污泥对苗圃生长的银合欢幼苗发芽和初期长势的影响_英文_

226 DOI: 10.1007/s11676-007-0046-4
Journal of Forestry Research, 18(3): 226–230 (2007)
Effects of sludge on germination and initial growth performance of Leucaena leucocephala seedlings in the nursery
G. M. A. Iqbal, S. M. S. Huda*, M. Sujauddin and M. K. Hossain
Institute of Forestry and Environmental Sciences, University of Chittagong, Chittagong-4331, Bangladesh
Abstract: 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. Keywords: Leucaena leucocephala; Sludge; Field germination; Seedling growth; Nodulation; Vigor index.
Introduction
Ipil ipil [Leucaena leucocephala (Lam) de Wit.] is a fast growing multipurpose tree species of the family Leguminosae (Mimosoideae). It is a large evergreen shrub or a small tree depending on its variety and the habitat in which it grows. The tree is native to Mexico and northern Central America and introduced to Indonesia, Philippines, Malaysia and other countries in South East Asia with varying degree of success (Luna 1996). Bangladesh Forest Department introduced L. leucocephala in 1977 from the Philippines for a trial plantation (Das 1985). It can produce nutritious forage, firewood, timber and rich organic fertilizer (Duke 1981). The wood has the potential to become a major source of pulp and paper, roundwood and construction materials (Anonymous 1980). The wood, leaves, twigs have a medicinal value as well as tannin. Due to its multipurpose utility and wide range of ecological amplitudes (especially suitable to Bangladesh Environment) L. leucocephala is being planted in different parts of Bangladesh by the government and other public and private sectors in different plantation programs, e.g. Agro-forestry, Community Forestry, Social Forestry, Village, Farm Forestry Program etc. (Khan et al. 2002). The species has potentiality in newly formed islands and coastal areas of the country where
Received: 2007-06-07; Accepted: 2007-06-25 Northeast Forestry University and Springer-Verlag 2007 Electronic supplementary material is available in the online version of this article at https://www.wendangku.net/doc/a03255377.html,/10.1007/s11676-007-0046-4 Biography: Gazi Mohammad Asif Iqbal (1983-) male, postgraduate student of Institute of Forestry and Environmental Sciences, University of Chittagong, Chittagong-4331, Bangladesh. *Corresponding Author: (E-mail: hudaifescu@https://www.wendangku.net/doc/a03255377.html,) Responsible editor: Hu Yanbo
need immediate plantations for suitability of soils and protecting the country from unexpected flood and other natural calamities (Alam et al. 2004). Sewage sludge, also referred as 'biosolids', is being used in agriculture/cropland as a fertilizer and an organic amendment to improve physical, chemical and biological properties of soil (Singh and Agrawal 2007; Sanchez-Monedero et al. 2004; Hossain and Miller 1994). The safe disposal of the sewage sludge is one of the major environmental concerns throughout the world (Singh and Agrawal 2007). Land application is commonly used in most municipalities (Selivanovskaya and Latypova 2006). Such application of sludge provides not only a means for sludge disposal but can also improve soil fertility and the physical properties of the soils (Peles et al. 1996; Ramachandran and D'Soura 1998; Gardiner et al. 1995; Jorba and Andres 2000). Disposal alternatives that have been tried so far include soil application, dumping at sea, landfilling and incineration (Sanchez-Monedero et al. 2004). The increasing cost of chemical fertilizers has reawakened interest in other sources of nutrients, including residential and industrial sludge. The main advantage of using sewage sludge is the soil enrichment at a lower cost that is possible with inorganic fertilizers (Hossain and Miller 1994). Generally sewage sludge is composed of organic compounds, macronutrients, a wide range of micronutrients, non-essential trace metals, organic micro pollutants and microorganisms (Singh and Agrawal 2007; Kulling 2001). The macronutrients in sewage sludge serve as a good source of plant nutrients and the organic constituents provide beneficial soil conditioning properties (Logan and Harrison 1995). Digested cake of sewage sludge contains dry solids (20–50%), organic matter (50%–70%), N (1.5%–2.5%), P (0.5%–1.8%), K (0.1%–0.3%), Ca (1.6%–2.5%) and Mg (0.1%–0.5%) (Byrom and Bradshaw 2001). Forested sites are increasingly receiving attention as potential sites for the disposal and biological recycling of both wastewater and sludges. These sites are potential for sludge disposal because

G.M.A. Iqbal et al. forests are typically located in the better drained areas and not subject to the periodic flooding occurring in alluvial agricultural lands. Moreover, as forests are not food chain crops, many of the public health concerns and land application regulations should not be as critical as those associated with agricultural sites (Cole et al. 1983). Fast growing tree species can be benefited from sludge application (Labrecque et al. 2006). Though much research has been done on the use of sewage sludge as crop fertilizers (Van den Berg 1993; Hue 1995; Merzlaya et al. 1995; Gardiner et al. 1995; Selivanovskaya et al. 1997; Selivanovskaya and Latypova 1999; Selivanovskaya and Latypova 2006), there is little study in case of L. leucocephala especially in soil conditions of Bangladesh. Thus this study is an attempt to find out the effect of sludges on field germination and growth performance as well as nodulation status of L. leucocephala seedlings.
227 periment for field germination test) and after completion of field germination only one seedling (best one) per polybag was maintained to observe the initial growth parameters of seedlings. Partial shade and covering was provided over the nursery to protect the seedlings from strong sunlight and rain. Proper care and maintenance were done from the starting time of sowing seed up to harvesting of seedlings. Watering, removal of weeds, grasses etc. were done regularly. Field germination was recorded daily from the date of seed sown and continued up to last field germination of the seed. The seedlings were allowed to grow for six months from the time of seed sowing. After three months, three seedlings from each replication of a treatment were randomly selected for measuring physical parameters of shoot and root length, collar diameter, leaf number, fresh and dry shoot and root weight, nodule number and their fresh and dry weight. For determining the seedlings dry weight, shoot and root were oven dried at 70C until the constant weight was obtained. Vigor index and total dry biomass increment (%) were also calculated by using the following formulae: Vigor index = Germination (%) × Seedling total length Total dry biomass increment (%) =
Total dry weight of the treatment - Total dry weight of the control treatment Total dry weight of the control treatment
Materials and methods
The experiment was carried out in the nursery of the Institute of Forestry and Environmental Sciences, University of Chittagong, Chittagong, Bangladesh. The seeds were collected from Bangladesh Forest Research Institute. Degraded soils were collected from hilly sites and were sieved (<3 mm) to obtain a uniform soil size. The brown hilly soils are sandy loam to sandy clay loam, moderately to strongly acid and poorly fertile with pH<5.5, organic matter<2.0%, CEC<10 me/100g and BSP<40% (Osman et al. 2001). Sludges were collected from municipal, industrial and residential sites of Chittagong city and dried properly. The dried sludges were also sieved (<3 mm) to make them free from root splinters and other foreign materials. Then the soil and sludges were mixed thoroughly at different ratios. A Complete Randomized Design (CRD) was adopted for a total of seven treatments including a control treatment and three replications for each treatment with 30 polybags for each replication (e.g. 90 polybags for each treatment and a total of 630 polybags for the whole experiment). There were seven different treatments including the control viz. T0 (soil, treated as control), T1 (soil + municipal sludge = 1:1), T2 (soil + municipal sludge = 2:1), T3 (soil + industrial sludge = 1:1), T4 (soil + industrial sludge = 2:1), T5 (soil + residential sludge = 1:1) and T6 (soil + residential sludge = 2:1). Polybags (15 cm ×10 cm in size) were filled with the prepared mixtures as mentioned above. Two seeds were sown in an individual polybag to observe the influence of sludge on field germination (e.g. a total of 180 seeds per treatment and 1260 seeds for whole ex-
×100
The same work had been done for six months old seedlings. All the data were analyzed statistically by using the computer software package SPSS and they were analyzed by DMRT.
T6 T5 T4 T3 T2 T1 T0
56
78
Treatment
70
73
70
65
64
0
20
40
60
80
Field Germination (%)
Fig. 1
Effect of sludge on field germination of L. leucocephala seeds
Table 1. Effect of sludge on shoot and root length, vigor index, collar diameter and leaf number of 3- and 6- month old L. leucocephala seedlings
Treatment T0 T1 T2 T3 T4 T5 T6 T0 T1 T2 T3 T4 T5 T6 Shoot 17.07 b* 41.00 a 47.44 a 46.44 a 44.78 a 46.11 a 42.78 a 24.67 b 57.33 a 65.11 a 67.22 a 59.22 a 71.22 a 64.22 a Length (cm) Root 15.72 b 19.11 ab 17.50 ab 24.44 a 20.11 ab 24.89 a 21.11 ab 20.00 b 37.89 a 37.89 a 39.33 a 36.00 a 43.89 a 40.44 a Vigor Index Total 32.79 b 60.11 a 64.94 a 70.88a 64.89 a 71.00 a 63.89 a 44.67 b 95.22 a 103.00 a 106.55 a 95.22 a 115.11 a 104.66 a 2098 b 3907 a 4546 a 5174 a 4542 a 5538 a 3578 a 2859 c 6189 b 7210 ab 7778 a 6665 ab 8978 ab 5861 ab Collar dia. (mm) 1.60 b 2.51 a 2.62 a 2.96 a 2.82 a 3.12 a 2.90 a 2.10 b 3.63 a 3.82 a 3.83 a 3.35 a 3.77 a 3.68 a Average number of compound leaf 7.1 c 9.8 b 10.2 b 13.4 a 10.8 b 13.8 a 10.0 b 11.3 b 13.1 ab 14.1 a 14.8 a 13.7 a 12.7 ab 12.4 ab
3-month old seedlings
6-month old seedlings
*- Means followed by the same letter (s) in the same column do not vary significantly at P<0.05, according to Duncan's Multiple Range Test (DMRT).

228
Journal of Forestry Research, 18(3): 226–230 (2007) Collar diameter was highest (3.12 mm) in T5 and was significantly (P<0.05) different from that of the control. Vigor index was highest (5538) in T5 followed by T3 and T2 and was also significantly (P<0.05) different from that of T0. The highest (13.8) average number of compound leaf was recorded in T5, whereas the lowest (7.1) was in T0 (control). In case of six months old seedlings, the highest shoot growth (71.22 cm) was also recorded in T5 and the lowest in T0. The highest root growth (43.89 cm) was found in T5. Collar diameter was highest (3.83 mm) in T3 and was significantly (P<0.05) different from that of T0. Vigor index was highest (8978) in T5 followed by T3 and T2 and was significantly (P<0.05) different from that of T0. The average number of compound leaf was maximum (14.8) in T3 followed by 14.1 and 13.7 in T2 and T4, respectively whereas, the lowest (11.3) was in T0.
Results
Field germination and morphological growth parameters of seedling The field germination percentage and growth parameters significantly (P<0.05) varied in different treatments. The highest field germination (78%) was observed in T5 and the lowest (56%) in T6 (Fig. 1). The effects of different sludges on morphological growth parameters of seedlings like shoot length, root length, total length, collar diameter and leaf number of three and six months old seedlings were shown in Table 1. In three months old seedlings, shoot growth was the highest (47.44 cm) in T2 whereas, the highest root growth (24.89 cm) was recorded in T5.
Table 2. Effect of sludge on shoot and root fresh, dry weight and total biomass increment of 3- and 6- month old L. leucocephala seedlings
Treatment Shoot 3-month old seedlings T0 T1 T2 T3 T4 T5 T6 T0 T1 T2 T3 T4 T5 T6 1.19 c * 3.87 b 4.35 b 5.42 ab 5.01 ab 7.31 a 5.05 ab 2.14 b 9.50 a 10.72 a 13.18 a 9.03 ab 13.27 a 10.76 a Fresh weight (g) Root 0.30 b 1.02 ab 1.00 ab 1.17 a 0.97 ab 1.33 a 0.87 ab 0.69 b 2.00 ab 2.87 a 2.84 a 2.42 ab 3.33 a 2.30 ab Total 1.49 c 4.89 b 5.35 ab 6.59ab 5.98 ab 8.64 a 5.92 ab 2.83 b 11.50 ab 13.59 a 16.02 a 11.45ab 16.60 a 13.06 a Shoot 0.31 b 1.22 ab 1.27 ab 1.43 ab 1.24 ab 1.90 a 1.55 a 0.61 b 3.48 a 3.82 a 4.76 a 3.06 a 4.62 a 4.00 a Dry weight (g) Root 0.03 b 0.34 a 0.14 ab 0.18 ab 0.17 ab 0.29 a 0.21 ab 0.22 b 0.78 ab 1.08 a 1.06 a 0.91 ab 1.26 a 0.89 ab Total 0.34 b 1.56 ab 1.41 ab 1.61 ab 1.41 ab 2.19 a 1.76 a 0.83 b 4.26 a 4.90 a 5.82 a 3.97 a 5.88 a 4.89 a 00.00 + 358.82 + 314.70 + 373.52 + 314.70 + 544.11 + 417.64 00.00 + 413.25 + 490.36 + 601.20 + 378.31 + 608.43 + 489.16 Total dry biomass increment (%)
6-month old seedlings
*- Means followed by the same letter (s) in the same column do not vary significantly at P<0.05, according to Duncan's Multiple Range Test (DMRT).
Table 3. Effect of sludge on nodule number and fresh and dry weights of 3- and 6- month old L. leucocephala seedlings
Nodule Number increased/ decreased (%) 00.00 + 500.00 + 400.00 + 500.00 + 400.00 + 600.00 + 300.00 00.00 + 275.00 + 250.00 + 375.00 + 250.00 + 500.00 + 300.00
Treatment T0 T1 T2 T3 T4 T5 T6 T0 T1 T2 T3 T4 T5 T6
Number 1d* 6 ab 5 bc 6 ab 5 bc 7a 4c 4d 15 c 14 c 19 b 14 c 24 a 16 bc
Weight (g) Fresh 0.020 c 0.057 ab 0.052 b 0.066 ab 0.055 b 0.075 a 0.053 b 0.077 bc 0.136 a 0.115 ab 0.136 a 0.075 bc 0.095 bc 0.068 c Dry 0.004 d 0.021 bc 0.020 bc 0.026 ab 0.020 bc 0.032 a 0.014 c 0.045 b 0.075 a 0.054 b 0.052 b 0.018 c 0.033 bc 0.020 c
3-month old seedlings
6-month old seedlings
Weight increased/ decreased (%) Fresh Dry 00.00 00.00 + 185.00 + 425.00 + 160.00 + 400.00 + 230.00 + 550.00 + 175.00 + 400.00 + 275.00 + 700.00 + 165.00 + 250.00 00.00 00.00 + 76.62 + 66.66 + 49.35 + 20.00 + 76.62 + 15.55 - 2.59 - 60.00 + 23.37 - 26.66 - 11.68 - 55.55
*- Means followed by the same letter (s) in the same column do not vary significantly at P<0.05, according to Duncan's Multiple Range Test (DMRT).
Fresh and dry matter production Fresh and dry matter production, e.g. shoot and root fresh weight, total fresh weight, shoot and root dry weight and total dry weight were shown in Table 2. In three months old seedlings, both fresh and dry shoot weights were maximum (7.31 g and 1.90 g, respectively) in T5 and were significantly (P<0.05) different from
those of T0. Fresh root weight was maximum (1.33 g) in T5 whereas, the highest (0.34 g) root dry weight was found in T1. In all the cases the lowest growth was observed in T0 (Table 2). Total dry biomass increment (%) was highest in T5 followed by T6 and T3 and was positive for all the treatments compared to T0. In case of six months old seedlings, fresh shoot weight was maximum (13.27 g) in T5, whereas, dry shoot weight was the

G.M.A. Iqbal et al. highest (4.76g) in T3 and significantly (P<0.05) different from those of T0. Both fresh and dry root weights were maximum (3.33 g and 1.26 g, respectively) in T5 and were significantly (P<0.05) different from those of T4, T6, T1 and T0. In all the cases the lowest growth was observed in T0 (Table 2). Total dry biomass increment (%) was highest in T5 followed by T3 and T2 and was positive for all the treatments compared to T0 treatment. Nodulation status of seedling Nodulation status of seedlings is presented in Table 3. In three months old seedlings, the highest (7) nodule number was found in T5 and the lowest in T0. Both fresh and dry weights of nodules were maximum (0.075 g and 0.032 g, respectively) in T5 and lowest (0.020 g and 0.004 g, respectively) in T0. The rate of nodule number increment was positive in all the treatments as compare to T0. Nodule fresh and dry weight increment were also found positive in all the treatments compare to T0. In case of six months old seedlings, nodule number was highest (24) in T5 and the lowest (4) in T0. Fresh weight of nodule was maximum (0.136 g) both in T1 and T3. Dry weights of nodules were maximum (0.075 g) in T1. Both fresh and dry weights of nodules were lowest (0.068 g and 0.020 g, respectively) in T6. The rate of nodule number increment was positive in all the treatments compare to T0. The increment rate of nodule fresh weight was positive in T1, T2, T3 and T5 and negative for T4 and T6. The increment rate of nodule dry weight was positive in T1, T2 and T3 and negative for T4, T5 and T6 in comparison with T0 treatment.
229 In the present study almost all growth parameters especially field germination (%), shoot length (cm) and shoot fresh weight (g) were found better than that findings. The parameters (total length, collar diameter and number of compound leaf) of L. leucocephala were better than that reported by Alam et al. (2004) where they used three types of media viz. peat soil + cowdung (3:1), soil + cowdung (3:1) and soil + peat soil (1:1) in three types of containers viz. transparent polybag (10 cm × 15 cm), plastic seed-tray (24.5 cm dia.) and open seed bed. Thus the influence of sludge amended soil on plants is positive which is comparable to findings recorded by others (Jorba and Andres 2000; Labrecque et al. 2006; Selivanovskaya and Latypova 2006).
Conclusion
From the present findings it may be concluded that residential (soil + residential sludge = 1:1) sludge may be used for obtaining maximum seed field germination and optimum seedling growth and nodule formation of L. leucocephala and helps to obtain healthy seedlings that can be easily established in degraded sites. Results from sludge fertilization experiments in forests in many parts of the world showed that most tree species respond positively to sludge fertilization. Residential sludges provide a potential source of nutrients to the forest crops especially fast growing species and such use can satisfy the needs for environmentally safe disposal of sludge.
Discussion
The present study indicates that the field germination percentage, growth parameters (shoot and root length, vigor index, collar diameter, leaf number, fresh and dry weight of shoot and root and total dry biomass increment) and nodule formation of seedlings recorded from different combinations of sludge treatments in L. leucocephala varied significantly compared to control. The present findings are in agreement with Jorba and Andres (2000) that sewage sludge could serve as a good organic fertilizer to maximize plant germination. Sludge amendments enhanced the germination and decreased the mortality of the seedlings. The effects were more obvious for the soil with the highest sludge treatment. The beneficial effects on the biomass of seedlings and the height of the shoots as well as on the length of the roots of the pine seedlings were greater in plots with the highest rates of composted sludge (Selivanovskaya and Latypova 2006). The present study was also coincided with Labrecque et al. (2006) who reported that fast growing species can get benefit from sludge amended soil. Sludge typically contains large amounts of plants available N and P, smaller amounts of all the secondary and micronutrients and in addition, supplies organic matters (Bates et al. 1979). The nitrogen content in the sludge is usually released more slowly than commercial fertilizers (Riha et al. 1983). This slower release is probably more appropriate for tree growths. Unfortunately, sewage sludge may also contain a range of potentially toxic metals, such as Cu, Cd, Pb, Zn and Ni (Logan and Chaney 1983). The simultaneous phyto-separation of toxic and beneficial elements from sewage sludge are possible by co-cropping using specific plants without the input of any chemicals (Wu et al. 2007). Khan et al. (2002) also noticed positive growth on L. leucocephala by using beneficial microbial inoculants (Effective Microorganisms) in different combinations.
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Chinese Abstracts 黑曲霉对二氯甲烷提取物进行抑菌性能测试,结果表明该提 取物对黑曲霉没有抑菌能力.图4表2参29. 关键词:日本花柏;心材外缘;二氯甲烷提取物;气质联机; 抑菌. CLC number: Q946.8 Document code: A Article ID: 1007662X(2007)03-0042-08 07-03-009 ACQ 防腐剂对扭叶松蓝变部分木材力学性能的影响/江京辉 任海青 吕建雄 骆秀琴 吴玉章 (中国林业科学研究院木材工 业研究所,国家林业局木材科学与技术重点实验室,北京 100091)//Journal of Forestry Research.-2007, 18(3): 213216. 本文利用三种不同浓度 ACQ 防腐剂对扭叶松蓝变木材 进行浸注处理,其浓度分别为 1.2%,2.0%和 2.8%.研究其 抗弯弹性模量,抗弯强度,冲击韧性和顺纹剪切强度(弦面) 与未处理 蓝变木 材 相应 力学性 能 的差 异,测 试 标准参照 GB1927~1943-91.研究结果显示,经浸注处理后的试样均达 到美国 AWPA 标准 UC4A 等级规定的药剂保持量;ACQ 防 腐处理大约降低了 20%扭叶松蓝变木材的冲击韧性,与未防 腐处理试样对比,在 0.01 水平上有显著差异,但不同浓度间 差异不显著; 三种浓度 ACQ 处理间以及与未处理的扭叶松蓝 变木材的抗弯强度,抗弯弹性模量和顺纹剪切强度差异不显 著;随着 ACQ 浓度的降低,冲击韧性,抗弯强度,抗弯弹性 模量和顺纹弦面剪切强度有所增大,但影响都很小.图 4 表 10 参 6. 关键词:扭叶松,蓝变处理材,非处理材,冲击韧性,抗弯 强度,抗弯弹性模量,顺纹剪切强度(弦面) CLC number: S781.2 Document code: A Article ID: 1007662X(2007)03-0213-04 07-03-010 不同水分条件下紫藤叶片光合作用的光响应/张淑勇(中国林 业科学研究院林业研究所, 北京 100091;国家林业局林木 培育重点实验室,北京 100091),夏江宝(滨州学院黄河三角 洲生态环境研究中心,滨州 256603),周泽福(中国林业科学 研究院林业研究所, 北京 100091;国家林业局林木培育重 点实验室,北京 100091),张光灿(山东农业大学林学院,泰 安 271018 ) //Journal of Forestry Research.-2007, 18(3): 217220. 通过测定 2 年生紫藤叶片气体交换参数的光响应,确定 紫藤正常生长发育所需的土壤水分条件.结果表明:紫藤的 光合速率(Pn) ,蒸腾速率(Tr)及水分利用效率(WUE)对 土壤湿度和光照强度的变化具有明显的阈值.维持紫藤同时 具有较高 Pn 和 WUE 的土壤湿度范围, 在体积含水量 (VWC) 为 15.3%～26.5%,其中最佳土壤湿度为 23.3%.适宜的土壤 水分条件下,紫藤光饱和点在 800molm-2s-1 以上,在水分 不足(VWC 为 11.9%,8.2%)或渍水(VWC 为 26.5%)时, 光饱和点低于 400molm-2s-1.此外,光响应曲线表明,随着 光合有效辐射(PAR)增加到一特殊点,气孔限制值(Ls)和 胞间 CO2 浓度出现相反的变化趋势.这个点的光合有效辐射 称为光合作用由气孔限制转变为非气孔限制的转折点.并且 不同水分条件下的转折点各不相同,当 VWC 为 28.4%,
3
15.3% 11.9%和 8.2%, 转折点分别为 600,1000, 1000 and 400 mol.m-2.s-1.总之,紫藤通过对自身生理机能的调节,对水 分胁迫具有较高的适应能力.图 6 参 26. 关键词:净光合速率;土壤湿度;光合有效辐射;水分利用 效率;紫藤 CLC number: Q945.11 Document code: A Article ID: 1007662X(2007)03-0217-04 07-03-011 传感器数量对应力波检测原木内部缺陷精度的影响/王立海, 徐华东, 周次林, 李莉, 杨学春 (东北林业大学,哈尔滨 150040) //Journal of Foresetry Research.-2007, 18(3): 221225. 木材无损检测技术是高效利用木材的方法之一.该文阐 述了应力波法检测木材缺陷的原理,分析了传感器数量对图 像的拟合度和误差率两个指标的影响.结果表明,当原木直 径在 20～40cm 范围内时, 若需对原木缺陷进行精确测量, 要 求图像拟合度接近 90%和误差率在 0.1 左右时,至少需 12 个 传感器才能满足要求;当不需要对原木缺陷进行精确测量, 只需确定缺陷的大致位置时,宜选用 10 个传感器进行测量; 当仅仅需要判断原木是否存在缺陷时,选用 6 个传感器就能 满足要求.图 3 表 4 参 8. 关键词:传感器数量;原木缺陷检测;应力波;图像拟合度 CLC number: S 781.2 Document code: A Article ID: 1007662X(2007)03-0221-05 07-03-012
污泥对苗圃生长的银合欢幼苗发芽和初期长势的影 响/G. M. A. Iqbal, S. M. S. Huda*, M. Sujauddin and M. K.
Hossain (Institute of Forestry and Environmental Sciences, University of Chittagong, Chittagong-4331, Bangladesh)//Journal of Forestry Research.-2007, 18(3): 226230. 研究了不同类型的污泥(城市的,工业的和住宅污泥) 对苗圃生长的银合欢幼苗田间萌发,生长和分枝的影响.播 种前先将不同类型污泥的混合物与养分匮乏的自然林土壤混 合.播种的 3 和 6 月后,记录幼苗大田发芽,分枝状况和其 他物理生长参数(枝条或根长,活力指数,茎直径,叶片数, 分枝或根鲜重和干重,总的生物量干重增长)等.与对照幼 苗相比,混合污泥的土壤中生长的幼苗田间发芽,分枝状况 及其他生长参数均发生了显著变化.与其它条件生长的幼苗 相比,住宅污泥与土壤混合(1:1)条件生长的 3 月龄和 6 月龄幼苗分枝数和分枝鲜或干重均最高.就生长参数而言, 住宅污泥与自然林土壤混合(1:1)生长的幼苗长势最好. 研究表明:退化的土壤补偿以住宅污泥可促进银合欢的田间 发芽,生长以及分枝的形成.图 1 表 3 参 29. 关键词:银合欢;污泥;田间发芽;幼苗生长;分枝;活力 指数 CLC number: S718 Document code: A Article ID: 1007662X(2007)03-0226-05 07-03-013 鄂尔多斯高原油蒿灌丛群落土壤呼吸日变化和季节变化特征 /金钊(中国科学院地理科学与资源研究所,北京 100101;中

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向前飞去，可是，刚要动一下，整个身体便从树叶上滑落，重重地摔在了地上，它好像很疼，它想要打消起飞的念头，经过好长时间的努力，它没有动一下。突然，它积蓄力量，一下子跳了起来，迎接它的是又一次摔落，但这一次它没有犹豫，马上煽动羽翼，终于一点点飞了起来，它惊喜地颤栗。它继续努力，不用说，接下来是它的第三次摔落，可是第四次起飞又开始了，好像比前几次稳了些，没有摔倒。成功了，终于成功了！一阵微风吹过。花儿、草儿，颤抖了一下，它也跟着花儿、草儿有节奏地倾斜，而后终于稳住，它一直向前不停地迎着蓝天飞去…… 又是那个美丽的春天，一只斑斓的蝴蝶在绕着一片树叶，翩翩于万木花草之间，上下翻飞于丽日之下。百花吐露芬芳，万物尽显生机，缤纷盛宴正等待它来分享。原来这就是传说中最美的春天，这就是它梦想中自由的飞翔…… 描写蝴蝶生长过程的作文篇2一只小小的蝴蝶是怎样变成得？这是在一个秋天，一群小动物从家里出来找食物，准备过冬。 一只让人瞧不起的毛毛虫，从家里慢慢悠悠地爬出来找吃的，一只小熊看见它说：“这只丑陋无比的小东，西真是让人瞧不起，怪不得让人们说你是只害虫呢！”毛毛虫不服气的说：“你别看我现在丑陋无比，以后我比你美丽多了！几个月后，毛毛虫变成了一只美丽无比的蝴蝶，小动物惊讶的说：”

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植物，幼虫时期是蝴蝶主要的觅食阶段，不停的吃、长大、脱皮。幼虫刚孵化出来称为「初龄幼虫」，而后每脱一次皮就多增加一龄，每次脱皮前不动称为「眠」，在成长过程中将会经过4~6次的脱皮，最后成为「终龄幼虫」，这时候它会去寻找适当地方开始分泌胶质包裹身体，并且逐渐形成蛹的形状，而整个化蛹的过程大概要花上一天的时间。 3. 蛹：蝴蝶的蛹虽然看起来一动也不动，其实在它体内正在进行大变化。一方面必须破坏幼虫时期的身体构造，另一方面又要创造组合蝴蝶成虫美丽的身躯，这种破坏又建设的行为实在太不可思议了，令人不禁要赞叹生命的奥秘。蛹依照生长方式可以分成三种型式： (1) 垂蛹：蛹头朝上，蛹中央以丝环绕并绑於树枝上。 (2) 挂蛹：蛹尾朝上，丝在尾端，将蛹倒挂於枝条上。 (3) 包蛹：以丝包裹身体，而后藏於花、果中。蛹多具有保护色或拟态，而且都附著在隐蔽处，以防敌人发现。 4. 成虫：蛹在经过了一段时间之后，成虫会努力从蛹挣脱出来，这个过程我们称之为「羽化」，刚羽化的蝴蝶，爬出蛹壳后，蝴蝶身体内的液体会由肌肉挤压，经过翅膀送到翅内撑开皱皱翅膀，然后由腹部排出这些液体，这时翅膀也愈合了，等翅膀乾燥之后，蝴蝶就可以展翅高飞了。

蝴蝶作文之毛毛虫变蝴蝶的过程作文

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谜语导入： 教师：头上两根须，身穿花彩衣，飞在花丛中，快乐又自在。 教师：那现在小朋友来看看是什么?教师展示第一幅画，（蝴蝶） 小结：蝴蝶宝宝是一种昆虫，他喜欢花粉的味道，喜欢在花丛中自由自在的飞舞。哪你们知道蝴蝶宝宝小时候是什么样子的吗？谁来说一说，请个别幼儿。 二、基本部分 （一）故事进入主题 宝宝小时候到底是什么样子。要仔细地听，老师一会有问题要问小朋友。 教师：讲述故事 总结：蝴蝶宝宝小时候是毛毛虫，它经过不同时期的变化，变成了漂亮的蝴蝶，在花丛中自由自在的飞舞。 （二）幼儿和教师一起观察变化的过程 教师：现在我们班小朋友知道蝴蝶宝宝小时候是什么样子了吗？我们一起来看一看，蝴蝶宝宝是怎样长大的，从图一到图四，出示字卡，老师手里还有生活当中他们的图片，小朋友想不想看，然后教师把对应的图片贴上，让幼儿仔细观察。 总结：虫卵—毛毛虫—虫蛹—蝴蝶 三、操作部分 （一）通过肢体来模仿变化过程 教师：好，现在我们都知道了蝴蝶宝宝是怎样长大的了，那我们一起来学蝴蝶宝宝一样，从虫卵开始一步=步的长大，长成神奇的蝴蝶宝宝，好不好？

微分方程模型

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(完整版)常微分方程习题及解答

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旋转曲面之面积Asymptote： 渐近线 horizontal ：水平渐近线slant： 斜渐近线 vertical： 垂直渐近线 Average speed： 平均速率 Average velocity： 平均速度 Axes, coordinate： 坐标轴 Axes of ellipse： 椭圆之对称轴 Binomial series： 二项式级数 Binomial theorem ： 二项式定理

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V、X、Z: Value of function ：函数值 Variable ：变数 Vector ：向量 Velocity ：速度 Vertical asymptote ：垂直渐近线 Volume ：体积 X-axis ：x轴 x-coordinate ：x坐标 x-intercept ：x截距 Zero vector ：函数的零点 Zeros of a polynomial ：多项式的零点 T: Tangent function ：正切函数 Tangent line ：切线 Tangent plane ：切平面 Tangent vector ：切向量 Total differential ：全微分 Trigonometric function ：三角函数 Trigonometric integrals ：三角积分 Trigonometric substitutions ：三角代换法 Tripe integrals ：三重积分 S: Saddle point ：鞍点 Scalar ：纯量 Secant line ：割线 Second derivative ：二阶导数 Second Derivative Test ：二阶导数试验法Second partial derivative ：二阶偏导数 Sector ：扇形 Sequence ：数列 Series ：级数 Set ：集合 Shell method ：剥壳法 Sine function ：正弦函数 Singularity ：奇点 Slant asymptote ：斜渐近线 Slope ：斜率 Slope-intercept equation of a line ：直线的斜截式Smooth curve ：平滑曲线

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