摘要
水蚀风蚀交错带是黄土高原土壤侵蚀最严重地区,尽管提高植被盖度能有效减小土壤侵蚀,但有限的水资源限制了植被盖度的提高。与此同时,该地区脆弱的生态环境表明其水碳循环过程及机制具有一定的独特性。因此,研究植被盖度对土壤水碳循环过程的影响,从而确定最优植被盖度对维持该地区生态环境的可持续发展具有重要意义。本文以该区典型植被——柠条、沙柳为研究对象,通过野外观测土壤CO_2通量排放、植物叶片光合及土壤水分动态变化,系统分析土壤水碳循环过程对植被盖度的响应,利用SHAW模型模拟典型气象年型土壤水分在不同植被盖度下的动态变化,以水量平衡原理为基础,估算了两种植物的最优盖度。取得的主要研究结果如下:
1.土壤CO_2通量排放受植被盖度的影响,一般规律是植被盖度越高,土壤CO_2排放通量越大。对同一盖度处理,土壤CO_2排放通量表现出明显的月变化,在整个生育期中,8月份土壤CO_2排放通量达到最大。此外,植被类型对土壤CO_2通量排放产生显著影响,在黄绵土上种植柠条和沙柳,柠条地的土壤CO_2排放通量显著高于沙柳地。
2.生物因素和非生物因素调控着土壤CO_2通量排放对植被盖度动态响应。在整个试验期间,生物因素(根系生物量和地上生物量)为主要调控因子,显著影响土壤CO_2通量排放对植被盖度的响应。在非生物因素中,地表温度(0-5 cm)和土壤表层含水量(0-6 cm)及两者交互作用部分地调控着土壤CO_2通量排放对植被盖度的响应。与地表温度(0-5 cm)相比,土壤表层含水量(0-6 cm)与土壤CO_2排放通量动态变化的相关性更大。
3.植被盖度对植物叶片光合及植物生长产生显著影响。低盖度植被的叶片净光合速率明显高于高盖度,但其植被冠层光合固碳量却明显低于高盖度植被。植物叶片的光截获能力及植物本身土壤水分利用能力调控着叶片光合过程对植被盖度的响应。与低盖度相比,高盖度处理柠条的株高和茎粗相对较低,与沙柳结果相反。地下土壤水资源竞争(对称竞争)调控柠条植株生长对植被盖度的动态响应,而地上光源竞争(非对称竞争)调控沙柳植株生长对植被盖度的动态响应。
4.土壤质地和降雨脉冲对土壤CO_2通量排放及叶片净光合速率有显著影响。柠条和沙柳土壤CO_2通量排放对土壤质地响应截然不同:黄绵土中柠条土壤CO_2排放通量高于风沙土,但黄绵土中沙柳土壤CO_2排放通量低于风沙土。结果表明:柠条异养呼吸和沙柳自养呼吸对土壤质地响应比较敏感。土壤质地对叶片光合速率有显著影响,除了2010年的沙柳生育末期,黄绵土中两种灌木植物叶片净光合速率通常高于风沙土。土壤水分条件是调控植物叶片净光合速率对土壤质地响应的主要因子。土壤CO_2排放通量和叶片光合的月变化趋势表明:叶片光合速率峰值出现时间滞后于土壤CO_2排放通量峰值。当土壤由干变湿,降雨脉冲会对土壤CO_2通量排放产生较大影响。降雨所影响土层深度范围内的土壤水分分布是调控植物叶片净光合速率对降雨与土壤质地交互作用响应的主导因子。
5.植被盖度影响土壤水分时空分布。土壤剖面含水量、根层储水量、棵间蒸发(0-15 cm)随植被盖度的增加而降低,不同植被盖度土壤剖面含水量差异显著。0-100 cm土层土壤水分变化幅度较大,对降水、根系吸水及土面蒸发响应敏感。幼龄期,土壤干燥化程度随植被盖度、林龄的增大趋于严重。
6.水蚀风蚀交错带土壤侵蚀严重,提高植被盖度是减少土壤侵蚀的有效手段,但是该区有限的降水资源限制了植被盖度的提高,因此基于水量平衡理论确定最优植被盖度是区域生态环境可持续发展的关键。我们利用田间水分观测资料对SHAW模型进行校正和验证,并根据历史气候资料确定了一个代表性气候年型(典型干旱年,出现的概率是10%),确定了该区柠条和沙柳达到最优植被盖度时的最大叶面积指数分别为1.27和0.70。
本研究表明水蚀风蚀交错带不同植被盖度的土壤CO_2通量排放差异主要归因于根呼吸(自养呼吸)的不同。叶片光合及植物生长对植被盖度的响应是光源竞争、土壤水资源竞争和空间竞争相互作用的结果。土壤质地对土壤CO_2通量排放和叶片光合产生显著影响,表明土壤质地空间异质性在研究半干旱生态系统碳循环方面不容忽视。植被盖度对土壤水分时空动态变化的影响与植物生长状况和降雨季节分布特征密切相关。幼龄期,土壤干燥化程度随植被盖度、林龄的增大趋于严重化,因此,以水量平衡为基础最优植被盖度是维持半干旱区生态系统可持续性的关键。研究结果有助于揭示黄土高原水蚀风蚀交错带水碳循环过程,并对该地区植被恢复和重建具有重要指导作用。
The transitional belt of wind and water erosion is the center of the intensive soil erosion. Although increasing plant coverage can effectively control soil erosion, limited soil water resources restrict increasing plant coverage. At the same time, the fragile eco-environment of the transitional belt of wind and water erosion indicates that the cycling process and mechanism of soil water and carbon in the region are different from other region of the Loess Plateau. Therefore, it is very important for sustainable development of eco-environment to study the effect of plant coverage on cycling of soil water and carbon to determine the optimal plant coverage. In this study, we analyzed the responses of soil CO_2 efflux, leaf photosynthesis and soil water to plant coverage by field observation. The Simultaneous Heat and Water Transfer (SHAW) model was used to simulate soil water content variations with plant coverage for a representative climatic year to determine the optimal plant coverage for two dominant shrubs (Caragana korshinkii Kom and Salix psammophila) in this area, based on soil water balance. The main results are as follows:
1. Plant coverage had effect on soil CO_2 efflux. Generally, plant coverage was higher, soil CO_2 efflux was the larger. For the same plant coverage treatment, monthly variation of soil CO_2 efflux was observed during the growth period: maximum soil CO_2 efflux was achieved in August. In addition, vegetation type had pronounced impact on soil CO_2 efflux, the soil CO_2 efflux of C. korshinkii were significantly greater than those of S. psammophila, growing in silt loam soil.
2. The regulation of biotic factors and abiotic factors to the response of soil CO_2 efflux to plant coverage. During the experiment, biotic factors (root biomass and aboveground biomass) were important driving factors mediating the response of soil CO_2 efflux to plant coverage for two shrubs. Among the abiotic factors, the soil water content (0-6 cm), soil temperature (0-5 cm) and their interaction could partly regulate the response of soil CO_2 efflux to plant coverage. Soil water content (0-6 cm) was more closely correlated with soil CO_2 efflux than soil temperature (0-5 cm).
3. The significant effects of plant coverage on leaf net photosynthesis rate and plant growth. Leaf photosynthesis rate was significantly larger in low plant coverage than in high plant coverage for two shrubs, on the contrary, the canopy photosynthetic carbon fixation was significantly greater in high plant coverage than in low plant coverage. The interaction of light availability and plant water availability could mediate the response of leaf photosynthetic capacity to plant coverage. In C. korshinkii plots, high plant coverage plants had lower plant height and stem diameter compared to low plant coverage plants, which were in contrast to S. psammophila. The response of plant growth to plant coverage may be mainly caused by belowground competition for water (symmetric competition) in C.korshinkii plots, whereas by aboveground competition for light (asymmetric competition) in S. psammophila plots.
4. Soil texture and rain pulse significantly affected soil CO_2 efflux and leaf net photosynthetic rate. Soil CO_2 efflux of C. korshinkii was larger growing in silt loam soil than in sandy soil. On the contrary, soil CO_2 efflux of S. psammophila was lower growing in silt loam soil than in sandy soil. This showed that heterotrophic respiration of C. korshinkii was more sensitive to soil texture, but autotrophic respiration of S. psammophila. Soil texture had significant effects on leaf net photosynthesis rate: leaf net photosynthesis rate was significantly larger in silt loam soil than in sandy soil for two shrubs, except that the late growth stage of S. psammophila in 2010. Soil water condition was important driving factors mediating the response of leaf net photosynthesis rate to plant coverage for two shrubs. Significant monthly variation of soil CO_2 efflux and leaf photosynthesis showed that the maximum leaf photosynthesis rates lagged behind the maximum soil CO_2 efflux. When soil became wet, large amount of rainfall could have pronounced impact on soil CO_2 efflux. Soil water distribution from the depth of rainfall infiltration was the main factors mediating the leaf photosynthesis response to the interaction of rainfall event and soil texture.
5. The effects of plant coverage on temporal and spatial variation of soil water. The average soil water content, soil water storage in root layer and soil evaporation (0-15 cm) decreased with the increase of plant coverage. There were significant differences in soil water content of different plant coverage. The soil water content in the upper 0-100 cm had larger change range, which was sensitive to rainfall, root water uptake, and soil evaporation. During young-age period, the degree of soil desiccation increased for the shrubs with increasing plant coverages and stand age.
6. The transitional belt of wind and water erosion suffered intensive soil erosion. Although increasing plant coverage can effectively control soil erosion, limited soil water resources restrict increasing plant coverage. Therefore, the determination of optimal plant coverage, based on soil water balance, is the key for sustainable development of eco-environment. We used field observation data to calibrate and validate SHAW model. The representative dry year (i.e. 10% probability of a drier year) was determined, according to past climate data. Based on soil water balance, the optimal coverage for the C. korshinkii and S. psammophila shrub species corresponded to a maximum LAI of 1.27 and 0.70, respectively.
The results showed that the differences in soil CO_2 efflux among plant coverage could be attributed to the different root respiration (autotrophic respiration) in the transitional belt of wind and water erosion. The responses of leaf photosynthesis and plant growth to plant coverage were caused by interplaying of competition for light, water and space. The effects of soil texture on soil CO_2 efflux and leaf photosynthesis suggests that considering soil texture heterogeneous is important in carbon cycling of semiarid ecosystems. The effects of plant coverage on temporal and spatial variation of soil water were closely related with plant growth and seasonal distribution of rainfall. During young-age period, the degree of soil desiccation increased for the shrubs with increasing plant coverages and stand age. Therefore, based on soil water balance, the optimal coverage is the key to maintain the ecosystem sustainability in semiarid region. The conclusions of this study could help to reveal cycling processes of water and carbon in the transitional belt of wind and water erosion and to guide for vegetation restoration and revegetation.
引文
[1]唐克丽,贺秀斌.黄土高原生态环境建设与侵蚀环境调控[A].四川科学技术出版社, 1999.
[2]唐克丽.黄土高原水蚀风蚀交错区治理的重要性与紧迫性[J].中国水土保持, 2000, 11: 11-12,17.
[3] Misson L, Gershenson A, Tang J W, et al. Influences of canopy photosynthesis and summer rain pulses on root dynamics and soil respiration in a young ponderosa pine forest[J].Tree Physiology,2006,26: 833-844.
[4] Conant R T, Klopatek J M, Klopatek C C. Environmental factors controlling soil respiration in three semiarid ecosystems[J].Soil Sci.Soc.Am.J.,2000, 64: 383-390.
[5]田玉强,高琼,张智才,等.青藏高原高寒草地植物光合与土壤呼吸研究进展[J].生态环境学报, 2009, 18: 711-721.
[6]骆亦其,周旭辉.土壤呼吸与环境[M].北京:高等教育出版社, 2007.
[7] Adachi M, Bekku Y S, Rashidah W, et al. Differences in soil respiration between different tropical ecosystems[J]. Appl. Soil Ecol.,2006,34: 258-265.
[8] Townsend A R, Vitousek P M, Holland E A. Tropical soils could dominate the shortterm carbon cycle feedbacks to increased global temperatures[J]. Climatic Change, 1992, 22:293-303.
[9] Buchmann N. Biotic and abiotic factors regulating soil respiration rates in Picea abies stands[J]. Soil Biol. Biochem.,2000,32: 1625-1635.
[10]韩士杰,董云社,蔡祖聪,等.中国陆地生态系统碳循环的生物地球化学过程[M].北京:科学出版社, 2008.
[11] Davidson E A, Belk E, Boone R D. Soil water content and temperature as independent or confounded factors controlling soil respiration in a temperate mixed hardwood forest[J]. Global Change Biol.,1998,4: 217-227.
[12] Conant R T, Klopatek J M, Malin R C, et al. Carbon pools and fluxes along an environmental gradient in northern Arizona[J]. Biogeochemistry,1998,43: 43-61.
[13] Boone R D, Nadelhoffer K J, Canary J D, et al. Roots exert a strong influence on the temperature sensitivity of soil respiration[J]. Nature,1998,396: 570-572.
[14] Atkin O K, Edwards E J, Loveys B R. Response of root respiration to changes in temperature and its relevance to global warming[J]. New Phytologist,2000,147:141-154.
[15] Pregitzer K S, King J S, Burton A J, et al. Responses of tree fine roots to temperature[J]. New Phytologist,2000,147: 105-115.
[16] Pregitzer K S. Woody plants, carbon allocation and fine roots[J]. New Phytologist, 2003,158: 421-423.
[17] Maier C A, Kress L W. Soil CO 2 evolution and root respiration in 11 year-old loblolly pine(Pinus taeda)plantations as affected by moisture and nutrient availability[J]. Canadian Journal of Forest Research,2000,30: 347-359.
[18] Fierer N, Allen A S, Schimel J P, et al. Controls on microbial CO2 production: a comparison of surface and subsurface soil horizons[J]. Global Change Biol., 2003, 9: 1322-1332.
[19] Raich J W, Schlesinger W H. The global carbon dioxide flux in soil respiration and its relationship to vegetation and climate[J]. Tellus,1992,44: 81-99.
[20] Patrick L, Cable J, Potts D, et al. Effects of an increase in summer precipitation on leaf, soil, and ecosystem fluxes of CO2 and H2O in a sotol grassland in Big Bend National Park, Texas[J]. Oecologia,2007,151: 704-718.
[21] Xu L K, Baldocchi D D, Tang J W. How soil moisture, rain pulses, and growth alter the response of ecosystem respiration to temperature[J]. Global Biogeochemical Cycles,2004,18:1-10.
[22] Harper C W, Blair J M, Fay P A, et al. Increased rainfall variability and reduced rainfall amount decreases soil CO2 efflux in a grassland ecosystem[J]. Global Change Biol.,2005,11: 322-334.
[23] Huxman T E, Snyder K A, Tissue D, et al. Precipitation pulses and carbon fluxes in semiarid and arid ecosystems[J]. Oecologia,2004,141: 254-268.
[24] Liu X Z , Wan S Q, Su B, et al. Response of soil CO 2 efflux to water manipulation in a tallgrass prairie ecosystem[J]. Plant and Soil,2002,240: 213-223.
[25] Yuste J C, Janssens I A, Carrara A, et al. Interactive effects of temperature and precipitation on soil respiration in a temperate maritime pine forest[J]. Tree Physiology,2003,23: 1263-1270.
[26] Mielnick P C, Dugas W A. Soil CO2 efflux in a tallgrass prairie[J]. Soil Biology and Biochemistry,2000,32: 221-228.
[27] Lee M S, Nakane K, Nakatsubo T, et al. Effects of rainfall events on soil CO2 flux in a cool temperate deciduous broad‐leaved forest[J]. Ecological Research, 2002,17: 401-409.
[28] Wildung R E, Garland T R, Buschbom R L. The interdependent effects of soil temperature and water content on soil respiration rate and plant root decomposition in arid grassland soils[J]. Soil Biol.Bionchem.,1975,7: 373-378.
[29] Joffre R, Ourcival J M, Rambal S, et al. The key role of topsoil moisture on CO2 efflux from a Mediterranean Quercus ilex forest[J].Ann.For.Sci.,2003,60: 519-526.
[30] Harper C W, Blair J M, Fay P A, et al. Increased rainfall variability and reduced rainfall amount decreases soil CO2 efflux in a grassland ecosystem[J]. Global Change Biol.,2005,11: 322-334.
[31] Carlyle J C, Than U B. Abiotic controls of soil respiration beneath an eighteen-year-old Pinus radiata stand in south-eastern Australia [J]. Journal of Ecology,1988,76: 654-662.
[32] Lohila A, Aurela M, Regina K, et al. Soil and total ecosystem respiration in agricultural fields: effect of soil and crop type[J]. Plant and Soil,2003,251: 303-317.
[33] Bouma T J, Broekhuysen A G M, Veen B W. Analysis of root respiration of Solanum tuberosum as related to growth, ion uptake and maintenance of biomass[J]. Plant Physiology and Biochemistry,1996,34: 795-806.
[34] Saiya-Cork K R, Sinsabaugh R L, Zak D R. The effects of long term nitrogen deposition on extracellular enzyme activity in an Acer saccharum forest soil[J]. Soil Biology and Biochemistry,2002,34: 1309-1315.
[35] Berg B, Matzner E. Effect of N deposition on decomposition of plant litter and soil organic matter in forest systems[J]. Environmental Reviews,1997,5: 1-25.
[36] Vitousek P M, Howarth R W. Nitrogen limitation on land and in the sea: how can it occur?[J]. Biogeochemistry,1991,13: 87-115.
[37] Dilustro J J, Collins B, Duncan L, et al. Moisture and soil texture effects on soil CO2 efflux components in southeastern mixed pine forests[J]. Forest Ecology and Management,2005,204: 85-95.
[38] Bouma T J, Bryla R. On the assessment of root and soil respiration for soils ofdifferent textures: interactions with soil moisture contents and soil CO2 concentrations[J]. Plant and Soil,2000,227: 215-221.
[39] Cable J M, Ogle K, Williams D G, et al. Soil texture drives responses of soil respiration to precipitation pulses in the Sonoran Desert: Implications for climate change[J]. Ecosystems,2008,11: 961-979.
[40]韩广轩,周广胜.土壤呼吸作用时空动态变化及其影响机制研究与展望[J].植物生态学报, 2009, 33: 197-205.
[41] Jia B, Zhou G, Wang F, et al. Partitioning root and microbial contributions to soil respiration in Leymus chinensis populations.[J]. Soil Biol. Biochem., 2006, 38: 653-660.
[42] Zhu J, Yan Q, Fan A, et al. The role of environmental,root, and microbial biomass characteristics in soil respiration in temperate secondary forests of Northeast China[J]. Trees-Struct. Funct.,2009,23: 189-196.
[43] Kucera C, Ki rk ham D. Soil respiration studies in tall grass prairie in Missouri[J] Ecology,1971,52: 912-915.
[44]张东秋,石培礼,张宪洲.土壤呼吸主要影响因素的研究进展[J].地球科学进展, 2005, 20: 778-785.
[45] Lee M, Nakane K, Nakatsubo T, et al. Seasonal changes in the contribution of root respiration to total soil respiration in a cool-temperate deciduous forest[J]. Plant and Soil,2003,255: 311-318.
[46] Raich J W, Tufekcioglu A. Vegetation and soil respiration: correlations and controls[J]. Biogeochemistry,2000,48: 71-90.
[47] Shibistova O, Lloyd J, Evgrafova S, et al. Seasonal and spatial variability in soil CO2 efflux rates for a central Siberian Pinus sylvestris forest[J].Tellus, 2002,54: 552-567.
[48]李志刚,侯扶江.黄土高原不同地形封育草地的土壤呼吸日动态与影响因子分析[J].草业学报, 2010, 19: 42-49.
[49] Martin J G, Bolstad P V. Variation of soil respiration at three spatial scales: components within measurements, intra-site variation and patterns on the landscape[J]. Soil Biology & Biochemistry,2009,41: 530-543.
[50]鲍芳,周广胜.中国草原土壤呼吸作用研究进展[J].植物生态学报,2010,34: 713-726.
[51]谢艳兵,贾庆宇,李荣平,等.生物因子对盘锦湿地芦苇生态系统土壤呼吸影响的研究[J].安徽农业科学,2009,37: 18070-18072.
[52] S?e A R B, Buchmann N. Spatial and temporal variations in soil respiration in relation to stand structure and soil parameters in an unmanaged beech forest[J]. Tree Physiol.,2005,25: 1427-1436.
[53]常宗强,冯起,司建华,等.祁连山高山草甸土壤CO2通量的时空变化及其影响分析[J].环境科学,2007,10:2389-2395.
[54] Wiseman P E, Seiler J R. Soil CO2 efflux across four age classes of plantation loblolly pine (Pinus taeda L.) on the Virginia Piedmont[J]. Forest Ecology and Management,2004,192: 297-311.
[55] Han G X, Zhou G S, Xu Z Z, et al. Biotic and abiotic factors controlling the spatial and temporal variation of soil respiration in an agricultural ecosystem[J]. Soil Biology and Biochemistry,2007,39: 418-425.
[56] Epron D, Nouvellon Y, Roupsard O, et al. Spatial and temporal variations of soil respiration in a Eucalyptus plantation in Congo [J]. Forest Ecology and Management, 2004,202:149-160.
[57] Samuelson L J, Johnsen K, Stokes T, et al. Intensive management modifies soil CO2 efflux in 6-year-old Pinus taeda L. stands [J]. Forest Ecology and Management, 2004,200:335-345.
[58] Campbell J L , Sun O J, Law B E. Supply-side controls on soil respiration among Oregon forests[J]. Global Change Biology,2004,10: 1857-1869.
[59]栾军伟,向成华,骆宗诗,等.森林土壤呼吸研究进展[J].应用生态学报,2006,17: 2451-2456.
[60]袁渭阳,李贤伟,张健,等.不同年龄巨桉林土壤呼吸及其与土壤温度和细根生物量的关系[J].林业科学,2009,45: 1-8.
[61]王光军,田大伦,闫文德,等.亚热带杉木和马尾松群落土壤系统呼吸及其影响因子[J].植物生态学报,2009,33:53-62.
[62] Flanagan L B, Johnson B G. Interacting effects of temperature, soil moisture and plant biomass production on ecosystem respiration in a northern temperate grassland[J]. Agricultural and Forest Meteorology,2005,130: 237-253.
[63] Lyr H, Hoffmann G. Growth rates and growth periodicity of tree roots[J]. Int. Rev.For. Res.,1967,2: 181-236.
[64] H?gberg P, Nordgren A, ?gren G I. Carbon allocation between tree root growth and root respiration in boreal pine forest[J]. Oecologia,2002,132: 579-581.
[65] Lohila A, Aurela M, Regina K, et al. Soil and total ecosystem respiration in agricultural fields: effect of soil and crop type[J]. Plant and Soil, 2003, 251: 303–317.
[66] Rodeghiero M, Cescatti A. Main determinants of forest soil respiration along an elevation/temperature gradient in the Italian Alps[J]. Global Change Biology, 2005, 11: 1024-1041.
[67] H?gberg P, Nordgren A, Buchmann N, et al. Large-scale forest girdling shows that current photosynthesis drives soil respiration[J]. Nature,2001,411: 789-792.
[68] Wardle D A. Communities and Ecosystems, Linking the Aboveground and Belowground Components[M]. Princeton, NJ: Princeton University Press, 2002.
[69]周萍,刘国彬,薛萐.草地生态系统土壤呼吸及其影响因素研究进展[J].草业学报, 2009,18: 184-193.
[70] Sims P L, Bradford J A. Carbon dioxide fluxes in a southern plains prairie[J]. Agricultural and Forest Meteorology,2001,109: 117-134.
[71] Frank A B. Carbon dioxide fluxes over a grazed prairie and seeded pasture in the Northern Great Plains[J]. Environment Pollution,2002,116: 397-403.
[72]孙轶,魏晶,吴钢等.长白山高山冻原土壤呼吸及其影响因子分析[J].生态学杂志, 2005,24: 603-606.
[73]刘晨峰,尹婧,贺康宁.林下植被对半干旱区不同密度刺槐林地土壤水分环境的指示作用[J].中国水土保持科学,2004,2: 62-79.
[74]刘秉儒.红砂植被盖度对土壤不同形态碳、氮及细菌多样性的影响[J].干旱地区农业研究,2009,27: 155-160.
[75] Reichstein M, Rey A, Freibauer A, et al. Modeling temporal and large-scale spatial variability of soil respiration from soil water availability,temperature and vegetation productivity indices[J]. Global Biogeochemical Cycles,2003,17:1-15.
[76] Iverson L R, Hutchinson T F. Soil temperature and moisture fluctuations during and after prescribed fire in mixed-oak forests, USA[J]. Nat.Areas J.,2002,22: 296-304.
[77]王思砚,苏维词,范新瑞,等.喀斯特石漠化地区土壤含水量变化影响因素分析-以贵州省普定县为例[J].水土保持研究,2010,17: 171-180.
[78]付华,周志宇,陈善科.腾格里沙漠东南缘飞播区白沙蒿植被密度与土壤水分关系的研究[J].中国沙漠,2001,21: 265-270.
[79] Bullard M J, Mustill S J, Carver P, et al. Yield improvements through modification of planting density and harvest frequency in short rotation coppice Salix spp. -2. Resource capture and use in two morphologically diverse varieties [J]. Biomass Bioenerg,2002,22: 27-39.
[80] Giunta F, Motzo R. Sowing rate and cultivar affect total biomass and grain yield of spring triticale (×Triticosecale Wittmack) grown in a Mediterranean-type environment[J]. Field Crops Research,2004,87: 179-193.
[81]张永丽,肖凯,李雁鸣.种植密度对杂种小麦C6-38/Py85-1旗叶光合特性和产量的调控效应及其生理机制[J].作物学报,2005,31: 498-505.
[82]殷谷丽,唐建维,杨成源,等.四种省藤属植物的光合特征与叶片性状及生长的相关性[J].中南林业科技大学学报,2010,30: 104-112.
[83] Smith W K, Hinckley T M. Resource physiology of conifers: acquisition, allocation, and utilization[M]. London: Academic Press Limited, 1994.
[84]徐冉,陈存来,邵历,等.夏大豆叶片光合作用与光强的关系[J].作物学报,2005,31: 1080-1085.
[85]武常青,胡彦波,贺国强.光照强度对烤烟叶片光合特性的影响[J].现代化农业,2010, 9: 1-3.
[86] Nederhoff E M. Light interception of a cucumber crop at different stages of growth. In: Short, T.H. (Ed.), Energy in Protected Cultivation [J]. Acta Hort.,1984,148: 525–534.
[87] Francescangeli N,Sangiacomo M A, MartíH. Effects of plant density in broccoli on yield and radiation use efficiency [J].Scientia Horticulturae,2006,110: 135–143.
[88]李文华,朱清科,赖亚飞,等.陕北柠条的光合特性[J].南京林业大学学报(自然科学版),2007,31: 37-41.
[89]王邦锡,黄久常,王辉.不同生长季节光照强度和温度对柠条叶片光合作用和呼吸作用的影响[J].中国沙漠,1996,16: 145-148.
[90]彭强,梁银丽,陈晨,等.土壤水分对辣椒叶片光合特性及保护酶系统的影响[J].灌溉排水学报,2010,29: 101-104.
[91]张义,谢永生,鞠艳,等.生产力调控对翌年苹果园土壤水分和苹果叶片光合特性的影响[J].植物生态学报,2010,34: 973-978.
[92] Comstock J, Ehleringer J. Photosynthetic responses to slowly decreasing leaf water potentials in Encelia frutescens[J]. Oecologia,1984,61: 241-248.
[93] Ehleringer J R, Cook C R. Photosynthesis in Encelia farinoas Gray in response to decreasing leaf water potential[J]. Plant Physiol,1984,75: 688-693.
[94] Kumar B, Pandey D M, Goswami C L,et al. Effect of growth regulators on photosynthesis, transpiration and related parameters in water stressed cotton[J]. Biologia Plantarum, 2001,44:475-478.
[95] Noormets A, Sóber A, Pell E J, et al. Stomatal and non-stomatal limitation to photosynthesis in two trembling aspen(Populus tremuloides Michx.) clones exposed to elevated CO2and /or O3.[J]. Plant, Cell and Environment,2001,24: 327-336.
[96]刘长利,王文全,崔俊茹,等.干旱胁迫对甘草光合特性与生物量分配的影响[J].中国沙漠, 2006,26:142-145.
[97] Chaves M M, Pereira J S, Maroco J. How plants cope with water stress in the field. Photosynthesis and Growth[J]. Annals of Botany,2002,89: 907-916.
[98] Maroco J P, Pereira J S, M Chaves M. Growth, photosynthesis and water-use efficiency of two C4 Sahelian grasses subjected to water deficits[J]. Journal of Arid Environments,2000,45: 119-137.
[99] Angelopoulos K, Dichio B, Xiloyannis C. Inhibition of photosynthesis in olive trees (Olea europaea L.) during water stress and rewatering[J]. Journal of Experimental Botany,1996,47: 1093-1100.
[100]杨莉,韩忠明,杨利民,等.水分胁迫对蒺藜光合作用、生物量和药材质量的影响[J].应用生态学报,2010,21: 2523-2528.
[101]邹养军,李嘉瑞,魏钦平,等.不同土壤质地对苹果幼树生长及光合特性的影响[A].中国园艺学会第六届青年学术讨论会论文集[C].陕西杨凌:中国园艺学会,2004, 66-69.
[102]王群,李潮海,栾丽敏,等.不同质地土壤夏玉米生育后期光合特性比较研究[J].作物学报,2005,31: 628-633.
[103]李潮海,卢道文,侯松,等.三种质地土壤冬小麦生长后期的生理特性[J].华北农学报,1996,11: 74-79.
[104]白样和,曲文章,吴存样,等.不同密度条件下甜菜叶片光合速率与块根产量关系的研究[J].中国甜菜, 1995, 2: 25-29.
[105]程伟燕,李志刚,李瑞平.密度对大豆光合特性和产量的影响[J].作物杂志,2010,14: 68-72.
[106]王珍,武志海,徐克章.玉米群体冠层光合速率与叶面积指数关系的初步研究[J].吉林农业大学学报,2001,23: 9-12,16.
[107]陈传永,侯海鹏,李强,等.种植密度对不同玉米品种叶片光合特性与碳、氮变化的影响[J].作物学报,2010,36: 871-878.
[108]杨晴,王文颇,韩金玲,等.冀东地区密度对夏玉米光合、呼吸及产量的影响[J].玉米科学,2009,17: 66-69.
[109]蒋高明,朱桂杰.高温强光环境条件下3种沙地灌木的光合生理特点[J].植物生态学报, 2001, 25: 525-531.
[110] Shangguan Z P, Shao M A, Dyckmans J. Effects of nitrogen nutrition and water deficit on net photosynthetic rate and chlorophyll fluorescence in winter wheat[J].Journal of Plant Physiology,2000,156: 46-51.
[111]白成科,王百群,张希彪,等.土壤养分对小偃22叶片光合特性影响的初步研究[J].麦类作物学报,2001,21: 56-60.
[112]郭建斌,赵陟峰,骆汉.晋西黄土区刺槐林种植密度对植被生长状况的影响[J].水土保持通报,2010,30: 80-84.
[113]王克勤,王百田,王斌瑞,等.集水造林不同密度林分生长研究[J].林业科学,2002,38: 54-60.
[114]熊先勤,赵明坤,刘正书.皇草不同种植密度对植被恢复速度的影响[J].牧草科学, 2005, 7:29-30,57.
[115]移小勇,赵哈林,崔建垣,等.科尔沁沙地不同密度(小面积)樟子松人工林生长状况[J].生态学报,2006,26: 1200-1206.
[116]章建新,翟云龙,薛丽华.密度对高产春大豆生长动态及干物质积累分配的影响[J].大豆科学,2006,25: 1-5.
[117]朱洪德,冯丽娟,于洪久.栽培措施对高油大豆光合生理及产量的影响[J].大豆科学, 2008,27: 966-972.
[118]何云丽,苏德荣,刘自学,等.不同修剪高度下日本结缕草叶面积指数与密度的关系[J].草地学报,2009,17: 527-531.
[119]白静,田有亮,韩照日格图,等.油松人工林地上生物量、叶面积指数与林分密度关系的研究[J].干旱区资源与环境,2008,22: 183-187.
[120] Lindroth A, Lagergren F, Aurela M, et al. Leaf area index is the principal scaling parameter for both gross photosynthesis and ecosystem respiration of Northern deciduous and coniferous forests[J]. Tellus,2008,60B: 129-142.
[121]肖万欣,谢甫绨,张惠君,等.不同肥力和密度处理对超高产大豆品种的光合特性和产量的影响[J].中国油料作物学报,2009,31: 190-195.
[122] Watson D J. The Dependence of Net Assimilation Rate on Leaf-area Index [J]. Annals of Botany,1958,22: 37-54.
[123]张旺锋,王振林,余松烈,等.种植密度对新疆高产棉花群体光合作用、冠层结构及产量形成的影响[J].植物生态学报,2004,28: 164-171.
[124]王玉魁,杨文斌,卢琦,等.半干旱典型草原区白榆防护林的密度与生物量试验[J].干旱区资源与环境,2010,24: 144-150.
[125]彭龙福.不同林分密度楠木人工林生物量初步研究[J].福建林业科技,2008,35: 15-18.
[126]吴福忠,王开运,杨万勤,等.缺苞箭竹密度对其生物量分配格局的影响[J].应用生态学报, 2005,16: 991-995.
[127]丁贵杰.马尾松人工林生物量和生产力研究Ⅰ.不同造林密度生物量及密度效应[J].福建林学院报,2003,23: 34-38.
[128]王百田,王颖,郭江红,等.黄土高原半干旱地区刺槐人工林密度与地上生物量效应[J].中国水土保持科学,2005,3: 35-39.
[129] Elwell H A, Stocking M A. Vegetal cover to estimate soil erosion hazard in Rhodesia[J]. Geoderma,1976,15: 61-70.
[130] Morgan R P C, McIntyre K, Vickers A W, et al. A rainfall simulation study of soil erosion on rangeland in Swaziland[J].Soil Tech,1997,11: 291-299.
[131] CerdáA. Parent material and vegetation affect soil erosion in eastern Spain.[J]. Soil Sci Soc Am J,1999,63: 362-368.
[132] Snelder D J, Bryan R B. The use of rainfall simulation tests to assess the influence of vegetation density on soil loss on degraded rangelands in the Baringo District, Kenya[J].Catena,1995,25: 105-116.
[133] García-Ruiz J M, Lasanta T, MartíC, et al. Changes in runoff and erosion as aconsequence of land-use changes in the central spanish pyrenees[J]. Phys. Chem. Earth.,1995,20:301-307.
[134] Molinillo M, Lasanta T, García-Ruiz J M. Managing mountainous degraded landscapes after farmland abandonment in the Central Spanish Pyrenees[J]. Environ Manage, 1997,21: 587-598.
[135]郭忠升.黄土高原半干旱区水土保持植被恢复限度———以人工柠条林为例[J].中国水土保持科学,2009,7: 49-54.
[136]郭忠升,邵明安.土壤水分植被承载力数学模型的初步研究[J].水利学报, 2004, 10: 95-99.
[137]郭忠升,邵明安.土壤水分植被承载力研究成果在实践中的应用[J].自然资源学报, 2009,24: 2187-2193.
[138]郭忠升,邵明安.雨水资源、土壤水资源与土壤水分植被承载力[J].自然资源学报, 2003, 18: 522-528.
[139]魏天兴.小流域防护林适宜覆盖率与植被盖度的理论分析[J].干旱区资源与环境,2010,24: 170-176.
[140]张建军,毕华兴,魏天兴.晋西黄土区不同密度林分的水土保持作用研究[J].北京林业大学学报,2002,24: 50-53.
[141]蒋定生.黄土高原水土流失与治理模式[M].北京:中国水利水电出版社, 1997.
[142]郭忠升.水土保持植被建设中的三个盖度:潜势盖度、临界盖度和有效盖度[J].中国水土保持,2000,4: 30-31.
[143]潘占兵,李生宝,郭永忠,等.不同种植密度人工柠条林对土壤水分的影响[J].水土保持研究,2004,11: 265-267.
[144]贾海坤,刘颖慧,徐霞,等.皇甫川流域柠条林地水分动态模拟--坡度、坡向、植被密度与土壤水分的关系[J].植物生态学报,2005,29: 910-917.
[145]王海涛,何兴东,高玉葆,等.油蒿演替群落密度对土壤湿度和有机质空间异质性的响应[J].植物生态学报,2007,31: 1145-1153.
[146]郭忠升.半干旱区柠条林利用土壤水分深度和耗水量[J].水土保持通报,2009,29: 69-72.
[147]黄登银.不同密度马尾松林下植被和土壤性质[J].防护林科技,2009,2: 21-23.
[148] Chen H S, Shao M A, Li Y Y. The characteristics of soil water cycle and water balance on steep grassland under natural and simulated rainfall conditions inthe Loess Plateau of China[J]. J Hydrol,2008,360: 242-251.
[149] Chen H S, Shao M A, Li Y Y. Soil desiccation in the Loess Plateau of China[J]. Geoderma,2008,143: 91-100.
[150] Wang Y Q, Shao M A, Shao H B. A preliminary investigation of the dynamic characteristics of dried soil layers on the Loess Plateau of China[J]. J Hydrol, 2010, 381: 9-17.
[151]李玉山.黄土高原森林植被对陆地水循环影响的研究[J].自然资源学报,2001,16: 427-432.
[152]杨文治,邵明安.黄土高原土壤水分研究[M].北京:科学出版社,2000.
[153]杨文治.黄土高原土壤水资源与植树造林[J].自然资源学报,2001,16: 433-438.
[154]陈洪松,邵明安.黄土区深层土壤干燥化程度的评价标准[J].水土保持学报,2004,18: 164-166.
[155]王力,邵明安,侯庆春.土壤干层量化指标初探[J].水土保持学报,2000,14: 87-90.
[156]程积民,万惠娥,王静,等.半干旱区柠条生长与土壤水分消耗过程研究[J].林业科学, 2005, 41: 37-41.
[157]霍竹,张斌亮.六道沟小流域主要灌木林地土壤干化研究[J].中国人口资源与环境, 2007,17: 95-98.
[158]侯庆春,韩蕊莲,韩仕锋.黄土高原人工林草地土壤干层问题初探[J].中国水土保持, 1999,5: 11-14.
[159]郭忠升,邵明安.半干旱区人工林草地土壤旱化与土壤水分植被承载力[J].生态学报, 2003,23: 1640-1647.
[160]陈洪松,邵明安,王克林.黄土区深层土壤干燥化与土壤水分循环特征[J].生态学报, 2005,25: 2491-2498.
[161]王玉魁,杨文斌,卢琦,等.半干旱典型草原区白榆防护林的密度与生物量试验[J].干旱区资源与环境,2010,24: 144-150.
[162]孙鹏森,马李一,马履一.油松、刺槐林潜在耗水量的预测及其与造林密度的关系[J].北京林业大学学报,2001,23: 1-6.
[163]张永涛,杨吉华.黄土高原降水资源环境容量下侧柏合理密度的研究[J].水土保持学报,2003,17: 156-162.
[164]张建军,贺维,纳磊.黄土区刺槐和油松水土保持林合理密度的研究[J].中国水土保持科学,2007,5: 55-59.
[165] Xia Y Q, Shao M A. Soil water carrying capacity for vegetation: A hydrologic and biogeochemical process model solution[J]. Ecol Model,2008,214: 112-124.
[166]夏永秋.黄土高原水蚀风蚀交错带小流域土壤水分植被承载力过程模拟[D].北京:中国科学院地理科学与资源研究所, 2009.
[167] Xia Y Q, Shao M A. Evaluation of soil water-carrying capacity for vegetation: the concept and the model[J]. Acta Agr Scand B– S P,2009,59: 342-348.
[168]唐克丽,侯庆春,王斌科,等.黄土高原水蚀风蚀交错带和神木试区的环境背景及整治方向[J].中国科学院水利部西北水土保持研究所集刊, 1993, 18: 2-15.
[169]查轩,唐克丽.水蚀风蚀交错带小流域生态环境综合治理模式研究[J].自然资源学报, 2000,15: 97-100.
[170]侯庆春.神木试区自然条件及环境整治综合分析[J].中国科学院水利部西北水土保持研究所集刊,1993,18: 136-137.
[171]张平仓,王斌科,唐克丽.神木试区环境特征[J].中国科学院水利部西北水土保持研究所集刊,1993,18: 16-22.
[172]成向荣.黄土高原农牧交错带土壤-人工植被-大气系统水量转化规律及模拟[D].北京:中国科学院教育部水土保持与生态环境研究中心, 2008.
[173]贾恒义,雍绍萍,王富乾.神木试区的土壤资源[J].中国科学院水利部西北水土保持研究所集刊,1993,18: 36-46.
[174] Xu M, Qi Y. Soil-surface CO2 efflux and its spatial and temporal variations in a young ponderosa pine plantation in northern California.[J]. Global Change Biol., 2001,7: 667-677.
[175] Hauser V L. Neutron meter calibration and error control[J]. Transaction ASAE., 1984,27: 722-728.
[176] Huang M B, Gallichand J. Use of the SHAW model to assess soil water recovery after apple trees in the gully region of the Loess Plateau, China[J]. Agr Water Manage, 2006,85: 67-76.
[177] Boast C W, Robertson T M. A“micro-lysimeter”method for determining evaporation from bare soil: description and laboratory evaluation[J]. Soil Sci Soc Am J, 1982, 46: 689-696.
[178] Daamen C C, Simmonds L P, Wallace J S, et al. Use of microlysimeters to measure evaporation from sandy soils[J]. Agr Forest Meteorol,1993,65: 159-173.
[179] Schlesinger W H, Andrews J A. Soil respiration and the global carbon cycle[J]. Biogeochemistry,2000,48: 7-20.
[180] Cox P M, Betts R A, Jones C D, et al. Acceleration of global warming due to carbon-cycle feedbacks in a coupled model[J]. Nature,2000,408: 184-187.
[181] Mikan C J, Schimel J P, Doyle A P. Temperature controls of microbial respiration in arctic tundra soils above and below freezing[J]. Soil Biol. Biochem.,2002, 34: 1785-1795.
[182] Davidson E A, Verchot L V, Cattanio J H, et al. Effects of soil water content on soil respiration in forest and cattle pastures of eastern Amazonia[J]. Biogeochemistry,2000,48: 53-69.
[183] Zhu H, Zhao C, Li J, et al. Analysis of impact factors on scrubland soil respiration in the southern Gurbantunggut Desert,central Asia.[J]. Environ. Geol., 2008,54: 1403-1409.
[184] McCarthy D R, Brown K J. Soil respiration responses to topography, canopy cover, and prescribed burning in an oak-hickory forest in southeastern Ohio[J]. Forest Ecol. Manage.,2006,237: 94-102.
[185] Cheng X R, Huang M B, Shao M A, et al. A comparison of fine root distribution and water consumption of mature Caragana korshinkii Kom grown in two soils in a semiarid region, China[J]. Plant and Soil,2009,315: 149-161.
[186] Raich J W. Aboveground productivity and soil respiration in three Hawaiian rain forests[J]. Forest Ecol. Manage.,1998,107: 309-318.
[187] Saraswathi S G, Paliwal K. Diurnal and seasonal trends in photosynthetic performance of Dalbergia sissoo Roxb. and Hardwickia binata Roxb. from a semi-arid ecosystem[J]. Photosynthetica,2008,46: 248-254.
[188] Harms W R, Whitesell C D, DeBell D S. Growth and development of loblolly pine in a spacing trial planted in Hawaii[J]. Forest Ecology and Management,2000,126: 13-24.
[189] Bullard M J, Mustill S J, McMillan S D, et al. Yield improvements through modification of planting density and harvest frequency in short rotation coppice Salix spp.—1.Yield response in two morphologically diverse varieties [J]. Biomass and Bioenergy,2002,22: 15-25.
[190] Will R E, Narahari N V, Shiver B D, et al. Effects of planting density on canopy dynamics and stem growth for intensively managed loblolly pine stands[J]. Forest Ecology and Management,2005,205: 29-41.
[191] Anten N P R, Hirose T. Limitations on photosynthesis of competing individuals in stands and the consequences for canopy structure[J].Oecologia,2001,129: 186-196.
[192] Givnish T J. On the adaptive significance of leaf height in forest herbs[J]. The American Naturalist,1982,120: 353-381.
[193] Hicks D R, Lueschen W E, Ford J H. Effect of stand density and thinning on soybean[J]. J.Prod.Agric.,1990,3: 587-590.
[194] Munoz A E, Holt E C, Weaver R W. Yield and quality of soybean hay as influenced by stage of growth and plant density[J]. Agron.J.,1983,75: 147-148.
[195] Wells R. Soybean growth response to plant density: Relationships among canopy photosynthesis,leaf area,and light interception[J].Crop Sci., 1991,31: 755-761.
[196] Angadi S V, Cutforth H W, McConkey B G, et al. Yield Adjustment by Canola Grown at Different Plant Populations under Semiarid Conditions[J].Crop Sci., 2003, 43: 1358-1366.
[197] Seiter S, Altemose C E, Davis M H. Forage Soybean Yield and Quality Responses to Plant Density and Row Distance[J]. Agron. J.,2004,96: 966-970.
[198] Giorio P, Sorrentino G, d'Andria R. Stomatal behaviour, leaf water status and photosynthetic response in field-grown olive trees under water deficit[J]. Environmental and Experimental Botany,1999,42: 95-104.
[199] Gollan T, Turner N C, Schulze E D. The responses of stomata and leaf gas exchange to vapour pressure deficits and soil water content III. In the sclerophyllous woody species Nerium oleander[J]. Oecologia,1985,65: 356-362.
[200] Kubiske M E, Abrams M D. Stomatal and nonstomatal limitations of photosynthesis in 19 temperate tree species on contrasting sites during wet and dry years[J]. Plant, Cell and Environment,1993,16: 1123-1129.
[201] Anten N P R. Optimal Photosynthetic Characteristics of Individual Plants in Vegetation Stands and Implications for Species Coexistence [J]. Annals of Botany, 2005, 5: 495-506.
[202] Weiner J, Berntson G M, Thomas S C. Competition and growth form in a woodland annual[J]. Journal of Ecology,1990,78: 459-469.
[203] Nagashima H, Terashima I, Katoh S. Effects of Plant Density on Frequency Distributions of Plant Height in Chenopodium album Stands: Analysis Based on Continuous Monitoring of Height-growth of Individual Plants [J]. Annals of Botany, 1995,75: 173-180.
[204] Retuerto R, Rochefort L, Woodward F I. The influence of plant density on the responses of Sinapis alba to CO2 and windspeed[J]. Oecologia,1996,108: 241-251.
[205] Yokozawa M, Hara T. Foliage profile, size structure and stem diameter-plant height relationship in crowded plant populations[J].Annals of Botany, 1995, 76: 271-285.
[206] Xiao S, Chen S Y, Zhao L Q, et al. Density effects on plant height growth and inequality in sunflower populations[J]. Journal of Integrative Plant Biology, 2006,48: 513-519.
[207] Bavec F, Bavec M. Effects of plant population on leaf area index, cob characteristics and grain yield of early maturing maize cultivars (FAO 100–400) [J].European Journal of Agronomy,2002,16: 151-159.
[208] Cannell M G R, Milne R, Sheppard L J, et al. Radiation interception and productivity of willow[J]. Journal of Applied Ecology,1987,24: 261-278.
[209] R?ttgermann M, Steinlein T, Beyschlag W, et al. Linear relationships between aboveground biomass and plant cover in low open herbaceous vegetation[J]. Journal of Vegetation Science,2000,11: 145-148.
[210] Dyer A R, Rice K J. Effects of competition on resource availability and growth of a California bunchgrass[J]. Ecology,1999,80: 2697-2710.
[211] Anten N P R. Optimal Photosynthetic Characteristics of Individual Plants in Vegetation Stands and Implications for Species Coexistence[J]. Annals of Botany, 2005,95: 495-506.
[212] Cable J M, Ogle K, Williams D G, et al. Soil texture drives responses of soil respiration to precipitation pulses in the Sonoran Desert: Implications for climate change[J]. Ecosystems,2008,11: 961-979.
[213] Hu W, Shao M A, Wang Q J, et al. Soil water content temporal-spatial variability of the surface layer of a loess plateau hillside in China[J].Sci.Agric.(Piracicaba, Braz.),2008,65: 277-289.
[214] Hu W, Shao M A, Wang Q J, et al. Time stability of soil water storage measured by neutron probe and the effects of calibration procedures in a small watershed[J]. Catena,2009,79: 72-82.
[215] Chen S P, Lin G H, Huang J H, et al. Dependence of carbon sequestration on the differential responses of ecosystem photosynthesis and respiration to rain pulses in a semiarid steppe[J]. Global Change Biology, 20 , doi: 10.1111/j.1365-2486.2009.01879.x.
[216] Larsen K S, Ibrom A, Beier C, et al. Ecosystem respiration depends strongly on photosynthesis in a temperate heath[J]. Biogeochemistry,2007,85: 201-213.
[217] Moyano F E, Kutsch W L, Rebmann C. Soil respiration fluxes in relation to photosynthetic activity in broad-leaf and needle-leaf forest stands[J]. Agricultural and Forest Meteorology,2008,148: 135-143.
[218] Austin A T, Yahdjian L, Stark J M, et al. Water pulses and biogeochemical cycles in arid and semiarid ecosystems[J]. Oecologia,2004,141: 221-235.
[219] Yang P C. Carbon dioxide flux within and above a boreal aspen forest[M]. Vancouver: University of British Columbia,1998.
[220]吴钦孝,杨文治.黄土高原植被建设与可持续发展[M].北京:科学出版社, 1998.
[221] Xiao C W, Zhou G S, Zhang X S , et al. Responses of dominant desert species Artemisia ordosica and Salix psammophila to water stress[J]. Photosynthetica,2005,43: 467-471.
[222]成向荣,黄明斌,邵明安.神木水蚀风蚀交错带主要人工植物细根垂直分布研究[J].西北植物学报,2007,27: 321-327.
[223] Hodnett M G, Silva L P, Rocha H R, et al. Seasonal soil water storage changes beneath central Amazonian rainforest and pasture[J]. Journal of Hydrology, 1995, 170: 233-254.
[224]吴钦孝,丁汉福,刘克俭.黄土丘陵半干旱地区柠条根系的研究[J].水土保持通报, 1989, 9: 45-49.
[225]侯喜禄,白岗栓,曹清玉.刺槐、柠条、沙棘林土壤入渗及抗冲性对比试验[J].水土保持学报,1995,9: 90-95.
[226]王幼奇,樊军,邵明安.陕北黄土高原雨养区谷子棵间蒸发与田间蒸散规律[J].农业工程学报,2010,26: 6-10.
[227] Kochendorfer J P, Ramirez J A. Ecohydrological controls on vegetation density and evapotranspiration partitioning across the climatic gradients of the central United States[J]. Hydrol. Earth Syst. Sci. Discuss,2008,5: 649-700.
[228]侯庆春,唐克丽.晋陕蒙接壤区水蚀风蚀交错带生态环境特征[J].水土保持通报, 1994, 14: 8-15.
[229] Flerchinger G N. The simultaneous heat and water (SHAW) model: technical documentation[R]. Boise, Idaho, USA: Northwest Watershed Research Center USDA Agricultural Research Service, 2000.
[230] Flerchinger G N, Saxton K E. Simultaneous heat and water model of a freezing snow–residue–soil system I. Theory and development[J]. Trans. ASAE, 1989, 32: 565-571.
[231] Flerchinger G N, Saxton K E. Simultaneous heat andwater model of a freezing snow-residue-soil system II. Field verification[J].Trans.ASAE.,1989,32: 573-578.
[232] Preston G M, McBride R A. Assessing the use of poplar tree systems as a landfill evapotranspiration barrier with the SHAW model[J]. Waste Manage. Res., 2004, 22: 291-305.
[233] Elshorbagy A, Barbour S L. Probabilistic approach for design and hydrologic performance assessment of reconstructed watersheds[J].J Geotech and Geoenvir,Engrg, 2007, 133: 1110-1118.
[234] Eitzinger J, Trnka M, H?sch J, et al. Comparison of CERES, WOFOST and SWAP models in simulating soil water content during growing season under different soil conditions[J]. Ecological Modelling,2004,171: 223-246.
[235] Garrison M V, Batchelor W D, Kanwar R S, et al. Evaluation of the CERES-Maize water and nitrogen balances under tile-drained conditions[J]. Agricultural Systems, 1999, 62: 189-200.