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1.
Yuichiro Yashiro Na-Yeon M. Lee Toshiyuki Ohtsuka Yoko Shizu Taku M. Saitoh Hiroshi Koizumi 《Journal of plant research》2010,123(4):463-472
Quantification of carbon budgets and cycling in Japanese cedar (Cryptomeria japonica D. Don) plantations is essential for understanding forest functions in Japan because these plantations occupy about 20% of
the total forested area. We conducted a biometric estimate of net ecosystem production (NEP) in a mature Japanese cedar plantation
beneath a flux tower over a 4-year period. Net primary production (NPP) was 7.9 Mg C ha−1 year−1 and consisted mainly of tree biomass increment and aboveground litter production. Respiration was calculated as 6.8 (soil)
and 3.3 (root) Mg C ha−1 year−1. Thus, NEP in the plantation was 4.3 Mg C ha−1 year−1. In agreement with the tower-based flux findings, this result suggests that the Japanese cedar plantation was a strong carbon
sink. The biometric-based NEP was higher among most other types of Japanese forests studied. Carbon sequestration in the mature
plantation was characterized by a larger increment in tree biomass and lower mortality than in natural forests. Land-use change
from natural forest to Japanese cedar plantation might, therefore, stimulate carbon sequestration and change the carbon allocation
of NPP from an increment in coarse woody debris to an increase in tree biomass. 相似文献
2.
Yuji Isagi 《Ecological Research》1994,9(1):47-55
Gross production and carbon cycling in aPhyllostachys bambusoides stand in Kyoto Prefecture, central Japan, were determined, and then a compartment model showing the carbon stock and cycling
within the ecosystem was developed. Aboveground carbon stock was 52.3 tC ha−1, increasing at a rate of 3.6 tC ha−1 year−1. Belowground carbon stock was 20.8 tC ha−1 in the root system and 92.0 tC ha−1 in the soil. Aboveground net production was 11.2 tC ha−1 year−1. Belowground net production was crudely estimated at 4.5 tC ha−1 year−1. The gross production was estimated at 41.8 tC ha−1 year−1 by summing the amount of outflow to the environment and the increment in biomass. Leaves consumed 13.7 tC ha−1 year−1 by respiration; the rest (41.8−13.7=28.1 tC ha−1 year−1) was surplus production of the leaves and flowed into the other compartments. The amounts of construction and maintenance
respiration of the aboveground compartments were 3.4 and 18.5 tC ha−1 year−1, respectively. The annual amount of soil respiration was 11.2 tC ha−1 year−1. Soil respiration levels of 4.3 and 3.1 tC ha−1 year−1 were estimated for the flow of root respiration and root detritus. The proportion of net to gross production was 37%, which
fell within the range of young and mature forests. A shorter life span of culms, compared to tree trunks, resulted in smaller
biomass accumulation ratio (biomass/net production) in the ecosystem, of 4.66. 相似文献
3.
Biomass and aboveground net primary production (ANPP) in a monospecific pioneer stand of a mangrove Kandelia obovata (S., L.) Yong were quantified. The estimated biomasses in leaves, branches, stems, roots, aboveground and total were 5.61
(3.68%), 28.8 (18.9%), 46.1 (30.2%), 71.8 (47.2%), 80.5 (52.8%) and 152 Mg ha−1 (100%), respectively. Stem phytomass increment per tree was estimated using allometric relationships and stem analysis. Stem
volume without bark of harvested trees showed a strong allometric relationship with D
0.12
H (D
0.1, diameter at a height of one-tenth of tree height H) (R
2 = 0.924). Annual stem volume increment per tree showed a strong allometric relationship with D
0.12
H (R
2 = 0.860). Litterfall rate ranges from 3.87 to 56.1 kg ha−1 day−1 for leaves and 0.177 to 46.2 kg ha−1 day−1 for branches. Seasonal changes of litterfall rate were observed, which showed a peak during wet season (August–September).
Total annual litterfall was estimated as 10.6 Mg ha−1 year−1, in which 68.2% was contributed by the leaves. The ANPP in the K. obovata stand was 29.9–32.1 Mg ha−1 year−1, which is ca. 2.8–3.0 times of annual litterfall. The growth efficiency (aboveground biomass increment/LAI) was 5.35–5.98 Mg ha−1 year−1. The low leaf longevity (9.3 months) and high growth efficiency of K. obovata makes it a highly productive mangrove species. 相似文献
4.
Kristell Hergoualc’h Ute Skiba Jean-Michel Harmand Catherine Hénault 《Biogeochemistry》2008,89(3):329-345
The objective of this study was to evaluate the effect of N fertilization and the presence of N2 fixing leguminous trees on soil fluxes of greenhouse gases. For a one year period, we measured soil fluxes of nitrous oxide
(N2O), carbon dioxide (CO2) and methane (CH4), related soil parameters (temperature, water-filled pore space, mineral nitrogen content, N mineralization potential) and
litterfall in two highly fertilized (250 kg N ha−1 year−1) coffee cultivation: a monoculture (CM) and a culture shaded by the N2 fixing legume species Inga densiflora (CIn). Nitrogen fertilizer addition significantly influenced N2O emissions with 84% of the annual N2O emitted during the post fertilization periods, and temporarily increased soil respiration and decreased CH4 uptakes. The higher annual N2O emissions from the shaded plantation (5.8 ± 0.3 kg N ha−1 year−1) when compared to that from the monoculture (4.3 ± 0.1 kg N ha−1 year−1) was related to the higher N input through litterfall (246 ± 16 kg N ha−1 year−1) and higher potential soil N mineralization rate (3.7 ± 0.2 mg N kg−1 d.w. d−1) in the shaded cultivation when compared to the monoculture (153 ± 6.8 kg N ha−1 year−1 and 2.2 ± 0.2 mg N kg−1 d.w. d−1). This confirms that the presence of N2 fixing shade trees can increase N2O emissions. Annual CO2 and CH4 fluxes of both systems were similar (8.4 ± 2.6 and 7.5 ± 2.3 t C-CO2 ha−1 year−1, −1.1 ± 1.5 and 3.3 ± 1.1 kg C-CH4 ha−1 year−1, respectively in the CIn and CM plantations) but, unexpectedly increased during the dry season. 相似文献
5.
Estimates of biomass and primary productivity in a high-altitude maple forest of the west central Himalayas 总被引:4,自引:0,他引:4
S. C. Garkoti 《Ecological Research》2008,23(1):41-49
The paper describes the biomass and productivity of maple (Acer cappadocicum) forest occurring at an altitude of 2,750 m in the west central Himalayas. Total vegetation biomass was 308.3 t ha−1, of which the tree layer contributed the most, followed by herbs and shrubs. The seasonal forest-floor litter mass varied
between 5.4 t ha−1 (in rainy season) and 6.6 t ha−1 (in winter season). The annual litter fall was 6.2 t ha−1, of which leaf litter contributed the largest part (59% of the total litter fall). Net primary productivity of total vegetation
was 19.5 t ha−1 year−1. The production efficiency of leaves (net primary productivity/leaf mass) was markedly higher (2.9 g g−1 foliage mass year−1) than those of the low-altitude forests of the region. 相似文献
6.
Litterfall dynamics in carbonate and deltaic mangrove ecosystems in the Gulf of Mexico 总被引:1,自引:0,他引:1
Carlos Coronado-Molina H. Alvarez-Guillen J. W. DayJr. E. Reyes B. C. Perez F. Vera-Herrera R. Twilley 《Wetlands Ecology and Management》2012,20(2):123-136
From 1996 to 2002, we measured litterfall, standing litter crop, and litter turnover rates in scrub, basin, fringe and riverine
forests in two contrasting mangrove ecosystems: a carbonate-dominated system in the Southeastern Everglades and a terrigenous-dominated
system in Laguna de Terminos (LT), Mexico. We hypothesized that litter dynamics is driven by latitude, geomorphology, hydrology,
soil fertility and soil salinity stress. There were significant temporal patterns in LT with litterfall rates higher during
the rainy season (2.4 g m−2 day−1) than during the dry season (1.8 g m−2 day−1). Total annual litterfall was significantly higher in the riverine forest (12.8 Mg ha−2 year−1) than in the fringe and basin forests (9.7 and 5.2 Mg ha−2 year−1, respectively). In Southeastern Everglades, total annual litterfall was also significantly higher during the rainy season
than during the dry season. Spatially, the scrub forest had the lowest annual litterfall (2.5 Mg ha−2 year−1), while the fringe and basin had the highest (9.1 and 6.5 Mg ha−2 year−1, respectively). In LT, annual standing litter crop was 3.3 Mg ha−1 in the fringe and 2.2 Mg ha−1 in the basin. Litter turnover rates were significantly higher in the fringe mangrove forest (4.1 year−1) relative to the basin forests (2.2 year−1). At Southeastern Everglades there were significant differences in annual standing litter crop: 1.9, 3.3 and 4.5 Mg ha−1 at scrub, basin and fringe mangrove sites, respectively. Furthermore, turnover rates were similar at both basin and fringe
mangrove types (2.1 and 2.0 year−1, respectively) but significantly higher than scrub mangrove forest (1.3 year−1). These findings suggest that litter export is important in regulating litter turnover rates in frequently flooded riverine
and fringe forests, while in infrequently flooded basin forests, in situ litter decomposition controls litter turnover rates. 相似文献
7.
Kirsten Falk Uta Friedrich Goddert von Oheimb Kerstin Mischke Konrad Merkle Hartmut Meyer Werner Härdtle 《Plant Ecology》2010,209(1):47-56
In the present study we analysed whether airborne N pollution may constitute one important driver for the encroachment of
Molinia caerulea in dry heathland ecosystems. Based on full-factorial field experiments (in 2006 and 2008) and complementary greenhouse experiments
(in 2008), we quantified growth responses of Molinia caerulea to N and P fertilisation (50 kg N ha−1 year−1, 20 kg P ha−1 year−1). Aboveground biomass production of Molinia
caerulea was limited by P in 2006, but by N in both experiments in 2008. In the greenhouse experiment, N addition caused a sixfold
increase of the biomass of vegetative tillers, and in all experiments the biomass and numbers of flowering tillers showed
a significant increase due to fertilisation. Our experiments indicated that growth of Molinia caerulea was primarily limited by N, but in dry heaths the kind of nutrient limitation may be mediated by other factors such as water
availability during the vegetative period. Shifts in biomass allocation patterns resulting from N fertilisation showed that
Molinia
caerulea encroachment in dry heaths is not only attributable to increased leaf biomass, but also due to higher investments in reproductive
tissue that allow for increased seed production and thus accelerated encroachment of seedlings in places where the dwarf shrub
canopy has been opened after disturbance. 相似文献
8.
Ana Isabel Lillebø J. P. Coelho M. R. Flindt H. S. Jensen J. C. Marques C. B. Pedersen M. A. Pardal 《Hydrobiologia》2007,583(1):195-204
During the last decades the Mondego estuary has been under severe ecological stress mainly caused by eutrophication. In this
salt march system, Spartina maritima covers about 10.5 ha of the intertidal areas. The objective of the present study was to evaluate the effect of Spartina maritima marshes on the dynamics of phosphorus (P) binding in the surface sediment. We compare phosphate and oxygen fluxes, P-adsorption
capacity, phosphate concentrations and total amount, and the extractable P forms in the upper 20 cm of sediment in vegetated
sediment with adjacent mudflats without vegetation. Sediment pore-water profiles followed a clear trend, with lower P concentrations
in more superficial layers, and increasing with depth. The vegetated mudflats presented lower concentrations of dissolved
inorganic phosphorus than adjacent bare bottom mudflats, lower phosphate total amount, as well as higher P-adsorption capacity.
Results from the extraction procedure show that the superficial layers are the most important for estuarine phosphorus dynamics,
since maximum concentrations of labile P pools are present here. In contrast, higher proportions of refractory P pool are
found in deeper layers. Spartina marsh sediments had less total P, less iron bound P, and less exchangeable P than adjacent bare bottom mudflats. Also the
pool of loosely sorbed P is lower in the Spartina marsh. Phosphate regeneration from the sediment to the overlying water was only 11.8 kg ha−1 year−1 in vegetated sediment while 25.8 kg ha−1 year−1 in the bare mud flat. Plant uptake for growth combined with an enhanced P-adsorption capacity of the sediment, may explain
these differences. Therefore, Spartina marshes are very important agents in the sedimentary P cycle worldwide, and can be considered a useful management tool in
estuarine ecosystem recovery efforts. 相似文献
9.
Soil carbon storage, litterfall and CO2 efflux in fertilized and unfertilized larch (Larix leptolepis) plantations 总被引:1,自引:0,他引:1
Choonsig Kim 《Ecological Research》2008,23(4):757-763
This study evaluated the effects of forest fertilization on the forest carbon (C) dynamics in a 36-year-old larch (Larix leptolepis) plantation in Korea. Above- and below-ground C storage, litterfall, root decomposition and soil CO2 efflux rates after fertilization were measured for 2 years. Fertilizers were applied to the forest floor at rates of 112 kg
N ha−1 year−1, 75 kg P ha−1 year−1 and 37 kg K ha−1 year−1 for 2 years (May 2002, 2003). There was no significant difference in the above-ground C storage between fertilized (41.20 Mg C
ha−1) and unfertilized (42.25 Mg C ha−1) plots, and the C increment was similar between the fertilized (1.65 Mg C ha−1 year−1) and unfertilized (1.52 Mg C ha−1 year−1) plots. There was no significant difference in the soil C storage between the fertilized and unfertilized plots at each soil
depth (0–15, 15–30 and 30–50 cm). The organic C inputs due to litterfall ranged from 1.57 Mg C ha−1 year−1 for fertilized to 1.68 Mg C ha−1 year−1 for unfertilized plots. There was no significant difference in the needle litter decomposition rates between the fertilized
and unfertilized plots, while the decomposition of roots with 1–2 mm diameters increased significantly with the fertilization
relative to the unfertilized plots. The mean annual soil CO2 efflux rates for the 2 years were similar between the fertilized (0.38 g CO2 m−2 h−1) and unfertilized (0.40 g CO2 m−2 h−1) plots, which corresponded with the similar fluctuation in the organic carbon (litterfall, needle and root decomposition)
and soil environmental parameters (soil temperature and soil water content). These results indicate that little effect on
the C dynamics of the larch plantation could be attributed to the 2-year short-term fertilization trials and/or the soil fertility
in the mature coniferous plantation used in this study. 相似文献
10.
Stefan Kraan 《Journal of applied phycology》2008,20(5):825-832
The invasive marine macroalga Sargassum muticum was recorded from Kilmore Quay, Co. Waterford, for the first time in the Republic of Ireland in 2001. It was found at several
other places in that year and in subsequent years. An intensive survey was carried out from April 2003 to November 2003 to
map the geographical distribution and spread of this invasive brown macroalga, and data on distribution were collected in
subsequent years through 2006. This study indicated that S. muticum most probably arrived in the early or mid 1990s and has spread all around the Irish coastline colonising Co. Donegal for
the first time in 2006. The results indicate that spreading is facilitated by boating and perhaps via shellfish transport.
A rough rate of spread of 2–3 km year−1 has been calculated within one bay and for the Irish coastline of about 54 km year−1. Observations showed that S. muticum has been found growing in seagrass beds and in rock pools, which might have serious consequences for the biodiversity in
rock pools and for the protective status of seagrass habitats. It is recommended that monitoring of S. muticum should continue, especially in areas of high amenity value and economic importance in order to observe possible effects on
local flora and fauna, aquaculture, the seaweed industry and tourism. 相似文献
11.
Biomass and net production were measured in aPhyllostachys bambusoides stand in Kyoto Prefecture, central Japan, which had carried out gregarious flowering in 1969 and has been recovering vegetatively.
The culm density fluctuated around an average value of 12 040 ha−1 during the research period (1985–91). Annual recruirment and mortality rates of culms were 1340 and 1133 ha−1, respectively. The mean diameter at breast height increased from 7.28 cm in 1985 to 8.68 cm in 1991, and the biomass of culms
increased from 71.3 to 111.6t ha−1 over the same time period. Branch and leaf biomasses were almost constant, 10.0 and 9.4t ha−1 on average, respectively. The leaf area index of the stand was 11.6 ha ha−1, which is one of the largest values found in Japanese forests. The belowground biomass of 32.6t ha−1 for rhizomes and 14.8t ha−1 for fine roots resulted in the smaller ratio of aboveground parts to the root system (2.38) than those determined for forest
stands. The amount of litterfall, excluding culms and large branches, was large (9.13t ha−1 year−1), corresponding to those measured in equatorial stands. The aboveground net production was 24.6t ha−1 year−1, larger than the average value reported for forest stands under similar weather conditions. 相似文献
12.
Culm recruitment, standing crop biomass, net production and carbon flux were estimated in mature (5 years after last harvest)
and recently harvested bamboo (Dendrocalamus strictus (Roxb.) Nees) savanna sites in the dry tropics. During the 2 study years bamboo shoot recruitment was 1711–3182 and 1432–1510
shoots ha−1 in harvested and mature sites, respectively. Corresponding shoot mortality was 66–93% and 62–69%, respectively. Total biomass
was 34.9 t ha−1 at the harvested site and 47.4 t ha−1 at the mature site. Harvesting increased the relative contribution of belowground bamboo biomass. Annual litter input to
soil was 2.7 and 5.9 t ha−1 year−1 at the harvested and mature sites, respectively. The bulk of the annual litterfall (78–88%) occurred in the cool dry season
(November to February). The mean litter mass on the savanna floor ranged from 3.1 to 3.3 t ha−1; at the harvested site wood litter contributed 70% of the litter mass and at the mature site leaves formed 77% of the litter
mass. The mean total net production (TNP) for the two annual cycles was 15.8 t ha−1 year−1 at the harvested site and 19.3 t ha−1 year−1 at the mature site. Nearly half (46–57%) of the TNP was allocated to the belowground parts. Short lived components (leaves
and fine roots) contributed about four-fifths of the net production of bamboo. Total carbon storage in the system was 64.4
t ha−1 at the harvested site and 75.4 t ha−1 at the mature site, of which 23–28% was distributed in vegetation, 2% in litter and 70–75% in soil. Annual net carbon deposition
was 6.3 and 8.7 t ha−1 year−1 at harvested and mature sites, respectively. 相似文献
13.
Net anthropogenic phosphorus inputs: spatial and temporal variability in the Chesapeake Bay region 总被引:4,自引:0,他引:4
Marc J. Russell Donald E. Weller Thomas E. Jordan Kevin J. Sigwart Kathryn J. Sullivan 《Biogeochemistry》2008,88(3):285-304
We estimated net anthropogenic phosphorus inputs (NAPI) in the Chesapeake Bay region. NAPI is an index of phosphorus pollution
potential. NAPI was estimated by quantifying all phosphorus inputs and outputs for each county. Inputs include fertilizer
applications and non-food phosphorus uses, while trade of food and feed can be an input or an output. The average of 1987,
1992, 1997, and 2002 NAPI for individual counties ranged from 0.02 to 78.46 kg P ha−1 year−1. The overall area-weighted average NAPI for 266 counties in the region was 4.52 kg P ha−1 year−1, indicating a positive net phosphorus input that can accumulate in the landscape or can pollute the water. Large positive
NAPI values were associated with agricultural and developed land cover. County area-weighted NAPI increased from 4.43 to 4.94 kg P ha−1 year−1 between 1987 and 1997 but decreased slightly to 4.86 kg P ha−1 year−1 by 2002. Human population density, livestock unit density, and percent row crop land combined to explain 83% of the variability
in NAPI among counties. Around 10% of total NAPI entering the Chesapeake Bay watershed is discharged into Chesapeake Bay.
The developed land component of NAPI had a strong direct correlation with measured phosphorus discharges from major rivers
draining to the Bay (R
2 = 0.81), however, the correlation with the simple percentage of developed land was equally strong. Our results help identify
the sources of P in the landscape and evaluate the utility of NAPI as a predictor of water quality. 相似文献
14.
Fernando G. Brun Elleke van Zetten Eva Cacabelos Tjeerd J. Bouma 《Helgoland Marine Research》2009,63(1):19-25
Seagrasses are well known ecosystem engineers that can significantly influence local hydrodynamics and the abundance and biodiversity
of macrobenthic organisms. This study focuses on the potential role of the seagrass canopy structure in altering the abundance
of filter-feeding organisms by modifying the hydrodynamic driven food supply. We quantified the effect of two ecosystem engineers
with contrasting canopy properties (i.e. Zostera noltii and Cymodocea nodosa) on the food intake rate of a suspension-feeding bivalve Cerastoderma edule living in these seagrass meadows. Field experiments were carried out in two seagrass beds (Z. noltii and C. nodosa) and bare sediment, located on sandflat characterised by a relatively high hydrodynamic energy from waves and currents. Results
demonstrated that the filter-feeding rate was almost twofold increased when C. edule was inhabiting Z. noltii meadows (1.10 ± 0.24 μg Chl g Fresh Weight−1) when compared to cockles living on the bare sediment (0.65 ± 0.14 μg Chl g FW−1). Intermediate values were found within C. nodosa canopy (0.97 ± 0.24 μg Chl g FW−1), but filter feeding rate showed no significant differences with values for Z. noltii meadows. There were no apparent correlations between canopy properties and filter-feeding rates. Our results imply that food
refreshment within the seagrass canopies was enough to avoid food depletion. We therefore expect that the ameliorated environmental
conditions within vegetated areas (i.e. lower hydrodynamic conditions, higher sediment stability, lower predation pressure…)
in combination with sufficient food supply to prevent depletion within both canopies are the main factors underlying our observations. 相似文献
15.
The shrimp Caridina nilotica is a major prey of the introduced Nile perch in Lake Victoria. In spite of heavy predation, the density of shrimps increased
after the Nile perch boom and the concomitant disappearance of the haplochromine cichlids. In the same period, the mean size
of gravid shrimps and the size at first maturity declined. This seems to indicate an increased predation pressure on adult
shrimps. Before the Nile perch upsurge, specialised shrimp eaters and piscivores, among the haplochromine cichlids, only took
adult shrimps, whereas we assume that most haplochromines used to include juvenile shrimps into their diet. Another important
predator on adult shrimps was Bagrus docmak. The combined density of predators on adult shrimps in the pre-Nile perch era was estimated at 10 kg ha−1 and the potential predators on juveniles were estimated at 170 kg ha−1. After the Nile perch upsurge, only Nile perch up to 10 cm TL and Rastrineobola argentea fed on juvenile shrimps (ca. 36 kg ha−1) and Nile perch from 10 to 50 cm TL (ca. 13 kg ha−1) fed on adults. These rough estimates of the biomass of predators on shrimps before and after the Nile perch upsurge indicate
a reduced predation pressure on juvenile shrimps. The disappearance of the haplochromines may have released competition with
small Nile perch for juvenile shrimps, thus enhancing the recruitment of Nile perch. 相似文献
16.
The theoretical basis of fine root turnover estimation in forest soils is discussed, in relation to appropriate experimental
techniques of measurement. After sequential coring, the correct expression is the sum of significant positive increments of
live and dead roots of the various diameter categories, to which the transfer of dead roots to organic matter derived from
roots, OMDR, has to be added. This should not be confounded with dead root mineralization. The transfer rates should first
be estimated in root dimensions and not in weight of dry matter.
The measurements were carried out in a 120 year old beech (Fagus sylvatica L.) stand and a 35 year old Norway spruce (Picea abies Karst) stand, in the Eastern Ardennes, Belgium.
The turnover rate of fine roots (diam. <5 mm) was 4393 kg ha−1 year−1 (root dry weight), including 711.2 kg ha−1 year−1 for dead root transfer to OMDR, for beech.
For spruce, turnover rate was 7011 kg ha−1 year−1 (root dry weight), including 1498 kg ha−1 year−1 for dead root transfer to OMDR.
Under beech, there was a slight root density increase in spring. No seasonal fluctuations were observed under spruce, but
a strong irreversible drop in live root growth was found in the later season 1980–1981, corresponding to a decrease of tree
height growth and trunk radius increment.
Turnover rates were further expressed in dry weight and in amounts of elements (kg ha−1 year−1) (Ca, Mg, K, Na, Al, N, P, S).
Correlative relations between root dimensions and dry weight and element concentrations show that the derived values, and
in particular root specific density (dry weight volume−1) vary according to species, root category, and seasonal sampling.
Various schemes of seasonal variations of root growth, described in Europe, show that the major dependance on general climate
is obscured by environmental factors (soil, exposure, species). It is suggested that root density fluctuation approach the
steady state on an annual basis under mild Atlantic conditions. 相似文献
17.
The present study was undertaken to assess the benefit and compare the functioning of AM fungi on wheat grown conventionally
and on beds. Ten treatment combinations were used, treatments 1 and 2: no fertilizers with and without arbuscular mycorrhizal
(AM) fungi (In vitro produced Glomus intraradices); 3:100% of recommended NPK: (120 kg ha−1 N; 60 kg ha−1 P; 50 kg ha−1 K), and 4 and 5: 75% of recommended NPK dose with and without AM inoculation in a 5 × 2 split-plot design on wheat using
conventional/flat system and elevated/raised bed system. The maximum grain yield (3.84 t ha−1) was obtained in AM fungi inoculated plots of raised bed system applied with 75% NPK and was found higher (although non-
significant) than the conventional (3.73 t ha−1) system. The AM inoculation at 75% fertilizer application can save 8.47, 5.38 kg P and 16.95, 10.75 kg N ha−1, respectively, in bed and conventional system. While comparing the yield response with 100% fertilizer application alone,
AM inoculation was found to save 20.30, 15.79 kg P and 40.60, 31.59 kg N ha−1, respectively, in beds and conventional system. Mycorrhizal inoculation at 75% NPK application particularly in raised bed
system seems to be more efficient in saving fertilizer inputs and utilizing P for producing higher yield and growth unlike
non-mycorrhizal plants of 100% P. Besides the yield, mycorrhizal plants grown on beds had higher AM root colonization, soil
dehydrogenases activity, and P-uptake. The present study indicates that the inoculation of AM fungi to wheat under raised
beds is better response (although non-significantly higher) to conventional system and could be adopted for achieving higher
yield of wheat at reduced fertilizer inputs after field validation. 相似文献
18.
Yong-Suk Kim Myong-Jong Yi Yoon-Young Lee Kobayashi Makoto Yowhan Son 《Landscape and Ecological Engineering》2009,5(2):167-166
Alder is a typical species used for forest rehabilitation after disturbances because of its N2-fixing activities through microbes. To investigate forest dynamics of the carbon budget, we determined the aboveground and
soil carbon content, carbon input by litterfall to belowground, and soil CO2 efflux over 2 years in 38-year-old alder plantations in central Korea. The estimated aboveground carbon storage and increment
were 47.39 Mg C ha−1 and 2.17 Mg C ha−1 year−1. Carbon storage in the organic layer and in mineral soil in the topsoil to 30 cm depth were, respectively, 3.21 and 66.85 Mg C ha−1. Annual carbon input by leaves and total litter in the study stand were, respectively, 1.78 and 2.68 Mg C ha−1 year−1. The aboveground carbon increment at this stand was similar to the annual carbon inputs by total litterfall. The diurnal
pattern of soil CO2 efflux was significantly different in May, August, and October, typically varying approximately twofold throughout the course
of a day. In the seasonally observed pattern, soil CO2 efflux varied strongly with soil temperature; increasing trends were evident during the early growing season, with sustained
high rates from mid May through late October. Soil CO2 efflux was related exponentially to soil temperature (R
2 = 0.85, P < 0.0001), but not to soil water content. The Q
10 value for this plantation was 3.8, and annual soil respiration was estimated at 10.2 Mg C ha−1 year−1.
An erratum to this article can be found at 相似文献
19.
Julie C. Pett-Ridge 《Biogeochemistry》2009,94(1):63-80
The input of phosphorus (P) through mineral aerosol dust deposition may be an important component of nutrient dynamics in
tropical forest ecosystems. A new dust deposition calculation is used to construct a broad analysis of the importance of dust-derived
P to the P budget of a montane wet tropical forest in the Luquillo Mountains of Puerto Rico. The dust deposition calculation
used here takes advantage of an internal geochemical signal (Sr isotope mass balance) to provide a spatially integrated longer-term
average dust deposition flux. Dust inputs of P (0.23 ± 0.08 kg ha−1 year−1) are compared with watershed-average inputs of P to the soil through the conversion of underlying saprolite into soil (between
0.07 and 0.19 kg ha−1 year−1), and with watershed-average losses of soil P through leaching (between 0.02 and 0.14 kg ha−1 year−1) and erosion (between 0.04 and 1.38 kg ha−1 year−1). The similar magnitude of dust-derived P inputs to that of other fluxes indicates that dust is an important component of
the soil and biomass P budget in this ecosystem. Dust-derived inputs of P alone are capable of completely replacing the total
soil and biomass P pool on a timescale of between 2.8 ka and 7.0 ka, less than both the average soil residence time (~15 ka)
and the average landslide recurrence interval (~10 ka). 相似文献
20.
Nelusetta ayraudi (the ocean leatherjacket) is an endemic Australian monacanthid species distributed from North West Cape (Western Australia)
south to southern Queensland. The commercial and recreational fisheries targeting Nelusetta ayraudi have expanded substantially along the coast of New South Wales (NSW) in recent years but there exists little biological information
on which to base effective management of this growing fishery. World-wide, only a few studies have aged monacanthids. Of these,
researchers have interpreted periodic increments in bony structures such as vertebrae and anterior dorsal spines in preference
to those found in otoliths. In this study we estimated age of N. ayraudi by counting growth increments in sectioned otoliths. The periodicity of increment formation was validated using a vital stain,
(oxy-tetracycline), injected into young-of-the-year fish. Growth was rapid especially as juveniles with N. ayraudi attaining approximately 220 mm after 1 year and 340 mm after 2 years. No differences in growth rates were detected between
sexes or between fish captured at different latitudes (zones). The largest male (605 mm, Total Length—TL) and female (656 mm,
TL) were both recorded from northern NSW, with both sexes attaining the maximum age of 6+ years from northern and southern
NSW. The von Bertalanffy parameters describing growth for N. ayraudi were L¥ {L_\infty } = 591 mm (TL), k = 0.377 year−1 and t
o = −0.247 years. 相似文献