首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Effects of arbuscular mycorrhizal fungi (AMF) on the growth, nutrient absorption, and inoculation effectiveness of AMF on pioneer plants Pharagmites japonica (C4) and Polygonum cuspidatum (C3) were evaluated by performing a pot experiment in a greenhouse at Saitama University, Japan. AMF spores were collected from the commercial product, Serakinkon. The average colonization levels of P. japonica and P. cuspidatum were 24–33% and 0.2–0.5% respectively and no colonization was found in sterilized soil treatment. AMF colonization increased the plant dry mass, phosphorus (P), and nitrogen (N) concentrations of P. japonica’s roots, stems, and leaves when AMF applied with natural and sterilized soil compared with only sterilized and natural soil. This was a significant effect for N-loss minimization from soil. Maximum value showed when P. japonica was grown with natural soil in combination with AMF whereas P. cuspidatum showed very less or a negative response to AMF colonization in all cases.  相似文献   

2.
[目的]研究秸秆覆盖对富集植物重金属积累的影响,筛选能促进荠菜生长和镉积累的镉耐性植物.[方法]通过盆栽试验研究镉污染条件下,覆盖4种镉耐性植物(扬子毛茛、通泉草、邻近风轮菜和车前)秸秆对荠菜生长及镉积累的影响。[结果]覆盖扬子毛茛、通泉草、邻近风轮菜和车前秸秆后,荠菜的地上部分生物量、总生物量和叶片叶绿素含量值均低于未覆盖处理。覆盖扬子毛茛、通泉草、邻近风轮菜和车前秸秆的荠菜总生物量则较未覆盖分别降低了34.04%,49.85%,40.27%和18.39%。只有覆盖邻近风轮菜秸秆提高了荠菜根系镉含量,而覆盖扬子毛茛和通泉草秸秆则提高了荠菜地上部分镉含量(较未覆盖分别提高了18.61%和12.87%)。然而,覆盖4种耐性植物的荠菜根系、地上部分及整株镉积累量均低于未覆盖。[结论]在盆栽条件下,覆盖镉耐性植物(扬子毛茛、通泉草、邻近风轮菜和车前)秸秆不能提高荠菜对镉污染土壤的修复能力。  相似文献   

3.
4.
Ecosystems of northern North America existed without earthworm fauna until European settlers arrived and introduced European species. The current extent of invasion by some of these species, Lumbricus terrestris L., Octolasion tyrtaeum Savigny and Dendrobaena octaedra Savigny, into an aspen forest in the Canadian Rocky Mountains and the effects of the invasion on soil chemistry, microflora, soil microarthropods and vegetation were investigated. Densities of earthworm species, soil structure, plant coverage and abundance were determined along three transects starting at the edge of the forest. At locations with L. terrestris, litter was incorporated into the soil, and where O. tyrtaeum was present, organic layers were mixed with mineral soil layers. Organic layers disappeared almost entirely when both species occurred together. Carbon and nitrogen concentrations were reduced in organic layers in the presence of L. terrestris and O. tyrtaeum. Microbial biomass and basal respiration were reduced when L. terrestris and O. tyrtaeum were present, presumably due to resource competition and habitat destruction. Microarthropod densities and the number of microarthropod species were strongly reduced in the presence of O. tyrtaeum (−75% and −22%, respectively), probably through mechanical disturbances, increasing compactness of the soil and resource competition. The coverage of some plant species was correlated with earthworm abundance, but the coverage of others was not. Despite harsh climatic conditions, the invasion of boreal forest ecosystems by mineral soil dwelling earthworm species is proceeding and strongly impacts soil structure, soil chemistry, microorganisms, soil microarthropods and vegetation.  相似文献   

5.
Microbial biomass C and N, and activities related to C and N cycles, were compared in needle and leaf litter, and in the uppermost 10 cm of soil under the litter layer in Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L.) and silver birch (Betula pendula L.) stands, planted on originally similar field afforestation sites 23–24 years ago. The ground vegetation was differentiated under different tree species, consisting of grasses and herbs under birch and pine, and mosses or no vegetation with a thick layer of needles under spruce. The C:N ratio of the soils was 13–21 and the soil pHCaCl 2 3.8–5.2. Both showed little variation under different tree species. Microbial biomass C and N, C mineralization, net ammonification, reduction) did not differ significantly in soil under different tree species either. Birch leaf litter had a higher pHCaCl 2 (5.9) than spruce and pine needle litter (pH 5.0 and 4.8, respectively). The C:N ratio of spruce needles was 30, and was considerably higher in pine needles (69) and birch leaves (54). Birch leaves tended to have the highest microbial biomass C and C mineralization. Spruce needles appeared to have the highest microbial biomass N and net formation of mineral N, whereas formation of mineral N in pine needles and birch leaves was negligible. Microbial biomass C and N were of the same order of magnitude in the soil and litter samples but C mineralization was tenfold higher in the litter samples.  相似文献   

6.
Despite the impact of soil millipedes on litter fragmentation in tropical forests, there have been few studies dealing with factors determining their habitat preference in these ecosystems. In a natural secondary dry forest of Guadeloupe on Leptosol, two complementary studies were carried out in order to test the hypothesis that litter N-content strongly influences millipede distribution. Millipede abundance and species richness were described in the field under two tree species, Bursera simaruba and Pisonia subcordata, and were related to the chemical characteristics of their foliage. In addition, a laboratory experiment was done in order to assess millipede feeding preferences regarding the chemical characteristics of leaves from various species. Millipede abundance and species richness were significantly higher under P. subcordata than under B. simaruba, probably due to the higher N content of P. subcordata leaves. Moreover, millipedes fed preferentially on N-rich leaves. The present study confirms that there was a close correlation between the preferred food, its chemical composition and the local distribution of millipede populations.  相似文献   

7.
Summary The evolution of mineral and hydrosoluble organic N released from two soils differing in pH and treated with leaves of Leucaena leucocephala (0, 8.3, 16.7, and 33. g kg-1 soil), Dactyladenia barteri (syn. Acioa barteri; 0 and 16.7 g), and their mixtures was studied in the laboratory using the aerobic incubation-leaching method. N mineralization in untreated soils and in soils supplemented with 8.3 g leucaena leaves was 41–53% higher in the soil from Onne (pH 4.7) than in the soil from Ibadan (pH 6.2), but the organic N content was similar with these treatments in the leachates of the soils from both locations. The application of 16.7 or 33.3 g of either or both type of leaves reduced the rate of mineral N production during the first 4 weeks, particularly in soils treated with dactyladenia leaves (C:N=36). After this lag period, N mineralization proceeded at a faster rate in the soil from Ibadan treated with 16.7 or 33.3 g of leucaena leaves (C:N=12), even in the presence of dactyladenia leaves. In Ibadan soil, after 12 weeks, mineral N apprently derived from leaves of both dactyladenia and leucaena averaged 6.3% of the N applied, and organic N from leaves averaged 9.5%. The addition of dactyladenia and leucaena leaves did not increases the mineral N content in the acid soil from Onne but leaching of soluble organic N with addition of 16.7 or 33.3 g of leaves contributed an N-mineralizable pool of 5.9% of the N applied.  相似文献   

8.
9.
Erythroxylum coca var. coca Lam. (E. coca) and Erythroxylum novogranatense var. novogranatense (Morris) Hieron (E. n. novogranatense) are two of four Erythroxylum species grown in the tropics of South America for cultural medicines and the alkaloid benzoylmethylecgonine. In a published study of biomass production over a soil pH range of 3.5 to 7.0, E. coca grew best at a pH equal to and below 5.5, and E. n. novogranatense grew best within the pH range of 4.7 to 6.0. Erythroxylum coca was tentatively classified as more tolerant to metal toxicities [aluminum (Al) and manganese (Mn)] than E. n. novogranatense, however, concentration patterns of mineral elements for E. coca and E. n. novogranatense tissue have not been reported, nor have the mechanisms of differential acid‐soil‐tolerance been elucidated. In the current study, the effects of soil pH on concentrations of Al, calcium (Ca), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), Mn, and zinc (Zn) in leaves, stems, and roots were investigated. At pH 3.5, roots of both species accumulated high concentrations of Al that decreased as soil pH increased, however, there was no pH × species interaction. The highest concentration of Ca was found in the leaves of both species, however, E. coca accumulated more Ca as soil pH increased than did E. n. novogranatense. Manganese and Zn levels were highest in roots of both species (E. coca and E. n. novogranatense); levels in all tissues decreased with increasing pH. Manganese concentration was highest in roots of E. coca and Zn concentration was highest in tissues of E. n. novogranatense. Copper, Fe, K, and Mg levels were erratic with increasing pH, indicating that sufficient amounts of these nutrients are acquired at low pH levels. Root concentrations of Fe and K in E. coca increased markedly between pH 3.5 and 4.7. At pH 3.5, E. coca demonstrated no symptoms of mineral deficiency and/or toxicity, however, chlorosis, leaf distortion and root atrophy were prevalent at pH 6.5 and 7.0. By contrast, E. n. novogranatense demonstrated diminished growth and root atrophy at soil pH 3.5, whereas at pH 6.5 and 7.0, although biomass production was reduced, no symptoms of mineral deficiency and/or toxicity were present. The species obviously behave differentially at pH extremes and E. coca appears to be most tolerant of extremely acid soils; the two species may also differ in mineral sensitivities between the species at higher pH levels. Erythroxylum coca may compete more effectively with Al for Ca binding sites within the root, and may have greater internal tolerance of Mn, compared with E. n. novogranatense.  相似文献   

10.
The aim of the study was to determine the effect of adding two tropical earthworm species, Rhinodrilus contortus and Pontoscolex corethrurus, to mesocosms on the availability of mineral N (NH4 + and NO3 concentrations), soil microbial biomass (bio-N), and the decomposition rates of three contrasting leaf litter species, in a glasshouse experiment. The mesocosms were filled with forest soil and covered with a layer of leaf litter differing in nutritional quality: (1) Hevea brasiliensis (C/N=27); (2) Carapa guianensis (C/N=32); (3) Vismia sp., the dominant tree species in the second growth forest (control, C/N= 42); and, (4) a mixture of the former three leaf species, in equal proportions (C/N=34). At the end of the 97-day experiment, the soil mineral N concentrations, bio-N, and leaf litter weight loss were determined. Both earthworm species showed significant effects on the concentrations of soil NO3 (p<0.01) and NH4 + (p<0.05). Bio-N was always greater in the mesocosms with earthworms (especially with R. contortus) and in the mesocosms with leaf litter of H. brasiliensis (6 µg N g–1 soil), the faster decomposing species, than in the other treatments (0.1–1.6 µg N g–1). Thus, earthworm activity increased soil mineral-N concentrations, possibly due to the consumption of soil microbial biomass, which can speed turnover and mineralization of microbial tissues. No significant differences in decomposition rate were found between the mesocosms with and without earthworms, suggesting that experiments lasting longer are needed to determine the effect of earthworms on litter decomposition rates.  相似文献   

11.
Microbial morphology fundamentally constrains how species interact with their environment, and hence ultimately affects their niche. However, the methodology of functional microbes in the soil ecosystem is still poorly studied since it is difficult to capture and identify the active monospecific community from the complicated environment and enormous number of microbial species in soils. To comprehensively reveal the morphology of active microbes in soil ecosystem, magnetic nanoparticle-mediated isolation (MMI) and single-cell image recognition (SCIR) were employed to study soil active Bacillus community, which functionally boosted the soil fertility in organic fertilisation compared to mineral fertilisation and unfertilised control treatments in our previous study. The results showed that MMI and SCIR can efficiently isolate active Bacillus from soil particles and other microorganisms. High throughput sequencing showed that the captured Bacillus showed similar community structure in different long-term fertilisation soils, while SCIR revealed that the active Bacillus was greater in number and larger in size in organic fertilisation treatment compared to mineral fertilisation and unfertilised control treatments. Our study demonstrates that the combination of MMI and SCIR is a potentially powerful tool to capture and identify the morphology of active and functional microbes in the soil ecosystem.  相似文献   

12.
Trees interact in a complex manner with soils: they recycle and redistribute nutrients via many ecological pathways. Nutrient distribution via leaf litter is assumed to be of major importance. Beech is commonly known to have lower nutrient concentrations in its litter than other hardwood tree species occurring in Central Europe. We examined the influences of distribution of beech (Fagus sylvatica L.), ash (Fraxinus excelsior L.), lime (Tilia cordata Mill. and T. platyphyllos Scop.), maple (Acer spp. L.), and clay content on small‐scale variability of pH and exchangeable Ca and Mg stocks in the mineral soil and of organic‐C stocks in the forest floor in a near‐natural, mature mixed deciduous forest in Central Germany. The soil is a Luvisol developed in loess over limestone. We found a positive effect of the proportion of beech on the organic‐C stocks in the forest floor and a negative effect on soil pH and exchangeable Ca and Mg in the upper mineral soil (0 to 10 cm). The proportion of ash had a similar effect in the opposite direction, the other species did not show any such effect. The ecological impact of beech and ash on soil properties at a sample point was explained best by their respective proportion within a radius of 9 to 11 m. The proportion of the species based on tree volume within this radius was the best proxy to explain species effects. The clay content had a significant positive influence on soil pH and exchangeable Ca and Mg with similar effect sizes. Our results indicate that beech, in comparison to other co‐occurring deciduous tree species, mainly ash, increased acidification at our site. This effect occurred on a small spatial scale and was probably driven by species‐related differences in nutrient cycling via leaf litter. The distribution of beech and ash resulted not only in aboveground diversity of stand structures but also induced a distinct belowground diversity of the soil habitat.  相似文献   

13.
Abstract

Two native grasses, Festuca ovina of dry and Agrostis stolonifera mainly of moist habitats of calcareous grasslands, were studied in an experiment with the objective of elucidating the effect of soil moisture level on soil solution chemistry, biomass production and shoot mineral nutrients. Eight levels of moisture, corresponding to 30–100% of the water‐holding capacity (WHC) of the soil, were tested. High correlation coefficients with soil moisture were observed for magnesium (Mg), phosphorus (P), and HCO3 in soil solution. Amounts of calcium (Ca), Mg, and iron (Fe) in soil solution were lowest in the intermediate soil moisture range (60–70%). Shoot production, relative to maximum, was higher at low moisture levels for F. ovina than for A. stolonifera. Differences of P, Fe, and potassium (K) concentrations in shoots and maximum relative shoot production between the two species, are consistent with their field distributions as related to soil moisture. Lower soil moisture on calcareous soil is more favorable for F. ovina than for A. stolonifera. Variation in soil moisture regimes may greatly influence amounts of mineral nutrients in soil solution and uptake by plants and might even be a prerequisite for adequate acquisition of mineral nutrients and growth of plants on limestone soils.  相似文献   

14.
Community structures of soil Sarcodina in 7 different habitats within Baiyun Mountain in Guangzhou, China were investigated with qualitative and quantitative analyses. The abundance, dominance, species diversity and community similarity index of soil sarcodina with different physicochemical parameters were comparatively analyzed. A total 67 species of sarcodina belonging to 4 Super-groups, 6 First ranks and 14 Second ranks were identified. The first dominant group was Tubulinea, followed by Flabellinea, with dominance of 59.7% and 13.4%, respectively. The highest abundance of sarcodina appeared in autumn of Site 5, reaching 1.20 × 105 ind g?1; the lowest in spring of Site 2 with 1.73 × 103 ind g?1. Margalef's biodiversity index ranged from 1.26 (winter of Site 6) to 2.51 (summer of Site 1). Statistical analyses showed the sarcodina abundance was positively correlated with organic matter, soil moisture, soil pH, ammonia nitrogen and total nitrogen, but the correlation coefficient of total potassium was negative. Total phosphorus, nitrate nitrogen and sulphate showed no significant effect on sarcodina abundance in the present study.  相似文献   

15.
[目的]研究不同生境条件下(林内、林外、林缘)藏东南急尖长苞冷杉林(Abies georgei var.smithii)凋落物分解特征与土壤养分特征之间的关系,为深入了解高寒高山森林生态系统物质循环过程提供依据。[方法]采用野外分解袋法和室内分析相结合,在林内、林外、林缘3种不同生境条件下对藏东南急尖长苞冷杉林凋落物进行了原位分解试验。[结果]分解速率总体上呈现出:林内林缘林外的特点,逐月分解率的变异系数表现为:林内(34.83%)林缘(57.35%)林外(72.09%);Olson指数衰减模型的模拟结果显示不同生境条件下(林内、林缘、林外)凋落物分解50%需要的时间为2.11,2.52,2.34 a,分解95%需要的时间为8.96,10.01,10.84 a;3种不同生境土壤养分在空间上差异显著,林内生境中与凋落物分解速率呈现极显著相关的土壤养分因子有土壤总有机碳(TOC)含量、N含量、土壤微生物量碳(SMBC)含量、土壤微生物量氮(SMBN)含量以及W_C∶W_N值;林外、林缘生境中与凋落物分解速率相关性最大的为土壤TOC含量,其次为W_C∶W_N值。[结论]生境条件的差异对凋落物分解速率有显著影响,在不同的生境条件下对凋落物分解影响起主导作用的土壤养分因素不同,凋落物—土壤生物地化循环紧密联系,相互作用关系复杂,生境作用效应突出。  相似文献   

16.
A few species of fuelwood trees were established on highly alkaline wasteland at Aligarh (27°5′ N., 78°4′ E.) in a tropical environment. Of these Prosopis juliflora produced maximum biomass (12.05 t ha−1) and had an energy content of 242.11 GJ ha−1 after 3.5 years growth period. The survival percentage of Terminalia arjuna was highest of those the species tried, but their growth and biomass production were inferior to that of Prosopis juliflora and Acacia nilotica. Some of the fuelwood tree plantations were raised without adding any soil amendment but suffered heavy mortality and could not produce any significant quantity of biomass. In another experiment Leucaena leucocephala was identified as a most promising species for afforestation on substandard soils; also it was found that a relatively high population density (of about 7,500 plants per hectare) is required to rehabilitate such land. Of the soil amendments tried, gypsum with farmyard manure and sand in equal proportion gave the better response (gypsum alone was also tried). Two species of shrubs: Sesbania sesban and Tamarix dioca have shown good adaptability in difficult habitats. After five years of afforestation the soil properties of the sites improved significantly, showing marked reduction in pH, EC and ESP values and an increase in organic carbon content.  相似文献   

17.
Abstract

Silicon (Si) is a beneficial nutrient for sugarcane (Saccharum spp.) and yield responses to Si amendment have been determined on soils with low soluble Si. Because a soil test Si calibration has not been published for sugarcane grown on Florida mineral soils, the objectives were to determine sugarcane yield response to silicon soil amendment on two mineral soils (Entisol and Spodosol) and to relate sucrose yield to soil-extractable Si. Calcium silicate application rates were 0, 3.4, and 6.7?Mg ha?1 (Site 1) and 0, 2.2, 4.5, and 6.7?Mg ha?1 (Site 2) in small-plot (120 m2 plot?1) experiments, with Si application resulting in significant increases in biomass and sucrose ha?1. Calcium silicate requirements of 6.7 and 4.3?Mg ha?1 were determined with initial acetic acid-extractable Si of 21 and 46?g m?3, respectively. Nonlinear models indicated that Si amendments will be required with acetic acid-extractable Si <105?g m?3.  相似文献   

18.
As ecosystem engineers, earthworms play a key role in the soil environment. However, due to increasing anthropogenic pressure, soil organisms,including earthworms, are being threatened by habitat loss. In this study, we undertook a qualitative and quantitative investigation of earthworms of the family Lumbricidae in four types of Carpathian beech woodland(Fagetum carpaticum), characterized by their understory vegetation(I, F. c. festucetosum drymejae; II, F. c. typicum; III, F. c. lunarietosum; and IV, F. c. allietosum), in the Bieszczady National Park(Eastern Carpathians, Southeast Poland). At each investigated site, soil monoliths(25 cm × 25 cm × 25 cm) were examined by hand sorting. Earthworms were expelled from deep soil layers using a weak formalin solution(0.4%). Depending on the phytocoenosis, 7 species of Lumbricidae were identified at each of the sites I, II, and III and 10 at site IV. Site IV(F. c. allietosum) differed significantly(P 0.05) from the other three sites with respect to earthworm biomass(59.71 ± 39.53 g m~(-2))and the Shannon-Wiener diversity index(0.52 ± 0.12). Although present three decades ago, the deep-burrowing species Octodrilus transpadanus and the litter-dwelling species Dendrobaena octaedra were not found at site IV in the present study. We suspect that these two species may have been displaced by the invasive Lumbricus terrestris, which was not found at the same site in the 1980 s. Such observations warrant further investigation to verify the predicted effects of an invasive earthworm, including the potential effects on soils and other fauna and flora, which have been documented in numerous countries.  相似文献   

19.
Purpose

Soil physico-chemical properties, biomass production, and root density are considered key factors indicating soil health in an agroecosystem. The soil physico-chemical changes and plant growth (e.g., shoot biomass production and root density) in a 6-year cultivation of plant species used as green manure in a sandy soil from Tropical ecosystem, North-eastern Brazil, were investigated between July and December 2019.

Material and methods

We characterized soil physical and chemical properties, shoot biomass production, and root density under ten plant species used as green manure: Brachiaria decumbens Stapf. cv. Basilisk, Canavalia ensiformis (L.) DC, Crotalaria juncea L., Crotalaria ochroleuca G. Don, Crotalaria spectabilis Roth, Lablab purpureus (L.) Sweet, Mucuna pruriens (L.) DC, Neonotonia wightii (Wight & Arn.) J.A. Lackey, Pennisetum glaucum L., and Stilozobium aterrimum Piper and Tracy.

Results and discussion

The highest values of soil pH, exchangeable cations, CEC, and soil available water capacity were found on the plots where Poaceae plants were cultivated, whereas for H++Al3+, C.E.C., soil available water, and soil available water capacity were found on the plots where Fabaceae plants were cultivated. On the plots where C. ensiformis and N. wightii were cultivated, we found the highest shoot dry biomass and root density, respectively. The results highlight the importance to consider plant species from both Poaceae and Fabaceae family used as green manure as soil conditioner (by promoting soil fertility, nutrient cycling, and hydraulic properties into plant root zone), and thus creating a positive plant-soil feedback.

Conclusions

Our findings suggest that (1) a consecutive green manure practice without any input of fertilizers after 6 years changed positively both soil physical and chemical properties, and improve plant growth (e.g., shoot dry biomass and root density) in tropical savanna climate conditions; and (2) by altering soil fertility, both Poaceae and Fabaceae plants used as green manure may create a sustainable cycle into the soil profile thus promoting soil health.

  相似文献   

20.
The community structure of soil sarcodina in three different habitats within a typical mangrove forest in Dongzhaigang, Hainan, China was investigated with qualitative and quantitative analyses. The three habitats were Site A (bare land without vegetation), Site B (artificially planted mangroves) and Site C (natural mangroves). The abundance, species diversity, dominance and community similarity index of soil sarcodina in fresh and air-dried soils with different physical/chemical properties were comparatively analyzed. Statistical analyses showed that the sarcodina abundance was positively correlated with moisture, salinity, organic matter (OM), total nitrogen (TN), total phosphorus (TP) and sulfate (SO42?) of the mangrove soil, but the correlation coefficients with pH and total potassium (kalium, TK) were negative. The abundance and diversity index of sarcodina followed the order of Site A < Site B < Site C in both fresh and air-dried soils; Site B showed the highest community similarity with Site C; whereas, Sites A and C had the smallest community similarity in both fresh and dried samples from these three different habitats.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号