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101.
区域水资源系统仿真预测及优化决策研究──以汉中盆地平坝区为例 总被引:13,自引:1,他引:13
本文运用系统动力学(SD)模型对汉中盆地平坝区水资源系统进行仿真预测分析,并以系统动力学模型为基础,建立了汉中盆地平坝区水资源系统开发的多个方案,通过多方案、多目标综合评价,优选出本区水资源系统开发的最佳方案和配套政策。 相似文献
102.
103.
Responses of butachlor degradation and microbial properties in a riparian soil
to the cultivation of three different plants 总被引:1,自引:0,他引:1
A pot experiment was conducted to investigate the biodegradation dynamics and related microbial ecophysiological responses to butachlor addition in a riparian soil planted with different plants such as Phragmites australis, Zizania aquatica, and Acorus calamus. The results showed that there were significant differences in microbial degradation dynamics of butachlor in the rhizosphere soils among the three riparian plants. A. calamus displays a significantly higher degradation efficiency of butachlor in the rhizosphere soils, as compared with Z aquatica and P. australis. Half-life time of butachlor degradation in the rhizospheric soils of P. australis, Z aquatica, and A. calamus were 7.5, 9.8 and 5.4 days, respectively. Residual butachlor concentration in A. calamus rhizosphere soil was 35.2% and 21.7% lower than that in Z aquatica and P. australis rhizosphere soils, respectively, indicating that A. calamus showed a greater improvement effect on biodegradation of butachlor in rhizosphere soils than the other two riparian plant. In general, microbial biomass and biochemical activities in rhizosphere soils were depressed by butachlor addition, despite the riparian plant types. However, rhizospheric soil microbial ecophysiological responses to butachlor addition significantly (P < 0.05) differed between riparian plant species. Compared to Z aquatica and P. australis, A. calamus showed significantly larger microbial number, higher enzyme activities and soil respiration rates in the rhizosphere soils. The results indicated that A. calamus have a better alleviative effect on inhibition of microbial growth due to butachlor addition and can be used as a suitable riparian plant for detoxifying and remediating butachlor contamination from agricultural nonpoint pollution. 相似文献
104.
冬小麦根系生长与土壤水分利用方式相互关系分析 总被引:20,自引:0,他引:20
1995~1996年在中国科学院栾城农业生态系统联合站布置了冬小麦水分试验,在土壤连续干旱条件下考察了冬小麦返青至成熟阶段根系生长和土壤水分利用方式。给出并验证了可用于分析二者相互关系的定量模型。根据以下两点分析了作物利用土壤水分特征:①将土壤含水量开始降低时间视为吸水峰到达某一深度时间;②吸水峰下达到某一土层后,土壤含水量即随生育进程以指数形式逐渐降低。愈接近地表的土层,根系分布量愈大,根系日增长率在抽穗期最大,至扬花期根量及根深达最大值,根系吸水范围和深度基本取决于营养阶段根系生长发育状况。返青时,根系已下扎到1m,根系生长峰与吸水峰基本同步下移,根系下扎到某一土层后继续生长发育,直至土壤有效含水量只剩40%~20%时为止。根系下扎虽深达180cm,而且下层根系吸水功能较强,有效水量较大,但终因根系分布量太少,致使作物利用水分的土层深度只达120cm,吸收的水量大多来自0~60cm土层。在土壤连续干旱条件下,土壤水分不足亦是制约根系吸水功能的一个重要因素。在作物利用土壤水分初期,根系吸水速率最大,随着土壤含水量逐渐减少,根系吸水速率随之降低。土壤中有效含水量比例在08以上,根系吸水速率大致以线性关系大 相似文献
105.
滑动弧放电等离子体裂解正己烷实验研究 总被引:4,自引:0,他引:4
考察了一种新型低温等离子体发生方式滑动弧放电对正己烷的裂解效果,检测了主要裂解产物,并分析了供给电压、正己烷初始浓度、电极材料和反应器结构对裂解率的影响.结果表明,该法可以有效处理正己烷,最高裂解率达96%.在空气中的主要裂解产物为CO2、CO、NO2和H2O.增大供给电压可以提高正己烷裂解率;初始浓度增大后裂解率下降,但绝对处理量增大;相同能耗情况下,采用铁电极时能量利用率最低,正己烷裂解率低于铝电极和铜电极;电极最小间距和喷嘴直径之间的比例关系影响裂解效果,优化两者的匹配关系可以提高裂解率. 相似文献
106.
现代水泥工业是近代科学技术的产物,也是社会物质文明和经济增长的支撑之一.根据现今科技发展成果及其应用趋势来判断,水泥在今后相当长的时期内仍是一种难以被替代的经济实用的建筑材料.虽然水泥工业在整个国民经济产值中所占的比例很小,但是水泥在整个国家经济建设中则是一种不可或缺的大宗建筑材料. 相似文献
107.
Organic phosphorus fractions in organically amended paddy soils in continuously and intermittently flooded conditions 总被引:1,自引:0,他引:1
Soil organic phosphorus (SOP) can greatly contribute to plant-available P and P nutrition. The study was conducted to determine the effects of organic amendments on organic P fractions and microbiological activities in paddy soils. Samples were collected at the Changshu Agro-ecological Experiment Station in Tahu Lake Basin, China, from an experiment that has been performed from 1999 to 2004, on a paddy soil (Gleysols). Treatments consisted of swine manure (SM), wheat straw (WS), swine manure plus wheat straw (SM + WS), and a control (chemical fertilization alone). Organic amendments markedly increased soil total organic phosphorus (TOP) and total organic carbon (TOC), especially in continuously flooded conditions. Based on the fractionation of SOP, organic amendments significantly increased soil labile organic phosphorus (LOP), moderately labile organic phosphorus (MLOP), and moderately stable organic phosphorus (MSOP) compared with the control. For SM and SM + WS treatments, LOP in continuously flooded soils decreased by 30.1 and 36.4%, respectively, compared to intermittently flooded soils. In organically amended soils, continuous flooding showed significantly lower microbial biomass phosphorus (MBP) and alkaline phosphatase activities (APA) than intermittent flooding. In intermittently flooded conditions, incorporating organic amendments into soil resulted in greater P uptake and biomass yield of rice than the control. In the intermittently flooded soils, APA (P < 0.05) and MBP (P < 0.01) were significantly and positively related to TOP, LOP, MLOP, and MSOP, whereas in continuously flooded soils, there was a significant (P < 0.05) negative relationship between MBP, TOP, and MSOP. Based on soil organic P fractions and soil enzymatic and microbiological activities, continuous flooding applied to paddy soils should be avoided, especially when swine manure is incorporated into paddy soil. 相似文献
108.
The characteristics of ammonia in drinking water sources in China were evaluated during 2005-2009. The spatial distribution and seasonal changes of ammonia in different types of drinking water sources of 22 provinces, 5 autonomous regions and 4 municipalities were investigated. The levels of ammonia in drinking water sources follow the order of river > lake/reservoir > groundwater. The levels of ammonia concentration in river sources gradually decreased from 2005 to 2008, while no obvious change was observed in the lakes/reservoirs and groundwater drinking water sources. The proportion of the type of drinking water sources is different in different regions. In river drinking water sources, the ammonia level was varied in different regions and changed seasonally. The highest value and wide range of annual ammonia was found in South East region, while the lowest value was found in Southwest region. In lake/reservoir drinking water sources, the ammonia levels were not varied obviously in different regions. In underground drinking water sources, the ammonia levels were varied obviously in different regions due to the geological permeability and the natural features of regions. In the drinking water sources with higher ammonia levels, there are enterprises and wastewater drainages in the protected areas of the drinking water sources. 相似文献
109.
环境科学的非线性理论及其意义 总被引:14,自引:0,他引:14
在前人和本课题研究成果的基础上,通过综合分析和理论推断,提出了环境科学的非线性理论概念,并以若干实测阐述了非线性理论在环境科学研究和污染控制中的推导意义。 相似文献
110.
Ye Changming 《环境科学学报(英文版)》1995,7(3):259-265
FoundationofregionalecologyanditsmethodologiesYeChangming(ResearchCenterforEco-EnvironrnentalSciences,ChineseAcadernyofScienc... 相似文献