Impact of effective micro-organisms (EM) on the yield, growth and bio-chemical properties of lettuce when applied to soil and leaves.

Background: In today's conditions, it is not possible to eliminate chemical inputs without reducing food production. Therefore, integrated methods that reduce the negative effects of chemical inputs are needed. One of the alternatives is the use of beneficial bacteria, which can both improve the yield and quality of vegetable crops and reduce the use of chemical fertilisers. This research was carried out to test the effects of a microbial fertiliser combined with inorganic fertiliser on the growth, biochemical properties and yield of lettuce and whether the use of chemical fertilisers could be reduced. Caipira curly lettuce variety was used as plant material. The microbial fertilizer used contains 7 different microorganisms and 2 different yeasts. The experiment consisted of eight treatments: Control (T), 100% Chemical Fertilisation (T), 50% Chemical Fertilisation + Microbial Fertilisation (T), 75% Chemical Fertilisation + Microbial Fertilization (T), 100% Chemical Fertilisation + Microbial Fertilisation (T), Microbial Fertilisation Alone (T), 50% Chemical Fertilisation + Microbial Fertilisation + Foliar Microbial Fertilisation (T), 75% Chemical Fertilisation + Microbial Fertilisation + Foliar Microbial Fertilisation (T).

Results: The results of the research were statistically evaluated using analysis of variance at a significance level of p < 0.05, and the means were compared using the LSD test. It was observed that the microbial fertiliser did not adversely effect on the growth characteristics of lettuce and even had an ameliorative effect. The highest root dry weights were obtained in the T, T, T and T treatments. T treatment had 7.8% and 5.5% more dry weight than T and T respectively. Biochemical properties were significantly affected by treatments and it was significant that T and T had similar results. Because chemical fertilizer dose was reduced by 50% in the T treatment. The chemical fertiliser dose was reduced by 50% in the T treatment. Microbial fertiliser treatments had no negative effect on lettuce colour formation and even greener lettuces were harvested from T, T, T and T treatments. The highest total yield was obtained from T (30638.89 kg ha) and T (30518.52 kg ha). In other words, when the recommended dose of chemical fertiliser was reduced by 25%, higher yields were obtained. The yields in T and T were 6.71% and 6.29% higher than in T, respectively. The marketable yield did not differ statistically between treatments except T and . Although there was no statistical difference, the highest numerical values belonged to the T (28907.41 kg ha) and T (28814.82 kg ha) treatments. In terms of marketable yield, T and T treatments gave 5.05% and 4.71% more than T, respectively.

Conclusions: It was determined that the microbial fertiliser used had no negative effect on the lettuce crop and even had an ameliorative effect. With the use of microbial fertiliser, both chemical fertilisation was reduced and higher yield and quality values were obtained from T3 and T treatments compared to chemical treatment alone (T). In addition, the ameliorative effects of the foliar application of microbial fertiliser were also noted in the T treatment. As a result, this study showed that the use of microbial fertiliser could increase yield and quality and save at least 25% of fertiliser.