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1.
Allelopathic effects of Eucalyptus camaldulensis Dehnh. were confirmed in Petri dish and pot experiments in our previous studies. However, the degree to which such effects under controlled experiments exist in more complex ecological settings remains to be tested. Thus, the present study was carried out by incorporating different proportions of ground litter of E. camaldulensis in soil. The growth of three agricultural crops: falen (Vigna unguiculata (L.) Walp.), chickpea (Cicer arietinum L.), and arhor (Cajanus cajan (L.) Millsp.), and two tree species, kala koroi (Albizia procera (Roxb.) Benth.) and ipil ipil (Leucaena leucocephala (Lam.) de Wit) were tested. There were inhibitory effects of leaf litter on germination, shoot and root growth, leaf number, and collar diameter as well as a reduction of nodulation by legume crops (25–80% reduction). The extent of the effects was dependent on the proportion of leaf litter, the species and the type of traits. In contrast to shoot growth, the effect on root growth was more severe. No effect on germination was found with the agriculture crops while the two tree species showed reduced germination. The effect was greater in the presence of higher proportions of leaf litter mixed in soil while in some cases lower proportions stimulated growth. Not all species were suppressed; A. procera, C. cajan, V. unguiculata showed compatible growth while C. arietinum and L. leucocephala were found incompatible. This study provides evidence that E. camaldulensis has allelopathic potential under field conditions and a careful selection of associated crops in agroforestry systems is highly recommended. 相似文献
2.
利用随机区组试验评估了孟加拉国吉大港大学苗圃内的银合欢落叶对森林作物种白格、黄金檀和农田作物种长豇豆、鹰嘴豆和木豆的他感作用。结果表明,凋落叶诱导抑制作物的萌发和生长,该抑制作用依赖于萃取物浓度、凋落物及受体物种类型。萃取物浓度越高则他感作用越强。受体植物的生长响应随应用的凋落叶而变化。低浓度(10g·m-2)凋落叶对农田作物嫩芽生长有促进作用,而其他浓度的凋落叶则呈现明显的抑制作用,施用的凋落叶浓度越大抑制作用也越大。但是不同处理所表现出的抑制趋势并不均一,根系生长受到的影响大于嫩芽。图3表4参34。 相似文献
3.
观察了含羞草叶子提取物对孟加拉常见农作物种子萌发生长的抑制作用.实验在27-30℃的室温和24小时的光照条件下进行.结果表明：不同浓度的含羞草叶子提取物明显影响所选的植物种子根,茎和侧根的延长和生长.生物学测定表明：高浓度（50%-100%）的提取物有较强的抑制作用.而低浓度 （10%-25%） 的提取物的抑制作用较弱.研究还显示,提取物对植物根和侧根的抑制作用比对种子萌发和茎的生长抑制作用更显著. 相似文献
4.
Nutrient release from plant residues can be manipulated as per crop demand through several approaches. A pot study was conducted
to study the influence of incorporation of leaf litter of poplar (Populus deltoides), eucalypt (Eucalyptus hybrid) and dek (Melia azedarach) inoculated with cellulolytic fungus culture (Aspergillus awamori) on the nutrition and biomass of wheat (Triticum aestivum, cv. PBW 343) in loamy sand and sandy loam soils. The residual effect of leaf litter after wheat harvest was studied on sorghum
(Sorghum bicolor, cv. Punjab Sudax Chari 1). The treatments consisted of a control (no leaf litter) and three uninoculated as well as inoculated
leaf litter levels of tree species–0.15%, 0.30% and 0.45% (w/w, dry weight basis). A uniform dose of N, P and K @ 50, 11 and
10 mg kg−1 soil, respectively from inorganic fertilizers was applied to all the treated pots. Straw and grain yield, and nutrient content
of wheat increased with increasing level of uninoculated or inoculated leaf litter in both the soils. The inoculated leaf
litter augmented the yield and nutrient content of crop significantly (P < 0.05) as compared to the corresponding uninoculated treatments. Poplar and dek leaf litter produced higher wheat yield,
plant nutrient content and available nutrients in soil after wheat harvest than eucalypt leaf litter. Dry matter yield of
sorghum raised on residual fertility increased significantly with increasing levels of leaf litter application. The comparative
responses in yield and nutrient content of crops were higher in loamy sand than in the sandy loam soil. The study shows the
beneficial influence of use of cellulolytic microorganisms on enhancement in decomposition and nutrient release from litterfall
of tree species. 相似文献
5.
G. M. A. Iqbal S. M. S. Huda M. Sujauddin M. K. Hossain 《林业研究》2007,18(3):226-230
A study was carried out to determine the influence of different types of sludges （municipal, industrial and residential） on field germination, growth and nodulation of L. leucocephala seedlings in the nursery. Before sowing of seeds, different combinations of sludges were incorporated with the nutrient deficient natural forest soils. Field germination, nodulation status and physical growth parameters of seedlings （shoot and root length, vigor index, collar diameter, leaf number, fresh and dry weight of shoot and root and total dry biomass increment） were recorded after three and six months of seed sowing. Field germination, nodulation status and growth parameters were varied significantly in the soil amended with sludges in comparison to control. The highest number of nodule was recorded from soil amended with residential sludge （ 1：1 ） and highest fresh and dry nodule weight was also found from the same combination in both three and six month old seedlings. In case of growth parameters, the highest growth was recorded from soil and residential sludge （ 1：1 ） combination compared to control. From the study, it can be recommended that soil amended with residential sludge （ 1：1 ） provide better field germination, growth and nodule formation of L. leucocephala in degraded soil. 相似文献
6.
Romel Ahmed Mohammad Bela Uddin Mohammed Abu Sayed Arfin Khan Sharif Ahmed Mukul Mohammed Kamal Hossain 《林业研究》2007,18(4):301-304
An experiment was conducted to understand the growth inhibitory effects of aqueous extracts derived from Lantana camara L. （a globally recognized invasive alien weed） on six popular agricultural crops of Bangladesh. The test was conducted in sterilized petridishes with a photoperiod of 24 hours and an average temperature of 29℃. The effect of different concentrations ofL. camara leaf extracts were recorded and compared with control （i.e., distil water）. Result showed different concentrations of aqueous leaf extracts caused significant inhibitory effect on germination, root and shoot elongation and development of lateral roots of receptor crops. Bioassays also indicated that the inhibitory effect was proportional to the concentrations of the extracts and higher concentration had the stronger inhibitory effect whereas the lower concentration showed stimulatory effect in some cases. The inhibitory effect was much pronounced in root and lateral root development rather than shoot and germination. 相似文献
7.
Mountain birch (Betula utilis) is the most important treeline species in alpine forests of southwestern China. In order to understand the effects of future
warming on treeline birch, this study was conducted to examine the effects of experimental warming on leaf phenology, growth
and gas exchange of B. utilis saplings using the open top chamber (OTC) method in a treeline ecotone of eastern Tibetan Plateau. The OTCs enhanced daily
mean air temperature by 2.9 K throughout the growing season. Conversely, soil moisture within the OTCs on average declined
by 3% over the experimental period. Experimental warming did not affect the timing of bud break, although treeline birch saplings
growing in the OTCs manifested later leaf abscission, resulting in longer leaf life span. Artificial warming significantly
accelerated the leaf and shoot growth rates of treeline birch saplings, resulting in larger leaf area and longer shoot elongation
late in the growing season. Moreover, experimental warming significantly reduced the leaf fluctuating asymmetry (FA) and tended
to increase specific leaf area (SLA). Moreover, elevated temperatures significantly enhanced the transpiration rate (E), stomatal conductance (g
s), maximum net assimilation rate (A
max), dark respiration rate (R
d) and apparent quantum yield (AQY) but did not influence the light compensation point (LCP) and light saturation point (LSP)
of treeline birch saplings. Taken together, our results indicated that short-term experimental warming markedly altered structural/functional
leaf traits and enhanced photosynthetic capacity of treeline birch saplings; such positive responses in treeline birch would
be favorable for the growth of this species under future warmer world. 相似文献
8.
Time of pruning application and mixing prunings of varying qualities could be important management options to increase the rate of nitrogen recovery from multipurpose-tree prunings that are used as a source of nitrogen to crops. A field experiment was conducted in the semiarid zone of Zimbabwe to test this hypothesis, using prunings of calliandra (Calliandra calothyrsus) and leucaena (Leucaena leucocephala), alone and in mixtures, and maize (Zea mays) as the test crop. Time of pruning application significantly improved N uptake, N recovery, and grain yield of maize. Applying prunings of calliandra at maize planting was significantly better in terms of N uptake, N recovery, and grain yield than applying them four weeks after planting. However, with leucaena, time of prunings application had no significant effects on N recovery. Mixing prunings of leucaena and calliandra had no effect on maize N uptake, N recovery, and grain yield. Split application of available prunings during the crop growth cycle had no effect on N recovery compared to one-time application of entire amounts of prunings at planting. 相似文献
9.
The potential allelopathic effect ofCupressus lusitanica, Eucalyptus globulus, E. camaldulensis andE. saligna on seed germination, radicle and seedling growth was investigated with four crops:Cicer arietinum (chickpea),Zea mays (maize),Pisum sativum (pea) andEragrostis tef (teff). Aqueous leaf extracts of all the tree species significantly reduced both germination and radicle growth of the majority of the crops mostly starting from concentrations of 1% or 2.5%. The shoot and root dry weight increase of the crops was significantly reduced after 10 weeks treatment with leaf extracts. Among the four crops, chickpea and teff were most susceptible with respect to germination, and teff with respect to growth. From the overall data the leaf extracts of the four tree species can be arranged according to increasing allelopathic potential:C. lusitanica, E. globulus, E. saligna andE. camaldulensis. It is suggested that the planting ofE. camaldulensis andE. saligna in integrated land use systems should be minimized, whereas the use ofC. lusitanica andE. globulus seems less environmentally damaging in this respect. 相似文献
10.
Agroforestry systems based on poplar (Populus deltoides) are becoming popular in eastern and northern parts of India. Therefore studies on the structure and function of the systems
are important. The investigations included allometric equations for above- and belowground tree components, crop and plantation
floor biomass and litter fall estimation at Pusa, Bihar, India. Biomass, floor litter mass, litter fall and net primary productivity
(NPP) of plantations increased with an increase in age of trees whereas, crop biomass for any specific crop interplanted with
poplar decreased with the age of the plantation. The total plantation biomass increased from 12.08 to 90.59 Mg ha−1 and NPP varied from 5.69 to 27.9 Mg ha−1 year−1. The biomass accumulation ratio ranged from 2.1 to 3.2. Total annual litter fall was in between 1.95 and 10.00 Mg ha−1 year−1, of which 92–94% was contributed by leaf litter. Compartmental models were developed for dry matter distribution in agroforestry
systems involving young (3-year-old) and mature (9-year-old) poplar trees interplanted with various crops, the crops being
grown in two rotations maize (Zea mays) – wheat (Triticum aestivum) – turmeric (Curcuma domestica) and pigeonpea (Cajanus cajan) – turmeric. This study substantiates the potential of Populus deltoides G3 under agroforestry combinations. 相似文献
11.
[目的]研究外源性氮和磷对马占相思凋落叶的分解速率、分解过程中N、P、K含量和土壤生化特性的影响,以便为森林土壤养分管理提供参考。[方法]以广东省云勇林场马占相思林下凋落叶为试验材料,采用尼龙网袋分解法,设置对照(CK)、施N(10 g·m~(-2))、施P(5 g·m~(-2))、施N+P(N 10 g·m~(-2)+P 5 g·m~(-2))4种处理,每隔3个月取样1次,并测定凋落叶残留量和N、P、K含量。[结果]表明:施N、P和N+P处理对马占相思凋落叶的分解均为促进作用。各处理马占相思凋落叶的N含量在分解过程中大致保持稳定,施P和N+P处理的凋落叶P含量在分解过程中总体呈波动性上升,而各处理的凋落叶K含量变化规律不明显。施N、P和N+P处理提高了马占相思林土壤的有机质和全N含量,促进脲酶、磷酸酶及过氧化氢酶的活性。[结论]施N、P和N+P处理促进了马占相思凋落叶的分解,有利于马占相思林的养分循环。 相似文献
12.
K. G. Macdicken K. Hairiah A. Otsamo B. Duguma N. M. Majid 《Agroforestry Systems》1996,36(1-3):131-149
Imperata is shade-intolerant, although little is known of the relative roles of competition for light, water and nutrients in suppressing its growth. Shading of Imperata results in reduced carbohydrate storage, reduced rhizome and tuber-bulb production, reduced shoot dry weight, increased susceptibility to competition, increased susceptibility to herbicides and decreased vigor/regeneration. Herbaceous cover crops in the genera Calapogonium, Crotoleria, Mucuna and Pueraria have been shown to effectively suppress Imperata growth and can be used to prevent and in some cases eradicate Imperata. Tree fallows with fast-growing species such as Sesbania sesban, Acacia nilotica and Leucaena leucocephala can improve soil physical and chemical properties and suppress weed growth. Forest plantations have been successfully used, particularly with the use of moderate to high tillage, weeding and fertilizer inputs to suppress Imperata growth. These plantations produce marketable wood and reclaim the site for other uses. Additional research is needed to evaluate the specific nature of competition and allelopathic effects from Imperata. Continued evaluation of tree species and provenances for Imperata suppression, forms of tillage after woody fallow crops and the constraints to adoption of cover crops and trees as Imperata control measures are also needed. 相似文献
13.
《Journal of Sustainable Forestry》2013,32(3-4):95-118
Abstract Rates of litter decomposition and nutrient release from litter provide valuable information on the capacity of different tree species to replenish soil nutrients in degraded tropical areas. Leaf litter decomposition, leaf litterfall, plantation floor leaf litter, and mulch performance were studied for four indigenous timber species, Virola koschnyiWarb, Dipteryxpanamensis(Pittier) Record and Mell, Terminalia amazonia(J.F. Gmel.) Exell., and Albizia gua-chapele(H.B.K.) Little, grown in mixed and monospecific plantations in the Atlantic humid lowlands of Costa Rica. Terminalia amazonialitter decomposed the fastest: no litter remained after 6 months. After 12 months, D. panamensis, A. guachapele, and the mixed litter decomposed completely, while 15% of the original weight of V. koschnyilitter remained. Differences in decomposition rates were closely related to leaf nutrient content. Total annual leaf litterfall was highest in T. amazonia(872.9 g/m2), followed by D. panamensis, V. koschnyi, and the mixed plots. A. guachapelehad the lowest leaf litterfall (236.0 g/m2). The highest plantation-floor leaf litter was found in V. koschnyiand D. panamensis.Both litterfall and plantation-floor litter accumulation fluctuated least in the mixed plots. A. guachapeleand D. panamensismulch most positively affected maize seedling growth, followed by the mixed mulch. Recommendations are drawn from the results to suggest species choice for sustainable land management in the region. 相似文献
14.
Litterfall and decomposition were studied in agroforestry systems involving large cardamom (Amomum subulatum) and mandarin (Citrus reticulata) in the Sikkim Himalaya, India. There were stands with N2-fixing trees (Alnus nepalensis over large cardamom, and Albizia stipulata over mandarin agroforestry) or without them (native non-symbiotic mixed tree species) in both systems. The total annual litter (litter + crop residue) production was higher in the Alnus-cardamom than in the forest-cardamom stand and in the mandarin than in the Albizia-mandarin stand. The ratio of litter production to floor litter was higher in the N2-fixing stands than in the non-N2-fixing stands, indicating a faster litter turnover in the former. Tree litterfall occurred throughout the year, but with marked peaks during November to April. Total soluble polyphenolics of fresh litter were higher in N2-fixing species than in mixed tree species and crops. Half-life values for ash-free mass were shortest in the leaves of N2-fixing species. N loss was higher from N2-fixing Alnus and Albizia leaves, whereas P loss was faster and nearly equal in Alnus leaf litter and cardamom residue in cardamom, and Albizia leaf litter and crop residue in mandarin agroforestry systems. The P turnover in N2-fixing Alnus and Albizia twigs was faster than in the twigs of mixed tree species. The N2-fixing tree species increased the N and P cycling through production of more above-ground litter and influenced greater release of these nutrients. 相似文献
15.
Three multipurpose tree species (MPTS)-leucaena (Leucaena leucocephala), sesbania (Sesbania sesban var. nubica) and pigeonpea (Cajanus cajan) were pruned at a height of 60 cm above the ground every two months, and resulting plant biomass was incorporated into the soil as green manure. For comparison, maize (Zea mays) stover was also incorporated into some plots, while some other plots were left fallow. Varying quantities of plant biomass which were incorporated into the soil over a period of 12 months caused large changes in major soil plant nutrients, and it substantially improved soil fertility. To test for improved soil fertility, test crops of maize and beans (Phaseolus vulgaris) were grown on the plots after six biomass incorporations of 4806, 13603, 16659 and 7793 kg. ha–1yr–1 for pigeonpea, sesbania leucaena and maize, respectively. Responses of the test crops indicated that sesbania and leucaena green manures improved maize stover, cobs and grain yields; and bean haulms and grain yields by 77.6% when compared to fallow plots. Residual effects of green manures still resulted in significant (P < 0.05) yield differences in the test cropin the third testing season. Economic significance of green manures in increasing food crop yields to small scale farmers is discussed. 相似文献
16.
Soil microarthropod populations under natural and planted fallows in southwestern Nigeria 总被引：1，自引：0，他引：1
Microarthropods, such as soil mites (Acari) and springtails (Collembola), with body width between 0.08 mm and 0.5 mm play important roles in soil fertility maintenance through their regulatory activities in decomposition and nutrient turnover. Observations were made at IITA, Ibadan, southwestern Nigeria to evaluate the effects of natural regrowth of vegetation — mainly the shrub Chromolaena odorata — and three planted woody fallow species (Acacia leptocarpa, Senna siamea, and Leucaena leucocephala) on soil microarthropods in a degraded Alfisol. Populations of soil microarthropods were higher in the rainy season than the dry season, and populations were greater under natural fallow than for continuous cropping with maize (Zea mays) and cassava (Manihot esculenta). Populations of soil microarthropods were comparable under leucaena and natural fallow, but populations in the rainy season were 38% higher under senna than natural fallow and 36% higher under acacia than natural fallow. Regression analysis indicated that soil microarthropod population under fallow species was positively correlated with the lignin contents of leaf litter.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
17.
Kathryn Corio Amy Wolf Michael Draney Gary Fewless 《Forest Ecology and Management》2009,258(7):1059-1066
The invasion of exotic earthworms in previously earthworm-free northern deciduous forests has been linked to the disappearance of forest floor litter, declines in plant species richness, and the development of monotypic stands of Carex pensylvanica. However, the impact of exotic earthworms on the regeneration of trees and understory plants is largely unknown. We examined the relationships between earthworm density, plant species richness, leaf litter accumulation, number of tree (Acer) seedlings, and cover of C. pensylvanica at 14 sites in mesic hardwood forests of the Chequamegon-Nicolet National Forest in northern Wisconsin. Earthworm biomass, especially of the genera Lumbricus, Aporrectodea, and Octolasion was negatively associated with leaf litter mass and number of Acer seedlings. Nine plant species, including two spring ephemerals (Dicentra cucullaria and Osmorhiza claytonii), a sedge (Carex deweyana), and an invasive mint (Galeopsis tetrahit) were negatively correlated with exotic earthworm densities. Dryopteris intermedia and Allium tricoccum, on the other hand, were associated with high earthworm densities. The activities of exotic earthworms appear to have significant impacts on Acer regeneration and the persistence of many herbaceous plants. Our findings suggest that the effects of exotic earthworms on litter mass are strongly related to the observed effects on species composition. Sensitive species can be used as indicators of high and low earthworm densities and might be useful for identifying forests of high conservation value where future invasions of exotic earthworms should be prevented. 相似文献
18.
Litterfall,litter decomposition and the use of mulch of four indigenous tree species in the Atlantic lowlands of Costa Rica 总被引：1，自引：0，他引：1
Litterfall, forest-floor litter biomass and nutrients, short-term litter decomposition and the effects of leaf mulches on initial growth of maize were studied for four indigenous tree species with agroforestry potential:Stryphnodendron microstachyum Poepp. et Endl.(S. excelsum), Vochysia ferruginea Mart,Vochysia guatemalensis Donn. Sm. (V. hondurensis) andHyeronima alchorneoides (O), growing in a young experimental plantation in the Atlantic humid lowlands of Costa Rica. Total annual leaf litterfall was higher inV. ferruginea plots, followed byS. microstachyum, V. guatemalensis andH. alchorneoides; all with values comparable to those reported for other tree species grown in agroforestry combinations in humid tropical regions. Forest-floor litter accumulation was highest underV. ferruginea andV. guatemalensis. Both litterfall and forest-floor litter material had similar patterns in nutrient concentrations: N was higher inS. microstachyum, Ca was higher inV. guatemalensis, K was higher inH. alchorneoides; Mg was higher inV. guatemalensis andH. alchorneoides; H. alchorneoides andV. guatemalensis had the highest P.V. ferruginea litter decomposed more slowly, whileS. microstachyum apparently decomposed faster than the other species. The twoVochysia species showed increases in N and P concentration in decomposing litter after seven weeks in the field,H. alchorneoides showed an increase in litter N and a decrease in litter P, andS. microstachyum showed a net decrease in both N and P over the same time period. The patterns found in the litter bag study were confirmed by results obtained in a tethered-leaves experiment.S. microstachyum andV. ferruginea litters lost more weight when mixed in a 11 proportion than either of them alone. Maize seedlings growing in plots mulched withS. microstachyum andH. alchorneoides leaves showed greatest initial growth, confirming patterns found in decomposition and nutrient release studies. The results show that these species could be used in agroforestry combinations with different advantages according to the specific objectives desired, whether these are soil protection, nutrient recycling, or enhancement of the growth of associated crops. 相似文献
19.
Observations on the growth performance, rooting behaviour and distribution of fine roots of five tree species viz., Bauhinia purpurea, Grewia optiva, Eucalyptus tereticornis, Leucaena leucocephala and Ougeinia oojeinensis (Family: Papilionaceae) are being presented here. Roots were exposed at the time of planting, 6 months, 16 months, and 28 months after planting. Total root weight and root volume were highest in Eucalyptus tereticornis and lowest in Bauhinia purpurea. Major part of the root system confined within 90–120 cm soil depth in case of Bauhinia purpurea, Grewia optiva and Leucaena leucocephala but Eucalyptus tereticornis and Ougeinia oojeinensis strike their roots to deeper depths. Bauhinia purpurea had its roots evenly distributed down to 120 cm. In general, the vertical distribution of fine roots (< 2 mm in diameter) of the five species indicate that more the depth, fewer the number of roots. The observations on soil binding capacity, indicated that Ougeinia oojeinensis had the maximum and Eucalyptus tereticornis had the minimum binding value. Due to leaf shading and other litter fall significant increase of nutrient components in soils under the tree canopies has been observed. The study indicates that bulk of the roots of the five tree species are found near the surface, but observation on soil moisture and nutrient content does not indicate variation under the tree canopies and in open, hence there may not be root competition in initial years of plantation.Authorised for publication by the Institute as contribution No.3311/239/89. 相似文献
20.
The effect of naphthaleneacetic acid (NAA), benzylaminopurine (BAP), L-glutamine (L-gln), and combinations of these substances on mycelial growth of Phaeolus schweinitzii was studied in vitro. NAA (1 mg × 1?1), L-gln (500 mg × 1?1) and a combination of NAA with L-gln inhibited the growth of fungal mycelium. BAP (1 mg × 1?1) enhanced the inhibitory effect of NAA while in combination with L-gln it reduced the inhibitory effect of L-gln. 相似文献