【作者】 刘影；

【导师】 王青；

【作者基本信息】 西南科技大学 ， 环境科学与工程， 2017， 硕士

【摘要】 土地利用变化是影响土壤碳库动态的重要因素。本研究选择岷江上游理县2个相邻的羌族聚落——佳山村和九子村,分别位于干旱河谷的阴坡和阳坡,基于3S技术,分析1999～2014年研究区土地利用空间分布格局,利用野外采样分析不同土地利用类型(玉米、林地、草地、车厘子、李子、苹果、核桃、花椒)的土壤有机碳和全氮含量,研究传统作物转变为不同果园地对土壤有机碳库变化的影响,为评估岷江上游的生态服务价值提供科学依据。主要结果和结论包括:(1)1999～2014年羌族聚落土地利用变化显著。佳山聚落总面积为573.90 hm2,1999～2014年耕地减少188.17 hm2,而果园地增加95.03 hm2,林地增加147.50 hm2;九子聚落总面积267.20 hm2,1999～2014年耕地减少100.27 hm2,果园地增加65.40 hm2,林地增加14.95 hm2。羌族聚落土地利用正处于快速调整阶段,传统耕地(以种植玉米、蔬菜为主)大幅度转变为林地(洋槐)和果园地(种植车厘子、李子、苹果等),这种土地利用变化主要是退耕还林政策、比较利益和聚落人口空心化共同驱动作用的结果。(2)不同土地利用土壤有机碳差异明显,阴坡和阳坡同种土地利用土壤有机碳有一定差异,但大小关系不完全相同。佳山不同土地利用类型的土壤有机碳浓度为:车厘子(19.65 g·kg-1)>林地(16.77 g·kg-1)>苹果(15.77 g·kg-1)>李子(15.42 g·kg-1)>玉米(11.07 g·kg-1)>草地(10.84 g·kg-1);九子不同土地利用土壤有机碳浓度为:车厘子(18.50 g·kg-1)>苹果(16.83 g·kg-1)>核桃(14.87 g·kg-1)>李子(14.3 1 g·kg-1)>林地(12.52 g·kg-1)>玉米(11.57 g·kg-1)>花椒(10.71 g·kg-1)>草地(10.47 g·kg-1)。结果表明果园地土壤有机碳浓度明显高于传统耕地,主要归因于种植车厘子、李子和苹果等需要多施用有机肥,而种植玉米等以施用化肥为主。(3)阳坡不同土地利用土壤剖面(0～60 cm)有机碳累积强于阴坡。佳山不同土地利用土壤有机碳密度为:车厘子(9.32 kg m-2)>林地(7.91 kg·m-2)>苹果(7.48 kg·m-2)>李子(6.59 kg·m-2)>草地(5.16 kg· m-2)>玉米(4.47 kg· m-2);九子不同土地利用土壤有机碳密度为:车厘子(10.78 kg · m-2)>核桃(9.81 kg · m-2)>苹果(9.01 kg · m-2)>李子(8.76 kg·m-2)>草地(7.74 kg·m-2)>林地(7.33 kg· m-2)>玉米(5.3 6 kg· m-2)>花椒(4.91 kg · m-2)。这些结果表明种植车厘子、林地(洋槐)、核桃、苹果和李子较有利于土壤有机碳累积,而种植花椒不利于有机碳累积。(4)基于1999～2014年土地利用变化格局和不同土地利用土壤有机碳密度,1999～2014年佳山土壤有机碳储量增加7012.56 t,九子土壤有机碳储量增加2985.97 t,主要原因在于1999～2014年羌族聚落大力发展生态果业和退耕还林,将耕地、草地转变成车厘子、李子、苹果等果园地和洋槐生态林。可见,种植类型转变明显增大了土壤有机碳储量,有效提升了该区的生态服务价值。更多还原

【Abstract】 Land use change is an important factor affecting the dynamic of soil carbon pool.In this study,I selected two adjacent Qiang Ethnic settlements of the Upper Reaches of the Min River-Jiashan settlement and Jiuzi settlement,which were located in the shady and sunny slopes of the arid valley.Based on 3S technology,to analysis the spatial distribution pattern of land use in the study area from 1999 to 2014.Analysis of soil organic carbon and total nitrogen in different land use types by field sampling,to study the effect of the transformation of traditional crops into different orchards on soil organic carbon pool,and provide scientific basis for assessing the value of ecological service in the Upper Reaches of Min River.The main contents and achievements of this paper are as follows:(1)Land use of Qiang ethnic settlement was significant changed from 1999 to 2014.The total area of Jiashan settlement is 573.90 hm2,From 1999 to 2014,the area of cultivated land decreased by 188.17 hm2,while the area of orchard increased by 95.03 hm2,and the area of woodland land increased by 147.50 hm2;The total area of Jiuzi settlement is 267.20 hm2,From 1999 to 2014,the area of cultivated land is reduced by 100.27 hm2,the area of orchard is increased by 65.40 hm2,and the area of woodland increased by 14.95 hm2.The land use of the Qiang ethnic settlement is in the stage of rapid adjustment.The traditional cultivated land(mainly is corn and vegetable)has been transformed into woodland(locust)and orchard(cherries,plum,apple,etc.).The change of land use is mainly driven by the policy of returning farmland to forest,the comparative benefit and the hollow of the settlement population.(2)The soil organic carbon of different land use was different,and the soil organic carbon of shady slope and sunny slope had difference,but the relationship was not the same.The soil organic carbon concentration of different land use types in Jiashan settlement is:cherries(19.65 g·kg-1)>woodland,(16.77 g·kg-1)>apple(15.77 g·kg’-1)>plum(15.42 g·kg-1)>corn(11.07 g·kg-1)>grassland(10.84 g·kg-1);The concentration of soil organic carbon in Jiuzi settlement is:cherries(18.50 g·kg-1)>apple(16.83 g·kg-1)>walnut(14.87 g·kg-1)>plum(14.31 g·kg-1)>woodland,(12.52 g(kg-1)>corn(11.57 g·kg-1)>pepper(10.71 g·kg-1)>grassland(10.47 g·kg-1).The results showed that the soil organic carbon concentration in the orchard was significantly higher than that in the traditional cultivated land,mainly due to the cultivation of cherries,plums and apples and so on need to apply organic fertilizer,and planting corn to the main application of fertilizer.(3)Different land use types soil profile(0～60 cm)organic carbon accumulation characteristics:sunny slope is stronger than shady slope.The soil organic carbon density of different land use in Jiashan settlement is:cherries(9.32 kg·m-2)>woodland>(7.91 kg·m-2)apple(7.48 kg·m-2)>plum(6.59 kg·m-2)>grassland(5.16 kg·m-2)>corn(4.47 kg· m-2);The soil organic carbon density of different land use in Jiuzi settlement is:cherries(10.78 kg m-2)>walnut(9.81 kg·m-2)>apple(9.01 kg· m-2)>plum(8.76 kg· m-2)>grassland(7.74 kg·m-2)>woodland(7.33 kg·m-2)>corn(5.36 kg·m-2)>pepper(4.91 kg·m-2).These results indicate that planting the cherries,woodland(locust),walnut,apple and plum is more conducive to the accumulation of soil organic carbon,and planting pepper is not conducive to the accumulation of organic carbon.(4)Based on the pattern of land use change and the soil organic carbon density in different land use types from 1999 to 2014,it can be seen that the soil organic carbon storage increased from 7012.56 t in Jiashan settlement from 1999 to 2014,and the soil organic carbon storage in Jiuzi settlement increased by 2985.97 t.The main reason is that the Qiang ethnic settlement vigorously develop ecological fruit industry and returning farmland to woodland,convert the farmland and grassland to cherries,plum,apple and other orchard and locust ecological woodland from 1999 to 2014.It can be seen that the change of planting structure significantly increased the soil organic carbon storage,and effectively promoted the ecological service value of the region.更多还原