Nitrogen fertilizer equivalence of black soldier fly frass fertilizer and synchrony of nitrogen mineralization for maize production

Abstract

The use of black soldier fly frass fertilizer (BSFFF) is being promoted globally. However,information on nitrogen (N) fertilizer equivalence (NFE) value and synchrony of N mineralization forcrop production remains largely unknown. Comparative studies between BSFFF and commercialorganic fertilizer (SAFI) were undertaken under field conditions to determine synchrony of N releasefor maize uptake. The BSFFF, SAFI, and urea fertilizers were applied at the rates of 0, 30, 60,and 100 kg N ha−1. The yield data from urea treated plots were used to determine the NFE of bothorganic inputs. Results showed that maize from BSFFF treated plots had higher N uptake than thatfrom SAFI treated plots. High N immobilization was observed throughout the active growth stagesof maize grown in soil amended with BSFFF, whereas soil treated with SAFI achieved net N release atthe silking stage. Up to three times higher negative N fluxes were observed in SAFI amended soils ascompared with BSFFF treated plots at the tasseling stage. The BSFFF applied at 30 and 60 kg N ha−1achieved significantly higher NFE than all SAFI treatments. Our findings revealed that BSFFF is apromising and sustainable alternative to SAFI or urea for enhanced maize production