【作者】 王静；

【导师】 程积民；

【作者基本信息】 西北农林科技大学 ， 生态学， 2003， 硕士

【摘要】 黄土高原半干旱区多年来由于不合理的土地利用和滥垦滥牧等现象，致使土壤沙化，草地退化，水土流失等一系列生态环境问题严重威胁着人类的生存与发展，多年的研究已证明，生物措施是生态环境建设与治理的根本性措施，因此，针对目前的自然现状，选择抗逆性强、生长快、生产中急需的优良牧草进行了定位试验研究。 本文研究了在黄土高原大面积生长的优良禾本科牧草—芨芨草的生理生态特性、水肥因子对它的影响以及同其它两种牧草(本氏针茅和厚穗冰草)间的比较，为芨芨草的开发利用提供科学依据。研究结果如下： 1、芨芨草草地土壤含水量季节变化和垂直变化较为显著。在整个生育期土壤含水量可以划分为3个阶段：春初为水分缓慢蒸发期(3月份)，春季为水分大量损耗期(4-7月)，夏秋为水分恢复期(8-9月)。在整个土壤剖面上，可以划分为3层：即0-30cm为活跃层；30-120cm为次活跃层；120-200cm为稳定层。芨芨草草地土壤容重较本氏针茅草地和裸地小，各层的总孔隙度和毛管孔隙度明显高于本氏针茅草地和裸地，但非毛管孔隙度较本氏针茅草地和裸地低。 2、芨芨草株高初期增加较慢，在生长的6月至8月进入快速生长期，之后几乎不变，甚至减小，生长速率曲线为多峰型。水分对株高的增加影响较大，施肥对芨芨草株高的增加有影响，差异不甚明显，但对分蘖有较强的促进作用。 3、水分对芨芨草叶片的生长影响极为明显，水分越低，叶片长度越小，单叶叶面积越小，但水分过多，会抑制叶片的伸长。施肥对芨芨草叶片长度和叶面积存在显著影响，各施肥处理对叶片长度和叶面积均有不同幅度增加，但各施肥处理间差异不甚明显。 4、芨芨草的生物量在整个生育期呈单峰曲线，植株组织含水量随生长时间的延长逐渐下降。芨芨草非同化器官生物量鲜重在7月达到最大值，同化器官生物量鲜重8月达到最大值。地上部分生物量主要集中在0-100cm，各时期产量结构趋势几乎相同。水分、施肥对芨芨草地上部生物量积累和生物量分配的影响差异显著。芨芨草适宜生长的降水量为400-500mm。 5、叶片的水分状况与降水量和牧草物候期相关，随时间的延长，叶片含水量越来越小。在干旱胁迫下，叶片含水量减少，叶片水分亏缺严重。施肥对芨芨草叶片含水量影响不大，但造成水分饱和亏增加。 6、芨芨草叶片光合速率日进程受环境影响，在不同时期差异较大，6月、7月呈双峰曲线，8月和9月，光合速率则呈单峰曲线；芨芨草蒸腾速率和气孔导度日进程在整个生育期内基本上呈单峰曲线。回归分析和相关分析表明，不同时期对芨芨草叶片光合速率、蒸腾速率和气孔导度起决定性作用的环境因子不同，而在整个生育期它们三者之间都存在着极显著的正相关关系。芨芨草光合蒸腾速率的季节变化存在极强的规律性，即分别在6月和8月达到峰值。水分和肥料对友友草光合生理生态特性的影响差异显著，光合速率随灌水量、施肥量的增加而增加。 7、对照牧草厚穗冰草于8月份生物量达到高峰，本氏针茅则于5月份达到高峰期。单位面积最大生物产量的大小顺序为:厚穗冰草)友友草)本氏针茅。在产量最高时期，友友草同化器官占的比例较大(凡七习)，而厚穗冰草同化器官所占比例较小(凡七<l)。岌友草、本氏针茅和厚穗冰草的光合速率差异显著，而蒸腾速率差异不大。友岌草的光合能力和单叶水分利用效率比两种对照牧草高。更多还原

【Abstract】 Due to irrational land utilization, absurd assarting and herding, a series of environmental problems, such as sandy soil, grassland degeneration, soil and water loss, appeared, which severely threatened to survival and development of human being. It was proved that biomic-measure was the radical measure of ecology environment construction and harnessing. Thus, a research on choosing a kind of grass, which was good, stronger stress resistance and faster growth velocity, was carried out.In the paper, the ecophysiological characteristics of Achnatherum splendens, the effects of water and fertilizer on it and a comparative research to other grass were studied, which provided scientific basis on utilization and exploitation of Achna therum splendens. The results were as follows:1. The seasonal and vertical variation of soil water content was significant. During the whole growing stages the variation of soil water content could be divided into three distinct stages: water-evaporated slowly in the initial spring (March), water-consumed largely in spring (April to July) and water-recovered in summer (August to September). The soil section could be divided into three parts: active water layer (0-30cm), sub-active water layer (30-120cm) and stable water layer (120-200cm). Compared to Stipa Bungeana grassland and fallow ground, the volume weight was smaller, total porosity and capillary porosity were higher, but non-capillary porosity was lower.2. Achnatherum splendens height increased slow in the initial stages, fast from June to August and slow again after that. The growth velocity curve of height was multi-humped. The effect of water on height increase was significant, fertilizer could boost in tillering but influenced not markedly on height.3. The effect of water on leaf was very marked. Leaf length and leaf area increase were restrained under water stress and excessive water supply could limit them, too. Fertilizer could increase leaf length and leaf area, but the difference of the effect among different fertilizer levels was not significant.4. The biomass was single-humped curve. Water ratio in plant decreased gradually from the beginning. The highest wet biomass of non-assimilation organ appeared in July, while that of assimilation organ arrived in August. The ratio of biomass in different layer was almost the same in different periods and the majority of biomass distributed in Ocm to100cm above ground. Water and fertilizer had a strong influence on biomass accumulating and biomass distribution. The water supply level that was fit for growth was 400- 500mm.5. Leaf water content was correlated with precipitation and phonological period and induced gradually with time passed. Under water stress, leaf water content decreased and leaf water deficit intensified. Fertilizer influenced trivially on leaf water content, while intensified markedly on the water saturation deficit.6. Due to the environmental influence, the daily variation of photosynthesis rate of Achnatherum splendens leaf in different months was different ,Which was expressed as a two-humped curve in June and July and a single-humped curve in August and September. And the daily change of transpiration rate and stomatal conductance were single-humped curve. Correlation analysis showed that in different months the decisive environmental factor that influenced photosynthesis rate, transpiration rate and stomatal conductance was different, but they had positively correlativity each other. The seasonal variation of photosynthesis rate and transpiration rate of Achnatherum splendens leaf was regular and reached the higher point in June and August. Water and fertilizer influenced the ecophysiological characteristics of Achnatherum splendens leaf markedly which raised with the increase of water and fertilizer.7. The highest biomass of Aneurolepidium dasystachys appeared in August, while that of Stipa Bungeana appeared in May. The sequence of the highest biomass per area was: Aneurolepidium dasystachys} Achnatherum splendens} Stipa Bung更多还原