三峡水库消落带植被重建途径及其固土护岸效应

三峡水库蓄水运行后将出现一个落差达30 m的消落带,由于库水涨落和水文地质条件改变,导致其植被破坏,土壤裸露,在降水、库水位周期性地涨落和波浪的作用下,土壤侵蚀强烈,如何重建消落带植被成为广泛关注的热点问题。通过系统总结三峡水库消落带植被重建的科研实践及经验,提出了消落带植被重建的基本思路和途径,并利用侵蚀针定位观测方法,对比分析了不同植被重建途径下的固土护岸效应。结果表明,人工种植草地和自然恢复草地较其对照分别减少了土壤侵蚀74%和55%,显示出极显著的控制土壤侵蚀的效应。而表层土壤受人为扰动强烈的传统耕作耕地土壤侵蚀强度相较于对照高11%。     

农牧交错区保护性耕作对土壤含水量和温度的影响

试验比较了保护性耕作与常规翻耕处理土壤的含水量和温度。结果表明,保护性耕作土壤含水量比常规翻耕处理有所增加,整个生长季表现为:秸秆覆盖>留茬>常规翻耕;0-40 cm土层,随着土壤深度的增加含水量逐渐增加,其中留茬处理较常规翻耕处理增加11．8 g／kg,秸秆覆盖较常规翻耕处理增加23．2 g/kg。地温的变化规律表现为玉米大喇叭口期以前保护性耕作各土层地温均低于常规翻耕处理,即常规翻耕>留茬>秸秆覆盖;0-20cm耕作层内,播种时留茬处理土壤温度比常规翻耕处理低0．5℃,秸秆覆盖处理比常规翻耕处理低6．6 ℃;出苗时,留茬处理的土壤温度较常规翻耕处理低0．8℃,秸秆覆盖处理较常规翻耕处理低413℃;大喇叭口期以后,各处理地温逐渐降低并趋于一致。保护性耕作土层的含水量增加,有利于作物生长;而早春地温低则不利于出苗,易对作物生长造成不利影响,两者有一定的补偿效果,有必要进一步深入研究以克服其早春地温低回升慢的缺点。     

凉山光叶紫花苕生物性状与影响草、种生产因素的分析

对凉山光叶紫花苕Vicia villosa多生态观测分析,低山河谷区、二半山区秋季播种可完成全部生育过程,高寒山区越冬率低,随海拔增高植株性状表型值出现明显差异;经性状相关程度通径分析得出,影响产草的主要性状是叶质量和分枝长度,影响产种的主要性状是单株质量、结荚数、分枝长度;单株产种量及种子质量低山河谷区优于二半山区,原种生产区宜建在凉山低山河谷区。研究得出8月底前播种为适宜期,生产草适宜用种量60~105 kg/hm2,生产种子适宜用种量为22.5~37.5 kg/hm2,生产种子应采用冬前刈割1次后留种,生产草在冬前刈割1次,开春后刈割1~2次。     

柳州甘蔗生育北界气候过渡带大规模种植的气候风险与应对策略

通过分析位于柳州甘蔗生育北界气候过渡带的融安县气候资源对甘蔗生长发育的利弊条件以及霜冻、干旱、洪涝灾害的气候风险,提出融安县大规模发展甘蔗生产的气候应对策略,从而论证了：只要合理利用山区特殊的气候资源,通过物力、人力做到趋利避害,位于甘蔗生育北界气候过渡带的融安县完全具备大规模发展甘蔗种植的气候可行性。     

对水池设计中几个常见问题的看法

通过作者多年在水池设计中所遇到一些常见问题,从结构专业的角度出发,分析探讨了地下水位的确定、伸缩缝的设置、后浇带的做法及设计与施工配合等问题。     

Durability and Meso Interfacial Transition Zone Optimization of Reinforced Concrete Cover

Aiming at the low service life and bad durability of the traditional concrete structure and concrete cover, the high dense concrete cover (HDC) was produced with the optimization of interfacial transition zone in meso scale(50 100μm) between cement mortar and aggregate of the ordinary concrete. Moreover, some properties of HDC were studied, including the impermeability, the anti corrosion behavior, anti acidic gas corrosion and freeze resistance. It was shown that the impermeability of HDC was excellent with very low permeability. Compared with ordinary concrete, the anti corrosion behavior of HDC was remarkably strengthened. And under the condition of erosion accelerated by CO2 and SO2, the freeze resistance such as the appearance after freezing and thawing, mass loss and relative dynamic modulus of HDC was better than that of ordinary concrete and neutralization depth of 90 day was less than 1 mm. On the other hand, the results of Scanning Electron Microscope (SEM) experiment indicated that the size of interfacial transition zone of HDC was effectively reduced and the microstructure compactness of concrete was increased. Therefore, it was found that the special producing technology and characteristics of HDC can improve the durability, and then the service life of structure was increased effectively.     

Cylindricity error evaluation using artificial bee colony algorithm with tabu strategy

For cylindricity error evaluation, the Least Squares Method (LSM) is not good enough because of the big error, while the bionics algorithms such as Genetic and Ant Colony Algorithm need to set many parameters and converge slowly, an Artificial Bee Colony Optimization Algorithm is proposed to evaluate the minimum zone cylinder (MIC). This Algorithm refers the tabu strategy for tabu search algorithm to use the Tabu table to save the local optimization results. It enhances the control effect of parameter limit and improves the global convergence ability. Experiment results indicate that this method can converge to the global optimization very quickly. The average runtime is nearly 1.2 s. It is applicable to the real time processing system such as Three Coordinate Measuring Machine.     

The potential of hinoki (Chamaecyparis obtusa [Sieb. et Zucc.] Endlicher) plantation forests for the restoration of the original plant community in Japan

We estimated the potential of plantation forests for the restoration of the original plant community. We compared the understory vegetation in hinoki (Chamaecyparis obtusa [Sieb. et Zucc.] Endlicher) plantations at the understory re-initiation stage and in adjacent natural forests. To estimate the effect of the original natural forests on the understory species composition of plantation forests, we established study sites in five types of natural forests (mature evergreen broadleaf, mature deciduous broadleaf, mature evergreen coniferous, immature deciduous broadleaf warm-temperate, and immature deciduous broadleaf cool-temperate) and nearby plantation forests. The understory vegetation of the plantation forests had a higher species richness, a higher proportion of early-seral species, and a higher proportion of herb or fern species than the natural forests. The differences between natural and plantation forests varied according to the species composition of the natural forests. The composition of the understory vegetation of the plantations at the understory re-initiation stage was similar to that of the immature deciduous forests. The characteristics of immature, disturbed forests remained in the understory vegetation of the hinoki forests. No great loss of species was observed. Our findings suggest that most of the original forest species still survive in the understory of the plantation forests. These forests have the potential to follow the successional pathway to broadleaf or mixed forests via thinning or clear-cutting without planting.     

河岸植被缓冲带规划及重建研究——以长株潭湘江河岸带为例

分析了长株潭湘江河岸带现状及存在的景观生态问题,进行了河岸植被缓冲带典型区段的划分,依据河岸植被缓冲带规划及重建原理,提出了长株潭湘江河岸植被缓冲带的规划重建措施,对重建后的河岸植被缓冲带生态系统效能进行了预测,以期为长株潭湘江河岸带的管理、建设提供参考和借鉴.     

克拉玛依市中心城区绿地系统健康现状评价与分析

概要地介绍了利用专家打分法、层次分析法以及指数和法模型,构建克拉玛依市中心城区绿地系统研究区的健康评价体系的过程;同时结合该评价体系的评价结果与实际状况,划分了该市绿地种类。通过各主要权重指标分析了克拉玛依市中心城区绿地系统绿地现状,认为该市绿地系统总体处于亚健康状态,从而提出该市提高绿地健康指数的管理对策及措施。