施肥对山地枣果维生素C含量的影响

为了探究不同肥料、施肥次数对山地枣果维生素C含量的影响,筛选出适合枣树生长的施肥方案。本研究以狗头枣、骏枣、木枣3种山地枣果为材料,选用复合肥、生物有机肥、红枣专用肥、微生物菌肥分别在枣果生长的白熟期、青红期、成熟期进行不同施肥次数的施肥处理,用钼蓝比色法测定枣果在不同生长发育时期的维生素C含量。结果表明：对于狗头枣,在全年2次施用菌肥处理下,白熟期枣果维生素C含量达到最高,也显著提高了其青红期、成熟期维生素C含量;对于骏枣,在全年2次施用菌肥处理下,青红期和成熟期枣果维生素C含量达到最高,白熟期全年2次施用专用肥其维生素C含量达到最高。对于木枣,在白熟期全年2次施用专用肥可显著提高枣果维生素C含量,且达到最佳。在青红期全年2次施用菌肥处理可显著提高枣果维生素C含量,达到全组最高。在成熟期全年1次施用菌肥提高枣果维生素C含量的效果最佳且最为显著。对于3个品种枣果,在对其不同发育时期的枣树施肥时,全年采用2次施肥的方案可获得维生素C含量较高的枣果实,其中菌肥的效果尤为显著。     

嘉道年间河费使用问题探析

论述了嘉道时期河费激增的概况及其使用效率问题,认为河费除了治河所必需的部分以外,在清代形成了一个仰食河费的庞大社会阶层,影响了河费的正常使用。     

Preemptive Analgesia,Including Morphine,Does Not Affect Recovery Quality and Times in Either Pain-Free Horses or Horses Undergoing Orchiectomy

Recovery quality and times from general anesthesia in horses may be influenced by surgery, analgesia with morphine or combinations of both. Twenty-three adult healthy horses were enrolled in this prospective experimental trial in a clinical setting and were randomly allocated to one of the following groups: anesthesia only (GA; n = 6), preemptive analgesia and anesthesia (GAA; n = 5), anesthesia and castration (GC; n = 6), or preemptive analgesia, anesthesia, castration, and intraoperative local analgesia (GCA; n = 6). All horses were sedated with intramuscular (IM) xylazine (0.5 mg/kg). Anesthesia was induced with intravenous (IV) guaifenesin (100 mg/kg) and thiopental (5 mg/kg) and maintained with isoflurane in oxygen. Animals in groups with preemptive analgesia received IM morphine (0.2 mg/kg) and dipyrone (10 mg/kg) and IV flunixin meglumine (1.0 mg/kg) immediately before sedation. Recoveries from general anesthesia were rope-assisted. Recovery scores (from 8 [excellent recovery] to 70 [worst recovery]) and times were compared between groups, using a one-way analysis of variance followed by a Tukey's test (P < .05). Mean ± standard deviation (SD) and range recovery scores were 22 ± 14 (8–45), 9 ± 2 (8–12), 14 ± 5 (8–22), and 12 ± 1 (10–13) in groups GA, GAA, GC, and GCA, respectively. Mean ± SD times to stand in minutes were 21 ± 10, 18 ± 7, 33 ± 12, and 35 ± 21 in groups GA, GAA, GC and GCA, respectively. No statistically significant differences were found for any of the variables. Neither preoperative administration of analgesics, including morphine, nor castration interfered with the recovery qualities and times in horses undergoing general anesthesia. Preemptive morphine did not worsen anesthetic recovery quality in horses.     

Dynamics of Aggregate Stability Influenced by Soil Management and Crop Residues

Abstract

The type of tillage and crop systems used can either degrade or cause a recovery of the structure of agricultural soils. The objective of this study was to determine the structural stability of the soil using mean weight diameter (MWD) of soil aggregates in three different periods of a succession of crops consisting of beans/cover plants/maize under no tillage (NT) and conventional tillage (CT) management systems. Soils were sampled at 0‐ to 5‐cm and 5‐ to 15‐cm depths in three periods (P1, P2, P3): 1) November 2002 (spring/summer), 2) April 2003 (beginning of autumn), and 3) December 2003 (end of spring/beginning of summer). Aggregate stability was determined by wet sieving. The effects of the tillage systems, vegetal residues, and sampling depths on the structural stability of the aggregates were assessed and then related to organic matter (OM) contents. Aggregate stability showed temporal variation as a function of OM contents and sampling period. No tillage led to high MWD values in all study periods. The lowest MWD values and OM contents were observed 4 months after the management of the residues of cover plants. This finding is consistent with the fact that at the time of the samplings, most of the OM had already mineralized. The residues of sunn‐hemp, millet, and spontaneous vegetation showed similar effects on soil aggregate stability.     

杨树速生林适宜采伐期的测定研究

确定杨树速生林适宜采伐期,与树种结构、林龄、林分密度和林木连年生长量有直接关系,当林分密度进入极限时,林木连年生长量开始从高峰下降,说明林分已进入适宜采伐期,实行适宜采伐期采伐作业,可获最佳经济效益。     

华南虎哺乳期母幼行为的初步研究

对梅花山华南虎繁育研究所内 4号母虎及其所产幼虎的母幼行为进行了初步研究 ,着重描述了华南虎母幼的各种行为 ,并对其中的一些行为作了初步探讨。母幼间接触的部位主要是头部等感官较敏感区域 ,通过各种接触是建立母幼友好、亲昵关系的主要途径。母虎主要通过哺乳、舔、嗅等行为与幼虎接触 ,其次是拱、衔、护幼行为等 ;而幼虎主要是通过吮乳、舔、嗅闻与母虎接触 ,其次是叫等方式     

论先秦时期我国的竹资源及利用

根据历史文献和考古资料,考证了我国史前时期、夏商周时期竹林资源的分布,论述了先秦时期在生产、生活、文化、兵器等方面对竹资源的开发利用.     

毛竹林出笋与幼竹生长发育规律的研究

本文以江苏宜兴林场、江西宜丰花桥林场以及南京林业大学下蜀实习林场等试验地内毛竹林出笋与幼竹生长资料和从江苏宜兴气象站抄录整理而成的1976～1986年中每年的11个气象资料为原始材料,定量地对毛竹林出笋及幼竹的生长发育的内在规律性及其与气象因子之间的关系进行了系统的研究。回归分析表明,影响翌年竹林出笋及幼竹生长发育的6个主导气象因子是7、8、9三个月的平均温度、年平均温度、年降水量、温暖指数、日均温≥10℃积温和7、8、9三个月的平均降水量。借助于有序样本聚类分析方法,将竹林整个出笋期划分为三个时期即出笋初期、出笋盛期和出笋末期。最佳拟合求算表明,毛竹幼竹高生长用单分子生长式来拟合精度较高。通过对正态累积函数和概率单位之间关系的研究可知,毛竹高生长在竹笋出土后21天左右进入速生期,竹笋出土后30天左右达高生长高峰期,竹笋出土后38天左右达高生长速生末期。本文还就如何根据幼竹的生长发育规律,采用相应的营林措施来培育速生丰产林等有关问题进行了探讨。     

木麻黄皮暗斑螟生物学特性的研究

木麻黄皮暗斑螟（ＥｕｚｏｐｈｅｒａｂａｔａｎｇｅｎｓｉｓＣａｒａｄｊａ）在福建省一年发生５代，以幼虫于１２月中旬在树干被害处的虫道内越冬（亦有少数以蛹越冬），林间世代重叠现象明显。成虫羽化盛期的温度为３０．３—３４．０℃，相对湿度为７５．７％—８４．３％，平均寿命７．９天，产卵量４５．７粒。卵孵化率９０．５％。幼虫共５龄，具群集性，以第一代幼虫取食量最大，老熟幼虫喜在粪粒层与树干交界部结茧化蛹，蛹期８．５天。皮暗斑螟的天敌有１０余种，其中拟小腹茧蜂在自然界的寄生率达１６％。     

Phenological phases of common beech (Fagus sylvatica L.) and their dependence on region and altitude in Southern Germany

Long-term observational data of the phenological network of the German Weather Service (DWD) were used to derive the altitudinal dependence of leaf unfolding (LU), leaf discolouration (LD) and the length of the vegetation period (LD-LU) of common beech (Fagus sylvatica L.) in different regions of Southern Germany. Depending on altitude, the vegetation period starts in Bavaria between the 2nd and 24th May with a delay of around 2 days per 100 m altitude increase (averaged over the last 30 years). In Southern Bavaria, LU starts a few days earlier as well as increases slightly faster into higher altitudes than in the northern regions. This can be explained by a more favourable supply of warmth and radiation in the south. The end of the vegetation period, defined here as the beginning of LD, showed no altitudinal dependence, which reflects an interaction of endogenous and exogenous factors as triggers for LD. In the Bavarian Forest region, altitudinal dependences are strongly influenced by sites which are affected by cold-air tailback (‘Kaltluftstau’) was obtained. Hence, phenological gradients should only be derived and applied above a phenological inversion zone. The calculated vertical gradients for LU can be used together with available observational data to estimate the beginning of the forest vegetation period of beech for different altitudes of Bavaria.