To characterize effects of plant roots on preferential flow（PF）,we measured root length density（RLD）and root biomass（RB） in Jiufeng National Forest Park,Beijing,China.Comparisons were made for RLD and RB between...To characterize effects of plant roots on preferential flow（PF）,we measured root length density（RLD）and root biomass（RB） in Jiufeng National Forest Park,Beijing,China.Comparisons were made for RLD and RB between soil preferential pathways and soil matrices.RLD and RB declined with the increasing soil depth（0–10,10–20,20–30,30–40,40–50,50–60 cm） in all experimental plots.RLD was greater in soil preferential pathways than in the surrounding soil matrix and was 69.5,75.0 and72.2 % for plant roots of diameter（d） ／1,1 ／ d ／ 3 and3 ／ d ／ 5 mm,respectively.Fine root systems had the most pivotal influence on soil preferential flow in this forest ecosystem.In all experimental plots,RB content was the sum of RB from soil preferential pathways and the soil matrix in each soil depth.With respect to 6 soil depth gradient（0–10,10–20,20–30,30–40,40–50,50–60 cm） in each plot,the number of soil depth gradient that RB content was greater in soil preferential pathways than in the soil matrix was characterized,and the proportion was68.2 % in all plots.展开更多
Two pilot subsurface wastewater infdtrafion systems （SWISs） were filled with the same mixed matrix and operated in the intermittent feeding mode with hydraulic loading of 0. 1 m3/ （m2 d） for 140 d. One of SWISs w...Two pilot subsurface wastewater infdtrafion systems （SWISs） were filled with the same mixed matrix and operated in the intermittent feeding mode with hydraulic loading of 0. 1 m3/ （m2 d） for 140 d. One of SWISs was fed with wastewater which was previously settled （ ST）, and the other with the same wastewater but in addition treated with a coagulation process （CT）. After 140 d of operation, in the upper layer of ST system the effective porosity decreased by 4.1% and the organic matter （OM） content increased by 246.4 %, whereas only decreased by 0.7 % and increased by 35. 7% of CT system, respectively. During the study, dogging didn＇t occur in CT system and occurred in ST system. Effluent chemical oxygen demand （COD）, total phosphorus （TP） and ammonia nitrogen （NH4＋ --N ） concentrations in CT system were less than those in ST system. In ST system, effluent COD, TP, NH4＋ --N concentrations increased and suspended solid （SS） concentration decreased after dogging. The results indicated that the use of a prior coagulation treatment was a good alternative for improving the effluent quality and avoiding an anticipated dogging.展开更多
基金supported by a grant from the Natural Science Foundation of China(41271044)
文摘To characterize effects of plant roots on preferential flow（PF）,we measured root length density（RLD）and root biomass（RB） in Jiufeng National Forest Park,Beijing,China.Comparisons were made for RLD and RB between soil preferential pathways and soil matrices.RLD and RB declined with the increasing soil depth（0–10,10–20,20–30,30–40,40–50,50–60 cm） in all experimental plots.RLD was greater in soil preferential pathways than in the surrounding soil matrix and was 69.5,75.0 and72.2 % for plant roots of diameter（d） ／1,1 ／ d ／ 3 and3 ／ d ／ 5 mm,respectively.Fine root systems had the most pivotal influence on soil preferential flow in this forest ecosystem.In all experimental plots,RB content was the sum of RB from soil preferential pathways and the soil matrix in each soil depth.With respect to 6 soil depth gradient（0–10,10–20,20–30,30–40,40–50,50–60 cm） in each plot,the number of soil depth gradient that RB content was greater in soil preferential pathways than in the soil matrix was characterized,and the proportion was68.2 % in all plots.
基金National Natural Science Foundations of China(Nos.41001321,41471394,41571455)Major Original Program in Shenyang Normal University,China(No.ZD201403)+2 种基金Ecology and Environment Research Center Director Foundation of Shenyang Normal University,China(No.EERC-T-201601)Natural Science Foundation of Liaoning Province,China(NO.2015010585-301)Liaoning BaiQianWan Talents Program,China(No.2015(45)
文摘Two pilot subsurface wastewater infdtrafion systems （SWISs） were filled with the same mixed matrix and operated in the intermittent feeding mode with hydraulic loading of 0. 1 m3/ （m2 d） for 140 d. One of SWISs was fed with wastewater which was previously settled （ ST）, and the other with the same wastewater but in addition treated with a coagulation process （CT）. After 140 d of operation, in the upper layer of ST system the effective porosity decreased by 4.1% and the organic matter （OM） content increased by 246.4 %, whereas only decreased by 0.7 % and increased by 35. 7% of CT system, respectively. During the study, dogging didn＇t occur in CT system and occurred in ST system. Effluent chemical oxygen demand （COD）, total phosphorus （TP） and ammonia nitrogen （NH4＋ --N ） concentrations in CT system were less than those in ST system. In ST system, effluent COD, TP, NH4＋ --N concentrations increased and suspended solid （SS） concentration decreased after dogging. The results indicated that the use of a prior coagulation treatment was a good alternative for improving the effluent quality and avoiding an anticipated dogging.
基金Project(41973078)supported by the National Natural Science Foundation of ChinaProject(2022SK2073)supported by the Hunan Provincial Natural Science Foundation,China。
