Exploring Black Soldier Fly Frass as Novel Fertilizer for Improved Growth, Yield, and Nitrogen Use Efficiency of Maize Under Field Conditions

Abstract

Black soldier fly frass fertilizer (BSFFF) is increasingly gaining momentum worldwide as organic fertilizer. However, research on its performance on crop production remains largely unknown. Here, we evaluate the comparative performance of BSFFF and commercial organic fertilizer (SAFI) on maize (H513) production. Both fertilizers were applied at the rates of 0, 2.5, 5, and 7.5 t ha-1 , and 0, 30, 60, and 100 kg nitrogen (N) ha-1. Mineral fertilizer (urea) was also applied at 0, 30, 60 and 100 kg N ha-1 to establish the N fertilizer equivalence (NFE) of the organic fertilizers. Maize grown in plots treated with BSFFF had the tallest plants and highest chlorophyll concentrations. Plots treated with 7.5 t ha-1 of BSFFF had 14% higher grain yields than plots treated with a similar rate of SAFI. There was a 27% and 7% increase in grain yields in plots treated with 100 kg N ha-1 of BSFFF compared to those treated with equivalent rates of SAFI and urea fertilizers, respectively. Application of BSFFF at 7.5 t ha-1 significantly increased N uptake by up to 23% compared to the equivalent rate of SAFI. Likewise, application of BSFFF at 100 kg N ha-1 increased maize N uptake by 76% and 29% compared to SAFI and urea, respectively. Maize treated with BSFFF at 2.5 t ha-1 and 30 kg N ha-1 had higher nitrogen recovery efficiencies compared to equivalent rates of SAFI. The agronomic N use efficiency (AE N) of maize treated with 2.5 t ha-1 of BSFFF was 2.4 times higher than the value achieved using an equivalent rate of SAFI. Also, the AE N of maize grown using 30 kg N ha-1 was 27% and 116% higher than the values obtained using equivalent rates of SAFI and urea fertilizers, respectively. The NFE of BSFFF (108%) was 2.5 times higher than that of SAFI. Application rates of 2.5 t ha-1 and 30 kg N ha-1 of BSFFF were found to be effective in improving maize yield, while double rates of SAFI were required. Our findings demonstrate that BSFFF is a promising and sustainable alternative to commercial fertilizers for increased maize production.

Suitability of Black Soldier Fly Frass as Soil Amendment and Implication for Organic Waste Hygienization

“…While total C contents were similar in all types of frass, FV frass showed a C:N-ratio of 26.6, compared to 18.5 and 18.2 in CF frass and GC frass, respectively. Similar C:N ratios as found in CF and GC frass have been reported by other studies that used brewery spent grains as larval substrate [11,16]. A C:N-ratio > 20 bears the risk of soil N immobilization, which may favor plants with a more efficient N exploitation attributed to their rhizobiome [46,52].…”

“…Recent observations at field-scale by Beesigamukama et al showed that even at lower application rates of 30 kg N ha −1 , BSFF exceeded the performance of mineral N fertilizer in terms of grain yield and nitrogen fertilizer replacement values when applied at the same rates [16]. Compared with commercial fertilizers, nitrogen recovery rates and nitrogen use efficiency of plants have been shown to be improved when amended with BSFF [11]. Additionally, the higher P concentrations in the frass could facilitate N accumulation in plants by improving N uptake, as P plays an important role in energy transfer [62,63].…”

“…BSFL could also play a valuable role for smaller decentralized waste management systems operated by e.g., hobbyists or farmers in areas where the fly occurs naturally [7][8][9]. Additionally, the exploitation of BSF and its by-products could create an affordable opportunity for revenue generation by entrepreneurs and smallholder farmers in low-income countries [9][10][11]. The main by-product in the bioconversion of wastes into high quality protein for animal feedstuff is summarized as 'frass'.…”

“…It is an inevitable side-stream during the mass-rearing of insects that can add up to 75% of the fed substrate [12] and is often merchandised as a fertilizing product. In recent years, an increasing number of studies started focusing on meaningful applications of insect frass [9,[13][14][15], and the first large-scale field studies provided promising perspectives for its application in agriculture, especially in terms of plant nutrient availability [10,11,16].…”

Conversion of Spent Coffee and Donuts by Black Soldier Fly (Hermetia illucens) Larvae into Potential Resources for Animal and Plant Farming

“…Perhaps to a greater extent than BSFL, the type of food provided will have a large impact on the frass composition [ 23 ]. For example, frass obtained from BSFL fed on distillers’ dried grains with solubles could be used as a viable fish ingredient [ 24 ], while those fed vegetable, fruits and other plants are more appropriately used as an organic fertilizer that can provide similar benefits to plant growth as synthetic fertilizers [ 25 , 26 , 27 , 28 ].…”