中文摘要：

为理解引起了水质的降级在的原因，更低的顺序流，系统的采样在 NortheastForestry 大学的 Maoershan 试验性的福雷斯特里沿着 Ashihe 河连续统的低顺序溪流(第 1st-5 ) 在不同空间地点被进行， Shangzhi 城市， Heilongjiang 省，中国。溪流水质的索引，即， pH ，溶解的氧()，混浊，温度，PO_4~(3-)-P,NO~(3-) -N andNH_4~+-N 集中，全部的溶解的无机的氮( TDIN-N ，包括集中ofNO_3~-- N 和 NH_4~+-N )，并且总计磷(无机、器官磷， TP )被测量并且分析。溪流顺序，相关环境背景和陆地使用类型为每个采样地点被记录。在有不同溪流订单和土地利用类型的不同地点的溪流水质的索引被 ANOVA 分析比较。在不同采样地点的溪流水质的索引被层次簇分析分析。水质有的 Resultshowed 在不同溪流订单和土地利用的重要差别打字；有不同溪流特征(溪流顺序和土地利用类型)的一些地点被组织进一样的簇，显示随机的骚乱在水质生产了变化，它与一般规则使溪流水质的空间变化不一致。

英文摘要：

For understanding the reasons that caused the degradation of water quality in lower order streams, systematic sampling was conducted at different spatial locations aiong the low order streams （1 st-5th） of Ashihe River continuum in Maoershan Experimental Forest of Northeast Forestry University, Sharlgzhi City, Heilongjiang Province, China. The indexes of stream water quality, i.e., the pH, dissolved oxygen（DO）, turbidity, temperature, PO43-P, NO3-N and NH4^＋-N concentrations, total dissolved inorganic nitrogen （TDIN-N, including concentrations of NO3^＋-N and NH4^＋-N）, and total phosphorus （inorganic and organic phosphorous, TP） were measured and analyzed. The stream order, related environmental settings and land-use type were recorded for each sampling location. The indexes of stream water quality at different locations with different stream orders and land use types were compared by ANOVA analysis. The indexes of stream water quality at different sampling locations were analyzed by Hierarchical cluster analysis. Result showed that water quality had significant difference in different stream orders and land use types; some locations with different stream features （stream order and land use type） were grouped into same clusters, indicating that random disturbances produced the variations in water quality, which made the spatial variances of stream water quality inconsistent with the general rules.