Vertical Transportation Characteristics of Nitrate Nitrogen Concentration in Nursery Alluvial Soil Under Different Fertilizer Treatments

According to the current status of the lower use efficiency of water and fertilizer on seedling cultivation in typical alluvial soil district of northern China,the seedling fostering base of fast-growing poplar in Changping district of Beijing was chosen as the research object in this paper.Field location monitoring experiments were carried out to study the vertical transport process of soil nitrate nitrogen in 0-100 cm soil profile under various fertilizer treatments.Monitoring results indicated that soil nitrate nitrogen content in the surface soil was higher than that of the other soil layers in 0-100 cm soil profile under three fertilizer treatments.Soil nitrate nitrogen content reduced gradually with the depth of soil profile and soil nitrate nitrogen content with treatment 3 was higher than those of treatment 1 and treatment 2.The average amount of nitrate nitrogen of 0-100 cm soil profile from high to low could be ordered as: Treatment 3 treatment 2 treatment 1.Among them,the average amount of nitrate nitrogen of 0-100 cm soil profile with treatment 3 was up to 307.856 kg/hm2.This showed that excessive fertilization led to nitrate nitrogen accumulation in the soil profile and it also increased the risk of nitrogen leaching loss by soil percolating water.Research results can reveal the mechanism of soil water and nitrate nitrogen vertical transport and leakage loss.This paper is helpful to provide powerful theoretical support and scientific guidance for making scientific fertilization scheme of seedlings,increasing fertilizer use efficiency and improving forest tending and management technology.