Effects Of Reducing Chemical Fertilizer And Increasing Biological Fertilizer On Growth And Rhizosphere Soil Environment Of Pigment Marigold

Pigment marigold continuous cropping obstacles and excessive application of chemical fertilizer led to the problem of yield and quality decline has become increasingly prominent,in order to promote the application of fertilizer reduction efficiency technology.In this study,the pigment marigold was taken as the object,and the reduction of chemical fertilizer was taken as the goal.In the seedling stage,water and urea were sprayed as controls.Randomized block experiment design was used to carry out different gradient foliar spraying treatments of two kinds of bacterial fertilizers,and the growth and transplanting survival of pigment marigold seedlings under different foliar fertilizer treatments were compared.After planting,drip irrigation cultivation mode was adopted.In the integrated management of water and fertilizer,the full application of chemical fertilizer was used as the control,and different gradient reduction of chemical fertilizer and increase of biological fertilizer were set to explore the effects of different reduction of chemical fertilizer and increase of biological fertilizer on the growth and rhizosphere soil environment of pigment marigold under the condition of water and fertilizer integration.The main results are as follows:（1）Compared with foliar spraying water,foliar spraying fertilizer significantly improved the survival rate of seedling transplanting.In terms of seedling growth,the overall performance of foliar spraying treatment with different dilutions of bacterial fertilizer 1 was particularly prominent,followed by the three groups of bacterial fertilizer 2,0.04%urea solution treatment also had a certain role in promoting the main root length and leaf length.In each treatment,the bacterial fertilizer 1 diluted 150 times foliar spraying treatment had better fertilizer effect.The crown width,stem diameter,leaf length,relative chlorophyll content（SPAD value）,and fresh weight of the whole plant were significantly increased by30.4%,33.1%,27.8%,48.5%,and 118.7%,respectively,compared with the foliar spraying water treatment.The survival rate of transplanting increased by 14.7%.（2）Under the condition of water and fertilizer integration,the plant height and stem diameter of pigment marigold in each treatment of reducing chemical fertilizer and increasing biological fertilizer increased rapidly after planting,and the growth slowed down after 70 d～80 d,and the crown width continued to expand rapidly.Among them,the treatment of half chemical fertilizer+half organic fertilizer+half bacterial fertilizer 1,full chemical fertilizer,organic fertilizer+bacterial fertilizer 1 had better plant growth.The number of the first,second,third and fourth branches was the most in the treatment of full chemical fertilizer,half chemical fertilizer+half organic fertilizer+half bacterial fertilizer 1,full chemical fertilizer,organic fertilizer+bacterial fertilizer 1.The three indexes of leaf growth（leaf number,leaf length and relative chlorophyll content）were more prominent in the treatment of organic fertilizer+bacterial fertilizer 1.The number of flowering branches at all levels was more in the treatment of half chemical fertilizer+half organic fertilizer+half bacterial fertilizer 1 and organic fertilizer+bacterial fertilizer 1.The peak value of flower diameter was the largest in the treatment of compound fertilizer 1 halved+half organic fertilizer+5/6 fertilizer bacterial fertilizer 2,followed by organic fertilizer+bacterial fertilizer 1.The fresh weight,dry weight and lutein content of flowers in each treatment were higher in the early stage of flowering,but decreased with the flowering process.The fresh weight of the full application of chemical fertilizer remained at a high level,but the dry weight and lutein were the opposite.The incidence rate and disease index of brown spot of full application fertilizer were significantly higher than those of other treatments.All the three treatments of bacterial fertilizer 1 achieved yield increase,and the treatment of organic fertilizer+bacterial fertilizer 1 had the best effect.The fresh flower yield and lutein yield increased by 18.8%and 53.5%,respectively.（3）Compared with before fertilization,the available potassium content in the rhizosphere soil of the pigment marigold in each treatment decreased significantly,and the organic matter increased significantly（except for the full application of chemical fertilizer）.Compared with the full application of chemical fertilizer,the application of biological fertilizer reduced the content of alkali-hydrolyzable nitrogen and the number of fungi,and increased the number of bacteria and catalase activity.Among them,the salt content in the soil treated with organic fertilizer+bacterial fertilizer 1 was only 0.503 g·kg^-1,and the invertase activity,the number of bacteria,the total number of microorganisms and the soil B/F value were higher,and the soil environment was better repaired.In summary,compared with the full application of chemical fertilizer,the application of bacterial fertilizer 1 diluted by 150 times for foliar spraying during the seedling stage of pigment marigold,the application of 600 kg·hm^-2 organic fertilizer before planting,and the application of 300 kg·hm^-2 bacterial fertilizer 1 as topdressing in the integration of drip irrigation and fertilizer after planting can better improve the soil environment,promote plant growth and development,reduce the occurrence of brown spot disease,and increase production.