CARMEN SIRBU, TRAIAN CIOROIANU, NICOLETA MARIN, BOGDAN RUJOI LIQUID FERTILIZERS WITH ORGANIC SUBSTANCES - AGROCHEMICAL EFFECTS OBTAINED BY APPLICATION The fertilization methods and technologies rapid development using extra-radicular fertilizers and liquid fertilizers with or without organic substances is due to both their controlled application possibilities depending on the vegetation phases, crop, agrochemical background, and nutrition deficiencies and efficiency increase of the indices regarding the fertilization costs -economical results The best agricultural practices application, compatible with the new climatic conditions, can actively contribute to environment preservation and protection at the same time with crops constancy and production capability securement. Fertilizers application with solid or liquid humic substances ensures all the needed compounds and minerals for creating and maintaining a fertile soil. At the same time their efficiency depends on multiple factors that include temperature, humidity, previous agricultural practices, soil physical and chemical characteristics, pesticides or other polluting products residues, microbial population present in the soil and the activity it develops. The humic compounds mediate pesticides and toxins degradation and contaminated soils biological reparation rests on humus help in microbial degradation. The paper presents the results obtained by radicular application of two experimental NPK type fertilizers with humic substances at the sunflower crop in vegetation pots. The fertilizers have been physically and chemically characterized and agrochemically tested as compared to an unfertilized control and two fertilized controls with a complex 15.15.15 NPK fertilizer in 120 and 180 kg/ha doses. The experimental fertilizers were applied in portions upon crops sowing and during vegetation in three 200, 300, respectively 400 liters fertilizer/ha and ensured significant gains as compared to the controls.The extracted humic substances and the fertilizers were physically and chemically characterized as well as through differential thermal gravimetric analysis and FT-IR spectrometry. The vegetal material and the sunflower seeds were analyzed regarding the nitrogen phosphorus, potassium, calcium, magnesium, zinc, copper, iron, and manganese contents.
Keywords: organic mineral fertilizers, organic fertilizers, humic substances