行间种草对火龙果果园土壤特性及果实产量的影响初探

通过在火龙果园中间种百喜草、柱花草、鸭茅等牧草,研究生草栽培模式对火龙果果园土壤理化性状及微生态环境的影响,为牧草在火龙果园生态栽培上的应用提供理论依据和技术指导。结果表明:行间种植百喜草可明显改善火龙果果园土壤物理性状,土壤容重下降了16.03%,土壤总孔隙度增加了20.82%,毛管孔隙度和土壤含水量分别增加了52.10%和53.36%,土壤有机质、全氮、碱解氮含量明显增加,同时行间种植百喜草能有效提高火龙果果园相对湿度,降低气温和土壤温度,并能抑制火龙果园杂草的滋生,有效减少了果园投入,增加了果园收入。     

高寒草甸表层土壤物理性状对短期放牧的响应

为探讨不同放牧强度对高寒草甸土壤物理性状的影响,设重度放牧(HG)、中度放牧(MG)和轻度放牧(LG)3个放牧强度样地,调查放牧样地表层土壤(0~10cm)的土壤容重、孔隙度、土壤饱和含水量、田间持水量、有效含水量并土壤持水和入渗性能。结果表明,LG和MG的初始含水量、毛管持水量与非毛管持水量均显著高于HG,LG的土壤饱和含水量和田间持水量均显著高于HG,但3个放牧强度间土壤容重、孔隙性状、土壤有效含水量和非毛管持水量均无显著变化;入渗曲线高低为LGMGHG,用模型模拟曲线,拟合精度为Horton模型通用经验模型Philip模型Kastiakov模型;初始入渗率、平均入渗率、稳定入渗率和90min入渗总量均表现为LG显著高于HG;土壤入渗性能均与土壤初始含水量、总孔隙度、非毛孔隙度、通气孔隙度、饱和含水量、田间持水量、有效含水量、非毛管持水量、毛管持水量、最大持水量显著正相关,与土壤容重显著负相关,与毛管孔隙度相关性不显著,但初始入渗率与初始含水量、田间持水量、有效含水量及毛管持水量无显著相关性。回归分析表明,土壤通气孔隙度和有效含水量是影响入渗率的限制因子。短期轻度放牧有利于土壤持水和导水,降低土壤物理结构退化风险;Horton模型适用于该区放牧草地入渗过程的模拟。     

黄泛平原风沙化土地种植牧草改良土壤效果研究

通过野外取样与室内分析相结合的方法,研究了黄泛平原风沙化土地种植高丹草、无芒雀麦、黑麦草、阿尔冈金苜蓿、沙打旺、草木樨后的土壤改良效果.结果表明:与对照风沙土相比,牧草种植区的土壤容重减小,土壤总孔隙度、毛管孔隙度与非毛管孔隙度增加,持水性能提高;土壤中的有机质、碱解氮、速效磷、速效钾含量分别提高了14.29%～126.53%、22.72%～376.15%、12.72%～364.09%和17.78%～114.76%,但不同牧草改良土壤的效果不同,豆科牧草对土壤的改良效果优于禾本科牧草.     

北方农牧交错带表层土壤孔隙度特征及其影响因素

本研究以张家口地区为研究区,分析农牧交错带土壤表土孔隙度特征及其影响因素。结果表明:土壤表土具有良好孔隙特征,土壤总孔隙度为42.6%,毛管孔隙度为24.6%,非毛管孔隙度为18.0%,毛管孔隙度占总孔隙度比重为56.8%,非毛管孔隙度比重为43.2%;土壤总孔隙度在不同地貌单元差异显著,表现为坝下区域(44.69%)坝上高原(39.98%)(P 0.05),土壤孔隙度在不同土地利用和土壤类型之间差异均不显著(P 0.05);研究区整体看,土壤孔隙度与土壤理化参数显著相关(P 0.05),但分类型区域看,主要在地势相对平坦的坝上高原二者存在显著相关关系(P 0.05);总体来看,土壤孔隙度决定了土壤持水能力,与土壤质地、有机碳和容重仅在某些分类型区域存在相关关系。     

甘南尕海草甸湿地不同海拔高度土壤性状研究

为探究海拔高度与草甸湿地土壤性状之间的关系,对甘南尕海草甸湿地不同海拔高度的土壤理化性状进行研究,在不同海拔高度设置样地,对土壤进行分层取样,室内测定土壤水分含量、容重、孔隙度、有机质、全氮、全磷、全钾含量和pH值。结果表明:尕海草甸湿地物理性质随着海拔高度的增加表现有所不同,其中湿地的土壤含水量、土壤通气度和总孔隙度均表现出随海拔高度上升而升高的趋势,与海拔存在显著相关性,而容重、非毛管孔隙度和毛管孔隙度随海拔高度的上升变化规律不明显,与海拔相关性不强;湿地土壤有机质、土壤全氮、全磷和pH值均表现为高海拔高于低海拔,全钾表现为高海拔低于低海拔;除全钾外,尕海草甸湿地土壤其他化学性质均随海拔高度的增加而增加,但和海拔并不都成显著相关。该湿地应结合当地植被类型和土壤状况,针对不同海拔草甸湿地土壤的特点,采取合理的管理模式,改善湿地生态环境,以维护其健康且可持续的发展。     

立式深旋松耕对西北半干旱区土壤水分性状及马铃薯产量的影响

合理耕作可增强土壤水分供给能力和促进作物根系发育,进而提高作物抗旱性和生产力,将是进一步挖掘半干旱区马铃薯产量和水分利用效率潜力的有效途径。在西北黄土高原半干旱区于2016-2017年设置定位试验,在全膜覆盖垄作模式下设计立式深旋松耕40 cm(VRT)、深松耕40 cm(DLT)和传统旋耕15 cm(TT)3个处理,测定土壤容重、总孔隙度、毛管孔隙度、饱和含水量、毛管含水量以及田间持水量和萎蔫系数、生育期土壤含水量、马铃薯产量等,计算土壤有效贮水量、耗水量和水分利用效率等指标,研究立式深旋松耕对土壤物理性状、马铃薯产量和水分利用的影响。结果表明,VRT显著降低了040 cm土层的土壤容重,较DLT和TT分别下降了10.8%25.3%和11.2%24.8%;土壤总孔隙度、毛管孔隙度分别提高了12.3%23.7%和29.7%46.6%,饱和含水量和土壤毛管含水量分别增加了26.1%54.4%和38.8%82.9%,萎蔫贮水量下降了11.0%49.0%。与TT相比,DLT降低了2040 cm土层的土壤容重和萎蔫贮水量,显著提高了饱和含水量、毛管含水量、总孔隙度和毛管孔隙度。基于土壤物理性状和水分特性的优化,VRT在040 cm土层的有效贮水量显著高于DLT和TT,分别增加了34.3%136.9%和44.6%75.2%,DLT较TT在2040 cm土层也有显著增加。较高的土壤有效贮水量促进马铃薯生长,并显著提高块茎产量,VRT分别较DLT和TT增产24.8%156.8%和47.8%41.0%,水分利用效率(WUE)分别提高18.9%92.3%和19.2%26.6%,干旱年份(2016)的增加幅度显著高于正常降水年份(2017)。因此,立式深旋松耕显著优化了土壤的水分特性,提高了土壤有效水含量,促进马铃薯发育,提高块茎产量和WUE,这一效果在干旱年份尤为明显,是适合于黄土高原半干旱区抗旱增产、水分高效的耕作方法。     

青藏高原东部高寒草甸草地土壤物理性状对氮元素添加的响应

依托设置于青藏高原东部夏河县桑科草原的天然草地刈割型草场培育定位试验,探讨不同氮元素添加量对高寒草甸草地土壤物理性状的影响。本试验共设4个处理,分别为对照（CK,0 kg N／hm2）、低氮（LN,50 kg N／hm2）、中氮（MN,100 kg N／hm2）、高氮（HN,150 kg N／hm2）。通过对高寒草甸草地土壤容重、孔隙度、紧实度、土壤团聚体等物理性状进行测定与分析,结果表明,MN 与 HN 处理可显著降低0～10 cm 土壤容重与土壤紧实度、增加土壤总孔隙度、非毛管孔隙度与最大持水量。20～30 cm 土层中 LN、MN、HN 处理均可显著增加土壤容重、土壤紧实度,降低土壤总孔隙度、最大持水量。对土壤团聚体的影响,与 CK 处理相比 MN、HN 处理可显著提高各土层≥0．25 mm 机械稳定性土壤团聚体含量、提升土壤团聚体平均重量直径（MWD）;较之 CK 处理,LN、MN处理可显著提升各土层≥0．25 mm 水稳性团聚体含量,同时不同氮元素添加处理均可显著提升水稳性团聚体和MWD,表明氮元素添加对该区土壤侵蚀性有较好的抑制作用,进而减少水土和养分的流失。对地上和地下生物量的影响,MN、HN 处理能显著提升草地地上生物量;MN 处理显著增加了地下生物量、HN 处理显著降低了地下生物量;LN 处理对地上与地下生物量的影响不显著。通过试验得出结论 MN 处理对土壤物理性状的改善效果较好,该处理改善了土壤容重、孔隙度及土壤紧实度,提高了土壤干筛≥0．25 mm 机械稳定性团聚体与湿筛≥0．25 mm水稳性团聚体含量及其稳定性（MWD）,增加了草地地上生物量和地下生物量。     

农牧交错带退耕还草对土壤物理性状的影响

农牧研究交错带地区退耕还草对土壤物理性状的影响。结果表明,与小麦比较牧草对土壤容重、含水量、孔隙度和团聚体等土壤物理性状的改善作用非常明显。0-20cm土层,单播草地以冰草土壤容重最小,孔隙度和>0.25mm团聚体总数最大,而混播草地则以无芒雀草+冰草的土壤容重最小,而孔隙度和含水量最大。     

星星草对碱化土壤物理性质的影响

研究不同生长年限的星星草对碱化土壤及对应碱斑土壤的机械组成、土壤孔隙度、容重和含水量的影响。结果表明,星星草生长1、2和3年后,粘粒和细砂所占比例减小,而粗粉和细粉所占比例增大。土壤总孔隙度、毛管孔隙度和非毛管孔隙度随着生长年数的增加呈不同程度的增加,而土壤容重则越来越小,>0.25mm的水稳定性团聚体随之增加。星星草地土壤含水量和田间持水量均高于碱斑土壤。星星草改善了碱化土壤结构、通透性、保水性和土壤物理环境。     

托木尔峰国家级自然保护区台兰河上游不同海拔草地土壤持水能力研究

为探究托木尔峰国家级自然保护区不同海拔草地土壤水源涵养能力的空间变化,本研究通过野外调查、土样采集及室内分析,对托木尔峰自然保护区台兰河上游河谷不同海拔草地表层土壤持水能力进行研究。结果表明:研究区草地土壤物理性质随海拔高度的增加表现有所不同,其中平均土壤含水量、非毛管孔隙度、毛管孔隙度和总孔隙度均与海拔表现出显著的正相关关系,随海拔高度的上升均呈现出不断增加的趋势;土壤容重则与海拔存在着极显著的指数负相关关系(R2=0.881 7),即随着海拔高度的增加,土壤容重呈减小趋势。研究区不同海拔草地土壤的水源涵养能力不同,其中最大持水量、非毛管蓄水量和毛管持水量的大小顺序均为山地栗钙土山地棕钙土山地棕漠土,即随海拔高度的增加而增大;土壤涵蓄降水量与有效涵蓄量的大小顺序均为山地棕漠土山地棕钙土山地栗钙土,随海拔高度的增加而呈下降趋势。海拔高度与放牧及人为活动的干扰强度是导致研究区草地土壤水源涵养功能差异显著的重要因子。     

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.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

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     

Avian brood parasitism — a growing research area in behavioral ecology (part Ⅱ)

正We are pleased to publish the second special issue on avian brood parasitism and to be responsible guest editors for the two special issues of Chinese Birds (Vol. 3, No. 4, 2012 and Vol. 4, No. 1, 2013), entitled "Avian Brood Parasitism - A Growing Research Area in Behavioral Ecology". The first issue was published in December 2012. The goal of the two special issues is to publish accumulated knowledge and some of the recent developments in     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -