| 1. |
- Wang, XP, et al.
(författare)
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Evapotranspiration of Artemisia ordosica vegetation in stabilized arid desert dune in Shapotou, China
- 2004
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Ingår i: Arid Land Research and Management. - : Informa UK Limited. - 1532-4982 .- 1532-4990. ; 18:1, s. 63-76
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Tidskriftsartikel (refereegranskat)abstract
- More than 40 years of revegetation using mainly Artemisia ordosica, Hedysarum scoparium, and Caragana korshinskii at Shapotou Desert Experimental Research Station near Lanzhou has established a dwarf-shrub and herbaceous cover on the stabilized sand dunes. The evapotranspiration (ET) of the xerophyte dwarf-shrub A. ordosica plant vegetation was measured by the autoweighing lysimeter method during the growing seasons from 1990 to 1995, and 2002 on the southeast edge of the Tengger Desert at Shapotou, China. The study showed that the average ET rates were 0.88 mm d(-1), and they varied from 0.6 mm d(-1) to 1.31 mm d(-1) during the 7-year experimental period from 1990 to 1995, and 2002. The ratios of ET/Precipitation (P) varied from 69.8% to 120.9% with an average of 90.9%. The higher ET/P value in 1991 was associated with the properties of intra year distribution of rainfall events, and resulted in soil moisture depletion. The correlation between the accumulative P and the accumulative ET was quite high. For the years 1990, 1993, and 1995, the relationship between the accumulative ET and the accumulative P had a closed linear relationship, resulting from the higher intensity of monthly P exceeding 40% of the overall P during the growing season. Whatever the variation in the monthly P, statistics showed that the relationship between the accumulative P and ET could be expressed as an equation, ET=0.8003 P+5.8914, with a correlation coefficient of R-2=0.9035. Results suggest that in areas similar to Shapotou it is practical to establish an artificial protection belt using xerophytic shrubs.
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| 2. |
- Wang, XP, et al.
(författare)
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Measurement of rainfall interception by xerophytic shrubs in re-vegetated sand dunes
- 2005
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Ingår i: Hydrological Sciences Journal. - : Informa UK Limited. - 0262-6667 .- 2150-3435. ; 50:5, s. 897-910
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Tidskriftsartikel (refereegranskat)abstract
- More than 40 years of re-vegetation using mainly xerophytic shrubs Artemisia ordosica Krasch. and Caragana korshinskii Kom. at Shapotou Desert Experimental Research Station near Lanzhou, China has resulted in established dwarf-shrub and herbaceous cover on sand dunes. Precipitation, as the sole source of water replenishment in the semiarid area, plays a pertinent role in sustaining the desert ecosystem. A field study was conducted to (a) measure interception loss on shrub canopies during individual rainfall events, (b) determine the canopy storage capacity of individual plants, and (c) explore the relationship between interception and rainfall parameters. The total rainfall and its respective partitions as throughfall were determined and the interception losses in the studied ecosystem were quantified. Interception loss was shown to differ among the xerophyte taxa studied. During the growing seasons, the average shrub community interception loss is 6.9% and 11.7% of the simultaneous overall precipitation, for A. ordosica and C. korshinskii, respectively. Taking into account the observed rainfall conditions and vegetation cover characteristics, it was concluded that the interception loss was 2.7% of the total annual precipitation verified in the period for the A. ordosica community with an average cover of 30%, canopy projection area of 0.8 m(2) and canopy storage capacity of 0.75 mm. In contrast, interception loss for the C korshinskii community was 3.8% with an average cover of 46%, canopy projection area of 3.8 m(2) and canopy storage capacity of 0.71 mm. For individual plants of both shrubs, the proportion of interception loss to gross rainfall decreased notably as the rainfall intensity increased between 0 and 2 min h(-1), while it tended to remain constant at about 0.1-0.2 for A. ordosica and 0.1-0.3 for C. korshinskii when the rainfall intensity was > 2 mm h(-1).
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| 3. |
- Wang, XP, et al.
(författare)
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Water balance change for a re-vegetated xerophyte shrub area
- 2004
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Ingår i: Hydrological Sciences Journal. - : Informa UK Limited. - 0262-6667 .- 2150-3435. ; 49:2, s. 283-295
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Tidskriftsartikel (refereegranskat)abstract
- Water balances for a re-vegetated xerophyte shrub (Caragana korshinskii) area were compared to that of a bare surface area by using auto-weighing type lysimeters during the 1990-1995 growing seasons at the southeast Tengger Desert, Shapotou, China. The six-year experiment displayed how major daily water balance components might vary for a bare and a re-vegetated sand dune area. Evapotranspiration from the C korshinskii lysimeter represented a major part of the water balance. The average annual ET/P ratios varied between 69 and 142%. No seepage was observed for the vegetated lysimeter. For the bare lysimeter, on the other hand, 48 rum or 27% of observed rainfall per year occurred as seepage. These results suggest that re-vegetating large sandy areas with xerophytic shrubs could reduce soil water storage by transpiration. Also, the experimental results indicate that revegetating large sandy areas could significantly change groundwater recharge conditions. However, from a viewpoint of desert ecosystem reconstruction, it appears that natural rainfall can sustain xerophytic shrubs such as C. korshinskii which would reduce erosion loss of sand. However, re-vegetation has to be balanced with recharge/ groundwater needs of local populations.
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