【作者】 朱珏；

【导师】 张彬； 谭支良；

【作者基本信息】 湖南农业大学 ， 特种经济动物饲养， 2009， 硕士

【摘要】 为了给选育与利用优质牧草资源提供理论依据,选取广西河池地区环江喀斯特生态观测站内一块面积为800 m~2洼地以及一块面积为240 m~2坡地(分成12个区,按照随机区组设计,设计成四个组)。进行了收获期和不同刈割强度对喀斯特地区人工种植牧草生理生态与营养价值影响的研究。试验结果表明:1收获期和刈割强度对牧草生理生态的影响随着收获期推移,桂牧一号及宽叶雀稗叶面积、叶长、叶宽、干物质、茎叶比、分蘖数、总叶绿素含量的大小变化都呈上升变化,而种群密度、游离水、叶绿素a/b值都呈下降变化。两种牧草株高相对生长速率(RGH)都随着收获期推移呈下降变化(桂牧一号株高RGH呈二次曲线相关,宽叶雀稗株高RGH呈一次曲线相关),而其株高、茎长、地上干(鲜)生物量随着收获期地推移呈直线上升变化。不同强度刈割收获宽叶雀稗地上干(鲜)生物量表现出极显著差异(P＜0.01,P＜0.001)。在整个刈割期中,75%重度刈割对宽叶雀稗地上鲜(干)生物量沉积有明显抑制作用,而25%刈割强度最能提高宽叶雀稗地上鲜(干)生物量在牧草体内的沉积。其中,25%强度刈割宽叶雀稗地上鲜(干)生物量比75%的最高可提高25.25 kg/m~2(5.5 kg/m~2)。另外,相比0%、50%及75%刈割强度,25%轻度刈割强度最能提高宽叶雀稗株高相对再生生长速率、叶茎比、总叶绿素含量及叶绿素a/b值。相比不刈割,25%、50%及75%刈割强度的宽叶雀稗叶面积最大值的出现时间都提前了。2收获期和刈割强度对牧草不同部位营养价值的影响收获期对桂牧一号及宽叶雀稗整株、茎及叶CP、DM、OM、NDF、ADF和HC影响显著。随着收获期推移,牧草整株、茎及叶DM、OM含量呈显著线性上升,CP含量呈显著线性下降。桂牧一号整株及叶中ADF和NDF含量都呈下降变化,而其茎中的则呈上升变化。宽叶雀稗不同部位的ADF含量都呈上升变化。宽叶雀稗整株及茎中NDF含量呈上升变化,而叶中的呈下降变化。两种牧草不同部位的HC含量都呈下降变化。比较25%、50%和75%强度刈割宽叶雀稗整株、茎及叶DM及OM含量,以25%刈割的最高。虽然,不同刈割强度收获宽叶雀稗不同部位CP含量变化都呈下降趋势,且差异极显著(P＜0.01,P＜0.001),但75%较其它三种刈割强度(0%、25%、50%)更能减缓宽叶雀稗整株、茎及叶CP含量下降速度。其中,最大减缓幅度分别达2.62%、1.71%和3.54%。在整个刈割期中,比较0%、25%、50%、75%四种不同刈割强度,宽叶雀稗不同部位的ADF、HC含量差异并不显著(P＞0.05)。而相对于NDF含量,以25%强度刈割宽叶雀稗整株、茎及叶中NDF含量显著(P＜0.05)高于其它强度刈割的,其最高提高了5.90%、2.30%和10.5%。3不同刈割强度对宽叶雀稗整株体外消化率的影响从整个刈割期来看,不同刈割强度对宽叶雀稗整株最大产气量(A)、最大理论产气速率常数(b)、产气发酵延长时间(LAG)、整株干物质消失率(IVDM)及有机质消失率(IVOM)的影响并无显著性差异(P＞0.05)。但是,7月份,50%刈割强度收获宽叶雀稗的b显著(P＜0.05)高出25%的0.95 ml/h;9月份,50%强度刈割的LAG值最小;25%轻度刈割强度对宽叶雀稗整株干物质消失率(IVDM)及有机质消失率(IVOM)都分别显著(P＜0.05)高于0%、50%、75%刈割强度的17.9%、8.8%、6.6%和17.9%、9.2%、6.7%。综上所述,收获期对桂牧一号和宽叶雀稗生理生态指标及不同部位营养物质含量变化都有很大影响,其原因很可能与牧草品种、牧草不同部位之间存在差异性以及牧草所处地理气候条件有关。在不同刈割强度中,25%轻度刈割对宽叶雀稗生理生态影响最大,其可以通过提高该牧草营养物质沉积来使其朝着有利于动物消化利用的方向沉积。75%重度刈割能有效减缓其不同部位CP含量下降速度;分析其原因很可能是适当刈割强度可以通过充分发挥牧草的超补偿性和均衡性生长作用来改变该牧草生理生态和体内某些营养物质沉积方向和沉积量,进而提高其在动物体外的消化率。更多还原

【Abstract】 In order to give the theoretical basis for the seed selection and using the high quality resources of grazing, this experiment was conducted with a billabong and a sloping field which the area are 800 and 240 square meters respectively in HuanJiang experimental station of karst ecosystem. The sloping field was divided into 12 blocks which were designed and randomly divided into four groups. To study the effect of harvest and different clipping intensities on physio-ecology and nutrition of grazing in Karst area. The results showed as follows:1 Effect of the harvest and clipping intensities on physio-ecology of grazingAlong with harvest, some of the physio-ecological index of Pennisetum purpureum and Broadleaf paspalum increased, which included leaf area, leaf length, leaf width, dry matter, ratio of stem and leaf, tiller number and total chlorophyl. On the other hands the value, population density, free water content and C_a/C_b decreased in the two grasses. The relative height growth rate (RGH) of Pennisetum purpureum was a katabatic conic curve. And the RGH of paspalum was a katabatic curve of first degree. The physio-ecological index which included plant height, stem height; aboveground fresh biomass and aboveground dry biomass linearly increased with the harvest.The aboveground regenerative fresh biomass and aboveground dry biomass of Broadleaf paspalum varied significantly (P < 0.01, P < 0.001) with the different clipping intensities. In the whole clipping times, for both the aboveground fresh and dry biomass of Broadleaf paspalum were restrained by 75% clipping intensity. The aboveground regenerative fresh and dry biomass of this grass which was cut at 25% clipping intensity gave the highest increase of 25.25 kg/m~2 and 5.5 kg/m~2 respectively compared with that of 75% intensities. Additionally, in comparison with 0%, 50% and 75% clipping intensities, 25% light clipping intensity was the best which could enhance the relative height regrowth rate, proportion of stem and leaf, total chlorophyll and a/b value compared with 0% clipping intensity. The arisen time of highest leaf area could be advanced by all of the clipping intensities which included 25%, 50% and 75% clipping intensities.2 Effect of the harvest and clipping intensities on nutrient composition of grazing materialsThe nutrient composition of different parts of Pennisetum purpureum and Broadleaf paspalum varied significantly with different harvest months. Along with harvesting period, the dry matter and organic matter contensts in the plant, stem and leaf of these two grasses were linearly raised, while the crude protein content decreased linearly. The ADF and NDF contents which were in the plant and leaf of Pennisetum purpureum declined, but increased in the stem. For the ADF of Broadleaf paspalum, the ADF content of the plant and stem of this grass was on the increase and that of the leaf. The HC content for different parts of Pennisetum purpureum and Broadleaf paspalum also declined.Compared with 25%, 50% and 75% clipping intensities, the highest dry matter and organic matter contents which were in plant, stem and leaf of Broadleaf paspalum were cut by 25% clipping intensity. The crude protein content which were in different part of this grass declined significantly (P < 0.01, P < 0.001) with different clipping intensities. The rate of decline of crude protein content in the plant, stem and leaf of this grass, cut at 75% clipping intensity, was less than those of 0%, 25% and 50% intensity. The highest degressive extents were 2.62%, 1.71% and 3.54% respectively for plant, stem and leaf. In the whole clipping time, and comparing among 0%, 25%, 50% and 75% clipping intensities, the ADF and HC components of the different parts of the Broadleaf paspalum had no significant difference (P > 0.05) .The NDF content of plant, stem and leaf of the Broadleaf paspalum which were cut at 25% clipping intensity showed significant increase (P < 0.05) by 5.90%, 2.30% and 10.5% respectively compared with other clipping intensities.3 Effect of the clipping intensities on the in vitro digestibility of Broadleaf paspalum plantIn the whole clipping time, there were no significant differences (P > 0.05) in the values of gas produced from maximum theoretic gas production (A), constant of rate of gas production (b) , LAG , in vitro dry matter digestibility (IVDM) and in vitro organic matter digestibility (IVOM) in total plant of Broadleaf paspalum subjected to different clipping intensities. But in July, the b value of total plant of Broadleaf paspalum which was cut by 50% clipping intensity was significantly higher (P < 0.05) than that of 25% intensity, enhanced 0.95 ml/h. In September, the LAG value indicated lowest. The IVDM and IVOM in the total plant of this grass were enhanced by 17.9%, 8.8%, 6.6% and 17.9%, 9.2%, 6.7% respectively at 25% clipping intensity compared with those of 0%, 50% and 75% clipping intensities.It was concluded that there was a prodigious effect of the harvest on physio-ecology and nutritive components of different parts of Pennisetum purpureum and Broadleaf paspalum, which may be caused by difference in the kind of grass, as well as the parts of grasses and also the prevailing climate condition where the types of grasses are located. In the different clipping intensities, the 25% light clipping intensity was judged the best which could significantly influence the physio-ecology of Broadleaf paspalum, leading to enhanced forage quality and better animal performance. The 75% heavy clipping intensity could slower the decline rate of crude protein content. All of these may be caused by over-compensation and functional equilibrium of plant.更多还原