Effects of soil, root mycorrhization, organic and phosphate fertilization, in organic lettuce production

Summary in the original language of the document

The influence of organic and phosphate fertilization, and root mycorrhization, in organic lettuce production, was assessed with factorial treatment combinations of: soil type (SOP – soil from organic and SCP – soil from conventional production) and organic fertilizer (0, 2 and 4 t ha-1) in the first trial; mycorrhizal inoculation (mycorrhized and non-mycorrhized plants) and Gafsa phosphate (0, 100 and 200 kg P2O5 ha-1) in the second. Lettuce yield decreased in the SCP with the application of increasing rates of organic fertilizer due to the very high electrical conductivity (50.1 dS m-1) and lack of maturation of this fertilizer. However, the harmful effects of the organic fertilizer were minimized in the SOP. The application of increasing rates of Gafsa phosphate increased lettuce yield and nutrient uptake. However, the mycorrhization did not increase lettuce yield and, for mycorrhized lettuces, yield did not increase with the highest rate of Gafsa phosphate application.