Inorganic nitrogen, phosphorus and potassium content of natural fertilizers for use in organic agriculture

Abstract

The indiscriminate use of fertilizers has contributed to soil salinity as well as to the depletion of soil mineral resources, causing farmers to depend on synthetic fertilizers. The objective of this study was to determine the content of plant-assimilable forms inorganic N, P, K in six organic fertilizers with potential use in organic agricultural production under principles of caring for the environment. Element determinations were performed with a HANNA spectrophotometer model HI83225-01. The fertilizer with the highest content of assimilable nitrogen was bat guano, followed by chicken manure and vermicompost Fertihum® In the case of phosphorus, the fertilizer that showed the highest amount was similarly bat guano followed by the chicken and cow manure. For the determination of potassium was bat guano that obtained the highest score along with the manure and vermicompost Fertihum®. The six organic fertilizers showed high values of electric conductivity (CE); chicken manure, bat guano and cow manure had the highest values. CE was signif icantly related to the nutrient content of organic fertilizers. The six organic fertilizers were within the values allowed by Mexican norms. The results generated in this study provide important information about the nutrient content of six organic fertilizers for their proper use.