毛乌素沙地臭柏与油蒿群落细根生物量的季节动态及其空间变化

 为了探讨沙地生态系统植物根系生物量的季节动态及其空间变化,采用根钻法,从2005年4月至2005年10月对毛乌素沙地天然臭柏、油蒿群落0—90 cm土层中细根（D≤2 mm, D为直径）生物量动态进行了测定,臭柏细根总生物量为13.87~18.22 t·hm-2,细根平均生物量占总根量的60.10%;油蒿的细根总生物量为1.173~1.389 t·hm-2,细根平均生物量占总根量的73.04%。臭柏细根平均生物量为油蒿的12.50倍（P＜0.05）。臭柏、油蒿群落细根生物量动态呈双峰曲线,峰值分别出现在4月、8月和6月、10月。两者的活细根生物量大致呈上升趋势,死根生物量则相反。臭柏、油蒿群落细根生物量的垂直分布随土层加深,生物量明显减少,细根在不同层次上的动态变化与总细根量的季节变化有所不同。臭柏细根生物量从坡顶到坡底分别为16.8067 t·hm-2、16.1656 t·hm-2、10.9834 t·hm-2,呈下降趋势,其细根生物量比率从坡顶、坡中到坡底依次增大;油蒿细根生物量最高值出现在坡顶,坡中与坡底变化不明显,其细根生物量比率随坡位变化并不明显。

Fine Root Biomass Seasonal Dynamics and Spatial Changes of Sabina vulgaris and Artemisia ordosica Communities in MU US Sandland

In order to study the seasonal dynamics and spatial changes of roots biomass in sandland ecosystem, the fine root biomass dynamic(≤2 mm in diameter) of Sabina vulgaris and Artemisia ordosica communities in the soil layers of 0—90 cm was surveyed by sequential root coring method in MU US sandland from early April to October, 2005. The results showed that the total fine root biomass of Sabina Vulgaris was between 13.87 and 18.22 t·hm-2, accounting for 60.10% of its total root biomass, the total fine root biomass of Artemisia ordosica fluctuated between 1.173 and 1.389 t·hm-2, being 73.04% of its total root biomass. The mean fine root biomass of Sabina Vulgaris was 12.50 times as high as that of Artemisia ordosica. The curves of fine root biomass of Sabina vulgaris and Artemisia ordosica showed two peaks, the appearance of higher fine root biomass of Sabina Vulgaris was in April and August, the maximum fine root biomass of Artemisia ordosica appeared in June and October. Living fine root biomass of Sabina vulgaris and Artemisia ordosica showed an increasing tendency, but dead fine root biomass was opposite. The fine root biomass of Sabina vulgaris and Artemisia ordosica decreased obviously along with the deepening of soil layers, whereas the dynamic changes of fine root between different soil layers were different to the total root biomass in different seasons. As for spatial distribution, the fine root biomass of Sabina vulgaris from slope top to bottom was 16.8067 t·hm-2, 16.1656 t·hm-2 and 10.9834 t·hm-2, showing a descending trend; the ratio of fine root biomass of Sabina Vulgaris was gently increasing. The highest value of fine root biomass of Artemisia ordosica was at the top of slope, the change of fine root biomass from middle to bottom was not obviously different; the ratio of fine root biomass of Artemisia ordosica did not change significantly with slope position.