| The flood in Minjiang River Basin has brought great losses on agriculture production, national economy, civilian lives and possessions. While from the point of forest, it plays an important role in the hydrological regulation through canopy, undergrowth, litterfall and soil layers. Especially, forest soils are regarded as "soil reservoir" due to its great function of water storage. At present the study of forest soil reservoir only rests on static observation and characterization. Trials of dynamic research in situ are lacking. Moreover, the effect of forest soil reservoir is complex and influenced by many factors, so the research about its properties and how the factors affect its function may help well-understanding the mechanism of forest soil reservoir on regulating runoff and reduce the flood peak, and then making good use of it. From 2001. properties of forest soil reservoir were studied on three forest lands, viz. Schima superba, Ctmninghamia lanceolate and enclosing and tending forest and control (bare land) in Jianou, Fujian province by establishment of runoff plot. The results showed that:(1) Total capacity of soil in Schima superba, Cunninghamia lanceolata, enclosing and tending forest was 503.94 mm, 471.62 mm, 451.46 mm, being 23.23%, 15.32% and 10.40% greater than that in the control (408.94 mm), respectively. The corresponding storage capacity in soils of three forest land was respectively 1.23, 1.25 and 1.16 times as high as that in the control. For flood control capacity, the value in three forest lands and the control was 62.79mm, 49.81mm, 40.08 and 41.10mm respectively.(2) Maximal available water capacity in Schima superba, Cwninghamia lanceolata, enclosing and tending forest was 389.66 mm, 382.02 mm and 350.02 mm, accounting for 77.32%, 81.00% and 77.53% of total capacity respectively and was 1.27,1.25 and 1.14 times greater than that in the control respectively. Furthermore, maximal available water capacity of soils in general decreased with increasing soil layers. At soil layer of 0-20cm, maximal available water capacity in three forests and the control was up to 21.28%, 23.26%, 26.45% and 23.40% of total respectively. Single correlation analysis showed that >0.25mm water-stable aggregate , non-capillary porosity,capillary porosity, bulk density, organic matter, total porosity were correlated with maximal available water capacity most-significantly.(3) Mean annual water storage of soils in Schima superba, Cunninghamia lanceolata, enclosing and tending forest and the control was 381.01 mm, 368.69 mm, 336.86 mm and 243.57 mm respectively. The trend of average monthly water storage of soil in different lands was consistent with the pattern of "W". In general it was high in May and August ,slow in October and July.(4) Monthly changes of water storage in different soil layers of three forest land and the control varied greatly, especially of surface 20 cm soil in the control. Water storage increased with the increase of soil depth in Schima superba, Cwminghamia lanceolata and the control ,it was also at 0-60 cm but different at 0-40cm in enclosing and tending forest . Water storage in different soil layers of three forest land and the control followed the rule: Schima superba >Cunninghamia lanceolata > enclosing and tending forest>the control.(5) Annual regulating water content of soils in Schima superba, Cunninghamia lanceolata, enclosing and tending forest and the control was 1506.11 mm, 1454.80 mm, 1347.19 mm and 1034.63 mm, being 93.84%, 90.65%, 83.94% and 64.47% of annual precipitation respectively. From March to June, regulating water content of soils occupied about 60% of the total in one year in rainy season, while only 18% from October to February.Mean monthly regulating soil water content in three forests was separately 57.84 mm, 51.27 mm and 33.83mm greater respectively than that in the control.(6) Analysis of mixed quantified model showe...
|
PDF Full Text Request