基于降雨-径流试验的高寒草甸产流机制研究

对黄河源区高寒草甸产流机制进行研究,为河源区生态环境保护、水资源科学规划管理提供基础水文理论认知。基于野外降雨-径流试验,通过回归分析构建考虑坡度和覆被因子的暴雨和中小雨产流计算模式,精度良好,能够反映暴雨和中小雨2种降雨模式下高寒草甸产流的一般特征。试验结果表明,因草甸土-植体系蓄容能力较强,高寒草甸区地表产流主要发生在暴雨模式下,中小雨模式下的地表产流量一般很小。模式应用表明,草甸发生退化后,暴雨和中小雨入渗均有减少,暴雨模式下退化草甸比高覆草甸入渗减少约12%,中小雨模式下减少约3%。     

江河源区高寒嵩草草甸土壤氨基酸成分和含量特征分析

通过高效液相色谱技术分析了青海省果洛州达日县窝赛乡原生嵩草草甸、严重退化草地及人工草地三类植被土壤中各种氨基酸成分及含量。结果表明:(1)三种类型土壤中都检测出19种常见氨基酸:精氨酸、天冬氨酸、丝氨酸、谷氨酸、苏氨酸、丙氨酸、甘氨酸、氨基丁酸、脯氨酸、蛋氨酸、缬氨酸、苯丙氨酸、异亮氨酸、亮氨酸、胱氨酸、组氨酸、鸟氨酸、赖氨酸、酪氨酸;(2)测定结果表明原生嵩草草甸土壤的氨基酸总量显著高于人工恢复重建草地和严重退化土壤氨基酸,而后两者之间差异不显著。原生高寒草地的土壤(6316.28μgg-1)严重退化草地土壤(2977.10μgg-1)人工恢复重建草地土壤(2975.90μgg-1)。(3)原生高寒草地土壤氨基酸总体呈现下降趋势:5月氨基酸含量最高,随后6月7月的显著下降,8月稍微有所回升,9月氨基酸含量到达最低;严重退化草地土壤与人工恢复重建草地土壤氨基酸含量季节变化相似,氨基酸总量在6月份到达最高点,随后7月8月显著下降,9月份稍微有所回升。     

基于FWO法与CR法的中蒙边境森林草原交错区沟塘草甸羊草热解动力学分析

以内蒙古自治区阿尔山市内沟塘草甸为研究区域,选取典型草本羊草为研究对象,运用热重分析法以通氧速率10、20、30 mL/min,在升温速率分别为40、80 ℃/min的条件下进行热失重行为研究。使用TG-DTG曲线分析样品的热解过程,利用Coats-Redfern（CR）积分法和Flynn-Wall-Ozawa（FWO）积分法对样品的快速热解阶段进行动力学分析,得出在不同氧气浓度下样品的热解活化能和指前因子并求得相应参数。结果表明羊草热解过程分为：失水阶段、快速热解阶段、炭化阶段。其中快速热解阶段为350～450 ℃,此阶段中升温速率越快,温度滞后现象越明显;通氧速率越快,温度超前现象越明显。热解过程及动力学参数分析表明,Flynn-Wall-Ozawa法更适用于羊草热解过程,引发火灾危险程度的通氧速率为：30 mL/min＞20 mL/min＞10 mL/min。     

百花山自然草甸群落结构与组成分析

为构建自然的混播组合,以百花山草甸的草本植物群落为调查对象,对其进行一个生长季的调查,记录分析草甸的植物组成、垂直结构、季相变化特征。结果表明：共记录野生花卉27科、51属、62种,其中90.32%为多年生植物;将草甸按株高分为3个亚层,各亚层植物平均种数、株数、覆盖度的比例分别约为第一亚层:第二亚层:第三亚层=1:5:4、3:13:4、1:7:2;随时间变化第三亚层Shannon-Wiener指数、Pielou指数、Gleason指数均呈现先降低后升高的趋势,第二亚层3项指数均呈现先升高后降低的趋势,第一亚层3项指标均最低。自然草甸中的植物组成、垂直结构、季相变化特征等是影响草甸的重要因素,基于此可为模拟构建更加自然的混播组合提供参考。     

黄河源区河岸带高寒草甸植物根-土复合体抗拉特性研究

植物根系作为一种特殊的河岸物质组成材料,对改变土体力学特性具有重要作用。采用现场挖空法,在黄河源区二元结构河岸的3个点位开展2种植被群落类型的根-土复合体抗拉特性原位试验,分析滨河草甸植被根系对增强河岸物质抗拉特性的作用。高寒草甸河岸崩塌宽度为0.52~0.70m,明显大于一般黏性土河岸的崩塌宽度,而且原生草甸河岸的崩岸宽度大于中度退化草甸河岸。原位试验结果表明原生高寒草甸植物群落优势植物的华扁穗草的单根平均抗拉强度为31.67 MPa,比中度退化的优势植物垂穗披碱草高15.52 MPa,且其根面积比相比中度退化的植物群落高2~3倍。可见,植物根系的存在对抑制河岸崩塌速率具有一定的作用。应用河岸崩塌临界平衡公式,计算研究区3个点位的根-土复合体的抗拉强度值分别为66.86,21.29和22.63 kPa,这说明单根抗拉强度及根面积比对提高根-土复合体抗拉强度具有重要的作用。通过用修正系数后的Wu-Waldron根系增强模型公式验证,2种计算方法得出的根-土复合体抗拉强度值符合较好,相对误差在2.12%~9.21%。试验方法可为原位测量含根河岸土体的抗拉强度提供参考,同时为揭示黄河源区弯曲河流河岸崩退机制提供数据支撑。     

Plant quality and harvest in old meadows grazed by reindeer in spring

Dry matter (DM) production and nutritional quality of plants were recorded on an old meadow before, during and after it was grazed by reindeer (Rangifer tarandus tarandus; 15 reindeer ha⁻¹) in the spring of 1996 and 1997 in northern Norway. Mean herbage harvest after 54 and 50 days of growth including 25 and 24 days of reindeer grazing was 1217 ± 320 kg DM ha⁻¹ in 1996 and 2297 ± 495 kg DM ha⁻¹ in 1997 respectively. On ungrazed old meadow, in contrast (P < 0.05), mean herbage harvest after 54 and 50 days of growth was 4159 ± 1164 kg DM ha⁻¹ in 1996 and 3791 ± 275 kg DM ha⁻¹ in 1997 respectively. In 1997, mean herbage harvest after 50 days of growth including 7 days of grazing by reindeer was as high as 3441 ± 180 kg DM ha⁻¹ (P > 0.05). Crude protein content (% of DM) was 25% early in the growing season in both 1996 and 1997. After 54 and 50 days of growth including 25 and 24 days of reindeer grazing, crude protein content was about 17% of DM in both 1996 and 1997 respectively, compared with about 12% of DM in ungrazed old meadow in both years. In 1997, crude protein content was 13.3% of DM after 50 days of growth including 7 days of reindeer grazing. The grazed and ungrazed old meadow contained about 20% (of DM) water‐soluble carbohydrates throughout the summer in both years. Mean plant cell wall content in ungrazed plants harvested after about 50 days was higher (51.5 and 49.1% of DM; P > 0.05) compared with plant cell wall content in grazed meadow (49.0 and 46.4% of DM) in 1996 and 1997 respectively. In vitro dry matter digestibility (%) of herbage harvest using rumen fluid from domestic ruminants was about 10% higher (73.4 ± 0.30 and 75.7 ± 0.28) in samples from grazed meadow compared with ungrazed meadow (66.2 ± 0.93 and 65.4 ± 1.19) in 1996 and 1997 respectively. Reindeer grazing of old meadow in spring maintains the vegetation at a younger phenological stage during the growing season when compared with ungrazed meadow. Therefore grazing increased the quality of the herbage, but decreased herbage harvest under conditions of high grazing intensity. © 2000 Society of Chemical Industry     

心土培肥犁改良瘠薄土壤的效果

研究根据心土培肥的改土技术要求研制出心土培肥犁,并分别在瘠薄黑土和碳酸盐草甸黑钙土上开展大面积机械改土试验,明确自主研发的心土培肥犁改土后对土壤理化性质影响及对作物产量的效果,为其广泛应用到低产土壤改良提供机械及技术支持。试验设深松、心土培肥和常规对照耕作,采用大田对比方法。研究结果表明:心土培肥和深松在不同类型土壤上对土壤理、化性质,对作物产量及产量性状影响后效不完全一致;心土培肥降低土壤抗剪强度后效明显,碳酸盐草甸黑钙土>10～30 cm土层土壤抗剪强度比对照降低6.65~12.16 kPa,黑土比对照降低8.20~11.31 kPa,碳酸盐草甸黑钙土改土后效果明显,黑土改土后效长,心土培肥改土效果优于深松;土壤容质量和硬度趋势同上;心土培肥提高土壤透气系数为2.78~14.28倍,饱和导水率为2.38~11.62倍;深松和心土培肥可提高下层土水分消耗比例,>30~60 cm土层耗水量为心土培肥区> 深松区>对照区,心土培肥耗水量比照高10%;心土培肥处理可提高土壤磷含量和供磷强度,>20～30 cm和>30~40 cm土层土壤供磷强度比对照分别提高4.19~5.17倍和4.96~17倍,碳酸盐草甸黑钙土高于黑土;心土培肥可提高玉米产量,碳酸盐草甸黑钙土上心土培肥增产幅度为6.82%~18.01%,黑土增产幅度为6.45%~11.18%,平均增产效果碳酸盐草甸黑钙土>薄层黑土,但黑土持续增产效果好。     

An Assessment of Storage Terms in the Surface Energy Balance of a Subalpine Meadow in Northwest China

T The heat storage terms in the soil-vegetation-atmosphere system may play an important role in the surface energy budget. In this paper, we evaluate the heat storage terms of a subalpine meadow based on a field experiment conducted in the complex terrain of the eastern Qilian Mountains of Northwest China and their impact on the closure of the surface energy balance under such non-ideal conditions. During the night, the average sum of the storage terms was -5.5 W m-2, which corresponded to 10.4% of net radiation. The sum of the terms became positive at 0730 LST and negative again at about 1500 LST, with a maximum value of 19 W m-2 observed at approximately 0830 LST. During the day, the average of the sum of the storage terms was 6.5 W m-2, which corresponded to 4.0% of net radiation. According to the slopes obtained when linear regression of the net radiation and partitioned fluxes was forced through the origin, there is an imbalance of 14.0% in the subalpine meadow when the storage terms are not considered in the surface energy balance. This imbalance was improved by 3.4% by calculating the sum of the storage terms. The soil heat storage flux gave the highest contribution (1.59%), while the vegetation enthalpy change and the rest of the storage terms were responsible for improvements of 1.04% and 0.77%, respectively.     

Social and environmental factors influence the suppression of pup-directed aggression and development of paternal behavior in captive meadow voles (Microtus pennsylvanicus).

During summer, female meadow voles (Microtus pennsylvanicus) maintain territories and males do not engage in paternal care. As day length shortens, territories dissolve and males nest with females and young. Because paternal behavior has never been studied in free-living meadow voles during colder months or in the laboratory under short photoperiods, the authors examined whether males housed in short day (SD) lengths exhibited more frequent or better quality paternal behavior than males housed in long day (LD) lengths. Sexually and parentally inexperienced (naive) SD males exhibited proportionally more and qualitatively better paternal care than naive LD males. SD males were more responsive than LD males to classic social cues associated with preparturn aggression inhibition and paternal onset. SD sires also displayed qualitatively better paternal behavior than LD sires. These data suggest that meadow vole paternal state is regulated by specific social and environmental cues that may contain reliable information about ecological conditions that favor paternal care. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Enclosure size and hormonal state affect timing of nest return in female meadow voles (Microtus pennsylvanicus).

We investigated 2 aspects of the hormonal regulation of maternal behavior in meadow voles (Microtus pennsylvanicus): (a) when the transition in maternal responsiveness from primarily hormonal control to regulation by pup cues occurs; and (b) the effect of housing enclosure size on maternal nest attendance in voles injected with a prolactin suppressant, cysteamine hydrochloride (150 mg/kg) on Postnatal Day 2. In Experiment 1, meadow voles required 96 hr of pup contact to finish the transition from hormonal to pup-mediated maternal behavior; a period longer than found in other rodents. In Experiment 2, females housed in larger enclosures spent less time with pups after drug injection, primarily because they increased the amount of time they stayed away from the nest each time they left. In contrast, drug-treated females in standard cages showed no change in their patterns of nest attendance, possibly due to the presence of salient cues from nearby pups. Under naturalistic conditions, a female vole’s hormonal state may regulate nest approach, and help establish the necessary alternation between leaving the nest (e.g., to forage) and attending pups. (PsycINFO Database Record (c) 2010 APA, all rights reserved)