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1.
内蒙古磴口河套地区４ａ灌溉试验表明：（１）采用目前生产上的１５０００－２２５００ｍ＾３／（ｈｍ＾２．ａ）灌溉量，使土壤表层的含盐量由灌溉前的０．５ｇ／ｋｇ上升到１．０ｇ／ｋｇ以上。（２）按合理灌水定额公式计算，年灌溉量以７５００ｍ＾３／ｈｍ＾２为宜；最佳含水率下限１９．９９％；在灌水期地下水位为１．９７－３．０２ｍ，变幅１ｍ左右（３）年灌水次数应控制在８－１２次。 相似文献
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《技术与市场》2001,(4):8
目前，人参种植基地在起参以后，土壤的地力大受影响，肥力大大降低，尤其是微量元素会减少很多，致使再无法种植人参或其它木草植物，这种状态一般要持续几年才能得到恢复。人参土壤调节剂，完全可以改善人参种植土壤。它的配制成分如下： １．微量元素成分：氮、磷、钾、铁共计４０g～１００ｇ； ２．生物稀释剂成分：木粉、草粉或树叶、烟杆粉混合物共计３７０ｇ～５００ｇ； ３．广谱型消毒杀菌药：硫酸铜１５ｇ～３０ｇ； ４．水：１５０ｇ～３００ｇ， 在微量元素中氮、磷、钾、铁各含量为：２１ｇ～４０ｇ、２５ｇ～４５ｇ、２ｇ～１０ｇ、２ｇ～５ｇ。 其工艺流程是：生物稀释剂→热提取→合成→反应→粉碎→搅拌→化验→包装。 囊系人：段在民导 地址：吉林省自山市特产局 的钢：１３４３００人参土壤调节剂 相似文献
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毛白杨盐碱地扦插育苗技术洛益民，常彦周（咸阳市林科所）在咸阳市东郊渭河北岸的盐碱滩地（土壤含盐碱量为８．２μｇ／ｇ），进行毛白杨扦插育苗试验，１９９１年平均成活率９２％，当年生平均首高２．４１ｍ，最高３．０４ｍ；１９９２年平均成活率８５％左右。我们的... 相似文献
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本文对８２０３号和木材基本性质进行了测定，其结果：基本密度０．３４５ｇ／ｃｍ＾２；气干密度０．４０ｇ／ｃｍ＾２；干缩系数０．３６；纤维长度１３３７μｍ，长宽比５１；综纤维素含量８０％。８２０３号杨适宜制作各种板材及建筑用材，同时也是较理想的制浆、造纸材种。 相似文献
5.
两年田间小区试验表明：在粘壤土条件下，森草净有效成份１ｇ／６６７ｍ＾２土壤处理可在一个月内有效地控制果园草害，防效达９０％￣１００％，森草净有效成份１．５、３．０、６．０ｇ／６６７ｍ＾２土壤处理可在７０ｄ内控制杂草，防效在７５％￣１００％。上述处理对鸭趾草和多年生双子叶杂草防效较差，只有２０％￣７０％。当果园杂草２０￣２５ｃｍ，森草净有效成份４．０和６．０ｇ／６６７ｍ＾２茎叶处理可有效地控制杂草生 相似文献
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杉木光皮桦混交林效益的调查研究 总被引：2，自引：0，他引：2
对桂西北杉木光皮桦混交林和杉木纯林的对比研究表明,３５年生杉桦混交林的立木蓄积量为４４１．０８７ｍ＾３／ｈｍ＾２,比杉木纯林高３．６％。混交林枯枝地层现存量及其Ｎ、Ｐ、Ｋ、Ｃａ、Ｍｇ五种元素的积累量分别为１３．１８ｔ／ｈｍ＾２和２９９．５ｋｇ／ｈｍ＾２,分别比杉木纯林高９．７％和６９．９％。８混交林地（０～１００ｃｍ）土壤容重为０．８１～１．２２ｇ／ｃｍ＾３,比杉木纯林低１．０％～８．０％,而土壤孔隙度,通气度和持水量分别比杉木纯林高２．０％～３．９％。土壤有机质、全氮、水解氮、有效磷和速效钾分别比杉木纯高５．５％～４９．８％。 相似文献
9.
杉木福建柏混交林效益研究 总被引：5，自引：1，他引：4
通过对杉木福建柏混交林中单株生物量组成、土壤团粒组成、土壤孔隙和水分状况的研究分析， 结果表明： 混交林中杉木每ｈｍ ２ 蓄积量是杉木纯林的１６９ 倍， 细根量是杉木纯林的１５ 倍； 与纯林相比， 混交林中０～２０ｃｍ 土层＞ ０２５ｍ ｍ 水稳性团聚体高出９０１％ ； 结构体破坏率低１５８２％ ； 有机质和水解性 Ｎ 含量分别高０２４５％ 和１３１×１０－ ６； 毛管孔隙、非毛管孔隙、总孔隙高００９％ 、０９１％ 、１００％ ， 土壤容重低００５７ｇｃｍ － ３； 最大持水量、最小持水量、毛管持水量分别高３００％ 、３５０％ 、２０４％ ； 混交林４０ｃｍ 土层含水量也比纯林大１５５ｔ·ｈｍ － ２。由于混交林的结构较为合理，能一定程度改善土壤理化性质、提高林分生产力，是一种值得推广的造林模式。 相似文献
10.
橡胶间种砂仁、咖啡对林地枯落物、腐殖质和土壤性质的影响调查结果表明，作物的间种明显提高了林地枯落物的积累量，橡胶＋砂仁、橡胶＋咖啡、纯橡胶林分别为３６５３．５、２８６１．１、１９３４．３ｋｇ／ｈｍ２；土壤有机质含量随之提高，０～５ｃｍ土层有机质含量分别为４４．３０３、３２．９０５、２６．８４０ｇ／ｋｇ；三种胶园种植模式土壤腐殖质组成均以富里酸为主，间种砂仁、咖啡利于胡敏酸和胡敏素的形成；土壤性状因间种而得到改良，２～５ｍｍ最为良好稳定的多孔性团粒结构含量分别为３０．８９％、１３．６６％和１２．１３％。以橡胶间种砂仁对土壤肥力的提高最为理想。 相似文献
11.
《Scandinavian Journal of Forest Research》2012,27(5):427-435
In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads. 相似文献
12.
《Scandinavian Journal of Forest Research》2012,27(3):206-217
The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage. 相似文献
13.
Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and
also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the
amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter
bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K
was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed
significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week−1 for leaves and from 0.0225 to 0.0633 week−1 for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed
during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly
between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species
provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient
enrichment capacity and slower decomposition rates which would minimize leaching losses.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
14.
《Scandinavian Journal of Forest Research》2012,27(2):118-130
The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions. 相似文献
15.
Steven Maranz Amadou Niang Antoine Kalinganire Djeneba Konaté Bocary Kaya 《Agroforestry Systems》2008,72(3):231-239
Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional
data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral
contents and B1 and B2 vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising
germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B1 88 mg 100 g−1, B2 187 mg 100 g−1, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal
diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties
to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations. 相似文献
16.
《Wood material science & engineering》2013,8(2):76-84
Abstract Wood in general and wooden studs in particular are often distorted owing to uneven shrinkage during the drying process in the sawmill. Twist is often the most detrimental of all types of distortion, and it is caused by spiral grain in combination with variations in moisture content. For sawmills, the objective is to produce dried, straight boards, and one method of dealing with boards with excessive spiral grain is to sort them out and then dry them in a pretwisted position to obtain straight boards after drying. A model using the finite element (FE) method for the simulation of drying twist distortions was first calibrated against laboratory experiments in which boards were dried with and without restraints and pretwists. After the calibration, the FE results were compared with industrial test results for boards that were dried without restraints or with restraints with zero pretwist, i.e. straight restraints. The FE model used an elastic–ideally plastic material model to obtain permanent deformations. The calibration was to set the yield stresses so that there was a good match between FE results and results from the laboratory experiments. The comparison between the industrial test results and the FE results showed that the FE model is capable of realistic simulations of drying boards with and without restraints and presumably also pretwists. 相似文献
17.
Astra Zaluma Lauma Bruna Darta Klavina Natalija Burnevica Kristine Kenigsvalde Andis Lazdins Talis Gaitnieks 《Forest Pathology》2019,49(6)
Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered. 相似文献
18.
《Scandinavian Journal of Forest Research》2012,27(1):53-61
This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland. 相似文献
19.
《Scandinavian Journal of Forest Research》2012,27(1):15-27
The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions. 相似文献
20.
本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。 相似文献