Cotrufo M F, Gorissen A
Facoltà di Scienze Ambientali, Seconda Università di Napoli, 81100 Caserta, Italy.
DLO Research Institute for Agrobiology and Soil Fertility (AB-DLO), P.O. Box 14, 6700 A A, Wageningen, The Netherlands.
New Phytol. 1997 Nov;137(3):421-431. doi: 10.1046/j.1469-8137.1997.00839.x.
Three perennial grass species, Lolium perenne L., Agrottis capillaris L. and Festuca uvina L., were homogeneously labelled in phytotrons with CO at two CO concentrations (350 and 700μl l ). Plants were grown under two nitrogen regimes: one with a minor addition of 8 kg N ha , the other with an addition of 278 kg N ha . Carbon allocation over the different compartments of the plant/soil systems was measured: shoots, roots, rhizosphere soil (soil solution, microbial biomass and soil residue), and bulk soil. Elevated CO., increased total net C recovery in all species by 14%, and significantly enhanced the below-ground C allocation by 26%, this enhancement was 24%, 39% and 21 % for root, rhizosphere soil and bulk soil, respectively. Within the rhizosphere soil, the C amounts in the soil solution (+ 69%) and soil residue (+ 49%,) increased significantly. Total microbial biomass-C in the rhizosphere soil was also increased (15 %) by the elevated CO treatment, but only in proportion to the increased root mass. No interactions were observed between the elevated CO , and N treatments. The N treatment increased total net C recovery by more than 300% and C was preferentially allocated to the shoots, leading to a significant increase in shoot-to-root ratio. However, N fertilization also increased (+111%) the absolute amount of C in soil. The three species behaved differently, but no interactions were observed between CO treatment and plant species. These results show that elevated CO induces an increased C input into soil for all three grass species at both N levels. However, the highest absolute amounts were found in the soils of the fastest growing species and at the highest N level.
三种多年生草本植物，多年生黑麦草（Lolium perenne L.）、毛细翦股颖（Agrottis capillaris L.）和紫羊茅（Festuca uvina L.），在人工气候室中于两种二氧化碳浓度（350和700μl/l）下用二氧化碳进行均匀标记。植物在两种氮素供应条件下生长：一种少量添加8 kg N/ha，另一种添加278 kg N/ha。测量了植物/土壤系统不同组分间的碳分配情况：地上部分、根系、根际土壤（土壤溶液、微生物生物量和土壤残体）以及非根际土壤。二氧化碳浓度升高使所有物种的总净碳回收率提高了14%，并显著增强了地下碳分配，增幅达26%，其中根系、根际土壤和非根际土壤的增幅分别为24%、39%和21%。在根际土壤中，土壤溶液中的碳含量（+69%）和土壤残体中的碳含量（+49%）显著增加。二氧化碳浓度升高处理也使根际土壤中的总微生物生物量碳增加了（15%），但仅与根系生物量的增加成比例。未观察到二氧化碳浓度升高与氮处理之间的相互作用。氮处理使总净碳回收率提高了300%以上，且碳优先分配到地上部分，导致地上/地下比显著增加。然而，施氮也增加了（+111%）土壤中的碳绝对含量。这三个物种表现不同，但未观察到二氧化碳处理与植物物种之间的相互作用。这些结果表明，在两个氮水平下，二氧化碳浓度升高均导致所有三种草本植物输入土壤的碳增加。然而，在生长最快的物种的土壤中以及最高氮水平下发现了最高的碳绝对含量。
