Rebuilding soil hydrological functioning after swidden agriculture in eastern Madagascar
Rebuilding soil hydrological functioning after swidden agriculture in eastern Madagascar
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DOI：
10.1016/j.agee.2017.01.002
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发表时间：
2017-02
期刊：
影响因子：
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通讯作者：
B. Zwartendijk;H. V. Meerveld;C. Ghimire;L. Bruijnzeel;M. Ravelona;Julia P. G. Jones
中科院分区：
文献类型：
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作者：
B. Zwartendijk;H. V. Meerveld;C. Ghimire;L. Bruijnzeel;M. Ravelona;Julia P. G. Jones
由于普遍的刀耕火种式农业而造成的土地使用变化影响到生态系统服务的提供。然而，人们对土壤的水文功能-影响降雨渗透，从而影响洪水风险、旱季水流和地表侵蚀-如何受到反复的植被砍伐和焚烧的影响，在土地废弃和植被再生后这种功能能在多大程度上恢复，以及积极的恢复是否能加快恢复速度，了解相对较少。我们通过对当地土地使用者和指示植物物种的采访，重建了马达加斯加东部高地19个不同地点的土地利用历史，这些地点代表了四种不同的土地利用类型：从未被烧毁但直到15-20年前受到人工伐木影响的半成熟森林; 6-9年前积极重新造林的休耕地; 2-10年自然再生的休耕地;和高度退化的火烧顶极草原。表面和近表面（下至30厘米深）饱和土壤导水率（KSAT），以及渗透和渗滤的主要流动途径，确定每个土地覆盖类型。森林站点的表面K值非常高（中位数：724 mm h−1），渗透主要由沿沿着根系和其他优先流动途径（大孔隙）的流动控制，而退化土地的K值较低（中位数：45 mm h−1），渗透主要由近表面基质流动控制。蓝色染料染色的总面积与Ksat呈负相关。地表和近地表的Ksathad在森林更新6-9年后显著增加（再造林和自然更新的中值分别为203和161 mm h− 1）。需要更多的观察，以更充分地了解土壤水文功能可以重建的速度，以及是否积极补种减少所需的时间来恢复土壤水文功能或没有。
Land-use change due to the widespread practice of swidden agriculture affects the supply of ecosystem services. However, there is comparatively little understanding of how the hydrological functioning of soils, which affects rainfall infiltration and therefore flood risk, dry-season flows and surface erosion, is affected by repeated vegetation clearing and burning, the extent to which this can recover following land abandonment and vegetation regrowth, and whether active restoration speeds up recovery. We used interviews with local land users and indicator plant species to reconstruct the land-use history of 19 different sites in upland eastern Madagascar that represent four different land-use categories: semi-mature forests that were never burnt but were influenced by manual logging until 15–20 years ago; fallows that were actively reforested 6–9 years ago; 2–10 year old naturally regenerating fallows; and highly degraded fire-climax grassland sites. Surface- and near-surface (down to 30 cm depth) saturated soil hydraulic conductivities (Ksat), as well as the dominant flow pathways for infiltration and percolation were determined for each land-cover type. SurfaceKsatin the forest sites was very high (median: 724 mm h−1) and infiltration was dominated by flow along roots and other preferential flow pathways (macropores), whereasKsatin the degraded land was low (median: 45 mm h−1) with infiltration being dominated by near-surface matrix flow. The total area of blue-dye stains was inversely correlated to theKsat. Both surface- and near-surfaceKsathad increased significantly after 6–9 years of forest regeneration (median values of 203 and 161 mm h−1for reforestation and natural regeneration, respectively). Additional observations are needed to more fully understand the rates at which soil hydrological functioning can be rebuilt and whether active replanting decreases the time required to restore soil hydrological functioning or not.