亚热带森林林分更新对地表径流4种盐基离子浓度的影响

地表径流不仅是水循环的重要组成部分,也是森林物质迁移的重要途径,其动态过程可能受林分更新的调控,目前仍缺乏必要的关注。通过对福建省三明市米槠(Castanopsis carlesii)次生林、杉木(Cunninghamia lanceolata)人工林、杉木人工幼林和米槠人工幼林近5年的定位观测,探讨林分更新对地表径流和所含4种盐基离子(Ca²⁺、K~+、Na~+和Mg²⁺)浓度的影响。结果表明:米槠人工幼林的年均地表径流量为(306.3±48.40) m~3·hm^-2,是米槠次生林的2.8倍和杉木人工林的3.3倍;杉木人工幼林地表径流Ca²⁺、K~+、Na~+和Mg²⁺的浓度为(17.89±0.61)、(16.58±1.06)、(4.18±0.05)和(1.19±0.21) mg·L^-1,是米槠次生林的1.6、1.3、1.7和0.9倍;季节对地表径流盐基离子浓度具有显著影响,整体表现为离子浓度峰值几乎处于非生长季节;林分更新后人工幼林相较成熟林其地表径流...

Stand renewal effects on the concentrations of four base cations of surface runoff in subtropical forests

Surface runoff is not only an important part of water cycling,but also a major pathway for the material fluxes in forests.Stand renewal may have significant effects on the dynamics of forest surface runoff,but this process still remains elusive.Based on a 5-year field observation in Castanopsis carlesii secondary forest,Cunninghamia lanceolata plantation,Cunninghamia lanceolata young plantation and Castanopsis carlesii young plantation in subtropical region of Sanming,Fujian,we assessed how stand renewal affected surface runoff and the associated concentrations of four base cations(Ca²⁺,K⁺,Na⁺,and Mg²⁺).The average annual surface runoff in C.carlesii young plantation was(306.3±48.40) m³·hm^-2,which was 2.8 and 3.3 times of that in C.carlesii secondary forest and C.lanceolata plantation,respectively.The concentrations of Ca²⁺,K⁺,Na⁺,and Mg²⁺ of surface runoff in C.lanceolata young plantation were(17.8±0.61),(16.58±1.06),(4.18±0.05),and(1.19±0.21) mg·L^-1,which were 1.6,1.3,1.7 and 0.9 times of those in C.carlesii secondary forest.The concentrations of all base cations varied greatly over seasons,with a general pattern of peaking in non-growing seasons.These results indicated that the total amount of surface runoff and the concentrations of base cations of runoff in the young plantations were significantly higher than that of mature forests as well as after stand renewal.These findings will help to better understand the fluxes of nutrient elements along with surface runoff as affected by stand renewal in subtropical forests,and can provide basic data for forest management and soil and water conservation.