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| Characteristics of undergrowth herbage of different restoration models in the Loess Hilly region |
| Shi Yangyang1, Zhang Guanghui2, 3, Chen Yunming1,2, Wang Bing2,3 |
| (1.College of Forestry, Northwest A&F Univerisity, 712100, Yangling, Shaanxi;2.State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation,Chinese Academy of Sciences and Ministry of Water Resources, 712100, Yangling, Shaanxi;3.College of Geography, Beijing Normal University, 100875, Beijing:China) |
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Abstract Taken abandoned farmland (CK) as control, the undergrowth vegetation investigation wasconducted on four land-use types of Caragana korshinskii (CKK), Robinia pseudoacacia (RP), Pinustabulaeformis (PT) and mixed forest of Pinus tabulaeformis and Amorpha fruticosa (PA) in the loess hillyregion of Zhifanggou watershed. These five kinds of land types were restored for almost 37 years fromslope farmland. The variations of vegetation coverage, aboveground and underground biomass, litteramount, ratio of root to shoot and root length density and the relationship among them were studied. After37 years vegetation restoration and construction, abandoned farmland has the highest value of speciesdiversity, vegetation coverage and aboveground biomass, while Pinus tabulaeformis land has the lowestspecies diversity, and Caragana korshinskii land has the lowest vegetation coverage and abovegroundbiomass. The orders of species diversity, vegetation coverage and aboveground biomass were given asfollows: CK>PA>PT>RP>CKK, CK>CKK>RP>PA>PT and CK>RP>CKK>PA>PT, respectively. The results of ANOVA showed that there was a significant difference in aboveground biomasses (P<0.01),while no difference was found in underground biomass. Mixed forest of Pinus tabulaeformis and Amorphafruticosa has the highest value of the litter amount and underground biomass, while Robinia pseudoacaciawas the lowest. The orders of litter amount and underground biomass were given as follows: PA>CKK>PT>CK>RP and PA>CKK>CK>PT>RP, respectively. The results of ANOVA showed that there was asignificant difference in underground biomass (P<0.05), while no difference was found in litter amount.Mixed forest of Pinus tabulaeformis and Amorpha fruticosa has the highest value of the ratio of root to shootand root length density, while abandoned farmland was the lowest. The orders of the ratio of root to shootratio and root length density were given as follows: PA>PT>CKK>RP>CK and PA>CKK>RP>PT>CK,respectively. Root biomasses of different soil layers could be simulated well by indices of abovegroundvegetation characteristics with serious of power functions (P<0.01). The results of ANOVA showed thatthere was a significant difference in the ratio of root to shoot (P <0.05) and root length density (P <0.05).
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Received: 21 May 2012
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