岩棉作为草坪草育苗基质的化学安定性初探

通过测定草坪草及其生长液中微量元素的含量,研究岩棉作为草坪草育苗基质的可行性.结果表明:岩棉自身可以释放出大量的微量元素供草坪草初期生长利用;其中释放出的Fe,Cu,Al等微量元素已经超过了草坪草生长需要,过量吸收后容易发生中毒.总之,岩棉具有相对稳定的化学安定性,可以作为草坪草的育苗基质.     

硅对植物的有益作用及其对草坪草研究的启示

作为地壳中含量第二的元素,硅对植物的生长发育具有显著积极作用。通过分析硅在植物体内的分布、植物吸收硅的途径以及硅在植物抗逆过程中的积极作用,指出硅对草坪草和草坪管理的研究中具有如下几点启示:硅能够促进草坪草生长,缩短建植时间;提高植物水分利用效率,节约灌溉量;提高草坪草抗非生物胁迫能力,扩大建植区域;减少草坪和绿地管理中氮磷使用量,缓解土壤劣化;提高草坪绿地抗生物胁迫能力,减少农药使用量。     

踩踏对亚热带沟叶结缕草草坪冬季休眠期土壤呼吸的影响

随着城市化进程加快,城市绿地也在迅速扩张,人为踩踏是城市绿地重要干扰因素,其可能对草坪土壤呼吸产生显著影响,进而影响城市草坪碳循环。因此,在典型亚热带沟叶结缕草草坪内选取人为踩踏和对照处理,采用Li-8100土壤碳通量分析仪对冬季结缕草草坪土壤呼吸速率进行动态连续测定。结果表明,亚热带沟叶结缕草草坪冬季休眠期土壤呼吸动态呈单峰曲线,先降低后升高;人为踩踏显著降低了沟叶结缕草草坪休眠期土壤呼吸速率和土壤呼吸温度敏感性(Q₁₀);休眠期土壤呼吸速率主要受温度控制,而与土壤水分无关;试验期间,踩踏平均使土壤呼吸速率下降53.6%;踩踏引发的土壤物理特性和植物生长的变化综合作用而导致沟叶结缕草草坪土壤呼吸速率下调。     

不同pH值处理对两种草坪草生长及质量的影响

为研究不同pH值土壤对草坪草生长质量的影响,试验以不同pH值土壤生长的马尼拉、早熟禾草坪草生长苗为研究对象,测定了植物的发芽率、发芽势、发芽指数、叶绿素含量、株高、生物量等指标。结果表明:1)马尼拉草坪草的发芽率、发芽势、株高在pH值为4~6时呈逐渐上升趋势,在pH值为4~9时地上、地下部鲜重与干重都有较明显的增减趋势;土壤pH值不同马尼拉草坪草的发芽率及地上、地下部干重和鲜重与对照比较差异很大,而发芽势与发芽指数差异不显著(P0.05);不同pH值土壤生长的马尼拉草坪草叶绿素含量差异很大,在土壤pH值为5~7时叶绿素含量呈逐渐下降趋势,在土壤pH值为7~9时叶绿素含量呈逐渐上升趋势。2)早熟禾草坪草发芽率、发芽势及发芽指数在pH值为4~7时呈上升趋势,在pH值为4~9时地上、地下部鲜重与干重都有较明显的增减趋势;不同pH值土壤生长的早熟禾发芽率、发芽指数、株高、地上部鲜重、地下部鲜重及干重与对照比较都差异很大,而发芽势差异不显著(P0.05);在pH值为6~8时早熟禾的叶绿素含量呈逐渐增长趋势,土壤pH值不同叶绿素含量差异很大。     

如何防除草坪杂草

草坪常常由于杂草的侵入而影响美观、使用和导致衰败 ,因此及时清除杂草是草坪管理中的一项重要工作。防除草坪杂草的措施有以下几个方面 :一是利用自然竞争的原理 ,创造适于草坪生长而不适宜于杂草生长的条件 ,达到自然连续工作的目的而减少人工防除的劳作。二是减少杂草种子入侵草坪的机会 ,使用无杂草种籽、肥料、工具和在草坪上适时进行处理防止杂草种籽萌发。三是在杂草最易伤害的阶段使用除草剂。四是采用物理机械方法灭除。1　以草制草、生物控制　　草坪内杂草的大量生长表明该环境条件并不适合草坪草。自然界控制一定类型植被的固有方法是提供目标植被一种激烈竞争的条件 ,而淘汰那些不适者。适应性强的草坪草组成的优质草坪 ,在良好的管理条件下杂草是很难生长或代替草坪草的。因此当草坪杂草大量出现时草坪管理者就应检查并改善以下条件 :现有草坪草种是否适应草坪建设地的生态环境 ;土壤的 ｐＨ值 ;不完整的表面和内部排水系统 ,水的渗透性是否抑制了草坪草的生长活力。在目标草坪草取得最大效益的季节 ,施肥量是否保证了整个季节的连续供应。草坪草的修剪高度及修剪频率是否符合目标草种的生长特性。其它物体的荫蔽是否成为抑制草坪草正常生长的因素。灌水量及灌...     

昆明市草坪枯草层改良措施的研究

草坪枯草层的厚度和形成速度直接影响草坪的质量及其寿命。研究表明,床土粘重、通透性差、土壤酸性化和草坪管理技术不规范是加速草坪枯草层累积的主要原因。生物控制是防止草坪枯草层累积的首选技术,即利用各种栽培和管理技术,可以促进枯草层的分解,避免草坪草枝条的过量生长和积累;表施土壤,增施生石灰,少量频繁施入氮肥,减缓草坪草的生长速率是主要的生物控制技术;在草坪枯草层累积过厚或草坪根系絮结过重的情况下,采用机械改良效果较好;在昆明地区,采用打孔机100孔/m2和120孔/m2两种处理,配合表施土壤,改良枯草层效果最佳。     

人工践踏对无土草坪基质的影响

本试验采用人工践踏的方式,研究了不同组合配比的基质对无土草坪耐践踏性的影响。结果表明,良好的无土草坪基质配比及适合的厚度是保证无土草坪优良的耐践踏性及观赏性的关键。本试验中,草坪草生长基质层和弹性材料层均为25 mm,结构合理、厚度适中,克服了现有草坪基质薄、持水力差的缺点。在相同践踏强度下,能维持较高水平的草层高度、草坪盖度和草坪草分蘖数,分别达到了5.14 cm、97.60%和123.97 个·dm-2,且停止践踏后草坪质量能快速恢复。均匀混合的草坪草生长基质层和弹性材料层,在厚度一致的前提下并不耐践踏,实际效果不好。土壤坪床的处理效果最差。因此,具有独立的草坪草生长基质层和弹性材料层且厚度适中的基质,适用于生产耐践踏性好的无土草坪。     

生长调节剂在草坪上的应用

生长调节剂对草坪草有不同的功效.有的促进草坪草的生长,有的起抑制作用,并且对草坪草抗寒性的影响与草坪草类型有关.本文对这些作用进行了探讨.     

生长调节剂在草坪上的应用

生长调节剂对草坪草有不同的功效。有的促进草坪草的生长 ,有的起抑制作用 ,并且对草坪草抗寒性的影响与草坪草类型有关。本文对这些作用进行了探讨。     

《草坪管理手册》

<正> 《草坪管理手册》(Turf ManagementHandbook)为美国 Howard B.Sprague所著。现已出两版,1970年出第一版,1976年出第二版,在此介绍的是该书第二版。该版共245页,分十五章:一、基础知识;二、良好草坪的土壤条件;三、土壤酸度及石灰中和;四、草坪施肥;五、土壤腐殖质和草坪草管理;六、草坪草的生长;七、冷     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein     

Evaluation of the Microbiological Status of Milk and Various Structures in Mammary Glands from Naturally Infected Dairy Cows

A knowledge of the microbiological status of milk and of the different structures in the mammary glands has great importance in elucidating the pathogenesis of mammary gland infections. The objective of this study was to evaluate the microbiological status of various structures in the mammary glands from naturally infected dairy cows following slaughter. A total of 94 samples of milk, 184 samples of mammary parenchyma, 168 samples of gland cisterns, and 168 samples of teat cisterns were collected for microbiological examination. Microorganisms were detected in 59.9% of all samples, 67.0% of the milk samples, 70.1% of the mammary parenchymas, 55.9% of the gland cisterns and 48.8% of the teat cistern samples. When all samples were considered, coagulase-negative Staphylococcus were the most prevalent (35.7%) followed by coagulase-positive Staphylococcus (12.2%), Corynebacterium bovis (2.4%), Prototheca sp. (1.9%), and Streptococcus dysgalactiae (1.5%). There was a significantly higher occurrence of microorganisms in the milk and mammary parenchyma compared to the gland cisterns and teat cisterns. This revised version was published online in July 2006 with corrections to the Cover Date.     

Development and survival of free-living stages of gastrointestinal nematodes of sheep and goats on pasture in the Nigerian derived savanna

Four grass plots were sequentially contaminated with goat faeces containing known numbers of unembryonated eggs of predominantly Haemonchus contortus and Trichostrongylus spp. between October 1982 and April 1983. Four other plots were similarly contaminated with sheep faeces between February and May 1987. An additional plot was repeatedly contaminated with sheep faeces from February to April 1987. Populations of free-living stages in faeces and of infective larvae (L₃) in the herbage were subsequently monitored until the end of April and June of 1983 and 1987 respectively. During February and May 1987 two control cultures of sheep faeces were incubated in the laboratory at 25°C–30°C and at a constant temperature of 50°C and the free-living development was also monitored. L₃ developed very readily in the faeces cultured at 25°C–30°C and in those spread on a grass plot in October, at the end of the wet season, but developed less on the plot contaminated in May at the start of the wet season. Worm eggs in faeces deposited on plots during the hot dry season (December to April) or incubated at 50°C died and disintegrated after 24–48 h exposure to the high environmental temperatures. The results indicate that it is unlikely that gastrointestinal nematodes of sheep and goats can develop or survive on open pasture during the dry season in the Nigerian derived savanna zone.