| The experimental material for this study was the annual seedlings of Cassia nodosa.The experimental design method was orthogonal experimental design.Experiments of N,P and K fertilization on Cassia nodosa seedlings were conducted.The effects of N,P and K fertilization on growth and physiology and soil properties of Cassia nodosa seedlings were studied.Based on the results of various indicators,the growth and physiology and soil properties of seedlings under fertilization treatment were analyzed.Finding the optimum proportion of fertilizing of Cassia nodosa seedlings.Providing a reference for cultivating high-quality seedlings of Cassia nodosa.This is the result of this experiment.1.NPK fertilization could promote the growth of Cassia nodosa seedlings in varying degrees.The growth indexes of Cassia nodosa seedlings were different under NPK fertilization.Among the growth indicators,the optimal group of treatment for increment of plant height,dry weight of aboveground,dry weight of underground and dry weight of total biomass was group S6,N2P3K1.The optimal group of treatment for diameter increment and primary lateral roots(>5cm)was group S5,N2P2K3.In a certain concentration of fertilization,the growth index of plant height,ground diameter,biomass,and primary lateral roots(>5 cm)of Cassia nodosa seedlings would increase with the increase of fertilizer application amount.If the concentration of fertilizer was higher than this concentration,the growth rate of plant would decrease.N,P and K fertilization had significant effects on the growth of Cassia nodosa seedlings.In a certain concentration,NPK fertilization had a positive effect on the growth of Cassia nodosa seedlings.Nitrogen had the greatest impact on growth indicators of seedlings.2.N,P and K fertilization had effects on chlorophyll content,soluble sugar content,soluble protein content and superoxide dismutase activity of seedlings.The third level of potassium had the greatest effect on soluble protein content and soluble sugar content.The third level of nitrogen had the greatest effect on chlorophyll content and SOD activity.Nitrogen had the greatest influence on N content and P content of leaf.Phosphorus had the greatest impact on K content of leaf.This showed that nitrogen,phosphorus and potassium affected each other in the nutrient of the leaves.The influence of phosphorus on the nutrient index of the leaf was P3>P2>P1.The second level of nitrogen and phosphorus had a greater impact on nutrient of leaf.3.After NPK fertilization,the soil full nutrients,soil available nutrients and soil enzyme activities were increased.N and P were the most important factors that affected soil properties.The available soil nutrient in the treatment group was greater than that in the control group.This showed that after the seedlings absorbed the soil's available nutrients,NPK fertilization could supplement the soil's available nutrients.This could make the plant grow well.The second level of nitrogen had a positive effect on the soil properties of the seedlings.4.From the correlation analysis,the indicators of various properties of Cassia nodosa seedlings basically became a significant positive correlation.There was a significant correlation among growth indicators,leaf nutrient,and soil properties.Physiological indicators,growth indicators,leaf nutrient,and soil properties were basically positively correlated.Under the evaluation of quality of seedlings,the group of the best quality of seedlings was N2P2K3.In the fuzzy comprehensive evaluation analysis of membership functions,the group of the best treatment was also N2P2K3.The two results were the same.The result was that the most suitable ratio of fertilization for seedlings of Cassia nodosa was urea:superphosphate:potassium chloride = 1.6 g/strain:1.0 g/strain:0.9 g/strain. |
PDF Full Text Request