Effect of nitrogen and phosphorus on one year old Sophora flavescens

The experiment was conducted to study the effect of nitrogen(N) and phosphorus(P) on one year old Sophora flavescens. The four levels of N were set up as 0(control), 38, 75, 113 kg/hm2 and four levels of P(P2O5) were set up as 0(control), 23, 45, 90 kg/hm2 in a two factor randomized block design field test. Results showed that there were significant stimulated effects of nitrogen and phosphorus on growth of annual S. flavescens, and the interactions of N and P were significant. The bud numbers, plant fresh weight, root fresh weight, root dry weight, aerial part fresh weight and aerial part dry weight were highest when applied with high nitrogen fertilizer of 113 kg/hm2 and low phosphorus of 23 kg/hm2 P2O5. That was increased by 95.6％, 57％, 57.6％, 50.6％, 60.1％, 41.5％, compared with the control（P0.05）, respectively. Secondly, there was also significant difference when applied with lowmedium nitrogen of the 38 kg/hm2, 75 kg/hm2 N and high phosphorus of 45 kg/hm2 P2O5 than control. The ratio of root dry weight to root fresh weight and ratio of root dry weight to total plant dry weight were increased with increasing P2O5 under all levels of N applied. The root diameter and the xylem diameter were the highest with 113 kg/hm2 N and 23 kg/hm2 P2O5, that was increased by 24.9％,20.2％compared with the control（P0.05）. Nitrogen and phosphorus had not significant positive effect on phloem thickness. The leaflet numbers of plant, leaflet area and plant area were highest by applying 113 kg/hm2 N and 23 kg/hm2 P2O5, that was increased by37.6％,40.2％,83.9％compared with the control（P0.05）, respectively. It was considered that the combination of 113 kg/hm2 N and 23 kg/hm2 P2O5, and the application of 38 kg/hm2, 75 kg/hm2 N and 45 kg/hm2 P2O5 could get higher yield of S.flavescens seedling, they were appropriate applications for the growth of one year old S. flavescens.