Variations and Typical Impact Factors of Soil Nitrogen Content during the Vegetation Succession in Limestone Mountains

Abstract

In order to explore the variations and impact factors of soil nitrogen contents, 0-20 cm mineral soil under herb, shrub, Platycladus orientalis plantation of limestone mountains after restoration for 5 years and 10 years were collected and examined in Jinan, Shandong province. The results showed that there was different soil mineral nitrogen content under different vegetation during the natural succession and artificial restoration succession. Shrub community (14.35 mg/Kg) > herb community (12.73 mg/Kg); Platycladus orientalis plantation restored for 10 years (27.82 mg/Kg) > Platycladus orientalis plantation restored for 5 years (20.76 mg/Kg). NO3--N has highly significant positive correlations with soil organic carbon and total nitrogen content (r = 0.626, 0.564, p 4+-N has not significantly correlated with total nitrogen and organic carbon content (r = 0.218, 0.155). However, it has highly significant positive correlation with the NO3--N (r = 0.531, p 3--N and NH4+-N have highly significant negative correlations with soil pH (r = -0.657, -0.605, p < 0.01), respectively. But the correlation with the soil moisture was not significant (r = -0.181, 0.114). The research provided base information for the evaluation of restoration effects and restoration practice on the limestone mountains.