黄土丘陵区丰水年产流产沙特征分析

设置标准径流小区进行长期定位监测,探讨天然降雨条件下,流域内不同土地利用方式对坡面产流产沙的影响,以期为该流域土地利用规划、水土流失综合治理、生态环境改善提供理论依据。基于汾河上游阳坡小流域内2种坡度、6种不同土地利用方式的8个径流小区,开展自然降雨观测、径流泥沙观测。结果表明：（1）试验期降雨超过多年同期平均雨量,属于丰水年;且年内雨量分布较多年平均差异较大;（2）不同土地利用方式条件下,坡面产流量差异明显,坡面为15°时,各径流小区的产流量大小顺序为裸坡地>坡耕地>草地;而18°各径流小区的产流量大小为裸坡地>草地>油松林地>灌木林地（黄刺玫）;（3）土地利用方式不同,坡面产沙量差异明显。15°径流小区坡面产沙量裸坡地>胡麻>土豆>草地;相比之下,18°径流小区产沙量以灌木林地和油松林地最少,均为0.30 t/hm²;裸坡地产沙量最多,是林地的92.08倍;林草地减流减沙效果明显。研究结果可为该流域的生态重建,土地利用以及汾河上游其他小流域的土地利用规划,从而减少水土流失提供借鉴。

Characteristics of Runoff and Sediment Yield in the Loess Hilly Region in High Flow Year

By setting up standard runoff plots to carry on long-term positioning monitoring, the authors explored the effect of different land use on slope runoff and sediment production under natural rainfall condition, aiming to provide a theoretical basis for watershed land use plan, comprehensive management of soil erosion, and improvement of ecological environment. Based on 8 runoff plots with 2 slopes and 6 different land use types, natural rainfall and runoff observation were conducted. The results showed that (1) the rainfall in the experiment period was higher than that of the average rainfall in the same period of many years, which was a high glow year, and the rainfall distribution of the year was larger than that of the average rainfall in many years; (2) the amount of runoff was significantly different under different land use patterns, the amount of runoff under different land use was the highest in bare slope land when the slope was 15°, followed by slope cropland and grassland; the amount of runoff under 18° was followed the order of bare slope land >grassland > forest plot (Pinus tabuliformis Carrière) > shrub plot (Rosa xanthina Lindl); (3) the land use patterns influenced clearly the amount of sediment, the amount of sediment under 15° slope followed the order of bare slope land > flax > potato > grassland; while as to 18° slope, the amount of sediment from the shrub plot and forest plot was the least, which was 0.30 t/hm², and the amount of sediment from the bare slope was the highest, which was 92.08 times of that of forest plot; the effect of reducing runoff and sediment in forest and grass was obvious. The study could provide reference for ecological reconstruction, and land use plan for small watersheds in the upper reaches of Fenhe River.