Study On Balanced Fertilization And Efficient Cultivation Of Cut Chrysanthemum Under Drip Integration

Chrysanthemum is one of the four major cut flowers in the world,with high ornamental and economic value.In the production of cut flowers,random application of fertilizers is very common.The random application of fertilizers not only causes waste of fertilizers and aggravation of plant diseases and insect pests,but also causes soil and water resources pollution,which leads to a decline in the yield,quality of cut flowers,and brings great economic losses to farmers and production enterprises.The rational application of nitrogen,phosphorus,and potassium and the combined application of plant rhizosphere growth promoting bacteria（PGPR）can not only improve the growth of cut flowers,but also significantly improve its quality and economic benefits.Therefore,proving the high-yield,high-quality,optimum nitrogen,phosphorus,and potassium application rates of chrysanthemum and the optimal PGPR growth-promoting combination has important guiding significance for improving the production efficiency of cut chrysanthemum and high-efficiency cultivation techniques.In this paper,cut chrysanthemum‘Qinhuai yulian’was used as the experimental material,combined with Bacillus velezensis and Pseudomonas aeruginosa,to explore its growth-promoting effect on the growth of cut chrysanthemum‘Qinhuai yulian’,as well as the nutrient content of the cultivation substrate and plant while exploring the impact of fertilization on soil microbial diversity.The main results are as follows:1.Three-factor orthogonal test was used to screen the dosages of nitrogen,phosphorus and potassium under drip irrigation conditions.Combined with the growth indexes at seedling stage,the dosage levels of nitrogen,phosphorus and potassium with significant differences were obtained.On this basis,the whole growth period test was carried out.Using the techniques of drip irrigation,water and fertilizer integration and substrate cultivation,and the method of comprehensive physiological characters and nutrient indexes,it was preliminarily determined that N₂P₁K₂and N₃P₂K₁treatments were the most suitable levels of nitrogen,phosphorus and potassium for cut chrysanthemum‘Qinhuai yulian’under soil and substrate culture.2.Leaf is the nutrient absorption and accumulation center of chrysanthemum.Nutrients are transferred from roots,stems and leaves to flowers in the later growth and development stage,and the nutrient absorption and accumulation amount of N₃P₂K₁treatment is higher.Under soil cultivation condition,N₃P₂K₁treatment had the highest nitrogen uptake efficiency,which was 38.17%.And the total potassium content>total nitrogen content>total phosphorus content.The balanced application of N,P and K can improve the content of acid,alkali and salt in the substrate,and have a great influence on the content of ammonium nitrogen.The N₃P₂K₁treatment can improve the soil fertility.After 90 days of transplanting,the content of ammonium nitrogen treated by N₃P₂K₁was 976.43 mg·kg^-1,which was 3.8 times of that treated by CK.3.Field experiments explored the effects of different amounts of nitrogen,phosphorus,and potassium on the growth of cut chrysanthemum‘Qinhuai yulian’and the diversity of soil microbial communities under soil conditions.According to different application doses of NPK,there are significant differences in soil bacterial and fungal communities.N₃P₂K₁resulted in significantly higher bacterial OTU abundance and relatively lower fungal OTU abundance,and its unique OTU number is284.And the nitrogen metabolism pathway observed with N₃P₂K₁treatment was predicted to have a positive nitrogen cycle function.This study shows that N₃P₂K₁plays a key role in enhancing the rhizosphere microbial diversity in the chrysanthemum cultivation soil.4.Using the method of molecular biology identification,it is determined that the strain X is Bacillus velezensis and the strain T is Pseudomonas aeruginosa.On the basis of the preliminary experiment,the most suitable combination for promoting growth in the whole growth period was determined as N₃P₂K₁+X+T by combining the application of strain X and T,soil rooting conditioner and the method of comprehensive physiological characteristics and nutrient indexes.Its plant height can reach 92.16 cm and flower diameter can reach 140.25 mm.In summary,this study suggests that N₃P₂K₁processing is cut-flower chrysanthemum‘Qinhuai yulian’balanced NPK fertilization optimum levels,in promoting the growth of chrysanthemum,quality formation and accumulation of nutrient absorption has good effect,at the same time,combining the Bacillus velezensis and Pseudomonas aeruginosa can better ensure the quality of chrysanthemum,improve soil nutrient conditions,improve soil fertility,To promote nutrient absorption,thus providing theoretical basis and scientific guidance for high quality and high yield of single-headed cut chrysanthemum and green and sustainable cultivation techniques.