The preserving rate,tree height,diameter at breast height (DBH),ground diameter,and crown-width of the Taxodium hybrid ‘zhongshanshan’ at different elevations after one,three,and six periodic flooding periods were studied,based on located observations on the hydro-fluctuation belt in Wanzhou,Chongqing.Results showed that,after one flood period,the preserving rate of trees at the 166～175 m elevation was 100％;after three flood periods,the preserving rate at the 168～175 m elevation was 100％;after six flood periods,the preserving rate at the 170～175 m elevation was 98％.In general,the tree height,DBH,ground diameter,and crown-width decreased with the reduction of elevation,but on a certain elevation range,the tree height instead increased.At initial stage of flooding,the growth of trees was influenced by flooding;after several flood periods,the effects became insignificant.The preserving rate decreased significantly in water logged zone,but the trees were still in good condition when root exposed.The Taxodium hybrid ‘zhongshanshan’ could improve the physical and chemical properties of soil,and protect the hydro-fluctuation belt from water and soil erosion.

本文探讨了北京低山区油松、刺槐、侧柏3种典型低效林林下植物组成和物种丰富度与环境因子之间的关系,以揭示不同层次物种组成对环境因子的响应,确定影响灌草2层物种丰富度的主要环境因子.在北京低山区设置34个样地进行群落学调查的基础上,运用CCA排序法分析灌木和草本2层的物种组成与海拔、坡向、坡位、坡度、郁闭度共5个环境因子之间的关系,偏CCA测算各环境因子的重要程度,灰色关联度评估各环境因子对物种丰富度的作用大小.结果表明:海拔和坡度对灌木层物种组成的净效应达到显著水平(P＜0.05),郁闭度对草本层物种组成的净效应达到显著水平(P＜0.05).坡度与灌木层物种丰富度的灰色关联度值为0.734,海拔与草本层物种丰富度的灰色关联度值为0.700.灌草2层的物种组成和物种丰富度对环境因子的响应存在差异,海拔和坡度是影响灌木层物种组成最主要的环境因子,郁闭度是影响草本层物种组成最主要的环境因子;坡度和海拔分别是影响灌木层和草本层物种丰富度最主要的环境因子.

The SCS-CN method is one of the most widely used hydrological models to predict surface runoff from watershed for a given rainfall event. However, runoff generation is governed by spatially and temporally heterogeneous factors including topography, landform, soil, climate, vegetation and land use, and using standard SCS-CN method to predict surface runoff, could thus result in large errors. Therefore, it is an effective way to modify the original model for particular region, specific watershed for improving the accuracy. The measured event rainfall-runoff datasets from three watersheds located in Caijiachuan watershed on the Loess Plateau of China during 2004 and 2011 were used for calibrating (2004 to 2009) and validating ( 2010—2011 ) the original and five modified SCS-CN models. The selected three watersheds are dominated by farmland and grassland, plantation forests, and secondary forests, respectively. We found that the standard SCS-CN method poorly estimated the event runoff for all three watersheds ( model efficiency coefficients E less than 0 ) . The performance of revised SCS-CN based on rainfall amount was better than the standard one even though overestimation for small runoff events and underestimation for large ones were observed across the watersheds. The optimized SCS-CN model by rainfall intensity revised and initial abstraction coefficient improved the prediction accuracy most among the five modified models for watersheds dominated by farmland and grassland and plantation forest. Interestingly, revised SCS-CN by rainfall amount only improved significantly the predicting accuracy for secondary forest dominated watershed ( E =0. 79 ) . In addition, the initial abstraction coefficient (λ) was 0. 069, 0. 189, and 0. 200 for watersheds dominated by plantation forest, farmland and grassland, and secondary forest, respectively, indicating that the water storage capacity was affected by the vegetation type.

通过生物测定法研究油松根际土对不同物种的化感效应,以期为油松林的乔灌草复合提供科学依据.设定油松根际土化感效应研究的质量浓度分别为0.5、1、3、5、7、10 mg/mL,测定提取液对油松、刺槐、侧柏、胡枝子、绣线菊、冰草、紫花苜蓿发芽与生长化感效应.结果显示:在所有研究浓度下,油松根际土对刺槐、紫花苜蓿呈抑制效应,且随浓度的加大抑制效应不断加强;对侧柏起促进作用;油松根际土对油松、胡枝子、绣线菊、冰草的化感效应呈低浓度促进、高浓度抑制.因此,从油松根际土化感效应的角度考虑,在油松林营造乔灌草复合植被时,应优先考虑侧柏,慎重选择刺槐、紫花苜蓿,选择复合胡枝子、绣线菊、冰草时应该注意油松林的间伐以及间作的密度.

三峡库区消落带耐淹植物的筛选一直是该区生态系统修复的关键问题.该文利用室内水淹模拟试验研究了不同程度水淹胁迫下饲料桑苗的生长及光合响应特性.试验以la生饲料桑为材料,水淹胁迫分为对照、根淹、深淹等不同水平处理.结果表明:①水淹胁迫下根淹处理和深淹处理桑苗都生出不定根,根淹处理桑苗出现的涝害症状较轻,而深淹处理则从水淹5d开始出现叶斑、黄化等症状,水淹结束严重落叶;②水淹明显影响桑苗的生长,影响程度为根淹小于深淹,且根淹处理桑苗能维持较高的株高、地径生长率;③水淹降低了桑苗的净光合速率、气孔导度和蒸腾速率.根淹处理桑苗的光合响应指标在水淹40d明显低于对照处理,但仍能维持较高水平,之后随水淹时间增加没有明显变化,而深淹处理桑苗的光合响应指标在水淹55d已很微弱.④深淹胁迫对桑苗水下叶片光合能力的影响大于对水上叶片的光合能力的影响.水淹55 d深淹处理水上叶片的净光合速率甚至和根淹处理很接近.因此la生饲料桑苗无法抵抗长期深淹,却可很好地适应根淹,适合在消落带海拔较高、水淹深度较浅的区域生长.研究为库区消落带的生物治理提供了理论支持.

The components of root exudates released from healthy and unhealthy black locust (Robinia pseudoacacia L.) root were determined by GC-MS. The results showed that the kinds and contents of root exudates released from Black Locust are different for healthy and unhealthy plants, so it may be evaluated whether the Black Locust plants are healthy or unhealthy by the root exudates. Healthy plants can release more kinds of exudates than unhealthy plants, especially the kinds of acids, alcohol and ester. There are 46 kinds of compounds in the healthy Black Locust, but only 24 kinds in the unhealthy Black Locust. Many compounds are released from healthy plant but not from unhealthy, while many kinds of compounds are released from unhealthy plant but not from healthy one.

This research aimed to provide a scientific basis for the construction of compound arbor-shrub-herb vegetation in Pinus tabuliformis forest by studying the allelopathic effect of P. tabuliformis root on varied plant species. The allelopathic effects of P. tabuliformis root aqueous extract ( RAE) on the germination and growth of seven plants ( P. tabuliformis, Robinia pseudoacacia, Platycladus orientalis, Lespedeza bicolor, Spiraea salicifolia, Agropyron cristatum, and Medicago sativa) were investigated with different concentrations of P. tabuliformis RAE, i. e. , 0.5, 1.0, 3.0, 5.0, 7.0, and 10.0 mg/mL. The results showed that P. tabuliformis RAE inhibited the growth of R. pseudoacacia, A. cristatum, and M. sativa, and such effect increased with the increase of RAE concentration. P. tabuliformis RAE promoted only the growth of P. orientalis at each concentration. At low concentrations, the P. tabuliformis RAE promoted the growth of P. tabuliformis, L. bicolor and S. salicifolia, while it inhibited at high concentrations;at 1 mg/mL the promoting effects changed into inhibiting. We suggest that when constructing compound arbor-shrub-herb vegetation in P. tabuliformis forest, we should give priority to P. orientalis, and carefully choose R. pseudoacacia, A. cristatum, and M. sativa. When choosing L. bicolor and S. salicifolia, we should control the thinning and intercropping density of P. tabuliformis forest.

在河北唐山南堡地区,利用穴状衬膜客土整地模式改良盐渍土,结合两年土壤水盐动态监测,研究了该整地模式对滨海盐渍土水盐动态的影响.结果表明:穴状衬膜客土整地改变了滨海盐渍土水分随土层深度增加而增加的分布规律,以20～60cm土层含水量最高,这在一定程度上有益与苗木根系的生长,但对土壤水分动态总体变化趋势影响不大.整地后,各土层电导率持续降低,不再伴随降雨规律出现周期性升降;年内和年际间周期性“返盐”现象有所削弱,积盐土层主要为60 ～ 80cm,盐分的表聚作用有所减弱.四种客土处理方式中,A4处理(客土b和原状土2:1混合的客土)持水性最好,A1处理(客土a和原状土2:1混合的客土)脱盐效果最好,脱盐率达63.4％.

为了增加土壤肥力,提高和保持土壤含水量从而提高作物产量,在山西省临汾市吉县国营红旗林场进行田间试验栽植饲料桑,对饲料桑施用新型有机肥料——生物抗蒸发保水菌肥,通过设置对照试验,探究生物抗蒸发保水菌肥的施用及用量对饲料桑生长和土壤水分状况的影响,得出试验最佳施肥量,并初步确定最大施肥量.结果显示:生物抗蒸发保水菌肥的施用可以明显提高土壤含水量,随着施肥量的增加,保水效果也会提高;合理的施用量会明显促进饲料桑植株的生长,每株施肥0.2 kg效果最佳,每株施肥量超过0.5 kg则已经抑制饲料桑的生长.本研究为该肥料的推广应用以及饲料桑的种植提供可行的理论依据.

Responses of transpiration (E c) to rain pulses are presented for two semiarid tree species in a stand of Pinus tabulaeformis and Robinia pseudoacacia. Our objectives are to investigate (1) the environmental control over the stand transpiration after rainfall by analyzing the effect of vapor pressure deficit (VPD), soil water condition, and rainfall on the post-rainfall E c development and recovery rate, and (2) the species responses to rain pulses and implications on vegetation coverage under a changing rainfall regime. Results showed that the sensitivity of canopy conductance (G c) to VPD varied under different incident radiation and soil water conditions, and the two species exhibited the same hydraulic control (−dG c/dlnVPD to G cref ratio) over transpiration. Strengthened physiological control and low sapwood area of the stand contributed to low E c. VPD after rainfall significantly influenced the magnitude and time series of post-rainfall stand E c. The fluctuation of post-rainfall VPD in comparison with the pre-rainfall influenced the E c recovery. Further, the stand E c was significantly related to monthly rainfall, but the recovery was independent of the rainfall event size. E c enhanced with cumulative soil moisture change (ΔVWC) within each dry–wet cycle, yet still was limited in large rainfall months. The two species had different response patterns of post-rainfall E c recovery. E c recovery of P. tabulaeformis was influenced by the pre- and post-rainfall VPD differences and the duration of rainless interval. R. pseudoacacia showed a larger immediate post-rainfall E c increase than P. tabulaeformis did. We, therefore, concluded that concentrated rainfall events do not trigger significant increase of transpiration unless large events penetrate the deep soil and the species differences of E c in response to pulses of rain may shape the composition of semiarid woodlands under future rainfall regimes.

In the process of high resolution images orthorectification, an uneven distribution of ground control points in mountainous area results in the phenomenon of ground objects dislocation between orthophotos edges in the overlap area. Followed image mosaic, fusion and interpretation are seriously affected. High-resolution (2.5 m) panchromatic images with a 30% forward overlap of ALOS satellite were acquired over topography complication zones in Beijing mountainous area. After being ortho-rectified in Geomatica PCI 2012, odd or even serial numbered orthophotos on the same satellite track without edge overlapping were mosaiced and then experimental automatic matching tests between mosaic orthophotos and residual orthophotos were carried out in Automatic Registration of ENVI 4.8 to obtain empirical automatic matching parameters and guiding ground control points in the overlap areas. Finally, automatic edge matching operation was conducted by using parameters and guiding GCPs previously acquired. The results showed that mosaic alternate orthophotos in course line or lateral course lines shortened edge matching time effectively. In Automatic Registration module of ENVI 4.8, Search Window Size = 361, Moving Window Size = 19, Area Chip Size = 256 were empirical automatic matching parameters of ALOS panchromatic orthophotos. This method can accomplish high resolution orthophotos edge matching fast and accurately.

Afforestation experiment were conducted in different saline-alkali soil on 14 tree species such as Salix psammophila and Robinia pseudoacacia L.etc.,their survival,growth and victimization were investigated and analized.According to the principle of salt-resistance = salinity stress/transformation caused by the threat,salt resistance of the test species were evaluated by single and multiple morphological index.The results showed that Amorpha fruticosa,Fraxinus velutina,Platycladus orientalis,Salix psammophila,Morus alba's salt resistance were stong,should be the preferred species for afforestation in saline-alkali soil in the Yellow River Delta region;while Armeniaca sibirica,Amygdalus persica 's salt resistance were weak,could not be used for afforestation in saline-alkali soil.It was proposed that tree species evaluation of salt tolerance must be combined with different types of salinealkali soil.

[Objective] The structure feature of low function’s pinus tabulaeformis plantation was explored.[Method]With the help of sample plot survey to inefficient Pinus tabulaeformis planted forest in the low mountain of Beijing,the Pinus tabulaeformis’tree species composition,tree height structure and diameter structure were analyzed.[Result]Over crowed,poor stand,human disturbance and no matching species with the site were the main reasons to lead to the forest inefficient.[Conclusion] According to the several main cause of low efficiency,the suggestions for the process of forest culture and management were proposed.

Taking Pinus tabulaeformis,Platycladus orientalis,Robinia pseudoacacia and Ouercus liaotungensis forests in the same period in the Beijing low mountain area as a case,this paper studied evaluation on health conditions of different tree species and different standing forests for soil and water conservation.Through the construction of the evaluation system,the establishment of a comprehensive evaluation model,calculation of the stand comprehensive evaluation index,different forest stands were evaluated.Then the soil and water conservation forest was divided into four classes： the first class forests for soil and water conservation with comprehensive evaluation value of S≥8;the second class with 5≤S〈8;the third class with 2≤S〈5;the fourth class with S〈2.Then growth conditions and site characteristics of the different types of forest for soil and water conservation was discussed,and a reasonable improvement measures was proposed.

As one of the largest reservoirs in the world, the Three Gorges Reservoir (TGR) has a huge area of water-level-fluctuation belt (WLFB). How to manage and utilize the WLFB of the TGR has been a highly domestic and international concern. Among many management and utilization measures, the biological one seems to be very efficient and attractive, however the plants planted on the WLFB must have high flood-tolerance. In this study, the 10 hm2 one-year-old mulberry seedlings were planted on the WLFB (located in Xiaohe Village, Kai County, Chongqing), with the elevation changing from 157 m through 175 m, in March, 2010, and an experiment had been conducted to investigate the flood-tolerant property of the mulberry seedlings from October, 2010 to April, 2011. During this period, the highest water level of the TGR reached 175 m and caused the complete submergence of the mulberry seedlings for 3 to 6 months. The result showed that: the area-weighted average of the bud flush ratio of the mulberry seedlings, which had suffered submergence for 90 to 118 d, was about 62.6%. The bud flush rate was generally determined by several factors, such as depth and duration of the submergence, drainage property of the WLFB, and whether the fall branches of the seedlings were cut or not. The limitation of the flood-tolerant duration of the annual mulberry seedlings could be less than 150 d, since almost all of the annual mulberry seedlings planted on the areas below 166 m were dead when the submergence period reached 150 d. The perennial mulberry trees planted on the area under 161.8 m, however, they could flush and form new crowns normally after a 214-day submergence. This experiment indicates that the mulberry trees are highly tolerant to submergence, thus, could be one of the most adaptable species and play an important role in managing and utilizing the WLFB of the TGR.

Using the methods of field investigation and laboratory analysis,anti-erodibility of soil with different vegetation restoration difficulty grades in Guizhou dolostone area were researched.The results showed that the bulk density of soils increased while the porosity decreased with the increasing of vegetation restoration difficulty grades.The content of soil organic matter was the highest in middle restoration difficulty grades soils and lowest in high restoration difficulty grades soils.Besides,the content of water stability aggregates and the condensation degree decreased while the dispersion coefficient of soils increased with the increasing of restoration difficulty grades.Above all,soil anti-erodibility decreased when the restoration difficulty grade increased.

Afforestation in saline-alkali land is a challenge faced by many countries.Coastal argillaceous saline-alkali land has such a high salt content that seedlings cannot be established there.The purpose of this paper is to study the use of a padded film around the roots of tree seedlings to protect the roots of the seedlings from salt infiltration.From 2007 to 2009,we compared and analyzed three techniques,two conventional afforestation models including 1) a comprehensive new soil conventional afforestation model and 2) a new soil in hole conventional afforestation model,and 3) a new afforestation model,which used the padded film.We measured the survival rate and growth of tree seedlings,as well as the soil moisture and conductivity(salt) inside the planting hole.There was an inverse relationship between water and salt content.With the arrival of rainfall,soil conductivity decreased and soil moisture rose.In August,with the reduction in rainfall,soil conductivity gradually rose and soil moisture content declined.When compared with the conventional afforestation models,the use of the new method which used the padded film conserved soil moisture and increased soil conductivity inside the film lined planting hole.Seedling survival rates,height and canopy area using the new afforestation model increased by an average of 150.00%,7.00% and 12.00%,respectively when compared with the comprehensive new soil conventional afforestation model.By using new soil in the planting hole,rather than just using the local soil and the conventional planting model,those figures increased even more dramatically to 838.00%,12.00% and 22.00%.Using new soil is less cost effective than the traditional model of afforestation and the cost is also much higher than the new afforestation model.Use of new soil should not be promoted.However,the cost of using the film is only 0.58 yuan.Compared with the conventional planting model,the new afforestation model is low in cost but provides very effective results.The new model of forest planting cost 12.29 yuan per plant,and the cost effectiveness with this new model of afforestation has been significantly better than other two traditional planting models.By using the new afforestation model,the survival rate,the average height,and canopy cover of seedlings of each species were,respectively: Fraxinus chinensis Roxb.,65.63%,2.04 m,0.93 m2;Populus deltoides W.Bart.ex Marshall cv.Zhonghua hongye,34.38%,1.97 m,0.84 m2;R.pseudoacacia,53.13%,2.11 m,1.02 m2;and Robinia pseudoacacia L.cv.idaho,81.00%,2.17 m,and 0.94 m2.Based on these results for these four species,R.pseudoacacia cv.idaho was the most suitable and P.deltoides cv.Zhonghua hongye was unsuitable for use with this tree seedling technique in coastal argillaceous saline-alkali lands.These results show the padded film effectively prevented the infiltration of salt around seedling trees and reduced evaporation.Padded film can increase the survival rate of seedlings and provides a suitable environment for seedlings in the coastal argillaceous saline-alkali lands.The results provide a theoretical basis for promotion of this effective,simple,and low-cost afforestation and land reclamation technique in saline-alkali lands.

The purpose of this paper is to study the effect of seed-base afforestation in saline-alkali land.Preparation of platform field,water-salt dynamic,the survival rate of different seed-base and tree species were investigated in coastal argillaceous saline-alkali land of Tang Shan.Results showed that,there was a close relation between the water content and salt content,in soil surface layer,the trend of soil salt and water was similar while the trend was reverse in middle and deep layers.The average salt of soil decreased year by year by preparation of platform field.The afforestation of seed-base has achieved initial success in saline-alkali land which the three-year survival rate of seed-base reached 30% in Rhus typhina,Locust,Amorpha fruticosa L.The survival rate of seed-base which the volume ratio of new soil,peat,vermiculite and perlite was 50∶30∶10∶10 was better than other seed-base.This seed-base which could improve the properties of plant growth environment was more suitable for tree species.

In order to provide sufficient theoretical basis for the template with carrying soil for afforesting on coastal muddy saline land, the author took the saline soil of Nanpu economic development area in Tangshan, Hebei Province as the research object. A field experiment was conducted to research the effect of template with carrying soil for afforesting on the dynamic of water and salt of coastal saline soil and compared the effect of salinity reducing between different template with carrying soil. The results showed that the law of soil water content of control group (not transform undisturbed soil) were the same with rainfall or there was a slight lag. The treatment group (template with carrying soil are made in different ways which were numbered A1, A2, A3, A4) also had the effect of rainfall, but there was significant differences between water content of each layer and the peak appear on different time. There were significant differences between influence of each manufacture ways on water content of 0-20 cm, 40-60 cm soil layer, but 20-40 cm, 60-80 cm soil layer are opposite. There was very significant negative correlation between the changes of salt and moisture of control group, and salt content was severe increased at the end of observation; on the contrary, the treatment group had no significant correlation relationship, the change tendency of salt content remain lower overall. There were significant differences between each manufacture ways on salt content of each soil layer, the reduce degree of average salt content of each treatment group was larger than the corresponding control group. The overall effect of salt content reducing rank was A1>A3>A2>A4; the effect of salt content reducing rank of root zone was A1>A2>A4>A3. Comprehensive analysis, the effect of reducing salt content of template with carrying soil of A1 which was produced by primary state soil and substrate soil with 1:2 was better than the others.

In order to explore the effects of soil salinization on afforestation,and use saline-alkali soil resources effectively,the degrees of mild(0.8-1.6 g/kg) ,moderate(2.0-3.1 g/kg) ,and severe(4.7-6.9 g/kg)salinity land in the Yellow River Delta were selected for afforestation with Fraxinus velutina Torr.and Platycladus orientalis(L.) Franco.The survival rate,growth of plant height and diameter,and damage symptoms were investigated and analyzed.The result showed that:F.velutina grew well in mild and moderate salinization land,the survival rate were 94.1%and 83.3%,respectively.P.orientalis grew well in mild salinization land,and the survival rate was 88.9%.The growth of two species were inhibited significantly in severe saline land,and the survival rates were 22.2% and 11.1%,respectively.The injured leaves were increased to 30%-50%in severe saline land.It was proposed that to achieve good results of plantation in the Yellow River Delta,key consideration should be soil salinization,F.velutina should be a major afforestation species in mild and moderate salinization land,but P.orientalis should be only used in mild salinity land.Severe salinization land must be improved to moderate before afforestation.