Fortier Julien, Truax Benoit, Gagnon Daniel, Lambert France
Fiducie de recherche sur la forêt des Cantons-de-l'Est / Eastern Townships Forest Research Trust, 1 rue Principale, J0B 2M0 Saint-Benoît-du-Lac, QC Canada ; Département des sciences biologiques, Université du Québec à Montréal, C.P. 8888, H3C 3P8 succ. Centre-ville, Montréal, QC Canada.
Springerplus. 2013 Oct 17;2:539. doi: 10.1186/2193-1801-2-539. eCollection 2013.
The objectives of this study were to compare coarse root (diameter > 2 mm) and fine root (diameter < 2 mm) biomass, as well as distribution of soil carbon stocks in 3 types of riparian land uses across 4 sites located in farmland of southern Québec, Canada: (1) hybrid poplar buffers (9th growing season); (2) herbaceous buffers; (3) natural woodlots (varying in tree species and age). For all land uses most of the root biomass was within the 0-20 cm depth range. Total coarse root biomass, to a 60 cm depth, ranged from 8.8-73.7 t/ha in woodlots, 0.6-1.3 t/ha in herbaceous buffers, and 9.2-27.3 t/ha in poplars. Total fine root biomass ranged from 2.68-8.64 t/ha in woodlots, 2.60-3.29 t/ha in herbaceous buffers, and 1.86-2.62 t/ha in poplars. Total root biomass was similar or higher in poplar buffers compared to a 27 year-old grey birch forest. This indicates that poplar buffers accelerated riparian soil colonisation by roots compared to natural secondary succession. Generally, fine root biomass in the surface soil (0-20 cm) was lower in poplar than in herbaceous buffers; the reverse was observed at greater depth. Highest coarse root biomass in the 40-60 cm depth range was observed in a poplar buffer, highlighting the deep rooted nature of poplars. On average, total soil C stocks (0-60 cm) were greater in woodlots than in riparian buffers. On most sites, soil C stocks tended to be lower in poplar buffers compared to adjacent herbaceous buffers, especially in surface soil, probably because of lower fine root biomass in poplar buffers. Across all sites and land uses, highest soil C stocks at the different soil depths were found in the soil layers of woodlots that also had the greatest fine root biomass. Strong positive linear relationships between fine root biomass and soil C stocks in the 0-20 cm depth range (R (2) = 0.79, p < 0.001), and in the whole soil profile (0-60 cm) (R (2) = 0.65, p < 0.01), highlight the central role of fine root biomass in maintaining or increasing soil C stocks.
本研究的目的是比较粗根（直径>2毫米）和细根（直径<2毫米）生物量，以及加拿大魁北克省南部农田中4个地点3种河岸土地利用类型的土壤碳储量分布：（1）杂交杨树缓冲带（第9个生长季）；（2）草本缓冲带；（3）天然林地（树种和树龄各异）。对于所有土地利用类型，大部分根系生物量都在0-20厘米深度范围内。到60厘米深度，天然林地的粗根总生物量为8.8-73.7吨/公顷，草本缓冲带为0.6-1.3吨/公顷，杨树为9.2-27.3吨/公顷。细根总生物量在天然林地为2.68-8.64吨/公顷，草本缓冲带为2.60-3.29吨/公顷，杨树为1.86-2.62吨/公顷。与一片27年树龄的灰桦林相比，杨树缓冲带的总根系生物量相似或更高。这表明与天然次生演替相比，杨树缓冲带加速了河岸土壤的根系定殖。一般来说，杨树地表土壤（0-20厘米）中的细根生物量低于草本缓冲带；在更深的深度则观察到相反的情况。在一个杨树缓冲带中，40-60厘米深度范围内的粗根生物量最高，突出了杨树根系深扎的特性。平均而言，天然林地的土壤总碳储量（0-60厘米）大于河岸缓冲带。在大多数地点，与相邻的草本缓冲带相比，杨树缓冲带的土壤碳储量往往较低，尤其是在表层土壤中，这可能是因为杨树缓冲带中的细根生物量较低。在所有地点和土地利用类型中，不同土壤深度的最高土壤碳储量出现在细根生物量也最大的天然林地土壤层中。0-20厘米深度范围内细根生物量与土壤碳储量之间（R（2）=0.79，p<0.001）以及整个土壤剖面（0-60厘米）之间（R（2）=0.65，p<0.01）存在强烈的正线性关系，突出了细根生物量在维持或增加土壤碳储量中的核心作用。
