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31.
City squares are an important part of urban public spaces and play an important role in improving the quality of urban landscapes. For mountain cities, city squares with mountainous characteristics formed by its special geographical environment, which have more identifiability and uniqueness than that in plain cities, have greater influence on the promotion of city image. Their unique regional cultural characteristics and local customs and practices have shaped the totally different temperament of mountain cities. Based on the dialectical relationship between the square, the landscape and the culture, this paper took Shiyan Broadcasting Media Center Square for example to explore the ideas of landscape design in mountain cities. 相似文献
32.
Growing media (substrate) is a fundamental part of a green roof, providing water, nutrients and support to plants. However, little research has reviewed how it affects plant performances in different climatic regions. This study aims to analyse published research on green roof growing medium across world’s climate zones. Findings are structured according to Köppen–Geiger climate classification, aiming to investigate the prevalence of research conducted in different climate zones. Results from full-scale studies and laboratory or greenhouse experiments were reviewed. The later were included as they provide systematic knowledge on the effect of individual factors on system performances although cannot provide climate specific information. Studies discussed effects of major substrate components and depths on plant survival and establishment using standard test procedures. Results showed that most research in the subject were in temperate (group C climate classification), continental (group D) and dry climates (group B), respectively. Considerable number of investigations was conducted in controlled laboratory or greenhouse environments. Based on the results, future green roof research and guidelines should consider climate specifications of the region in designing growing medium, depths and attribute of green roof substrates in order to ensure enhanced plant performance. Especially, for more fragile but less investigated dry climate, considerations should be made to tackle heat fluctuations and drought stress by enhancing water holding capacity and thermal isolation of the substrate. To move forward, sustainable building solutions as a part of future urban forms, climate-adaptive green roof systems should be included into future research, practice and guidelines. 相似文献
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复垦土壤贫瘠,磷素含量极低,严重影响作物的生长发育。研究化肥、有机肥配施荧光假单胞菌对玉米产量和复垦土壤磷素形态以及酶活性的影响,为加速培肥矿区复垦土壤提供技术支持和理论依据。该研究在山西省晋中市采煤塌陷区进行了2a的定位培肥试验,共设置7个处理:不施肥(CK)、单施化肥(CF)、化肥配施荧光假单胞菌(CFB)、单施有机肥(M)、有机肥配施荧光假单胞菌(MB)、化肥配施有机肥(MCF)、化肥有机肥配施荧光假单胞菌(MCFB)。采集各处理土壤样品测定相关指标,并通过相关性分析和结构方程模型来探究各形态磷与有效磷以及土壤磷酸酶之间的关系。结果表明:1)在整个试验周期(2021—2022年),与CK相比,不同施肥处理均能显著提高玉米产量以及各形态磷素。其中,以MB处理下的玉米产量、有效磷、磷活化系数、不稳定态磷以及部分不稳定态磷含量最高,与CK处理相比,玉米产量显著提高2.4倍,有效磷含量、磷活化系数值、不稳定态磷含量、部分不稳定态磷含量分别显著提高4.5倍、4.67倍、0.98倍、1.16倍。2)与CK处理相比,化肥、有机肥配施荧光假单胞菌能够显著提高土壤微生物量磷以及酸性和碱性磷酸酶活性,配施荧光假单胞菌后,微生物量磷水平和碱性磷酸酶活性均以MB较M处理提升效果最佳,分别显著提高27.08%和9.56%。3)结合相关性分析以及结构方程模型,随着荧光假单胞菌和化肥有机肥的施入,在提高不稳定态磷素含量的同时也提高有效磷的供应能力,促进磷素在农田生态系统中的循环转化,产生积极的正向影响。化肥、有机肥配施荧光假单胞菌能够一定程度上影响复垦土壤玉米产量及产量性状、各形态磷素及有效性和微生物活性,对复垦土壤脆弱的农田生态系统产生积极影响。 相似文献
35.
Fatty acid methyl ester (FAME) profiles, together with Biolog substrate utilization patterns, were used in conjunction with
measurements of other soil chemical and microbiological properties to describe differences in soil microbial communities induced
by increased salinity and alkalinity in grass/legume pastures at three sites in SE South Australia. Total ester-linked FAMEs
(EL-FAMEs) and phospholipid-linked FAMEs (PL-FAMEs), were also compared for their ability to detect differences between the
soil microbial communities. The level of salinity and alkalinity in affected areas of the pastures showed seasonal variation,
being greater in summer than in winter. At the time of sampling for the chemical and microbiological measurements (winter)
only the affected soil at site 1 was significantly saline. The affected soils at all three sites had lower organic C and total
N concentrations than the corresponding non-affected soils. At site 1 microbial biomass, CO2-C respiration and the rate of cellulose decomposition was also lower in the affected soil compared to the non-affected soil.
Biomarker fatty acids present in both the EL- and PL-FAME profiles indicated a lower ratio of fungal to bacterial fatty acids
in the saline affected soil at site 1. Analysis of Biolog substrate utilization patterns indicated that the bacterial community
in the affected soil at site 1 utilized fewer carbon substrates and had lower functional diversity than the corresponding
community in the non-affected soil. In contrast, increased alkalinity, of major importance at sites 2 and 3, had no effect
on microbial biomass, the rate of cellulose decomposition or functional diversity but was associated with significant differences
in the relative amounts of several fatty acids in the PL-FAME profiles indicative of a shift towards a bacterial dominated
community. Despite differences in the number and relative amounts of fatty acids detected, principal component analysis of
the EL- and PL-FAME profiles were equally capable of separating the affected and non-affected soils at all three sites. Redundancy
analysis of the FAME data showed that organic C, microbial biomass, electrical conductivity and bicarbonate-extractable P
were significantly correlated with variation in the EL-FAME profiles, whereas pH, electrical conductivity, NH4-N, CO2-C respiration and the microbial quotient were significantly correlated with variation in the PL-FAME profiles. Redundancy
analysis of the Biolog data indicated that cation exchange capacity and bicarbonate-extractable K were significantly correlated
with the variation in Biolog substrate utilization patterns.
Received: 8 March 2000 相似文献
36.
Martin Wegehenkel 《植物养料与土壤学杂志》1998,161(5):577-582
Using TRIME-TDR for the determination of soil water dynamics on sandy soils In this study the suitability of the TRIME-TDR system for the determination of soil water content was analysed. For this purpose a period of three years with continuous data of soil water contents, measured by TRIME-TDR, and soil water suction measured by tensiometer were available. Additionally soil samples at different times were taken for gravimetric moisture analysis. The determinations of soil moisture with the TRIME-TDR is based on a new measuring technique. The soil water contents measured by TRIME-TDR were analysed by comparison with corresponding soil moisture values from gravimetric measurements of soil samples. The soil water contents determined by TRIME-TDR in comparison with gravimetric soil moisture values show an absolute mean error of 7.9 Vol%. In most cases the soil water contents measured by TRIME-TDR were distinctly higher than the corresponding soil moisture values from gravimetric measurements. After correcting the TRIME-TDR the absolute mean error was reduced to 2.5 Vol%. Due to the results of this study soil water contents measured by TRIME-TDR-technique cannot be used in hydrological or ecological studies without a check based on the comparison with gravimetric soil moisture values. 相似文献
37.
B. Rivera-Hernández J.J. Obrador-Olán L.A. Aceves-Navarro 《Agricultural Water Management》2010,97(9):1365-5774
In Mexico, corn production, part of which is sweet corn, is mainly destined for human consumption. In the present work, the morphological quality of sweet corn ears was assessed in response to four levels of soil moisture tension indicating irrigation start (−5, −30, −55, and −80 kPa) and three levels of phosphate fertilization (60, 80 and 100 kg ha−1) in carstic soils in the south-east of Mexico. A factorial experimental design with three replicates was used. The following variables were determined: fresh weight (SCFWh), dry weight (SCDWh), diameter (SCDh), and length (SCLh) of sweet corn ears, all without husk, as well as number of kernels (NKxE), number of unfilled kernels (NUK), number of rows (NRxE), and dry kernel weight per ear (DKW). Yield of fresh (YFSCh) and dry (YDSCh) sweet corn ears, both without husk, and the harvest index (HI) were also determined. HI did not show significant statistical differences among irrigation or fertilization treatments. Regarding the other variables, the effect of the more humid treatments (−5 and −30 kPa) and the effect of the higher phosphorus doses (80 and 100 kg ha−1) were statistically equal (P ≤ 0.01) with the lowest NUK and the highest values of all other variables; therefore, irrigation start at soil moisture tension of −30 kPa and phosphate fertilization application of 80 kg ha−1 are recommended. At this level of soil moisture, the mean values over the three fertilization levels and all the replicates, obtained for SCFWh, SCDh, SCLh and NKxE were 198.5 g, 4.39 cm, 26.72 cm and 467 grains, respectively. According to the regression models, moisture tensions from −11.8 to −24.0 kPa, and phosphate fertilization doses from 87.7 to 102.2 kg ha−1 minimize NUK and maximize the values of the rest of the variables. The highest irrigation water use efficiency was found in the moisture tension treatment of −30 kPa with an increase of 27 kg ha−1 ears for each millimeter of applied irrigation water. 相似文献
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为了研究如何在黑龙江省加快城乡一体化进程,实现城乡一体化建设目标,运用调查研究的方法,以黑龙江垦区的相关农场和地方试验区为样本,对黑龙江省城乡一体化建设进行了分析研究。研究结果表明:近10年来黑龙江省城镇化水平呈现出增长幅度放缓的态势,制约了城乡一体化的进程。黑龙江省要实现城乡一体化,必须以农民居住集中化、土地利用集约化为基础。其必要性表现在:有利于实现农业生产规模化和机械化;有利于提高农民组织化程度;有利于缩小城乡居民生活水平差异,实现城乡统筹发展;有利于整合和优化社会资源,集中财力物力加快城镇化建设步伐。同时又具有政治、经济与财政、技术、行政可操作性方面的可行性。 相似文献