不同草地利用方式对土壤有机碳、全氮和全磷的影响

以青海省共和县塔拉滩封育芨芨草(Achnatherum splendens)草原、过牧芨芨草草原、取土坑、人工草地和农田为研究对象,对不同利用方式及不同深度下土壤有机碳、全氮、全磷含量进行了分析研究。结果表明:0～10cm和10～20cm土层土壤有机碳含量顺序均为封育芨芨草草原>退化过牧芨芨草草原>取土坑>农田>人工草地,说明退化和开垦均导致表层土壤有机碳含量的下降。在同一土层内,农田和人工草地(退耕地)的有机碳含量差异不显著(P>0.05)。在0～10,10～20和20～40cm的3个土层,农田的全氮含量最高,人工草地次之,主要是由于人为施加氮肥和翻压枯草等因素造成,取土坑的全氮含量最低;同时,0～40cm的土层,封育芨芨草草原的土壤全氮含量高于退化过牧芨芨草草原,40～80cm的土层,封育芨芨草草原的土壤全氮含量低于退化过牧芨芨草草原,说明封育使土壤上层的全氮含量增加,而草原退化导致氮向下层转移。全磷含量的变化规律与全氮相似。各草地的有机碳、全氮和全磷含量随土壤深度增加而下降。     

贺兰山不同海拔土壤颗粒有机碳、氮特征

采用颗粒大小的物理分组方法,测定了贺兰山(西坡)不同海拔具有代表性的8个样地的草地土壤颗粒有机碳和颗粒有机氮含量,并且分析了土壤颗粒碳、氮分配比例与植被特征及环境因子的关系。结果表明,土壤颗粒碳、氮含量随海拔的降低而显著降低,随土层深度的增加而降低;在4个植被类型中,二者在高山草甸最高,在草原化荒漠最低。土壤颗粒碳、氮分配比例随海拔的降低表现出先降低后升高的趋势,在高山草甸最高,山地荒漠草原最低。土壤颗粒碳、氮分配比例与植被盖度、地上生物量、年均降水量呈极显著的正相关关系,与年均温呈极显著的负相关关系。     

高寒草地土壤理化性质特征及质量评价

以黄河源区4类高寒草地为研究对象,测定了0～20 cm土层土壤理化性质,并运用主成分分析法对土壤质量进行评价,结果表明：1)土壤容重和pH值表现均为高寒草原>人工草地>高寒草甸>沼泽草甸;土壤含水量、有机碳、全碳、氨氮、全氮含量均表现为沼泽草甸>高寒草甸>人工草地>高寒草原;土壤硝氮含量表现为人工草地>沼泽草甸>高寒草原>高寒草甸;土壤速效磷和全磷含量均表现为沼泽草甸>高寒草甸>人工草地>高寒草原;土壤速效钾和全钾含量均表现为人工草地>高寒草原>高寒草甸>沼泽草甸;2)土壤有机碳含量与全碳、氨氮、全氮、速效磷、全磷含量之间呈极显著正相关关系(P<0.01),土壤全碳含量与氨氮、全氮、速效磷、全磷含量之间呈极显著正相关关系(P<0.01),土壤碳氮磷元素呈强相关关系,三者之间高度耦合;3)在0～10、10～20以及0～20 cm土层,土壤质量高低排序均为沼泽草甸>高寒草甸>人工草地>高寒草原,各草地0～10 cm土层土壤质量均高于10～20和0～20 cm土层,0～20 cm土层土壤质量高于10～20 cm土层。     

黄土高原云雾山草地土壤有机碳、全氮分布特征

2007年11月28日-12月1日对云雾山4类天然草地,以及不同生长年限的人工紫花苜蓿(Medicago stativa L.)草地、沙棘(Hippophae rhamnoides Linn.)灌木、农田进行土壤有机碳、全氮分布分析,以期为该地区的草地生态系统的合理利用和减排温室气体提供科学依据。结果表明:土壤有机碳、全氮含量的排序为:天然草地(人工草地(灌木(农田。对0~40 cm土壤每10 cm土层土壤有机碳、全氮含量测定发现:除9年生人工苜蓿草地在20~30 cm土层的有机碳含量相对10~20 cm无降低外,其他均表现为随土层深度的增加而依次降低。有机碳、全氮含量天然草地10~20,20~30,30~40 cm,以及5年、7年、9年人工草地土层之间差异水平基本达到显著水平。天然草地和人工草地土壤有机质含量与其全氮含量呈极显著线性相关(P<0.01)。人工草地土壤有机碳,全氮含量随种植年限增长而增加,全氮含量增加程度大于有机碳。因此,云雾山天然草地有机碳、全氮含量最高,人工草地随着生长年限的延长也是碳氮积累的过程,农田含量最低,天然草地在碳氮储存方面发挥着更积极的作用。土壤有机碳、全氮在土壤表层(0~10 cm)含量最高,在云雾山地区通过退耕还草,加强植被恢复管理,有利草地生态系统的健康发展。     

贺兰山西坡草地土壤碳特征及潜在退化损失分析

本研究分析了干旱区贺兰山西坡山前草地土壤碳的分布特征及其与气候、植被和土壤因子的关系,并探讨了潜在退化状态下土壤碳的变化特点。结果表明,随着海拔的增加,土壤有机碳含量和密度逐渐增加,表现为山地草原荒漠草原草原化荒漠;而土壤无机碳、全碳含量和密度随海拔增加先逐渐增加随后有所降低。偏相关及逐步回归分析表明,土壤有机碳含量与全氮显著相关,而影响土壤无机碳含量的因素因土层不同而有所差异,土壤无机碳与土壤容重显著相关,且受年降水量和年均温因子的共同影响。土壤碳密度受土壤碳含量的影响大于土壤容重。另外,当各高海拔草地群落潜在退化为低海拔草地群落时,土壤有机碳含量及密度变化较大,呈减少趋势,无机碳和全碳表现不一致,但当草地类型发生改变时,两指标减少幅度较大。上述结果表明,草地退化对土壤有机碳和无机碳影响显著,且土壤无机碳受土壤母质的影响也强烈。     

草地对碳汇的作用

草地利用和管理方式是维系草地农业生态系统土壤碳平衡的重要机制之一,土壤植被的改变是土壤有机碳变化的驱动力,不同利用方式的土壤有机碳含量有明显差异,0~100cm土壤有机碳密度的变化顺序为:人工灌木林地次生天然草地人工草地弃耕地农田。放牧作为主要草地利用方式,不同强度对草地有机碳含量有显著影响,0~10cm和10~20cm土层中土壤有机碳含量随放牧强度的增加而下降,中度放牧区和重放牧区分别显著低于未放牧区。乱开乱垦对草地植被初级生产力产生严重影响,使植被盖度和草地初级生产力严重下降,导致0~20cm和20~40cm土壤有机碳含量降低。     

不同草原类型土壤有机碳和全氮的差异

对典型草原和荒漠草原的土壤有机碳（OC）和全氮（N）进行的比较分析结果表明：两种草原土壤SOC和TN含量差异显著,且典型草原的SOC和TN含量高于荒漠草原;在0～20cm土层内,两种草原的SOC和TN含量随土壤深度的增加呈下降趋势.典型草原的气候、植被及土壤质地状况优于荒漠草原,可能是导致上述结果的可能原因.     

土地利用方式对陇中黄土高原土壤理化性状的影响

对陇中黄土高原至少50年传统耕作历史的农耕地和退耕20年的草地土壤理化性状进行了比较研究。结果表明,1)不同土地利用方式对土壤有机碳、全氮、速效磷、pH值和容重有显著影响。0~10 cm土层土壤有机碳含量草地显著高于农田,全氮含量差异不显著,20~100 cm土层有机碳和全氮农田高于草地(P<0.05);土壤全磷含量农田虽高于草地但无显著差异。土壤C/N除0~10 cm土层外,农田高于草地。在整个土壤剖面上,草地土壤pH值显著高于农田(P<0.05);除10~20 cm和底层土壤外,草地土壤容重也高于农田。2)草地土壤有机碳和全氮随土壤深度增加而降低,而农田土壤在0~30 cm土层随土壤深度的增加而增加,在30 cm土层以下与草地有相同趋势。草地土壤全磷含量各土层间没有显著差异,农田土壤全磷含量与土壤有机碳和全氮含量变化趋势一致;草地和农田土壤速效磷含量都呈减少趋势。土壤pH值随土壤深度的增加而增加。3)各样地土壤有机碳、全氮、全磷、速效磷与土壤容重和土壤pH值之间呈极显著负相关,土壤容重与土壤pH值呈极显著正相关,土壤有机碳、全氮、全磷和速效磷之间也呈极显著正相关关系。     

不同恢复措施对宁夏荒漠草原土壤碳氮储量的影响

以放牧(CK)、深翻耕(S)、浅翻耕(Q)、免耕(M)和封育(F)5种不同生态恢复措施处理的荒漠草原为对象,研究不同恢复措施条件下0~40 cm土层土壤有机碳,全氮储量的变化特征。结果表明,0~10 cm和10~20 cm土层,有机碳含量均以浅翻耕处理草地最高,分别为14.90和14.50 g·kg^-1,显著高于深翻耕处理草地、封育草地和放牧草地(P<0.05);20~30 cm土层,不同处理草地有机碳含量变化范围为5.03~9.93 g·kg^-1,以浅翻耕处理草地最高,封育草地最低(P<0.05)。土壤全氮含量,0~10 cm和10~20 cm土层均以浅翻耕处理草地最高,分别为0.17和0.22 g·kg^-1,显著高于封育和放牧草地(P<0.05);20~30 cm和30~40 cm土层均以深翻耕处理草地最高,分别为0.14和0.13 g·kg^-1,显著高于封育草地(P<0.05)。不同处理草地各土层土壤有机碳和全氮密度的分布范围为0.49~1.58 kg·m^-2和0.013~0.039 kg·m^-2,其中,0~40 cm各土层有机碳密度及0~10 cm和10~20 cm土层全氮密度均以浅翻耕处理草地较高,封育草地较低,20~40 cm土层全氮密度以深翻耕处理草地最高,封育草地较低。0~40 cm各土层土壤有机碳和全氮储量均以浅翻耕处理草地最高,分别为47.72和1.09 t·hm^-2,显著高于封育草地(P<0.05)。浅翻耕处理草地更有利于该区荒漠草原土壤有机碳和全氮储量的积累。     

不同管理模式对干旱区草地土壤有机碳氮库的影响及其影响因素探究

土壤有机碳和全氮含量及其动态平衡过程是反映土壤质量和草地健康状况的重要指标,直接影响到草地土壤肥力和草地生产力。本研究对新疆阿勒泰地区禁牧草场、弃耕草地、天然草地3种管理模式下的土壤有机碳、全氮、土壤水分、团粒结构、pH、土壤容重等的分布特征,以及它们的关系进行分析后发现,3种管理模式下,土壤有机碳含量在010 cm、1030 cm和3050 cm土层间无显著差别(P>0.05),相反,土壤碳氮比、土壤全氮含量、土壤有机碳储量和全氮储量随土层深度增加显著增加(P<0.05);3种管理模式间,在010 cm、1030 cm和3050 cm土层,天然草地和禁牧草地的全氮和有机碳含量均高于弃耕草地,但对土壤碳氮比在3种草地管理模式间的差异不尽相同;不同管理方式下,在010 cm、1030 cm和3050 cm土层,禁牧草地的土壤电导率和pH均显著高于天然草地(P<0.05);在010 cm和3050 cm土层,禁牧草地的土壤含水量显著高于弃耕草地(P<0.05),禁牧草地与弃耕草地中间团聚体含量差异显著(P<0.05);含水量、大团聚体、中间团聚体、微团聚体、pH、电导率可以组成原因组,土壤全氮储量和土壤有机碳储量可以组成结果组,原因组对结果组的解释度高达75.70%;原因组中,土壤水分贡献率最高,土壤含水量对土壤水分-团粒结构起到主要决定作用。综合可知,土壤碳氮含量和储量在管理模式不同的草地间不同,土壤水分和土壤团粒结构是引起草地土壤碳氮库变化的主要原因。在土壤水分和团粒结构组成的原因组中,水分起主要的决定作用。     

白术、微米白术和白术多糖对断奶仔猪生长性能和肠道形态及微生态区系的影响

试验选用96头平均体重14.82 kg左右的杜×长×大断奶仔猪,随机分成4组,每组3栏,每栏8头(公母各半)。对照组饲喂基础日粮,试验1、2、3组分别添加1%80目白术、0.2%白术多糖和1%微米白术。试验期30 d。结果表明:在生长性能方面,与对照组相比,1%微米白术添加组可显著提高日增重(P0.05)、降低饲料增重比和腹泻率,而且效果优于1%80目白术组和0.2%白术多糖组,在肠道形态和肠道微生态区系方面,与对照组相比,日粮添加1%80目白术、0.2%白术多糖、1%微米白术均可不同程度的提高十二指肠和空肠的绒毛高度,加深十二指肠和空肠的隐窝深度,并且增加肠道微生态区系的多样性,其中以1%微米白术添加组的效果最佳。     

Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia

Sissay, M.M., Uggla, A. and Waller, P.J., XXXX. Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia. Tropical Animal Health and Production, XXXX. A 2-year abattoir survey was carried out to determine the prevalence, abundance and seasonal incidence of gastro-intestinal (GI) nematodes and trematodes (flukes) of sheep and goats in the semi-arid zone of eastern Ethiopia. During May 2003 to April 2005, viscera including liver, lungs and GI tracts were collected from 655 sheep and 632 goats slaughtered at 4 abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga in eastern Ethiopia. All animals were raised in the farming areas located within the community boundaries for each town. Collected materials were transported within 24 h to the parasitology laboratory of Haramaya University for immediate processing. Thirteen species belonging to 9 genera of GI nematodes (Haemonchus contortus, Trichostrongylus axei, T. colubriformis, T. vitrinus, Nematodirus filicollis, N. spathiger, Oesophagostomum columbianum, O. venulosum, Strongyloides papillosus, Bunostomum trigonocephalum, Trichuris ovis, Cooperia curticei and Chabertia ovina), and 4 species belonging to 3 genera of trematodes (Fasciola hepatica, F. gigantica, Paramphistomum {Calicohoron} microbothrium and Dicrocoelium dendriticum) were recorded in both sheep and goats. All animals in this investigation were infected with multiple species to varying degrees. The mean burdens of adult nematodes were generally moderate in both sheep and goats and showed patterns of seasonal abundance that corresponded with the bi-modal annual rainfall pattern, with highest burdens around the middle of the rainy season. In both sheep and goats there were significant differences in the mean worm burdens and abundance of the different nematode species between the four geographic locations, with worm burdens in the Haramaya and Harar areas greater than those observed in the Dire Dawa and Jijiga locations. Similar seasonal variations were also observed in the prevalence of flukes. But there were no significant differences in the prevalence of each fluke species between the four locations. Overall, the results showed that Haemonchus, Trichostrongylus, Nematodirus, Oesophagostomum, Fasciola and Paramphistomum species were the most abundant helminth parasites of sheep and goats in eastern Ethiopia.     

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

Tropical Animal Health and Production -     

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.     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

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.     

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.     

Y‐chromosomal variation of local goat breeds of Turkey close to the domestication centre

Genetic variations in chromosome Y are enabling researchers to identify paternal lineages, which are informative for introgressions and migrations. In this study, the male‐specific region markers, sex‐determining region‐Y (SRY), amelogenin (AMELY) and zinc finger (ZFY) were analysed in seven Turkish native goat breeds, Angora, Kilis, Hair, Honaml?, Norduz, Gürcü and Abaza. A SNP in the ZFY gene defined a new haplotype Y2C. All domestic haplogroups originate from Capra aegagrus, while the finding of Y1A, Y1B, Y2A and Y2C in 32, 4, 126 and 2 Turkish domestic goats, respectively, appears to indicate a predomestic origin of the major haplotypes. The occurrence of four haplotypes in the Hair goat and, in contrast, a frequency of 96% of Y1A in the Kilis breed illustrate that Y‐chromosomal variants have a more breed‐dependent distribution than mitochondrial or autosomal DNA. This probably reflects male founder effects, but a role in adaptation cannot be excluded.     

Changes in proportion of canine urinary calculi composed of calcium oxalate or struvite in specimens analyzed from 1981 through 2001

The objective of this report was to characterize 20-year changes in proportion of calcium oxalate (CaOx) calculi and struvite calculi in dogs, and associations with breed, age, and sex. In this retrospective study, results of analysis of urinary calculi from dogs were reviewed for specimens received between July 1, 1981, and December 31, 2001. Breed, sex, age, year of submission of the specimen, and mineral type(s) were analyzed statistically. CaOx or Struvite or both were contained in 18,966 of 20,884 (91%) specimens. For both sexes, a 20-year statistically significant increase was observed in the proportion of calculus specimens that contained CaOx. The increase in this proportion was greater in females (1% to 31%) than in males (18% to 82%). From 1998 to 2001, when proportions may have plateaued, the odds of specimens containing CaOx were markedly higher in 18 breeds, markedly lower in 5 breeds, and not significantly different in 13 breeds compared with crossbreds. For both sexes, a 20-year statistically significant decrease was observed in the proportion of calculus specimens that contained struvite. This decrease in proportion was greater for males (79-16%) than for females (97-68%). From 1998 to 2001, when proportions plateaued, the odds of calculi containing struvite were markedly lower in 20 breeds, markedly higher in 1 breed, and not significantly different in 15 breeds when compared with crossbreds. Breed, age, and sex were associated statistically with CaOx or struvite urolithiasis. In conclusion, there appears to have been a long-term increase in the proportion of specimens of canine urinary calculi that contain CaOx as well as a long-term decrease in the proportion of specimens of calculi that contain struvite for both male and female dogs. The rate of change appeared to begin leveling off in the period 1998 to 2001. The recent proportion of dogs with either CaOx- or struvite-associated urolithiasis may depend on breed, age, and sex, and on interactions among these 3 factors.     

Smart Phone Assisted City-scale Wireless Sensor Network Deployment for Transportation System Monitoring

<正>1.INTRODUCTION Ensuring transportation network security is one Of the most daunting challenges confronting homeland security agencies today.Significant research has been dedicated.To model and analyze the vulnerability of transportation systems,while notably fewer studies propose specific strategies for deploying defensive technologies to safeguard these systems.