水保所知识产出(1956---)知识库

细根( ≤2 mm) 在陆地生态系统净初级生产力的分配中占有重要地位，在碳循环和 水土保持方面具有重要意义． 本文采用土钻法和内生长法，以黄土高原刺槐人工林、落叶灌 木、退耕草地和沙蒿群落4 种主要植被类型为对象，研究 0 ～ 40 cm 土层细根生物量、垂直分 布和细根年生产量． 结果表明: 细根生物量与纬度呈线性负相关． 4 种植被类型0 ～40 cm 土 层细根生物量的大小顺序为落叶灌木( 220 g·m －2) ＞ 刺槐人工林( 163 g·m －2) ≈退耕草地 ( 162 g·m －2) ＞沙蒿群落( 79 g·m －2) ． 退耕草地直径≤1 mm 细根生物量占直径≤2 mm 总 细根生物量的74． 1%，在4 种植被类型中最高; 4 种植被类型细根生物量随着土层深度的增 加而减少，最大值均出现在0 ～10 cm 土层． 退耕草地0 ～10 cm 土层细根生物量占0 ～40 cm 土层总细根生物量的44． 1%，显著高于其他3 种植被类型; 细根年生产量与纬度呈线性负相 关． 4 种植被类型0 ～40 cm 土层细根年生产量大小顺序为退耕草地( 315 g·m －2·a －1) ＞ 落 叶灌木( 249 g·m －2 ·a －1) ＞ 刺槐人工林( 219 g·m －2 ·a －1) ＞ 沙蒿群落( 115 g·m －2 · a －1) ，其中退耕草地显著高于其他3 种植被类型． 退耕草地0 ～10 cm 土层细根生产量占0 ～ 40 cm 土层总细根生产量的40． 4%，在4 种植被类型中最高． 退耕草地细根周转时间为0． 51 a，低于其他3 种植被类型．

Fine roots ( ≤2 mm) play a major role in biogeochemical cycling in ecosystems． By the methods of soil cores and ingrowth soil cores，we studied the biomass and annual production of fine roots in 0 －40 cm soil layers of four main vegetation types，i． e． ，Ｒobinia pseudoacacia plantation， deciduous shrubs，abandoned grassland，and Artemisia desertorum community in Loess Plateau， China． The spatial patterns of fine root biomass and production were negatively associated with latitudes． The fine root biomass in the 0 －40 cm soil layer was in the order of deciduous shrubs ( 220 g·m －2) ，Ｒ． pseudoacacia plantation ( 163 g·m －2) ，abandoned grassland ( 162 g·m －2) and A． desertorum community ( 79 g·m －2) ． The proportion of ≤1 mm fine root biomass ( 74． 1%) in the 0 －40 cm soil layer of abandoned grassland was significantly higher than those in the other three vegetation types． The fine root biomass of the four vegetation types was mainly distributed in the 0 － 10 cm soil layer and decreased with soil depth． The proportion of fine root biomass ( 44． 1%) in the 0 －10 cm soil layer of abandoned grassland was significantly higher than those in other three vegetation types． The fine root productions of four vegetation types were in the order of abandoned grassland ( 315 g·m －2·a －1) ＞ deciduous shrubs ( 249 g·m －2·a －1) ＞ Ｒ． pseudoacacia plantation ( 219 g·m －2·a －1) ＞ A． desertorum community ( 115 g·m －2·a －1) ，and mainly concentratedin the 0 －10 cm top soil layer and decreased with the soil depth． The proportion of the annual production ( 40． 4%) in the 0 －10 cm soil layer was the highest in abandoned grassland． Fine roots of abandoned grassland turned over faster than those from the other three vegetation types．