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1.
云南干热河谷旱坡地南洋樱植物篱水土保持效益研究 总被引:2,自引:0,他引:2
对云南元谋干热河谷旱坡地水土流失和土壤退化严重的地区,引进豆科速生树种南洋樱,以30 cm×40 cm株行距、品字形双行等高栽植快速形成植物围篱。结果表明,南洋樱植物篱在元谋干热河谷旱坡地生长良好,并且在种植3年间,治理区径流发生次数明显减少,年径流模数减少了29.13×104m3/km2,减少率76.90%;土壤年退化减少12 986.8 t/km2,减少率76.02%。研究区降水量与径流量间者的相关系数由建植篱前的显著相关变为不显著;有机质和钾流失减少量高达3 111.64 kg/hm2和3276.57 kg/hm2。南洋樱植物篱在控制旱坡地水土流失、减少土壤侵蚀和改善土壤养分等效益显著。 相似文献
2.
The heart wood of Gliricidia sepium stem yielded stigmastanol glucoside (1) and 3',4'-dihydroxy-trans-cinnamic acid octacosylester 2, along with three other known constituents. 相似文献
3.
Nutrient stocks of short-term fallows on a high base status soil in the humid tropics of Papua New Guinea 总被引:1,自引:0,他引:1
Alfred E. Hartemink 《Agroforestry Systems》2004,63(1):33-43
In order to understand nutrient dynamics in tropical farming systems with fallows, it is necessary to assess changes in nutrient
stocks in plants, litter and soils. Nutrient stocks (soil, above ground biomass, litter) were assessed of one-year old fallows
with Piper aduncum, Gliricidia sepium and Imperata cylindrica in the humid lowlands of Papua New Guinea. The experiment was conducted on a high base status soil (Typic Eutropepts), and
in Papua New Guinea such soils are intensively used for agriculture. Soil samples were taken prior to fallow establisment
and after one year when the fallows were slashed and above ground biomass and nutrients measured. The above ground and litter
biomass of piper was 13.7 Mg dry matter ha-1, compared to 23.3 Mg ha-1 of gliricidia and 14.9 Mg ha-1 of imperata. Gliricidia produced almost 7 Mg ha-1 wood. Total above ground biomass returned to the soil when the fallows were slashed was the same for piper and gliricidia
(8 Mg ha-1). Gliricidia accumulated the largest amounts of all major nutrients except for K, which was highest in the above ground piper
biomass. Imperata biomass contained the lowest amount of nutrients. The largest stocks of C, N, Ca and Mg were found in the
soil, whereas the majority of P was found in the above ground biomass and litter. Almost half of the total K stock of piper
and gliricidia was in the biomass. During the fallow period, soil organic C significantly increased under gliricidia fallow
whereas no net changes occurred in piper and imperata fallows. The study has shown large differences in biomass and nutrient
stocks between the two woody fallows (piper, gliricidia) and between the woody fallows and the non-woody fallow (imperata).
Short-term woody fallows are to be preferred above grass (imperata) fallows in the humid lowlands of Papua New Guinea because
of higher nutrient stocks. 相似文献
4.
Farming systems that minimize the rate of soil degradation and optimize food crop yields are needed to sustain soil productivity
on sloping, acid, infertile soils in the humid tropics. Research was conducted on two Oxisols with slopes ranging from 22
to 30% to evaluate the performance of several contour hedgerow systems, with and without the addition of 60 kg N ha−1 per
crop, on rice (Oryza sativa) and maize (Zea mays L.) production. Contour hedgerows were double rows of the tree legume Gliricidia
sepium (G); Gliricidia and the native grass Paspalum conjugatum (GPas); Gliricidia and an exotic fodder grass Penisetum purpureum
(GPen); double rows of Penisetum (Pen); and a conventional open field (C) farming system without hedgerows. Gliricidia prunings
and all crop residues were applied to the soil surface in the alleys, but Penisetum was harvested. Food crop yields in all
hedgerow treatments tended to be less than the Control for the first two years, presumably due to the displacement of land
planted to the food crop. In the third and the fourth years, the rice and maize yields of Treatments G and GPas exceeded the
Control, most consistently when N was not applied. Penisetum reduced food crop yields regardless of N application presumably
due to nutrient removal in the fodder. The results indicate that Gliricidia in a contour hedgerow increases food crop yield
on strongly acid Oxisols by recycling nutrients and partially supplementing the N demand by the food crops.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
5.
The potential of allye cropping systems to sustain a high productivity with low external inputs and the reduction of maize/weed competition through weed suppression in different alley cropping and sole-cropped mulched systems was studied in Costa Rica at CATIE. Data were recorded eight years after establishment of the experiment. Plant residues ofErythrina poeppigiana trees (10 t/ha dry matter) planted at 6 by 3 m reduced weed biomass by 52%, whileGliricidia sepium trees (12 t/ha dry matter) planted at 6 by 0.5 m reduced weed biomass by 28%, in comparison to controls.Erythrina had a considerable impact on grass weeds, whileGliricidia reduced the incidence of some dicot weeds. Weed competition significantly reduced maize yield in all systems. Nevertheless weed suppression contributed to the higher maize grain yield underErythrina andGliricidia alley cropping of 3.8 t per hectare as opposed to the unmulched control yield of 2.0 t per hectare. 相似文献
6.
Arnoud Budelman 《Agroforestry Systems》1988,6(1-3):137-145
The performance of the leaf mulches ofLeucaena leucocephala, Gliricidia sepium andFlemingia macrophylla in weed control has been tested in two trials. The length of the period during which a mulch layer yields significantly less
weedbiomass compared to the control plots is called the ‘effective life-span’ of the mulch.
Of the three mulch materials only that ofF. macrophylla shows promise in retarding weed development.
In the second trialF. macrophylla leaf mulch was applied at rates of 3, 6 and 9 tons dry matter per ha. The effective lifespan of a mulch layer of 3 tons is
between 12 and 13 weeks. The treatments 6 and 9 tons have effective life-spans of over 14 weeks.
For moderate quantities (up to 5 tons of dry leaf mulch per ha) the effective life-span is estimated at about a 100 days.
The value of mulching in weed control is limited to the control of weed species that multiply by seed. Regrowth originating
from roots or stumps from former vegetation is unlikely to be checked by a mulch layer.
The subject of this paper is part of a broader study, presently conducted in Southern Ivory Coast, on the production, agronomical
value and use in alley-cropping systems of the species mentioned in the title of the paper. A final report is scheduled for
publication in 1988. 相似文献
7.
Spice crops agroforestry systems in the East Usambara Mountains,Tanzania: growth analysis 总被引:1,自引:0,他引:1
A scarcity of cultivation land calls for more intensive and productive land use in the East Usambara Mountains in NE Tanzania.
Spice crops could generate cash in higher parts of the mountains, but the present cultivation methods are depleting the valuable
forest resources. The trial was established at the end of 2000 to find out how the two popular cash crops, cardamom (Elettaria cardamomum (L.) Maton.) and black pepper (Piper nigrum L.), normally grown under the natural forest, will produce in intensive agroforestry system with two multipurpose farm trees,
Grevillea robusta A.Cunn. and nitrogen fixing Gliricidia sepium Jacq. Results from 6 years showed that cardamom produced better with grevillea than in natural forest; 5.5 times more in
the fourth year than the average in the area. The Land Equivalent Ratios for black pepper and cardamom showed that pepper
intercropped with grevillea produced 3.9 times more than in monoculture whereas cardamom intercropped with grevillea and pepper
produced 2.3 times more than in monoculture. Gliricidia improved the nitrogen and organic matter content of the soil over
the levels found in natural forest. Soil acidity was, however, preventing the plants from using the available mineral nutrients
more effectively. 相似文献
8.
Field studies carried out in a forest transition site on a tropical Alfisol in southwestern Nigeria, show that shading by
gliricidia (Gliricidia sepium (Jacq.) Steud) and leucaena (Leucaena leucocephala (Lam.) de Wit) hedgerow species reduced density of speargrass (Imperata cylindrica (L.) Raeuschel) by 67% and 51%, respectively. Shoot biomass of speargrass decreased by 81% and 78% in gliricidia and leucaena
hedgerows, respectively. Reduction in speargrass rhizome biomass in gliricidia plots was 96% while rhizome reduction in the
leucaena plots was nearly 90%. Rhizome mortality was significantly higher in gliricidia plots than in leucaena and control
plots. The bulk of rhizomes was found between 10 cm and 20 cm of soil depth but rhizome did not penetrate further than 30
cm depth in the Alfisol in which this study was carried out. Gliricidia was better than leucaena hedgerow species in suppressing
speargrass. 相似文献
9.
Green manure applications in alley cropping systems often include twigs despite their potential to absorb (immobilize) nitrogen (N). To assess the impact of twigs on net N mineralization or immobilization from hedge row cuttings, we separated cuttings fromCalliandra calothyrsus andGliricidia sepium into leaf-only, twig-only, and mixed (leaf + twig) fractions and incubated them with moist soil in the laboratory. Soil extractable inorganic N did no differ among treatments after two weeks, but after four and eight weeks was greatest in leaf-only, and least in twig-only treatments. After two weeks, extractable N from the leaf-only treatment rose steadily, while that from the twig-only and mixed treatments was variable due to periods of net mineralization and net immobilization. The pattern of variation in mixed treatments paralleled that of twig-only, indicating that net immobilization in the mixture was largely caused by the presence of twigs. Extractable N from the mixture was somewhat lower than that predicted from the sum of leaf-only and twig-only treatments. We conclude that twigs in green manure reduce short-term N availability to associated crops in agroforestry systems. 相似文献
10.
Turnover of nitrogen-rich root nodules follows the pruning of legume trees, forming a potentially important yet little studied
way of N release to the soil. The effects of soil moisture, herbivory by soil mesofauna and microbial decomposition on the
disappearance rate of woody legume nodules was studied in two tree/grass forage production associations. Litter bags containing
nodules of Erythrina variegata L. (Papilionoideae: Phaseoleae) were incubated for four weeks in grass-covered alleys between Gliricidia sepium (Jacq.) Walp. (Papilionoideae: Robinieae) hedgerows, established on a deep alluvial Oxisol under a humid tropical climate
and on a shallow Vertisol under a subhumid tropical climate in Guadeloupe, French Antilles. Soil moisture was regulated by
irrigating or covering small plots from natural rainfall. Fine nylon mesh bags were used to study the rate of microbial decomposition,
and open-ended perforated cylinders were used to estimate nodule herbivory. The chemical traits, especially the lignin: nitrogen
ratio, of E. variegata and G. sepium nodules were similar (lignin: N 1.70 and 1.55, respectively), and suggest that the results are probably also applicable to
the G. sepium nodules in the associations. Both soil moisture and decomposing agent (microbes or mesofauna) had a significant effect on
the nodule disappearance rate, but soil type did not have any apparent effect. The nodule half-life varied from three to seven
days under different treatments. The N release rate from the nodules was high, with N half-life varying from three to five
days. Herbivory accounted for ca. 10% of total mass and N loss from nodules during the four-week field incubation period,
but its importance increased towards the end of the incubation, especially in Vertisol, after the most easily decomposable
part of the nodules had decayed. After pruning, the nodule N is released to soil more rapidly than from mulch.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献