WASTE-BASED ORGANIC FERTILIZERS FOR IMPROVED PLANT NUTRITION AND YIELD RESPONSES

Abstract

The increasing need to identify sustainable nutrient sources and reduce dependence on mineral fertilizers has intensified interest in organic materials derived from residual waste streams. This study evaluates several unconventional foliar fertilizers formulated from wheat bran, cornmeal, vinasse residue, bone glue and defatted sunflower meal, aiming to enhance plant nutrition. Chemical analyses of the concentrates revealed substantial macronutrient contents, with nitrogen ranging from 73.78 to 103.8 g/l, phosphorus from 14.48 to 18.09 g/l and potassium from 31.28 to 48.79 g/l, together with high levels of essential micronutrients such as manganese (545–1200 ppm) and iron (325–695 ppm). Field experiments conducted at the SCDA Podu Iloaiei on wheat and maize demonstrated significant yield responses across all tested variants. Wheat yields increased by 320–1040 kg/ha, while maize yields rose by 470–1240 kg/ha compared with foliar-unfertilized controls. Fertilizers based on wheat bran and cornmeal achieved the highest specific productivity, reaching up to 115.55 kg grain per liter in wheat and 82.66 kg per liter in maize. Additionally, nutrient-use efficiency improved by at least 20%, accompanied by a similar reduction in environmental pollution. These findings support the agronomic relevance and ecological benefits of integrating waste-derived fertilizers into sustainable crop management systems.