm2 low density type(2.841 ± 0.656) t/hm2 over-dense type(2.272 ± 0.580) t/hm2.(2) The maximal water-holding capacity of soil was in the order of suitable density type(180.59 ± 14.83) mm medium-low density type(173.84 ± 18.06) mm medium-high density type(169.27 ± 13.20) mm low density type(162.57 ± 8.79) mm over-dense type(150.77 ± 5.08) mm;and the suitable density type had significant difference with other four types.(3) The data from runoff plot observation for six times of rainfall has indicated that the sediment yield of the 5 stand types ranked from lower to higher as suitable type(360.07 kg/ hm2) medium-low density type(577.08 kg/ hm2) medium-high density type(625.98 kg/ hm2) low density type(878.51 kg/ hm2) over-dense type(1026.74 kg/ hm2),and significant difference existed among the 5 stand types.

Input, retention, and invertebrate colonization of allochthonous litter in streams bordered by deciduous broadleaved forest, a conifer plantation, and a clear-cut site in southwestern Japan

In headwater streams, conifer plantation forestry may affect stream communities through the quantity and quality of basal resources (allochthonous litter). We compared (1) the seasonal patterns of litter input from the riparian canopy, (2) those for the abundance of benthic and drifting litter in streams, and (3) the density of litter-associated invertebrates among streams bordered by deciduous broadleaved forest, a plantation of Japanese cedar (Cryptomeria japonica), and a clear-cut site, to extract the characteristics of conifer-plantation streams in terms of litter dynamics and benthic invertebrates. The results illustrate differences in litter input and in-stream processes between the broadleaved and plantation sites, although the total annual inputs from canopy were similar. In the broadleaved site, high litter storage was limited to winter, probably because pulsed inputs of litter in autumn were retained on the streambed but rapidly processed. In contrast, litter input was more constant at the plantation site, and litter was stored throughout the year. Although the litter-patch-specific density of total invertebrates was similar between the broadleaved and plantation sites, estimates of the reach-scale, habitat-weighted density considering differences in the coverage area of litter patches revealed considerable differences. Although the habitat-weighted density of total invertebrates was lower at the plantation site than at the broadleaved site in winter, it was noticeably higher at the plantation site in summer, owing to the seasonal stability of benthic litter abundance. Our results emphasized the importance of considering the spatiotemporal availability of benthic litter when assessing the effects of conifer plantations on stream ecosystems.

Impact of Land-Use Change on Carbon Stocks in Meadow Steppe of Northeast China

An improved understanding of changes in carbon storage of terrestrial ecosystems is very important for assessing the impacts of increasing atmospheric CO2 concentration and climate change on the terrestrial biosphere. Accurately predicting terrestrial carbon (C) storage requires understanding the carbon stock, because it helps us understand how ecosystems would respond to natural and anthropogenic disturbances under different management strategies. We investigated organic C storage in aboveground biomass, litter, roots, and soil organic matter (SOM) in five land-use types (i.e. artificial pasture, AP; natural meadow, NM; corn plantation, CP; temperate savanna, TS; and bush wood, BW) in meadow steppe of Northeast China. The primary objective of this study was to ascertain the impact of different land-use types on the carbon stock. The total C storage (including C stored in aboveground biomass, litter, roots, and 0–100-cm soil layers) did not significantly differ between one and another type among the five pairs (P&gt;0.05), with the exception of AP2-BW pair. The total C storage changes in value varying from 5958.09 g C m-2 for plot NM2 to 11922.87 g C m-2 for plot CP1. The C stored in the aboveground biomass was less than 1177.96 g C m-2, accounting for negligible amounts (&lt;1% of the total) of total C storage in the ecosystem except corn plantation. The amount of C stored in SOM accounted for less than 85% of the total C storage in TS, AP2, and NM3, and the C stored in litter was very low (&lt;1.5%), compared to other pools in the ecosystem. The amount of C stored in the roots varied from 0 g C m-2 for plot BW, CP1, and CP2 to 2032.32 g C m-2 for plot NM3, and it accounted for less than 20% of C storage in the grassland.

Review of Carbon Fixation in Bamboo Forests in China

Bamboo is widespread in the subtropics and tropics of Asia, Africa, and Latin America. The total area of bamboo forests of various species is 22.0 × 106 ha, accounting for about 1.0% of the total global area of forest. Although the total forest areas in many countries have decreased drastically, bamboo forests have increased at a rate of 3% annually. China has the richest resources of bamboo in the world, with over 500 species in 39 genera. Carbon storage of vegetation, soils, and litter in bamboo forest system in China was 0.2511 × 1015, 0.8516 × 1015, and 0.0361 × 1015 g C, respectively, giving a total of 1.1388 × 1015 g C. This paper reviews carbon storage of vegetation, soils, and litter in bamboo forest system and compares the carbon fixation abilities of bamboo forest ecosystems with those of other tree species in subtropical China.

Phosphorus Immobilization and Soil Aggregation in Chemically Amended Poultry Litter Used in Corn/Soybean Rotation

Excessive use of poultry litter (PL) on agricultural land is known to cause eutrophication of surface waters. Consequently, both poultry producers and PL users have to meet strict state and federal guidelines on litter storage and land application. This study examined the environmental benefits of adding lime, alum, ferrous sulfate, fly ash (FA), fluidized bed ash (FBA) and soil fix (SF) to PL for immobilizing excess phosphorus (P) while providing sufficient nutrients for proper growth of soybean [Glycine max (L.)] and corn [Zea mays (L.)] on a rotation. Amending PL with lime, alum, SF, FA and FBA significantly (p>0.05) increased corn and soybean yield. In contrast control plots that received a 10-10-10 (N-P2O5-K2) fertilizer showed lower yield and corn quality. Increased yield was observed when PL was amended with lime, alum and ferrous sulfate. Results from a soybean root, shoot, and nodule growth study indicated variability with respect to PL application and amendment use. Smaller size nodules were obtained with NPK fertilizer and PL plus lime treated plots, whereas PL with alum yielded fewer but larger nodules. Soil aggregation was significantly lower in soils treated with NPK compared to those treated with PL as indicated by water stable aggregation (WSA), mean aggregate diameter (MWD) and geometric mean of aggregate diameter (GMD) (p>0.05). Increased soil aggregation was a result of the combined effect of amendment and PL additions rather than PL alone. The amount of carbon (C) in soil aggregates was lowest with NPK and highest with PL treatments. In the presence of PL, alum and iron treatments showed higher capacities to store C and immobilize P in macro-aggregates (8 to 5 mm diameter). These results suggest that soil treatment with PL and chemical amendments, especially alum and ferrous sulfate, could result in improved crop yield, soil aggregation, carbon storage, and P immobilization.

Alternative Poultry Litter Storage for Improved Transportation and Use as a Soil Amendment

Transportation of poultry litter out of nutrient limited watersheds such as the Illinois River basin (eastern Oklahoma) is a logical solution for minimizing phosphorus (P) losses from soils to surface waters. Transportation costs are basedon mass of load and distance transported. This study investigated an alternative litter storage technique designed to promote carbon (C) degradation, thereby concentrating nutrients for the purpose of decreasing transportation costs through decreased mass. Poultry litter was stored in 0.90-Mg conical piles under semipermeable tarps and adjusted to 40% moisture content, tested with and without addition of alum (aluminum sulfate). additional study was conducted using 3.6-Mg piles under the same conditions, except tested with and without use of aeration pipes. Samples were analyzed before and after (8 wk) storage. Litter mass degradation (i.e., loss in mass due to organic matter decomposition) was estimated on the basis of changes in litter total P contents. Additional characterization included pH, total nutrients, moisture content, total C, and degree of humification. Litter storage significantly decreased litter mass (16 to 27%), concentrated nutrients such as P and potassium (K) and increased proportion of fulvic and humic acids. The addition of aeration pipes increased mass degradationrelative to piles without aeration pipes. Nitrogen volatilization losses were minimized with alum additions. Increases in P and K concentrations resulted in greater monetary value per unit mass compared with fresh litter. Such increases translate to increased litter shipping distance and cost savings of $17.2 million over 25 yr for litter movement out of eastern Oklahoma.

Produção, estoque e retenção hídrica da serrapilheira em encosta sob plantio de híbridos de Eucalyptus urophylla e Eucalyptus grandis: médio vale do rio Paraíba do Sul

Eucalyptus patches are spreading rapidly through middle Paraíba do Sul river valley and environmental effects of this activity are still ambivalent and poorly documented (Vianna et al., 2007). This study aims to evaluate the litter production and litter storage on slopes in Eucalyptus and verify its water retention capacity, to support understanding of the hydrological responses to rainfall inputs. This study aims to evaluate the litter production and litter storage of Eucalyptus. Study site is located at a headwater basin in Sesmarias river basin covered by Eucalyptus grandis x urophyla, 3 x 2 meters spaced (1666 trees. ha-1) planted in April 2004. Litter was collected in four different positions using 0.5 quadracts to litter production measurement, and 0.25 m quadracts to litter storage measurement. Samples were dried, weighted, separated in fractions (leaves, branches, grass, roots + fine material) and had the fractions weighted. Litter fall showed an increase with decreasing rainfall, and the litter fall was higher in the divisor (10.2 Mg.ha-1) than in the slope (6.6 Mg.ha-1). Litter storage presents an increase trend, with annual accumulation of 2,2 Mg.ha-1 and it is composed largely by leafs. Water retention capacity is 235%, which is close to values that are found in the Tropical rainforest (200% - 259%).

Occurrence of Arsenic and Phosphorus in Ditch Flow from Litter‐amended Soils and Barn Areas

Little is known about the fate of arsenic (As) in land-applied litter from chickens that have been fed roxarsone, an organic feed additive containing As. This study seeks to elucidate the transfer of As in runoff from ditch-drained soils of the poultry-producing region of the Delmarva Peninsula by tracking As and phosphorus (P) export from seven drainage ditches over two water-years (1 July 2005 to 30 June 2007). Annual losses of As from ditches ranged from 0.004 to 0.071 kg ha(-1) while P losses ranged from 0.33 to 18.56 kg ha(-1), with the largest loads associated with a litter storage shed that served as a point source. Event-based As and P losses in ditch flow fluctuated by a factor of 162 and 1882, respectively. The two elements were correlated in flow from the ditch draining a litter storage shed (r = 0.99), and in sediment extracts in soils near the litter shed (r = 0.73), pointing to similar behavior under point source conditions. Indeed, As and P exhibited similar behavior within storms for all ditches, characterized by relatively high initial concentrations subject to rapid concentration declines before peak flow, consistent with dilution of a finite source. However, As and P concentrations varied significantly between ditches and showed considerable temporal variability within ditches, with no clear seasonal trends or associations with current management strategies. The results suggest that similar management strategies might be effective for As and P point sources, but that field management practices geared toward controlling nonpoint source P losses may not readily transfer to the control of As losses.

Restauración ecológica de bosques tropicales en Costa Rica: efecto de varios modelos en la producción, acumulación y descomposición de hojarasca

Tropical forest restoration strategies have the potential to accelerate the recovery of the nutrient cycles in degraded lands. Litter production and its decomposition represent the main transfer of organic material and nutrients into the soil substrate. We evaluated litter production, accumulation on the forest floor, and its decomposition under three restoration strategies: plantation (entire area planted with trees), island (trees planted in patches of three different sizes) and control (natural regeneration) plots. We also compared restoration strategies to young secondary forest (7-9 yr). Restoration treatments were established in 50 x 50m plots in June 2004 at six sites in Southern Costa Rica. Planted tree species included two native timber species (Terminalia amazonia and Vochysia guatemalensis) interplanted with two N fixers (Erythrina poeppigiana and Inga edulis). Litter was collected every 15 days between September 2008 and August 2009 in 12 0.25m2 litter traps distributed within each plot; litter that accumulated on the soil surface was collected at four locations (0.25m2 quadrats) within each plot in February and May 2009. Total litter production in plantation (6.3Mg/ha) and secondary forest (7.3Mg/ha) did not differ, but were greater than in islands (3.5Mg/ha) and control (1.4 Mg/ha). Plantation had greatest accumulation of litter on the soil surface (10.6 Mg/ha) as compared to the other treatments (SF = 7.2; I = 6.7; C = 4.9). Secondary forest was the only treatment with a greater annual production of litter than litter accumulation on the soil surface. Carbon storage in litter was similar between plantation and secondary forest, and significantly greater than the other treatments. No differences were found for carbon concentration and storage in the soil among treatments. There was also high variability in the production and accumulation of litter and carbon among sites. Active restoration treatments accelerated the production of litter and carbon storage in comparison to areas under natural recovery. However, the nutrient cycle has not necessarily been restored under these conditions, as high litter accumulation on the soil surface indicates a low decomposition rate, which slows nutrient return to the soil.

Grass invasion causes rapid increases in ecosystem carbon and nitrogen storage in a semiarid shrubland

AbstractAccurately predicting terrestrial carbon (C) and nitrogen (N) storage requires understanding how plant invasions alter cycling and storage. A common, highly successful type of plant invasion occurs when the invasive species is of a distinctly different functional type than the native dominant plant, such as shrub encroachment throughout the western United States and annual grass invasions in Mediterranean shrublands, as studied here. Such invasions can dramatically transform landscapes and have large potential to alter C and N cycling by influencing storage in multiple pools. We used a manipulation of non‐native annual grass litter within a shrub‐dominated habitat in southern California (coastal sage scrub, CSS) to study how grass invasion alters ecosystem C and N storage. We added, removed, or left unchanged grass litter in areas of high and low invasion, then followed soil and vegetation changes. Grass litter greatly increased C and N storage in soil, aboveground native and non‐native biomass. Aboveground litter storage increased due to the greater inputs and slower decomposition of grass litter relative to shrub litter; shading by grass litter further reduced decomposition of both non‐native and native litter, which may be due to reduced photodegradation. Soil C and N pools in areas of high litter increased ∼20% relative to low litter areas in the two years following manipulation and were generally sinks for C and N, while areas with low litter were sources. We synthesize our results into a C cycle of invaded and uninvaded areas of CSS and link changes in storage to increases in the soil fungi : bacteria ratio, increased plant inputs, and decreased litter loss. Overall, we show that grasses, especially through their litter, control important abiotic and biotic mechanisms governing C and N storage, with widespread implications for C sequestration and N storage in semiarid systems undergoing grass or shrub invasions.

Soc stock in different forest-related land-uses in central Stara planina mountain, Bulgaria

Forest conversions may lead to an accumulation of carbon in vegetation, but little is known about changes in soil C storage with establishment of plantation forests. Understanding these effects is important to addressing issues relevant to ecosystem function and productivity, and to global balance of carbon. The study investigated the effects of the created coniferous plantations on former beech and pasture sites on the soil organic carbon storage. The major forest-related land-uses in the high mountainous regions of central Stara Planina Mountain were investigated: mountainous pasture, coniferous plantations (planted on previous pasture and beech forests between four and five decades ago) and natural beech forests. The experimental data of soil properties, conducted in 2005, 2006 and 2007, were used in determining the variations in organic carbon storage in forest litter and in mineral soil under different land-use patterns. At each site five representative soil profiles were opened and described giving a total 75 soil samples from the soil layers respectively at 0-10, 10-30 and 30-50 cm depth. A total of 55 samples from forest floor layers (Aol, Aof, Aoh and greensward) were collected with 25:25 cm plastic frame. The main soil properties were determined in accordance with the standardized methods in the Laboratory of soil science at the Forest Research Institute - BAS. The IPCC Good Practice Guidance for Land Use, Land Use Change and Forestry was used to estimate the soil organic carbon stock in soil and litter. The results obtained showed that the SOC stock was quite similar among forest land-uses. The conversion of natural beech forests to coniferous plantations in studied region is related with slightly expressed decrease in soil carbon storage. The values of SOC stocks in 0-50 cm soil layer in these sites were 8.5 (?2.1) tones/ha for pine and 11.0 (?1.4) tones/ha for spruce, while under the natural beech forest it was 14.8 (?1.0) tones/ha. The SOC stock in mountainous pasture was 20.7 (? 6.5) tones/ha, while in spruce plantation created on previous pasture it was 13.5 (?2.7) tones/ha. Our finding showed that forest conversions effect in central Stara Planina Mountain is expressed by decrease in SOC stock related with losses of carbon from the upper mineral soil decades after creation of coniferous plantations. Nevertheless the relatively large organic carbon storage in forest litter in the spruce plantations compensated C lost from mineral soil after the land-use change. The overall carbon stock both in forest litter and soil under plantations ranged from 56 tones/ha (pine) to 77 tones/ha (spruce), while under natural beech forest and pasture the values were 70 and 81 tones/ha respectively. But in terms of stability C sequestrated in mineral soil is more desirable than C sequestrated in forest floor which are more vulnerable to decomposition following disturbances. The application of silvicultural activities in coniferous plantations created by conversion of forest lands or grasslands in the region of central Balkan is desirable to improve the carbon sequestration in soils.

Physical Properties and Pyrolysis Behavior of Fractionated Poultry Litter

Due to environmental issues with the use of poultry litter for land application, alternative means for its value-added utilization need to be identified. One possible solution is the fractionating of poultry litter into a nutrient-rich fine fraction that can be used as fertilizer and a coarser fraction that has the potential of being used as bioenergy feedstock. In this study, physical properties relevant to storage, handling, and processing of poultry litter that were separated into three fractions (with average diameters of 0.396, 0.708, and 1.181 mm) were determined. The densities (bulk, particle, and tap) of the fractions increased with fraction size. The fine fraction was the most compressible and was the dominant contributor to the compressibility of unfractionated poultry litter. The coarse fraction was the least compressible. The flow index values of the coarse, middle, and fine fractions were 16.1, 13.2, and 11.5, respectively, and were significantly higher than the flow index of unfractionated poultry litter (3.6). The heating value, the carbon content, and the rate of thermal decomposition of the fractions increased with increase in particle size of the fractions. Maximum pyrolysis rates of 0.107 min-1, 0.126 min-1, and 0.154 min-1 were obtained for the fines, middle, and coarse fractions, respectively. For all fractions, the activation energy was highest for cellulose decomposition (133 to 145 kJ/mol) and lowest for lignin decomposition (45 to 56 kJ/mol). The reaction order varied from 0.64 to 2.23.

Moisture effect on the storage, handling and flow properties of poultry litter

Poultry litter, a combination of accumulated chicken manure, feathers and bedding materials, is a potential feedstock for bioenergy and other value-added applications. The effect of moisture on the physical properties, equilibrium moisture relations, flow properties and wall friction characteristics of poultry litter were measured. Poultry litter densities (bulk, particle and tap) reduced and compressibility increased with increase in moisture content. The fit of the GAB equation to poultry litter equilibrium moisture isotherm at 25 degrees C indicated that the monolayer moisture content for poultry litter is 5.5% (wb). Increasing the moisture content of the poultry litter reduced its flowability from easy flowing (flow index of 6.4) at moisture content of 10.3% (wb) to very cohesive (non-flowing) (flow index of 1.9) at moisture content of 30.9% (wb). Flow on a stainless steel surface was improved when the surface was mirror-finished or galvanized coated.

Degraded vegetation and wind erosion influence soil carbon, nitrogen and phosphorus accumulation in sandy grasslands

A field study was conducted in a semi-arid sand land ecosystem in eastern Inner Mongolia, China, to explore the mechanisms underlying how human-induced environmental degradation in sandy grasslands influences ecosystem plant diversity, productivity, soil erodibility, and soil carbon (C), nitrogen (N) and phosphorus (P) accumulation and storage. We investigated (1) C, N and P accumulation to 20cm soil depth; (2) C, N and P storage in plant litter, above- and below-ground biomass; and (3) the rate of surface wind erosion measured as the amount of aeolian soil accumulating in the traps and C, N and P output from the topsoil removal due to wind erosion during the erosive season in four habitats of differently degraded sandy grasslands. Environmental degradation has resulted in significant and differential reductions in soil C, N and P accumulation within the top 20cm soil layer across habitats. On average, the most severely degraded sandy grassland stored 474%, 198% and 56% less soil C, N and P, while the severely degraded sandy grassland stored 215%, 121% and 27% less soil C, N and P and the moderately degraded sandy grassland stored 111%, 60% and 17% less soil C, N and P than did the lightly degraded sandy grassland. Two key variables associated with reduced soil C, N and P accumulation in sandy grasslands as a result of environmental degradation are reduced plant litter and above- and below-ground biomass production (i.e. less plant C, N and P inputs in the soil) and increased C, N and P output from the removal of nutrient-rich topsoil layers resulted from increased rates of wind erosion. This study suggests a complex mechanism by which environmental degradation influences soil C, N and P accumulation and dynamics via its significant effects on ecosystem plant diversity, productivity and soil erodibility.

Carbon and nitrogen store and storage potential as affected by land-use in a Leymus chinensis grassland of northern China

Understanding the store and storage potential of carbon (C) and nitrogen (N) helps us understand how ecosystems would respond to natural and anthropogenic disturbances under different management strategies. We investigated organic C and N storage in aboveground biomass, litter, roots, and soil organic matter (SOM) in eight sites that were floristically and topographically similar, but which had been subjected to different intensities of disturbance by grazing animals. The primary objective of this study was to ascertain the impact of grazing exclusion (GE) on the store and storage potential of C and N in the Leymus chinensis Tzvel. grasslands of northern China. The results revealed that the total C storage (including that stored in aboveground biomass, litter, roots, and SOM, i.e. top 100-cm soil layer) was significantly different among the eight grasslands and varied from 7.0 kg C m −2 to 15.8 kg C m −2, meanwhile, the total N storage varied from 0.6 kg N m −2 to 1.5 kg N m −2. The soil C storage decreased substantially with grassland degradation due to long-term heavy grazing. 90% C and 95% N stored in grasslands were observed in the SOM, and they were minor in other pools. The limit range of C and N storage observed in these grassland soils suggests that GE may be a valuable mechanism of sequestering C in the top meter of the soil profile.