放牧牦牛食土对高寒草地植被特征变化的响应及其营养评价

发布时间：2018-02-28 06:26

本文关键词： 牦牛食土草地植被模型矿质营养　出处：《宁夏大学》2017年硕士论文　论文类型：学位论文

【摘要】：本文旨在研究放牧牦牛食土量与草地植被特征因子变化的关系,并探讨食土对牦牛矿物营养水平的潜在影响,为科学预测牦牛食土量和放牧生产实践中矿物营养调控提供理论依据。本试验位于祁连山东麓高寒草地,试验选取两块经围栏封育1年的天然草地作为耗牛放牧试验草地,面积均为2.5亩。选取5头3岁左右的去势公牦牛作为试验动物,分别在8月份(暖季)和11月份(冷季)两个时期,试验过程中对放牧草地植被高度、盖度、生物量进行连续测量。采集试验区表层土样、草地内牧草及耗牛血样、瘤胃液,并通过视频监控收集牦牛粪样,同时进行分析测定,以钛元素作为内源性标记物估测牦牛食土量。主要试验结果如下:1、冷暖季放牧试验草地主要优势植被的盖度、高度、生物量均随着放牧的进行而呈显著的下降趋势(P0.01)。季节差异性分析表明,试验前期暖季草地植被的盖度要高于冷季,而植被高度和生物量均低于冷季,但是冷季植被生物量的下降趋势要高于暖季。2、暖季试验牦牛拥有较高的日排粪量和日干物质采食量;试验牦牛食土现象广泛存在,暖冷季试验牦牛百分食土量分别在2.80%～10.11%和2.13%～13.42%之间;食土量存在显著的季节性变化,试验早期暖季牦牛百分食土量要高于冷季,试验后期冷季牦牛百分食土量要高于暖季。3、牦牛百分食土量与2天前试验草地植被优势牧草盖度、高度及生物量均存在显著的负相关,这也进一步证实通过元素Ti测定的牦牛食土来源于2天前放牧采食。冷暖季试验牦牛食土量占日粮比重与针茅盖度和高度、珠芽蓼盖度和高度以及总体生物量呈显著地负相关,与矮生嵩草盖度、线叶嵩草盖度和扁蓿豆盖度呈极显著地负相关,由其建立的暖季和冷季牦牛食土量估测数学模型分别为%SI=16.419+1.524 KHH-0.205 SCC+0.067 PVC-0.225 KHC-0.032 TB(R2=0.996,P0.01)和%SI=4.632+0.684 SCH-1.302 KCH-3.259 MRH+1.199 SCC+0.019 TB(R2=0.985,P0.01)。(矮生嵩草高度:KHH,Kobresiahumilis height;针茅盖度:SCC,Stipacapillata coverage;针茅高度:SCH,Stipacapillata height;珠芽寥盖度:PVC,Polygonum viviparum coverage;矮生嵩草盖度:KHC,Kobresiahumilis coverage;扁宿豆高度:MRH,Melissitus ruthenica height;线叶嵩草高度:KCH,Kobresia capillifolia height;百分食土量(食土量占日粮比重):%SI,%soilingestion,生物量:TB,Totalbiomass)。然而,本试验所建立的冷暖季牦牛食土量估算数据模型是在现有的植被特征条件下建立的,在其他草地植被特征条件下是否适应还需进一步的验证和优化。4、冷暖季放牧后期时牦牛血清中Na、K、Pi的含量上升,对K的影响显著(P0.05),Cu、Fe、Zn、Ca、Mg的含量发生下降,其中Fe的变化差异显著(P0.05),Ca、Cu含量低于临界水平,存在元素缺乏的风险。5、冷暖季试验后期牦牛瘤胃液中乙酸、丙酸、丁酸、异丁酸、戊酸和异戊酸的含量显著降低(P0.01),试验后期草地牧草供给不足,牦牛处于饥饿状态有关。
[Abstract]:The purpose of this paper is to study the relationship between grazing yak feeding soil quantity and grassland vegetation characteristic factors, and to explore the potential effect of grazing soil on the mineral nutrition level of yak. In order to provide a theoretical basis for scientific prediction of yak soil feeding amount and mineral nutrition regulation in grazing practice, the experiment was conducted on alpine grassland in the eastern foot of Qilian Mountain. Two natural grassland fenced for one year were selected as cattle grazing trial grassland. Five ovariectomized male yaks, aged about 3 years, were selected as experimental animals in the periods of August (warm season) and November (cold season). The biomass was continuously measured. The surface soil samples, grass and cattle blood samples, rumen fluid were collected, and yak dung samples were collected by video surveillance. The main results are as follows: 1. The coverage and height of main dominant vegetation in grazing trial grassland in cold and warm season. The biomass decreased significantly with grazing. The seasonal difference analysis showed that the vegetation coverage in warm season was higher than that in cold season, and the vegetation height and biomass were lower than that in cold season. But the decline trend of vegetation biomass in cold season is higher than that in warm season. The experiment yaks have higher daily excrement and daily dry matter intake. In the warm and cold season, the percentage of soil in yak was between 2.80% 10.11% and 2.13% and 13.42%, and there was a significant seasonal change in the amount of soil, and in the early warm season, the percentage of soil eaten by yaks was higher than that in cold season. In the late cold season, the percentage of soil in yak was higher than that in warm season. There was a significant negative correlation between the percentage of soil and the vegetation coverage, height and biomass of the grassland 2 days before the experiment. It was further confirmed that the yak feeding soil determined by element Ti came from grazing and feeding two days ago. In the cold and warm season, the proportion of the yak feeding soil to the diet was negatively correlated with the coverage and height of Stipa, the coverage and height of Polygonum hydrogonum and the total biomass. There was a significant negative correlation between the coverage of Kobresia humilis, Kobresia lanceolata and almond. The mathematical models for estimating the soil quantity of warm season yak and cold season yak were established as follows: SIX16. 419 1. 524 KHH-0.205 SCC 0.067 PVC-0.225 KHC-0.032 TBC R2 0.996P0. 01) and SI4. 632 0. 684 SCH-1.302 KCH-3.259 MRH 1. 199 SCC 0.019 TBP0. 985P0. 1. (KHHH Kobresia humilheightts; Stiapillcoverata; Stipacapillata ightata; Stipacapillata; sprouts); PVCPolygonum viviparum covering; KHCC: Kobresiahumilis coverage. asparagus ruthenica ruthenica height.KCHK Kobresia capillifolia height.The percentage of soil eaten (percentage of feed soil to ration weight), biomass: Tbb total biomassass.However, the ratio of the soil to the diet is the same as that of the Kobresia capillifolia. However, the ratio of Kobresia to Kobresia capillifolia height.The percentage of soil consumed in the diet is 1%, and the biomass is: TBT total biomass.However, the ratio of the soil to the specific gravity of the diet is 1%. The estimation data model of yak feeding soil in cold and warm season was established under the existing vegetation characteristics. It is necessary to further verify and optimize the adaptability of other grassland vegetation characteristics. During the late grazing period of cold and warm season, the content of Na + K Pi in yak serum increases, and the effect on K is significant. The variation of Fe content was significantly lower than the critical level, and there was a risk of element deficiency. In the late cold and warm season test, acetic acid, propionic acid, butyric acid, isobutyric acid in yak rumen fluid were detected. The contents of pentanoic acid and isovaleric acid decreased significantly (P 0.01), which was related to the deficiency of grass supply and the starvation of yak in the later stage of the experiment.
【学位授予单位】：宁夏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S823.85;S812.8

【参考文献】