Nutrient Chemical Forms, Storage Effects and Phyto-Toxicity of Organic Fertilizers to Selected Cereal and Legume Crops

The study aims to determine the nutrient chemical forms, storage effects, and phytotoxicity of fertilizers made from nutrient-rich materials and municipal organic waste in order to control the impact of farming practices on the ecology. Laboratory-scale experiments were conducted at 3-month intervals over a period of 15 months to determine the binding forms of phosphate and nitrogen, and other quality parameters of fertilizers. The germination index (GI) method was used to assess the phytotoxicity of the fertilizers at three different rates of applications- 2.0, 2.5, and 3.0 tonnes ha-1 on maize (Zea mays L.) and soybean (Glycine max). It was found that animal-based and organic mixture fertilizers had the highest levels of ammoniacal nitrogen and nitrate: NH4+-N (0.3 +/- 0.0%) and NO3-N (0.7 +/- 0.0%), respectively. Rock-based fertilizer had the highest levels of water-soluble (7.0 +/- 0.0%) and neutral ammonium citrate soluble (4.1 +/- 0.0%) forms of nitrogen and potassium, which are readily available to crops. The GI values of the fertilizers were generally above the safety standard of >= 80, except for synthetic fertilizer when applied on soybeans at 3.0 tonnes ha-1 (74.2). While organic fertilizers were deemed safe for application on the test crops, it is advised to avoid storing the fertilizers for an extended period of time due to potential chemical and biological changes that might affect the biome.