高尔夫球场果岭根系基质配方研究进展

综述了高尔夫果岭根系层基质配方研究的概况,总结了不同粒径混合沙、有机改良剂及不同厚度基质对饱和导水率、保水率等物理性质和对成坪、返青、根系生长及草坪质量的影响,提出了我国在果岭根系层基质方面应重点研究的内容.     

查干湖透明度高光谱估测模型研究

湖水透明度能直观反映湖水清澈和混浊程度,是水体能见程度的一个量度,同时也是评价湖泊富营养化,衡量水质优劣的一个重要指标。传统地表水透明度观测主要采用塞克盘(Secchi Disk)法,这种方法不仅费时费力,而且只具有局部的代表意义。遥感技术具有快速、大面积和周期性的特点,可以有效地解决这种局限性。该文通过查干湖高光谱数据,建立透明度(Secchi Disk Depth)单波段和比值高光谱估测遥感模型,并进行验证。结果表明:利用高光谱遥感监测模型对查干湖透明度进行估算和监测,能够获取较为准确的评价结果,相对于传统监测方法具有省时省力的特点。通过对单波段估测模型和比值估测模型进行比较发现,单波段模型估测结果好于比值模型,而对数比值模型又强于单纯的比值模型。查干湖透明度高光谱定量估测模型的建立,有利于今后利用遥感影像,对查干湖水体透明度进行全面估测,对于研究和监测查干湖水体水质状况有重要意义。     

The effects of sowing depth and flooding on the emergence, survival, and growth of Fimbristylis miliacea (L.) Vahl

Glasshouse experiments were conducted from March to July 2003 to determine the effects of sowing depth, and the time, duration, and depth of flooding on the emergence, survival, and growth of Fimbristylis miliacea (L.) Vahl. The treatments that were evaluated in the first experiment were three seeding depths (0, 0.5, and 1.0 cm), while in the second experiment, three flooding depths (saturated soil with no standing water and soil with water depths of 5 and 10 cm) and three flooding durations (7, 14, and 21 days from sowing) were evaluated. In the third experiment, three flooding depths (saturated soil with no standing water, and soil with water depths of 5 and 10 cm) and four flooding regimes (7, 14, 21 or 28 days after sowing [DAS]) were evaluated. Surface seeding gave the highest emergence rate compared to the 0.5 cm and 1.0 cm soil depths. A significantly higher emergence rate was recorded with the saturated conditions than with the flooded conditions. A flooding duration of ≥ 14 days showed a clear trend of reduced emergence with increasing flooding depth. A significantly higher survival rate, plant height, root length, number of leaves, and dry matter were recorded at soil saturation followed by the 5 cm and 10 cm flooding depths when flooding was simulated at 7 and 14 DAS. When the flooding was delayed to 21 and 28 DAS, the 10 cm flooding depth was required to suppress this weed. The results provide sufficient evidence to confirm that from deeper seed burial (1 cm sowing depth), flooding depths of ≥ 5 cm of durations of 14 and 21 days and at the onset of flooding within 14 DAS were effective in suppressing the emergence and growth of F. miliacea .     

不同播种深度对羊草出苗率和幼苗生长的影响

利用盆栽研究了7种播种深度(0cm、1cm、2cm、3cm、4cm、5cm和6cm)对羊草出苗率和幼苗生长的影响。结果表明,羊草出苗率与种子萌发率呈极显著正相关(r=0.9147),而与播深呈极显著负相关(r=-0.9408)。在浅播(0～2cm)条件下,羊草初始出苗时间为5.0～7.7d,最终出苗率为70.0%～80.7%;在深播(4～5cm)条件下,初始出苗时间延迟到16.3～20.0d,羊草种子萌发率下降到41.0%～43.0%,但出苗率不足7%,株高不超过2cm;当播深在6cm以上时,其萌发率为37.0%,但出苗率为0。此外,播种深度显著影响羊草幼苗株高、茎叶鲜重及叶片数量。     

茶树修剪时期和程度对早市名优茶品质的影响

本试验采取随机区组，就不同修剪时期和不同修剪深度对早市茶的品质影响作出了探讨。研究结果表明：不同修剪时期对茶多酚和氨基酸影响不显著，对可溶性糖影响较显著，而对水浸出物和叶绿素影响极显著；其中，以10月份轻修剪茶叶品质成分含量最高，早春2月份次之。在不同修剪程度方面，除了对氨基酸影响不显著外，对其它几种内质均极显著；茶叶主要内含成分的含量为未修剪＞轻修剪＞深修剪。从品质成分分析看，采摘茶园春茶前不修剪或10月份修剪有利于名优茶品质的提高。     

Influence of water flow velocity, water depth and colony distance on distribution and foraging patterns of terns in the Wadden Sea

Surface-feeding seabirds, such as Common ( Sterna hirundo ) and Arctic Terns ( Sterna paradisaea ) in the German Wadden Sea, are dependent on biological and physical processes that affect prey availability close to the water surface. We proposed the following four hypotheses: (i) relationships should exist between high water flow velocity and foraging activity of terns, as turbulence should enhance prey availability at the surface; (ii) the areas of highest foraging success should be located within areas of low water depth, due to enhanced biological productivity; (iii) as terns are known to have small foraging radii, the location of their breeding grounds should be related to the location of their foraging grounds; (iv) terns should forage intensely in river estuaries, as these should hold ample food supplies. The time between terns leaving the colony and their first foraging attempt differed significantly among different tidal stages: the time was shortest during flood and ebb tides (i.e., highest water flow velocities). Modelling of a long-term data set revealed the highest probability of foraging activity in conditions of high water currents, in both shallow areas and in areas of around 15–20 m depth. Foraging activity was negatively correlated with distance from colony. The distance to the closest estuary had no significant effect on foraging behaviour. Our findings emphasize the physical–biological coupling in the Wadden Sea and highlight the overall importance of small-scale physical processes in directly influencing prey availability for surface-feeding seabirds.     

水库异重流潜入点深度预测模型

研究水库异重流的输沙和排沙特性,首先要研究异重流的形成条件,通常是根据异重流潜入点的深度与水库水深的关系判别异重流的形成。通过研究一经过有坡度的浅河道进入水库的悬浮流体,应用连续方程、质量和动量守恒方程以及混掺缓慢变化的动量方程研究异重流潜入现象,根据控制问题的参数建立潜入点深度预测模型,这些预测参数包括密度佛汝德数F0,初始混合率γ,底坡S和全摩擦系数ft。这里提出的潜入点深度模型与实验室异重流和水库异重流观测数据吻合良好。     

半干旱黄土区典型林地土壤水分消耗与补给动态研究

通过对半干旱黄土丘陵沟壑区几种典型林地生长季土壤水分进行动态监测,研究不同林种对土壤水分消耗和补给的影响。结果显示,土壤总含水率大小依次为草地、沙棘、河北杨、油松、山杏,并且这一次序主要来源于120 cm深度(相对稳定层)以下的差异;不同林地及草地土壤含水率季节变化表现基本一致,3—8月波动下降,8—10月持续上升;各林地及草地土壤水分在0~60 cm内变化活跃,60~120 cm内由上至下逐渐趋于稳定,120~200 cm内保持相对稳定;林种、土壤深度、月份3种因素单独作用和交互作用均造成土壤水分差异显著;水分补给期后各林地土壤水分仍处于一定亏缺状态。     

太白山自然保护区立地研究

根据太白山自然保护区立地特征,以生态学作为立地分类理论依据,制定出一套较为完整的立地分类系统。将太白山自然保护区分为２个立地亚区。８个立地类型区,１５个立地类型亚区。根据立地因子相关分析结果确定土层厚度是进行立地类型划分的主要依据     

潮土水分入渗与再分布性能的模拟研究

对潮土入渗性能的室内土柱模拟研究结果表明,土壤水分的湿润深度深度与入渗时间呈指数关系,当湿润锋下移至额富饶饿加水深度后,其速度明显下降;水分湿润深度与湿润层的含水量呈线性关系,与湿润锋下移速度呈乘幂关系;湿润层的含水量与湿润速率呈指数关系;入渗时间与润湿层的土壤吸力呈线性关系。