【作者】 何丹；

【导师】 李向林；

【作者基本信息】 中国农业科学院 ， 草地资源利用与保护， 2009， 博士

【摘要】 本研究以内蒙古锡林郭勒草原南部太仆寺旗退化天然草地为研究对象,于2007-2008年在中国农业科学院草原研究所太仆寺旗试验基地采用不同措施进行改良退化天然草地的研究。在土壤和植被基本一致的退化天然草地上,采用划破草皮(H)、划破草皮+灌溉(H+G)、施用尿素+灌溉(N1:25 kg/hm~2、N2:50 kg/hm~2、N3:75 kg/hm~2、N4:100 kg/hm~2)、施用尿素(S:75 kg/hm~2)等措施对退化天然草地进行处理,以未做任何处理的天然草地作为对照。从植物个体、种群、群落、土壤的理化性质等方面研究各改良措施对退化天然草地的影响效果,探讨不同改良措施之间的差异,并提出适宜该区域的最佳改良措施,为退化草地改良提供理论依据。结果表明:1.对照和各处理群落内部植物的生长均呈单峰型变化,株高、盖度、密度和地上生物量等指标均在8月中旬左右达到最大值,但由于2008年雨量丰沛,植物生长期延长,羊草(Leymus chinensis T. )、米氏冰草(Agropyron cristatum L.)等部分植物的生长在9月份达到最大值。2.划破草皮可以增加土壤通气透水性,增强土壤保水力;灌溉增加了土壤含水量;施肥有效补充了土壤养分的不足,所以,各处理措施均可有效促进退化天然草地植物的生长。植被高度、盖度、种群密度与对照相比均有显著提高;叶面积指数增大,群落地上、地下生物量均有增加。3.各处理措施均可以有效促进群落内各种植物的生长,其中以羊草、米氏冰草、星毛委陵菜(Pottentilla acaulis L. )和糙苏(Phlomis tuberosa L.)四个物种种群对各处理措施的响应最为敏感,在群落中的组分及重要值变化相对较大。但不同处理措施对各物种种群的影响效果也不同。羊草是原草地植被的建群种,星毛委陵菜是现草地植被的优势种,本文主要以这两个植物种群及群落和土壤养分的变化作为主要指标,米氏冰草和糙苏种群的变化作为辅助指标来评价各种改良措施的效果。4.各处理措施相比,两年均以N2处理对羊草种群增长的促进效果最为显著。与对照相比,羊草种群高度两年分别增加了64.42%和45.14%;种群密度与分盖度也均有提高,分盖度最高可达40%,与对照相比提高了一倍;种群地上生物量两年分别提高了538.98%和249.53%;在群落中产量百分比最高,可达41%左右;在群落中的重要值也由最初对照的0.21增加到了0.45。当施肥量大于50kg/hm2时个体数量特征变化不再明显。5.各处理措施相比,两年均以N4处理对星毛委陵菜的种群变化影响最为显著。与对照相比,种群高度分别提高了32.7%和26.9%,密度和盖度也都有显著增加;显著提高了种群地上生物量,与对照相比两年分别增加了123.28%和12.37%。种群在群落中的重要值也有相应变化,2007年重要值与对照相比提高了0.4;2008年所有处理星毛委陵菜种群的重要值均低于对照,但N4处理相对降低较少。综合比较两年的处理效果发现,除H+G和N2处理外其它处理星毛委陵菜种群在群落中的重要值均在当年或次年高于羊草在群落中的重要值。6.各处理措施均可有效促进群落内各种植物的生长,可以显著增加群落的高度、密度,盖度和群落的地上生物量。与其他处理措施相比,施肥可以显著增加群落的密度、盖度和地上生物量,其中以N2和N3处理效果最好,群落地上生物量在2007年8月与对照相比分别增加了163.68%(N2)和169.71%(N3),2008年9月与对照相比分别增加了53.04%(N2)和51.57%(N3)。群落的多样性指数、均匀度指数、叶面积指数和根冠比等由于受多种因素的共同影响,年际变化较大,所以未把其当做衡量改良措施的直接指标。7.各处理措施相比,以N2处理对米氏冰草种群高度、密度、分盖度和地上生物量以及在群落中的重要值的增加效果最为显著,以N3处理对糙苏种群各项指标的增加效果最为显著。8. N2处理下土壤的养分含量均有相应的提高。土壤的全氮含量0-10cm与对照相比提高了2.86%;全磷含量各土层与对照相比分别提高了2.85%、13.76%和12.75%;10-20cm和20-30cm土层的碱解氮含量均显著高于对照,与对照相比分别提高了7.03%和26.86%;土壤的速效磷含量和有机质含量各土层也都有提高,与对照相比速效磷含量分别提高了21.56%、2.94%和22.92%;有机质含量分别提高了3.78%、12.91%和21.72%。9.综合各处理措施对四个物种种群、群落及土壤养分的影响,以N2处理对羊草种群增长、群落地上生物量和土壤养分的的增加效果最为明显,而且羊草的重要值两年均高于星毛委陵菜,取代星毛委陵菜成为群落中的主要物种,在群落中占有主导地位;同时也增加了优良饲用牧草冰草在群落中的组分,所以兼顾改良效果和草地的利用价值,几种措施相比,施肥50kg/hm2+灌溉是该区域最佳的改良措施。10.比较H和H+G,S和N3处理的效果可以发现,同一措施实行早春灌溉可有效促进群落内植物种群的增长,比后期增加降雨更为有效。11.两年间群落内物种洽草、糙苏、唐松草和矮韭等植物的开花期出现明显的差异。12.各改良处理影响了群落地上、地下生物量的分配,根冠比值均低于对照。两年间地上、地下生物量和根冠比值与生长季降雨量的关系均不明显;部分处理的地上生物量与温度存在一定关系,但总体表明气候因素对各处理效果并未起到决定性作用。更多还原

【Abstract】 The research was carried out at the country of Taipusi, south of Xilingol Grassland of Inner Mongolia, for two years from 2007 to 2008. The objective of the experiment is to research the effect of different improved measures on the degraded grassland. There were four measures adopted: turf scarifying(H), turf scarifying and irrigation(H+G), fertilizer(N1:25kg/hm~2, N2:50 kg/hm~2, N3:75 kg/hm~2, N4:100 kg/hm~2 urea per year) and irrigation, fertilizer(S:75 kg/hm~2 urea per year) and none as control to research the effect and mechanism of these measures from the characteristic of individual, populations, community and soil, and according to these to choose a more suitable measure of the region and provide theory foundation. The results indicated:1. The height、coverage、density、and biomass of all species in community got the maximum at the middle of August. Some species such as Leymus chinensis and Agropyron crastatum were got the maximum at the middle of September because of the abundant rainfall in 2008 year.2. The treatment of turf scarifying can improve the soil condition of air and water content. The treatment of irrigation can increase the water content of the soil and the treatment of fertilization can improve the deficiency of soil nutrient. So all the treatments could be effectively improved the recovery of the degraded grassland. The height, coverage, density and biomass of the community were significantly improved in contrast to the control and the leaf indexes were increased.3. The different measures could be effectively improved the growth of all plants. And the species of Leymus chinensis, Agropyron crastatum, Pottentilla acaulis and Phlomis tuberose were more sensitive to the measures. The percentage in community and the important value of those were changed relatively obviously by different measures. The species of Leymus chinensis and Pottentilla acaulis are seperately the constrative and the dominant species in the community and according to the changes of both species and community and the nutrient of siol as indexes to evaluate the effects of the treatments.4. The measures of 50kg/hm2 urea could be the best to the growth of Leymus chinensis in two years.The height increased 64.42% and 45.14% separately in 2007 and 2008 years to the control. And the coverage also increased 40%, double to the control. The biomass of community increased 538.98% and 249.53% separately in two years and the important values increased from 0.21 to 0.45.5. The measures of 100kg/hm2 urea could be the most significant to the growth of Pottentilla acaulis in two years. The height increased 32.7% and 26.9% to the control in two years. The density and coverage also increased. The biomass of community increased 123.28% and 12.37% separately in two years and the important value increased 0.4 to the control in 2007 year. The important values of Leymus chinensis were lower than Pottentilla acaulis except in H+G and N2 treatment of two years.6. All measures could improved the plant growth in the community, and the height、density、coverage and the above ground biomass of the community were significantly promoted. N2 and N3 treatments were the most effective in contrast to others. The aboveground biomass increased 163.68% and 169.71% in August of 2007 year separately and 53.04% and 51.57% in September in 2008 year. The richness (S and Margalef index)、diversity index (Simpon index and Shannon-Weaver index)、LAI index and the ratio root: shoot were changed a lot in two years relating to many factors, so they were not contained in the indexes of evaluate the effects of treatments.7. In contrast to all measures, N2 treatment was the most significant way to improve the height、density、coverage、aboveground biomass and the important value of the Agropyron crastatum species and the same of Phlomis tuberose species by N3 treatment.8. The soil nutrient of N2 treatment was all enhanced. The total nitrogen content of 0-10 cm soil depth was increased 2.86% to the control. The total phosphorus content were increased 2.85%、13.76% and 12.75% separately in 0-10cm, 10-20cm, 20-30cm soil depth. The available nitrogen content were higher in 10-20cm and 20-30 cm soil depth to the control, increased 7.03% and 26.86% separately. The available phosphorus content increased 21.56%, 2.94% and 22.92% and organic matters content were increased 3.78%, 12.91% and 21.72% in every soil depth separately.9. In contrast of the effects of changes of fours species, community and soil nutrient, N2 treatment was the most significant effective. And the important values of Leymus chinensis were higher than Pottentilla acaulis in two years and became the dominant species in the community. The percentage of Agropyron crastatum in community was also increased. So in considering of the treatments effects and the value in use of the grassland, 50kg/hm2 urea and irrigation was the most effective way in the region.9. The plant growth coule be better in the early spring than increasing rainfall later by the contrast of H and H+G, S and N3 treatments.10. The period of flowering of species such as Koeleria cristata, Phlomis tuberose, Thalictum petaloideum and Allium anisopodium were changed in two years.11. The distribution of aboveground biomass and belowground biomass were changed in different treatments and the ratio root: shoot were lower than the control. There were no obvious relationships of the aboveground biomass, belowground biomass and the ratio root: shoot to the rainfall in growing seasons, but had some correlation to the last month average temperature. And the climate factors did not have the determine function to the effects of treatment.更多还原