【作者】 赵锦梅；

【导师】 刘长仲；

【作者基本信息】 甘肃农业大学 ， 草业科学， 2010， 博士

【摘要】 本研究以位于祁连山东段的天祝金强河河谷阶地阳坡地带的退耕自然恢复地、当年弃耕地、坡耕地、人工草地和天然草地5种不同土地利用方式地为研究对象,探讨了不同土地利用方式下的植被和土壤理化性质变化,并对比分析不同土地利用方式对不同生态系统的有机物质生产、生物多样性维持、水源涵养、土壤保持、固碳功能和防风固沙功能等6个方面的水土保持生态服务功能的影响。主要结果如下:⑴不同土地利用方式对地表植被和土壤的理化性质有显著的影响。天然草地在地表植被分布和土壤理化性质方面均优于其它土地利用方式,而坡耕地和当年弃耕地在地表植被分布和土壤理化性质方面均较差。⑵不同土地利用方式下地上生物量表现为:坡耕地(369.6g·m-2)>人工草地(274.2g·m-2)>天然草地(211.1g·m-2)>退耕自然恢复地(176.4g·m-2)>当年弃耕地(66.8g·m-2)。地下生物量表现为:天然草地(2928.8g·m-2)>人工草地(738.3g·m-2)>坡耕地(315.8g·m-2)>退耕自然恢复地(296.3g·m-2)>当年弃耕地(62.9g·m-2)。地上生物量与植被盖度极显著相关(P<0.01),并符合二次函数变化关系;地下生物量与植被盖度和物种数极显著相关(P<0.01);地下生物量与植被盖度、物种数的变化分别符合对数和二次函数变化。不同土地利用方式下的生态系统产品提供功能的依次为:坡耕地>人工草地>天然草地>退耕自然恢复地>当年弃耕地。⑶天然草地物种丰富度最大(13),退耕自然恢复地次之(11),坡耕地和当年弃耕地最小(7)。天然草地生态优势度和物种多样性最高,坡耕地最低。退耕自然恢复地群落的物种均匀度最大(0.51),坡耕地最小(0.32)。不同土地利用方式地的多样性维持生态服务功能的依次为:天然草地>退耕自然恢复地>人工草地>坡耕地>当年弃耕地。⑷天然草地土壤有机碳储量最高(5.269kg·m-2),退耕自然恢复地最低(1.826kg·m-2)。当年弃耕地和人工草地的土壤有机碳储量接近,但均小于天然草地。土壤0~30cm土层总有机碳储量表现为天然草地(15.558kg·m-2)>当年弃耕地(7.706kg·m-2)>人工草地(7.559kg·m-2)>坡耕地(6.076kg·m-2)>退耕自然恢复地(5.477kg·m-2)。0~20cm土壤表层的土壤的碳贮量对土壤整体碳储量能力的发挥着起着非常重要的作用。不同利用方式生态系统固碳生态服务功能依次为:天然草地>当年弃耕地>人工草地>坡耕地>退耕自然恢复地。⑸不同利用方式地最大持水量分布在681.966～592.93t·hm-2之间;毛管持水量分布在537.52～622.207t·hm-2之间;非毛管持水量分布在36.019～62.894t·hm-2之间;土壤持水量天然草地最大,退耕自然恢复地最低。当年弃耕地地表径流量最大(2788.68m3·hm-2);退耕自然恢复地次之(2073.03m3·hm-2);天然草地(581.84m3·hm-2)最小。人为因素是影响地表径流量的主要因素。不同土地利用方式下水源涵养生态服务功能为:天然草地>坡耕地>人工草地>退耕自然恢复地>当年弃耕地。⑹不同土地利用方式地的土壤侵蚀量分布在0.037～0.208t·hm-2之间;依次为:当年弃耕地(0.208t·hm-2)>坡耕地(0.155t·hm-2)>退耕自然恢复地(0.139t·hm-2)>人工草地(0.121t·hm-2)>天然草地(0.037t·hm-2)。不同土地利用方式地养分富集比不同。土壤养分流失呈现出高肥力土壤养分高流失、低肥力土壤养分低流失的规律。土壤侵蚀模数当年弃耕地最大(104.05t·km-2·a-1),天然草地最小(18.308t·km-2·a-1)。不同土地利用方式土壤侵蚀模数的主要影响因子是径流量。不同土地利用方式土地生态系统土壤保持生态服务功能为:天然草地>人工草地>退耕自然恢复地>坡耕地>当年弃耕地。⑺临界侵蚀风速最大的是人工草地(16m·s-1),坡耕地和天然草地次之(14m·s-1),当年弃耕地和退耕自然恢复地最小(12m·s-1)。风蚀速率与风速变化成正相关,随着风速增大,风蚀速率相应增加;风蚀速率和风速变化服从幂函数变化关系。在近地表0～20cm范围内,降尘量总量依次为退耕自然恢复地>当年弃耕地>天然草地>人工草地>坡耕地;不同土地利用方式土地生态系统防风固土功能为:退耕自然恢复地=天然草地>人工草地>坡耕地>当年弃耕地。更多还原

【Abstract】 The study on the soil and water conservation ecological services under different land use patterns was conducted in Tianzhu, the alpine meadow area in the eastern part of Qilian Mountains. Five land use patterns, including naturally restored abandoned cropland (NRAC), abandoned cropland (AC), slope cropland (SC), sowed grassland (SG) and natural grassland (NG), were designed to study the impacts of different treatments on soil and water conservation and ecological service functions, including vegetation productivity, biodiversity maintenance, water conservation, soil conservation, carbon sequestration and wind erosion. The main results were as follows:1) The impacts of different land use patterns on the vegetation and soil properties were significant. The vegetation features and soil properties in nature grassland were better than any other land use patterns, while the ground vegetation and soil physical-chemical characteristics in slope cropland and abandoned cropland were the worse.2) The differences of aboveground and underground biomass among 5 types of land use patterns were significant. The order of aboveground biomass was SC (369.6 g/m2) > SG (274.2 g/m2) > NG (211.1 g/m2) > NRAC (176.4 g/m2) > AC (66.8 g/m2). And it was NG (2928.8 g/m2) > SG (738.3 g/m2) > SC (315.8 g/m2) > NRAC (296.3 g/m2) > AC (62.9 g/m2) for underground biomass. The following relationships were found: a logarithmic function relationship between underground biomass and vegetation coverage; a quadratic function relationship between underground biomass and species number. The aboveground biomass was significantly (P<0.05) correlated with vegetation coverage, the underground was significantly (P<0.05) correlated with species and vegetation coverage. The order of ecosystem product services was SC > SG > NG > NRAC > AC.3) Among different land use patterns, the species richness of NG was highest (13), NRAC was next (11), SC and AC were the lowest (7). The ecological dominance and diversity of NG was highest and SC was lowest. The uniformity index of NRAC was the highest (0.51) and SC was the lowest (0.32). And the order was NG > NRAC > SG > SC > AC.4) The storage of soil organic carbon in NG was the highest (5.269 kg/m2) and NRAC was the lowest (1.826 kg/m2). And that was close between SG and AC. The total storage of soil organic carbon within 0 to 30 cm soil layer was NG (15.558 kg/m2) > AC (7.706 kg/m2) > SG (7.559 kg/m2) > SC (6.076 kg/m2) > NRAC (5.477 kg/m2). The storage of soil organic carbon within 0 to 20 cm played an important role in the whole storage capacity of soil organic carbon. The storage capacity of soil organic carbon was NG > AC > SG > SC > NRAC.5) The maximum moisture holding capacity distribution ranged from 681.966 t/ha to 592.93 t/ha in different land use patterns. The capillary moisture distribution ranged from 537.52 t/ha to 622.207 t/ha. The non-capillary moisture distribution ranged from 36.019 t/ha to 62.894 t/ha. The soil water capacity of NG was the highest, while the performance of NRAC was the worse. The ground runoff of AC was the highest (2788.68 m3/ha), and that of NRAC was the next (2073.03 m3/ha), NG was the lowest (581.84 m3/ha). Human activity was the main factor affecting ground runoff. The order of water conservation in different land use patterns was NG > SC > SG > NRAC > AC.6) The soil erosion distribution ranged from 0.037 t/ha to 0.208 t/ha in different land use patterns. The order of soil erosion was AC (0.208 t/ha) > SC (0.155 t/ha) > NRAC (0.139t/ha) > SG (0.121t/ha) > NG (0.037 t/ha). The value of enrichment ratio of soil nutrients was different in different land use patterns. The characteristics of soil nutrient loss showed that high fertility soil lost more nutrients than low fertility soil. The soil erosion modulus of AC was the highest (104.05 t/km2·a), and NG was the lowest (18.308 t/km2·a). Main factor of soil erosion modulus was ground runoff. The order of soil conservation in different land use patterns was NG > SG > NRAC > SC > AC.7) The threshold of wind erosion velocity for SG was the biggest (16m/s),SC and NG were the next (14m/s),AC and NRAC was the smallest (12m/s). The results indicated that the rate of wind erosion positively interrelates with the wind speed. The rate of wind erosion increased with the increasing of wind velocity. A power function relationship was found between wind erosion rate and wind velocity under different land use patterns. The order of the dustfall amount within 0 to 20 cm of aboveground was NRAC > AC > NG > SC > SC. The order of resistance to wind erosion and soil holding capacity of 5 patterns was NRAC = NG > SG > SC > AC.更多还原