Improvement of plant nutrition by using bio fertilizers and biostimulants in organic lettuce growing and increasing yield and quality

The unconscious use of chemical fertilizers and pesticides in agricultural lands threatens the health of humans and other living things, and seriously damages natural resources. These practices are factors that limit the sustainable use of soils. For this reason, it is recommended to use natural organic products instead of synthetic products in order to increase productivity in agricultural production and improve the physical, chemical and biological structure of soils. The experiment has been carried out in greenhouse during the 2018-2019 and 2019-2020 winter growing seasons. Lettuce was grown in the greenhouse with organic fertilizers. Lettuce variety named Presidential of Syngenta company was used. As Top Applications; (1)Control group (2) Humic Acid (3) Seaweed (4) Amino acid group organic origin and certified fertilizers were applied at 10-day intervals. Control, Vermicompost, Mycorrhiza and Bacteria were applied as bottom fertilization. For the different applications in the experiment, 8 soil applications, 4 top applications, 3 replications and 13 plants (39 plants/application) in each replication were grown in a 2-factor factorial random blocks experimental design. The effects of the use of biofertilizers and biostimulants in organic farming on growth and development, yield and plant nutrients in lettuce plants were investigated. Plant height, number of leaves, fresh leaf weight, plant diameter, plant circumference, stem diameter, longest leaf length, dry weight percentage, SÇKM, Vitamin C, TEAM, chlorophyll (SPAD) and nitrate content were found to be significant in the experiment. Ph,,EC, the amount of substance was not affected by the applications. Looking at the results, marketable head weight has commercial significance for manufacturers. In the first year trial results, Vermicompost+Mycorrhiza/Humic acid (13.31kg/m2) and Mycorrhiza/Aminoacid (13.00.kg/m2) applications achieved the best results in terms of yield. In the 1st year trial results, 40%, 37% more yield increase was achieved, respectively, compared to the Control applications. In the 2nd year trial results,respectively,Bacteria/Aminoacid(15.38kg/m2),Vermicompost/Aminoacid(15.13kg/m2),Vermicompost+Mycorrhiza+Bacteria/Aminoacid(14.84kg/m2),Vermicompost+Mycorrhiza/HumicAcid(14.43.kg/m2) and Mycorrhiza/Aminoacid (14.21.kg/m2) applications have achieved the best results in terms of yield. In the 2nd year trial results, there was a 62%, 59%, 56%, 52% and 49% higher yield increase, respectively, compared to the Control applicationsThe leaf analysis, it was determined that lettuce plants provide increasing contributions in terms of N, P, Ca, Mg, Fe, Mn, Cu and Zn nutrition. Soil analyzes were also carried out before and after the experiment. At the end of the experiment, İSBA, soil pH, total lime percentage, soil organic matter, phosphorus potassium, calcium, magnesium, copper, zinc, manganese and iron contents were found to be statistically significant. EC and total salt contents were not affected. General results of the study: Lettuce production could be done in this way with the use of biofertilizers and biostimulants in organic lettuce cultivation. It is important to diversify and spread the use of organic origin fertilizers. This is very important for a clean environment and nature.It can be said that the application of solid and liquid vermicompost application as soil application can be an alternative to the application of chemical fertilizers or the rate of chemical fertilizer use can be reduced. It is important to diversify and spread the use of organic origin fertilizers. Key words: Lactuva Sativa Var. Longifolia,, organic farming, bio-fertiliser, bio-stimulant, yield, crop quality