Effects Of Planting Methods And Organic Fertilizer Application On The Growth And Quality Of Dandelion

Dandelion(Taraxacum mongolicum Hand.-Mazz)as a specialty wild vegetables of medicine and food homologous are more and more popular in the market due to containing rich nutrients and a variety of active ingredients with health benefits such as total flavonoids,caffeic acid,chlorogenic acid,et al.Wild dandelions grow scattered that was not benefited to harvesting centralized,and the yield can’t satisfy people’s demands,in addition to excessive collection causing destruction of ecological environment that urgently need us to conduct the artificial cultivation of dandelions.In view of the lack of artificial cultivation techniques and systematic researches on the accumulation of major qualities such as total flavonoids,caffeic acid,chlorogenic acid and Vc of dandelions,the research explored effects of different planting and organic fertilizer with different application amounts on the growth and quality of dandelions,anticipating to provide the theoretical foundation for dandelions cultivation with high quality and yield.The following conclusions were obtained through the research:(1)Comprehensive analysis of the yield and quality,under the ridge condition,the planting density of middle level(25000 plants/667 m~2,LM2 treatment)under was beneficial to the growth of dandelions,chlorogenic acid and caffeic acid accumulating in the body(leaves and roots),total flavonoids and Vc accumulating in leaves,while the low planting density level(15000 plants/667m~2,LM3 treatment)was more beneficial to the accumulation of total flavonoids and Vc accumulating in roots of dandelion.Leaf length,leaf width,number of functional leaves and yield per plant under LM2 treatment were all at the highest level,and above-ground dry weight,underground dry weight and yield per plant were significantly higher than the other treatments.The high planting density under the ridge condition(35000 plants/667 m~2,LM1 treatment)could acquire highest yield,followed by the middle planting density(LM2 treatment),LM1 was significantly higher than LM2 and other treatments.(2)The yield of dandelion and the accumulation of total flavonoids and Vc in the body(leaves and roots)could be significantly improved by applying 100-400 kg/667 m~2 commercial granular organic fertilizer or biochar-based organic fertilizer on the basis of fertilizer application and the appropriate amount of 100-300 kg/667 m~2 was contributed to the accumulation of chlorogenic acid and caffeic acid in the body(leaves and roots)of dandelion.The yield of dandelion and the accumulation of total flavonoids and Vc in the body(leaves and roots)were highest under the application of biochar-based organic fertilizer with 300 kg/667 m~2(TJ3),while TJ2 treatment with200 kg/667 m~2 could more improve the accumulation of chlorogenic acid and caffeic acid in the body(leaves and roots)of dandelion.(3)From 50 to 110 days after sowing,along with dandelions growing,regardless of planting density experiments of two tillage methods(ridge cropping and border cropping)or different level experiments of increasing application of two types of organic fertilizer(commercial granular and biochar-based organic fertilizer),the content of chlorogenic acid and caffeic acid in the body(leaves and roots)and total flavonoids in roots were elevated constantly,while the content of total flavonoids in leaves and Vc in the body(leaves and roots)showed first elevating,then decreasing trend.The accumulation of chlorogenic acid,caffeic acid,total flavonoids and Vc in dandelion leaves was higher than that in root within 50-110d after sowing.(4)From 50 to 110 days after sowing,along with dandelion growing,the content of chlorophyll,net photosynthetic rate,stomatal conductance,transpiration rates,three enzyme activities(POD、SOD、CAT)in leaves,soluble sugar and soluble protein content in the body(leaves and roots),soil urease activity,soil sucrase activity and soil phosphatase activity showed first elevating,then decreasing trends,on the contrary,the concentration of intercellular carbon dioxide showing first decreasing,then increasing trends,the content of soil nitrate nitrogen,soil available phosphorus,soil available potassium decreased continuously.(5)Enhanced photosynthesis,increased content of primary metabolites(soluble sugar and soluble protein)and higher levels of leaf antioxidant enzyme activities(POD,SOD,CAT),soil enzyme activities(urease,sucrase,phosphatase),soil nutrient content(nitrate nitrogen,available phosphorus,available potassium)were beneficial to improve the yield of dandelion and the accumulation of chlorogenic acid,caffeic acid,total flavonoids and Vc in the body(leaves and roots).(6)Several sets schemes of cultivation techniques for high quality and high yield of dandelion have been established.In order to increase reduced yield,ridge culture method should be adopted,the planting density should be 35000 plants/667 m~2,and 300 kg/667 m~2 of biochar-based organic fertilizer should be applied as the base fertilizer.In order to increase the content of chlorogenic acid and caffeic acid,ridge culture method should be adopted,the planting density should be 25000 plants/667 m~2,and 200 kg/667 m~2 biochar-based organic fertilizer should be applied as the base fertilizer.In order to increase the content of total flavonoids and Vc,ridge culture method should be adopted,300 kg/667 m~2 biochar-based organic fertilizer should be applied as the base fertilizer,in order to increase the content of total flavonoids and Vc in leaves,the planting density should be 25000 plants/667 m~2,and in order to increase the content of total flavonoids and Vc in roots,the planting density should be 15000 plants/667 m~2.