内蒙古典型草原枯落物的生态水文效应

枯落物是影响干旱和半干旱地区草原生态系统水文过程中重要的因素。本研究利用野外监测和室内试验结合的方法探究内蒙古典型草原枯落物的生态水文效应。结果表明：大针茅（Stipa grandis）群落的枯落物蓄积量显著高于羊草（Leymus chinensis）群落和克氏针茅（S.krylovii）群落的。糙隐子草（Cleistogenes squarrosa）的枯落物最大持水量最高,羊草的最低,均与大针茅的和克氏针茅的有显著差异;羊草群落的枯落物最大持水量显著低于克氏针茅群落的和大针茅群落的。3种群落保留枯落物的土壤水分含量高于去除枯落物的,在春季和夏季尤为明显,但在秋季具有趋同化的特征。降雨时,枯落物会降低小雨对2.5 cm处土壤水分的补充,但对中雨和大雨无显著影响。降雨后,枯落物可使土壤保持较高水分。综合枯落物的截留作用与保水效应,枯落物可以间接增加降雨的有效性。     

宁夏荒漠草原4种典型植物群落土壤活性有机碳垂直分布特征

以荒漠草原赖草（Leymus secalinus）、蒙古冰草（Agropyron mongolicum）、针茅（Stipa capillata）和白草（Penniseturn centrasiaticum）群落4种典型群落为研究对象,分析不同群落土壤活性有机碳（SLOC）的垂直分布特征及其影响因素。结果表明：不同典型群落SLOC垂直分布特征具有明显差异,赖草群落、蒙古冰草群落和白草群落SLOC含量在0~100 cm垂直分布表现为先增加后降低的趋势,浅根型的针茅群落SLOC含量垂直分布则持续降低,白草和赖草群落SLOC含量在10~20 cm最大,针茅和蒙古冰草群落SLOC含量在0~10 cm最大。相关性分析结果显示,SLOC与土壤总有机碳含量呈现极显著相关性（R²=0.9595）;与土壤理化性质等因子相关性比较,SLOC更依赖于植被覆盖度、地上生物量和地表枯落物,尤其是地表枯落物与SLOC的相关性更高。表明除了植被和根系分布特征,荒漠草原的枯落物对SLOC垂直分布特征有更大的影响。     

宁夏荒漠草原不同群落生物多样性与生物量关系及影响因子分析

通过测定生物多样性各指标、地上－地下生物量、枯落物量、土壤理化因子以及土壤微生物量碳氮,研究了自然状态下荒漠草原6种群落生物多样性与生物量的关系及其影响因子。结果表明：荒漠草原不同群落丰富度、均匀度与多样性指数变化趋势一致;地上生物量与地下生物量呈指数关系,表明荒漠草原群落呈异速生长模式;生物多样性与地上生物量呈单峰曲线,与地下生物量呈线性关系,初步表明荒漠草原不同群落地上部分种间作用、资源利用程度基本一致,生物多样性抑制了地上生物量,但并没有抑制其地下生物量;地表枯落物与地下生物量呈极显著的线性相关关系（P ＜0．01）,初步表明了地下生物量更加依赖于地表枯落物。相关分析表明,荒漠草原生物多样性指数和生物量影响因子存在明显差异,自然条件下土壤含水量、有机碳、全氮以及有效养分对地下生物量贡献较大,土壤含水量和有机碳对地上生物量贡献较大,土壤微生物量碳和氮对群落多样性指数贡献较大。     

模拟放牧采食对典型草原土壤中AM真菌分解枯落物的影响

丛枝菌根真菌(Arbuscular mycorrhizal fungi, AMF)在陆地生态系统中分布广泛，不仅可以促进宿主植物生长发育，还会参与枯落物的降解，间接影响土壤碳库。本研究使用典型草原优势种羊草(Leymus chinensis)做枯落物，通过适宜孔径尼龙网分离AMF根外菌丝与土壤中其他微生物，探究植物功能群和刈割处理对AMF参与枯落物分解的影响。结果表明AMF通过提升土壤中β-葡糖苷酶和多酚氧化酶的活性加速对枯落物的降解。植物功能群的改变会影响枯落物分解，其中杂类草处理中枯落物分解率较高(2016年：31.72%;2017年：31.02%),C₄禾草处理中的最低(2016年：23.22%;2017年：27.10%);但并不会改变AMF对枯落物的分解作用。刈割在短时间内对枯落物的分解无显著影响。本研究发现AMF促进了枯落物分解，植物群落组成的改变也会显著影响枯落物的分解。     

宁夏荒漠草原优势植物枯落物分解特征及其影响因素

为明确宁夏荒漠草原植物枯落物分解规律,以赖草（Leymus secalinus）、胡枝子（Lespedeza bicolor）及其混合物枯落物为研究对象,采用网孔分解袋法,调查了不同处理植物枯落物分解率及其影响因素。结果显示：植物枯落物分解率均呈现出前期显著增加、中期平缓变化趋势,但后期受网孔影响较大。70 d和210 d时,4 mm和2 mm网孔中分解率均表现为混合物最高,胡枝子居中,而赖草最低;但在0.01 mm网孔中,仅210 d分解率表现为混合物和胡枝子较高,而赖草最低。并且,140 d时仅4 mm网孔、280 d时仅2 mm和0.01 mm网孔中3种处理植物枯落物分解率呈现出显著差异性。分解50%和95%所需时间,随网孔减小,赖草和混合物枯落物则延长,而胡枝子枯落物则缩短。研究表明,210 d是3种处理枯落物分解率显著变化的重要节点。不同处理植物枯落物分解过程显著不同,并且受到不同土壤动物类群分布及温湿条件的深刻影响。     

干旱与半干旱区红砂枯落物分解初期节肢动物群落结构特征

选择宁夏盐池半干旱区和内蒙古乌拉特后旗干旱区荒漠草原为研究样地,以红砂枯落物为研究对象,利用网孔分解袋法,在灌丛内外微生境布设分解袋。通过调查分解袋中节肢动物群落组成与多样性分布特征,结合枯落物化学分析和土壤环境因子测定,研究灌丛微生境红砂枯落物分解初期节肢动物群落结构分布规律。结果表明：1）红砂枯落物节肢动物优势类群在盐池半干旱区灌丛中有3类,裸地中仅2类;而在乌拉特后旗干旱区表现为灌丛内外优势类群均有3类。常见类群在盐池半干旱区灌丛中有7类,而裸地中仅3类;而乌拉特后旗干旱区灌丛中有7类,裸地中有4类。稀有类群在盐池半干旱区表现为仅在裸地出现,而乌拉特后旗干旱区表现为仅在灌丛内出现。2）红砂枯落物节肢动物个体数和类群数在盐池半干旱区均表现为裸地显著高于灌丛,而在乌拉特后旗干旱区均表现为裸地显著低于灌丛（P<0.05）。红砂枯落物节肢动物Shannon-Wiener指数、Simpson指数、Margalef指数以及Pielou指数在盐池半干旱区和乌拉特后旗干旱区均表现为灌丛内外无显著差异（P>0.05）。3）红砂枯落物节肢动物个体数在盐池半干旱区仅与土壤pH值呈显著正相关性,而与土壤砂粒含量呈显著负相关性;类群数在盐池半干旱区仅与土壤砂粒呈显著负相关性（P<0.05）。在乌拉特后旗干旱区红砂枯落物节肢动物个体数和类群数与环境因子间均无相关性（P>0.05）。冗余分析（RDA）和偏RDA分析结果表明,枯落物K含量是影响干旱与半干旱区红砂枯落物节肢动物个体数分布的主要环境因子。4）综合表明,红砂枯落物节肢动物个体数和类群数受到灌丛微生境和气候因子的双重影响,但群落多样性受灌丛微生境和气候因子的影响均较小。并且,随干旱程度的加强,灌丛微生境对红砂枯落物节肢动物个体数和类群数分布的影响从溢出效应转变为聚集效应。     

典型草原枯落物分解过程中官能团的动态特征

选择锡林浩特东部国家气候观象台的生态监测研究样地,对大针茅(Stipa grandis)、羊草(Leymus chinensis)、糙隐子草(Cleistogenes squarrosa)、知母(Anemarrhena asphodeloides)枯落物的化学结构特征进行阐释。结果表明:(1)枯落物分解速率呈先增大后减小的变化趋势,且知母枯落物分解速率高于大针茅、羊草和糙隐子草;枯落物总碳(TC)含量为富集-释放模式,在第120d时,知母枯落物TC含量高于其他3种植物。(2)大针茅、羊草、知母、糙隐子草枯落物所含的主要官能团为-OH;=C-H、-CH 2、-CH 3;C=O;C=O、C=C;C-O。(3)不同植物枯落物官能团含量在分解初期迅速减少,在分解后期减少趋势较为缓慢,与分解过程中枯落物的分解速率变化趋势一致;知母的含碳官能团含量在分解结束后最低,而羊草的则最大,且知母和糙隐子草损失量最大,与分解过程中枯落物TC含量的特征一致。(4)大针茅的支链化指数最大,羊草的最小;糙隐子草的芳香性指数最大,知母的最小。不同植物芳香性指数在分解初期迅速减少,在分解后期减少趋势较为缓慢,与分解速率变化趋势一致。     

半干旱黄土丘陵沟壑区封禁流域植被枯落物分布规律研究

通过对陕北半干旱黄土丘陵沟壑区封育流域内不同立地条件下枯落物现存量的测定与分析,研究了枯落物的影响因子及分布规律。对60个样地调查研究结果表明:枯落物现存量与坡度呈二次回归关系,枯落物现存量最小值出现在坡度25.5°的位置;阴坡枯落物现存量比阳坡高25.1%,沟坡枯落物现存量比梁坡高41.7%;地表生物量与枯落物现存量呈显著的正相关性(P0.05);土壤含水量与枯落物现存量呈正相关性;土壤含水量与地表生物量两者的共同作用对枯落物现存量影响明显。     

三江平原湿地植物毛苔草枯落物分解过程中热值动态研究

根据三江平原毛苔草枯落物分解过程中热值及有机物组分含量的测定,分析了枯落物分解过程中热值动态变化及与有机物各组分含量之间的相关性。结果显示：（1）随着分解的进行,O～10cm埋藏深度下毛苔草枯落物热值呈先快速下降后缓慢上升,最后又快速下降的变化趋势;10～20cm埋藏深度下毛苔草枯落物热值呈逐渐降低的趋势,在分解初期降低速率较大,后期降低缓慢。（2）从分解天数与有机物各组分的相关性来看,0～10cm、10～20cm层枯落物中C、C／N和纤维素与分解天数呈显著负相关性,表明随着分解的进行,枯落物中C、C／N和纤维素含量呈显著减少的趋势;而10～20cm层枯落物中N与分解天数存在显著正相关关系。（3）从不同埋藏深度枯落物分解过程中热值与有机物各组分含量的相关性来看,枯落物分解过程中热值与枯落物中木质素含量呈显著相关。本研究有助于明确沼泽湿地植物枯落物分解过程中能量流动特征,为完善沼泽湿地生态系统能量生态学研究提供依据。     

坡向对云雾山典型草原枯落物分解特性的影响

为探讨不同坡向对草地枯落物分解特性的影响,应用尼龙网袋法研究云雾山典型草原主要优势种本氏针茅(Sti pa bungeona)和铁杆蒿(Artemisia sacrorum)(茎、叶)枯落物在阴阳坡1年内的分解失重情况及营养元素动态.结果表明:枯落物分解残留率呈逐渐下降趋势,1年后失重率在18.8％～39.94％之间,分解速率呈快-慢-快变化.指数回归方程拟合得到分解速率常数κ值大小顺序为铁杆蒿叶(0.446)＞本氏针茅(0.321)＞铁杆蒿茎(0.220),阳坡(0.355)＞阴坡(0.301),且不同物种和不同坡向对分解速率影响差异显著(P＜0.001).枯落物50％分解和95％分解所需的时间在1.39～3.45年和6.22～15.12年之间.Pearson相关分析显示分解速率常数κ与枯落物初始氮含量成显著正相关(r=0.895),与C/N比成极显著负相关(r=-0.940).枯落物1年分解过程中氮浓度波动上升,磷浓度波动下降,钾浓度持续下降.总体上N,P,K元素绝对量均下降,养分累积指数NAI＜100％.不同元素由于在枯落物中初始含量、存在方式及降解中微生物作用的不同,释放和积累模式也不同.     

科尔沁不同沙地类型植被动态特征及其与凋落物的关系研究

为探究科尔沁不同沙地类型植被动态特征及其与凋落物的关系，本试验以科尔沁沙地不同类型样地（流动沙丘、固定沙丘和封育草地）为研究对象，测定了2005-2016年生长季高峰期（8月中旬）植被特征和整个生长季（4-9月）凋落物量的动态，分析了二者的年际动态及关系。结果表明：不同类型样地植被特征差异极显著，植被密度、盖度和生物量均有明显的年际动态，且年际动态和样地类型间存在显著交互效应；凋落物量受样地类型、年、月3因素及其交互效应的影响；回归分析表明，植被特征与凋落物量呈极显著线性关系，但小区域范围内，植被特征与凋落物量关系不显著。综上，植被生长显著影响凋落物产生，但植被特征与凋落物量关系不显著，凋落物量可能还受其他因素的影响。     

紫穗狼尾草和狗牙根茎叶水文生态效应比较

研究了紫穗狼尾草Pennisetum alopecuroides地上部的生长状况、水文效应和生态效应。结果表明,紫穗狼尾草的成坪速度、成坪时间、草层高度和地上生物量均明显优于狗牙根Cynodon dactylon;其茎叶最大截留率45.35%,最大截留量5.12 mm,均高于狗牙根;其枯落物有效蓄水率304.88%,有效蓄水量0.19 mm,均低于狗牙根;其茎叶覆盖对降低地表温度和保持土壤水分更为明显、有效。     

Effectiveness of paraformaldehyde foam in continuous disinfection of poultry bedding and dried liquid waste of pigs]

In laboratory experiments 24-hour cultures of poultry strains E. coli, Staphylococcus, Pseudomonas on paper carriers without an agar coat and with it, after 6-hour exposure in dilutions from 10(-4) to 0, were devitalized by paraformaldehyde foam. The Bacillus strain was devitalized only after 24-hour exposure. After adding paraformaldehyde foam in an amount of 0.6% of the weight into litter under a multiplier flock of layers four months before expedition, and after adding paraformaldehyde foam in an amount of 5% and 10% of the weight into the litter for chick broilers, microbial contamination of the litter did not decrease in comparison with the control. 24-hour old cultures of tested microbial strains on carriers were not devitalized after 24-hour exposure in a mixture to litter and paraformaldehyde foam not even after adjusting the volume ratio of mixing to 1 : 9. The disinfecting effect on microbes growing in End's agar and in blood agar with crystal violet was manifested only after adding dried liquid manure of pigs with paraformaldehyde foam at a volume ratio of 50% to 50% after exposure times of 1, 3 and 6.0 weeks. Despite the excellent results obtained with paraformaldehyde foam in disinfecting test-microbes on carriers in laboratory experiments, practical application at a very low volume weight for continuous disinfection of poultry litter is technically unrealistic.     

营养调控对母猪繁殖性能的影响

为了探讨母猪妊娠早期日粮中添加一定量的甲基吡啶铬、叶酸、维生素E和维生素A对母猪窝产仔数、初生重、仔猪成活率的影响,选用日龄、体况基本一致的长大二元母猪共计56头进行试验。结果表明,在母猪妊娠早期的日粮中添加甲基吡啶铬、叶酸、维生素E、维生素A可显著提高母猪窝产仔数,提高比例平均为29.2%,其中对后备母猪提高比例更大。     

Ethologic selection studies with early weaned piglets kept in pens with different use of straw. 3. Results of studies of the position sequence of area size and stall air temperature]

In continuation of our earlier investigations on the range of environmental factors in housing systems with perforated floors and the experiments with or without free choice on litter or deep litter the effects of the size of the area and the environmental temperatures on the behaviour of early weaned piglets (8 kg to 30 kg) kept on litter and deep litter have been investigated. Both factors had a crucial but diametrical influence. While for the total activity of the pigs the size of the compartment proved more important than room temperature, for the total inactivity it was the other way around. Therefore some essential requirements have to be obeyed even for housing systems with litter or deep litter, which can be considered more suitable for the housing of pigs from the start on. Because of their different importance for the activity (20% of the total behaviour) and the inactivity (80%) the factors can't replace each other. For housing systems with litter size allocation shouldn't amount less than 0.45 m2/animal and with deep litter not less than 0.70 m2/animal with room temperatures starting at about 25 degrees C and 20 degrees C, respectively.     

Growth rate of growing pigs is weakly correlated genetically with litter size,while the amount of genetic variation for growth rate changes with litter size

Abstract

We reasoned that if we assessed pigs for litter size and growth rate during the grow-out stage of production (25–100 kg body weight) we would find: 1) an unfavourable genetic correlation between litter size and growth rate; and 2) that the amount of additive genetic variation expressed for growth rate varies with litter size. We tested these premises by assessing 2212 litters from the Yorkshire breed for litter size, while 3038 growing pigs from 550 of these litters were assessed for growth rate during the grow-out stage of production. Genetic correlations were estimated using the additive genetic (co)variances obtained from a bivariate linear animal model fitted to litter size and growth rate. The amount of additive genetic variation expressed for growth rate as a function of litter size was estimated by fitting a univariate linear animal model with random regression on litter size. Our findings did not support the first of our premises as we found that the genetic correlation between litter size and growth rate was favourable (0.28±0.27), albeit not significantly different from zero. However, we were able to support our second premise as we found that the relationship between amount of additive genetic variation for growth rate and litter size was quadratic; the amount of additive genetic variation was highest in small and large litters (h²=0.60 and 0.65), and lowest in intermediate litter sizes (h²=0.29). These findings indicate that: 1) breeding for litter size would not reduce the growth rate of growing pigs; and 2) the amount of genetic variation for growth rate changes with litter size.     

Effect of less intensive rearing conditions on litter characteristics, growth performance, carcase injuries and meat quality of broilers

1. The objective was to compare the effect of two litter types (wheat straw and wood shavings) and two different rearing conditions (Treated and Control) on welfare indicators, broiler performance, carcase injuries, particularly hock and foot pad dermatitis (FPD), litter characteristics and meat quality. 2. Treated conditions were characterised by a low stocking density (11 birds/m(2)), short photoperiod (16 h light: 8 h dark) and a large amount of litter (3 to 4.5 kg/m(2), respectively, for wheat straw or wood shavings). Control conditions were a high stocking density (14 birds/m(2)), long photoperiod (23 h light:1 h dark) and small amount of litter (2.3 to 3 kg/m(2), respectively, for wheat straw or wood shavings). In addition, the effects of two widely used litter materials, wheat straw and wood shavings, were investigated. 3. The combined effects of lower stocking density, greater amount of litter material and a photoperiod similar to the natural one, reduced the occurrence of FPD in Treated groups keeping the FPD score under the European threshold. 4. Improved rearing conditions led to faster growth rate associated with inferior feed efficiency, whereas litter type exerted negligible effects on broiler performance. 5. Litter moisture content, nitrogen and ammonia released by the litter were lower in Treated groups than Control groups. The use of wood shavings resulted in lower moisture and nitrogen concentrations in the litter.     

绵羊放牧绢蒿荒漠草地植物群落多样性及其环境解释

对天山北坡放牧条件下的绢蒿草地进行野外调查,以探讨植物群落物种组成、多样性特征及其与环境因子之间的关系。结果表明:1)绵羊放牧过程中形成了明显的放牧强度梯度,草地利用率适中。通过除趋势对应分析 (DCA)将放牧区内的植物群落划分为8个类型,各类型植物群落的物种多样性有显著差异,且群落间存在异质性;2)采用除趋势对应典范分析法(DCCA)中的前项选择,对所获取的9个环境因子进行筛选,最终土壤有机质含量、粪便量、放牧强度、凋落物生物量、海拔、坡向等6个环境因子成为决定物种分布和群落结构组成的主导因素。DCCA排序结果反映出了实际的生态意义,有机质、放牧强度、粪便量在第一排序轴有明显的梯度变化,而坡向和凋落物则在第2轴上呈现出明显梯度变化,物种和群落也沿着上述环境要素的梯度变化而依次分布,很好地解释了放牧条件下绢蒿荒漠草地物种、群落与环境条件之间的关系。     

不同粗蛋白、粗纤维水平对四川白獭兔种母兔生产性能的影响

本研究旨在探讨饲粮中不同粗蛋白、粗纤维水平对四川白獭兔种母兔生产性能的影响,以确定其适宜的蛋白质、粗纤维需要量。试验饲粮设计4个处理,粗蛋白/粗纤维水平分别是18.59%/15.62%、19.84%/16.06%、19.05%/17.55%、18.56%/16.00%。结果表明:饲粮粗蛋白/粗纤维水平为19.05%/17.55%时,母兔受胎率、仔兔平均初生窝重、窝仔数、初生个体重显著高于其余各处理(P<0.05),说明妊娠期母兔适宜的粗蛋白/粗纤维水平为19.05%/17.55%;饲粮粗蛋白/粗纤维水平为19.84%/16.06%、18.56%/16.00%时母兔泌乳量、仔兔生长性能高于其余各处理(P<0.05),说明泌乳期适宜的饲粮粗蛋白/粗纤维水平为19.84%/16.06%或18.56%/16.00%。