The Spatial Distribution Of Soil Nutrients Under Umbrella Bamboo (Fargesia Murielae) Seedlings In Shennongjia National Nature Reserve

Umbrella bamboo (Fargesia murielae) belongs to Fargesia of Bambusoideae (Gramineae) with sympodial rhizome, and it is a native Chinese bamboo endemic to the Shennongjia National Nature Reserve at Hubei Province in Central China. Umbrella bamboo is covering the ground of subalpine or shrub forest from2400m to the summit of3100m, which is the highest distribution of bamboo in shennongjia and has been introduced successfully in European garden. Also, umbrella bamboo is one of the food resources for giant panda. Due to the beneficial effects on soil and water conservation, surface runoff alleviation and microclimate regulation, researchers gradually carry out some basic study of umbrella bamboo, mainly about the altitude diversity of community, the vegetation renewal and the sprouting and distribution of seeds.Umbrella bamboo is naturally distributed in the region of shennongjia, as a result, the soil nutrients’dynamics under bamboo forest depends greatly on the auto-interaction of plants and soil. In order to explore the spatial distribution of soil nutrients under umbrella bamboo seedlings, the study selected four plots in different altitude (from2400m to3100m) in Shennongjia National Nature Reserve:Shennong Camp, Liaowang Tower, Banbi Rock and Monkey Stone. Through analysis of soil nutrient changes along with altitude, soil depth and distance from mother bamboo, it is clear for us to understand the spatial utilization pattern of soil nutrients and the settlement mode of clone reproduction of umbrella bamboo seedlings under natural regeneration. In addition, through correlation analysis of soil nutrients and environmental factors, we can explore the different strength of environmental factors on soil nutrients. The results were as follows:1. The descriptive statistics analysis of soil nutrients under umbrella bamboo seedlings in different sample plots showed that the effective nitrogen, available phosphorus, TP and TK contents in soil didn’t vary largely, without deflection, while rapidly available potassium and TN contents varied obviously, with deflection. This result demonstrated that the available potassium and TN contents of umbrella bamboo soil were significantly different among different sample plots.2. The correlation analysis of different soil nutrients under umbrella bamboo seedlings and environmental conditions showed that:the effective nitrogen, the rapidly available potassium, TN and TP contents in soil had significantly negative correlations with altitude, and the content of TK were significantly correlated with altitude (p<0.01, r=0.835**). Besides, the correlation between other soil nutrients and environmental conditions was not significant. All the soil nutrients had a significantly negative correlation with wet weight and dry weight of soil, and a positive correlation with soil moisture. The gravel proportion in soil had a remarkable effect on the content of rapidly available potassium and TN, and the correlation coefficient was r=0.143*(p<0.05), r=0.222**(p<0.01) respectively. The correlation among different soil nutrients under umbrella bamboo seedlings was also significant.3. The soil nutrients under umbrella bamboo seedlings had different change rules in different elevation sample plots. The TK content had a linear correlation with altitude:The TK content gradually decreased along with the altitude decreasing, which was similar to general bamboos. The remaining five soil nutrients had no significant linear relationship with altitude, that was to say there was no vertical zonal distribution of these nutrients. In addition, the effective nitrogen and TP contents in soil under umbrella bamboo were abundant, at very high levels, which was higher than other bamboos. The TN, effective phosphorus and rapidly available potassium contents in soil were on average level, and changed a lot in different altitude. The TK content was slightly lower, which meant the potential for potassium was deficient.4. The soil nutrients under umbrella bamboo seedlings had same change rules in different soil depth. The nutrients in soil layer of0-10cm were larger than that of10-20cm except TK, which meant the soil nutrients obviously decreased along with the soil depth increasing, as same as the general law of other bamboos. The TK content had a different changing along with the depth of soil, and basically represented0-10cm≤10～20cm. In addition, the stability of the soil nutrients in surface layer was lower than in subsurface layer.5. The soil nutrients under umbrella bamboo seedlings changed differently along with the distance to bamboo cluster. The change rules of the effective nitrogen, available phosphorus, rapidly available potassium, TP and TN contents in different distance were similar, which was with the increase of the distance to bamboo cluster, these nutrients in soil increased firstly, then decreased gradually. The TK content had a linear correlation with distance to bamboo cluster, which was with the increase of the distance to bamboo cluster, the TK content in soil gradually increased.