黄土高原丘陵区不同立地条件下柠条根系研究

Research on Root System of Caragana korshinskii at Different Site Conditions in the Hilly Regions of Loess Plateau

对黄土高原丘陵区不同立地条件下3年生柠条的根系作了初步研究，结果表明：柠条侧根发生的主要部位在距地表0～20cm的土层中，除在阳坡、半阳坡分布的植株外，其它的在50cm以下没有侧根发生，侧根总数以阳坡最多，半阴坡最少；不同立地下根系生物量的垂直分布，均表现为从土壤表层到深层逐次递减；在各土层中，0～60cm土层中分布的根系生物量所占的比重最大，超过了总量的80％。不同立地条件下单株根系生物量以阳坡最大，为66．63g，阴坡最低，仅为6．69g。不同立地条件下柠条的地上部分差异显著，阳坡、半阳坡的株高、生物量等都高于阴坡和半阴坡的。柠条在幼龄期适宜生长的立地类型为阳坡和半阳坡。

The root systems of 3 years Caragana korshinskii at different site conditions in the hilly regions of Loess Plateau were studied. The results showed that the lateral roots of Caragana korshinskii mainly grew in the depth of 0 -20 cm underground, and under all site conditions there were no lateral roots below 50 cm depth except sunny slope and semi-sunny slope. The total amount of lateral roots sunny slope was the most, and that of shady slope was the least. The vertical distribution of root biomass of Caragana korshinskii under different site conditions showed a gradually decreasing from soil toplayer to deep-layer. The ratio of root biomass in 0- 60 cm soil layer to the total was the biggest and beyond 80 percent. The individual root biomass in sunny habitat was 66.63 g and larger than that of others, the shady habitat was the lowest, only 6.69g. The aboveground of Caragana korshinskii under different site conditions had significant deference, the height and biomass of Caragana korshinskii in sunny and semi-sunny slope were higher than that on other site conditions. Caragana korshinskii in young-age period were suitable for growing on the sunny and semi-sunny slope on Loess Plateau.