江西大岗山不同密度杉木林枯落物持水与土壤贮水能力研究

Water-holding Capacity of Litter and Soil Under Chinese Fir Forest with Different Densities in Dagangshan Mountain of Jiangxi Province

对江西大岗山地区不同密度杉木林枯落物层和土壤层水文功能进行研究,结果表明:(1)枯落物总厚度、蓄积量以及土壤总孔隙度、饱和蓄水量大小均表现为N3500>N4700>N2700>N1700>N900,土壤容重大小顺序与之相反。(2)N3500林分枯落物最大持水量最大,为12.60t/hm2;N1700林分枯落物最大持水率最高,为254.98%。N2700林分最大持水量、持水率均最小,分别为9.69t/hm2,229.07%。各林分枯落物层有效拦蓄量在5.18～6.35t/hm2之间,大小排序为N3500>N4700>N1700>N900>N2700。(3)不同密度杉木林未分解层和半分解层持水率同浸泡时间呈显著对数关系(Q=aln t+b),吸水速率与浸泡时间呈显著幂函数关系(V=ktn)。(4)N3500林分毛管孔隙度、毛管蓄水量均最大,分别为40.04%,3 153.16t/hm2,N900林分最小,分别为38.56%,3 059.76t/hm2;土壤非毛管孔隙度为N4700>N3500>N2700>N900>N1700,变化范围为9.42%～11.33%,有效蓄水量表现为N3500>N4700>N2700>N900>N1700,大小在721.93～894.70t/hm2之间。(5)不同密度杉木林土壤稳渗速率在1.34～3.52mm/min之间。综上,林分密度在3 500株/hm2左右表现出很好的水源涵养能力,建议在今后的森林经营中选择合理的造林密度,以便更好地发挥森林水源涵养功能。

Hydrological function of litter and soil under Chinese fir forest with various densities was studied in Dagangshan mountain of Jiangxi province, the results showed as the following： （1）With regard to litter depth, amount of litter accumulation, total porosity and maximal soil water-storage, different fir forest had the same sort order like Na3500〉N4700〉N2700〉N1700〉N900, however, the order was contrary in term of soil bulk density. （2）Maximum litter water-holding capacity of N3500 was the maximum（12.60 t/hm2）, and the highest water-holding proportion of N1700 was the biggest （254. 98%）, however, both maximum water-holding capacity and the highest water-holding proportion of N27oo were the lowest, which were 9.69 t/hm2 and 229.07%, respectively. The effective retaining amount of litter in different fir forest ranged from 5.18 t/hm2 to 6.35 t/hm2, and the order was N3500〉N4700〉N1700〉N900〉N2700. （3）The relationships between water-holding rate and immersion time of whether semi-decomposed or un-decomposed litter in all different fir forests were significantly fitted by Logarithmic equation（Q=aln tq-b）. The relationships between water absorption speed rate and soaking time were described by power function（V= kt^n）. （4）Both soil capillary porosity and water storage of N3500 were the highest（40.04%, 3 153.16 t/hm2） , and the smallest values of both the factors were found in forest stand of N900 （38. 560//00, 3 059. 76 t/hm2）. The soil non-capillary porosity changed from 9. 42% to 11. 33%, and a sequence was N4700〉）N3500〉N2700〉N900〉N1700, while effective water storage showed a order like Na900〉N4700〉N2700〉N900〉N1700, and ranged from 721.93 t/hm2 to 894.70 t/hm2. （5）Soil stable infiltration rate of different forests stand ranged from 1.34 mm/min to 3.52 mm/min. In short, the forest with density about 3 500 tree per hectare showed better water conservation ability than the other forest. Consequently, a reasonable planting density should be taken account of in future forest management in order to perform better in water conservation.