Opportunities and challenges in upcycling agri-food byproducts to generate insect manure (frass): A literature review.

A range of issues related to sustainability in the agrifood industry have spurred interest in mass production of insects as human food and animal feed alternatives. This rapidly evolving sector addresses several challenges, including the management of food waste or agrifood by-products and the production of alternative animal proteins demonstrating low environmental impacts that improve sector circularity. The mass production of insects on agrifood processing wastes or by-products represents an opportunity to address these challenges. While the production of insects offers prospects for sustainable protein production, a major side stream is the production of frass or larval excrement including uneaten feed and chitin-rich exuviae (derived from multiple larval moults). The production of each tonne of edible insects generates 2 to 4 tonnes of frass with an interesting potential in agriculture versus traditional organic amendments (compost, manure, biochar). This review aims to demonstrate the characteristics of frass, its common harvest and conditioning methods, its optimal application rates for planting crops, the mechanisms by which it can protect plants against biotic and abiotic stresses and demystify the risks and potential associated with its application in agriculture. The characteristics of frass are compared with those of conventional fertilizers or other. This report also compiles the Canadian, US and European regulatory frameworks as a novel plant fertilizer and aims to pave the way for future research necessary for its valorization in plant production.

Potential Efficiency of Grassy or Shrub Willow Buffer Strips against Nutrient Runoff from Soybean and Corn Fields in Southern Quebec, Canada.

Riparian buffer strips (RBS) are encouraged to control agricultural diffuse pollution. In Quebec Province, Canada, a policy promotes 3-m-wide RBS. Abiding farmers minimally maintain herbaceous vegetation, but nutrient retention efficiency could be improved with woody biomass. This work aimed to assess if fast-growing willows ( Seemen 'SX64') could reduce nutrient loads to a stream, in addition to yielding biomass. Triplicate treatments of two stem densities and a herbaceous control plot were monitored from 2011 to 2013 in a randomized block design on agricultural fields of the St. Lawrence Lowlands with sandy loam (Saint-Roch-de-l'Achigan [SR]) and organic-rich (Boisbriand [BB]) soils. Runoff, interstitial water, and water from the saturated zone were sampled 16 (SR) and 14 (BB) times to quantify nutrient buffering (NO, NH, P, and K). Sampling campaigns followed (i) snowmelt or ≥15-mm natural precipitation events after (ii) fertilization and (iii) glyphosate-based herbicide applications. Concentration reduction before and after the RBS was highest for nitrates (77-81% in runoff at BB, 92-98% at 35- to 70-cm depth at SR) just after fertilization, when edge-of-field concentrations peaked. Total P removal was observed in runoff after fertilization at SR, and K removal was punctually witnessed at BB. Riparian buffer strips were inefficient for NH and dissolved P removal, and RBS effluents exceeded aquatic life protection standards. plantations, irrespective of stem density, were not more efficient than herbaceous RBS. This shows that without fertilizer input reductions, narrow RBS are insufficient to protect streams from excess nutrients in corn ( L.) and soybean [ (L.) Merr.] crops.

Herbaceous or Salix miyabeana 'SX64' narrow buffer strips as a means to minimize glyphosate and aminomethylphosphonic acid leaching from row crop fields.

Glyphosate is the most widely used herbicide worldwide and is now frequently detected in surface waters of agricultural regions, notably in Quebec (Canada). Numerous legislations require vegetated riparian buffer strips (RBS) along agricultural streams. Quebec policy requires 3-meter-wide RBS. The present study evaluates the efficiency of narrow herbaceous and low- or high-density (33,333 and 55,556stumps/ha) willow, Salix miyabeana 'SX64', RBS, to minimize leaching of glyphosate and its main degradation product (AMPA) from agricultural fields to streams. Our study compared triplicate treatments of herbaceous and willow-planted RBS located in an organic-rich soil at Boisbriand (BB) and in a mineral soil at Saint-Roch-de-l'Achigan (SR). Runoff water was sampled with surface collectors and interstitial water was collected with 35cm or 70cm tension lysimeters. Potential efficiency of the RBS is reported as the percent reduction between edge-of-field and edge-of-stream concentrations in runoff and interstitial waters. Neither glyphosate nor AMPA in runoff were significantly intercepted by the RBS. After field herbicide spraying, glyphosate measured in SR surface soils (0-20cm) was on average 210µg·kg-1 dw (range from undetected to ≤317µg·kg-1 dw). Glyphosate was found to be persistent and its infiltration towards groundwater may be enhanced by the RBS. Contrary to runoff trends, soil glyphosate was significantly less concentrated on the SR edge-of-stream compared to edge-of-field (27-54% potential efficiency). The potential efficiency of herbaceous, low- and high-density willow RBS were undifferentiated.

A dynamic model for organic waste management in Quebec (D-MOWIQ) as a tool to review environmental, societal and economic perspectives of a waste management policy.

A dynamic systems model of organic waste management for the province of Quebec, Canada, was built. Six distinct modules taking into account social, economical and environmental issues and perspectives were included. Five scenarios were designed and tested to identify the potential consequences of different governmental and demographic combinations of decisions over time. Among these scenarios, one examines Quebec's organic waste management policy (2011-2015), while the other scenarios represent business as usual or emphasize ecology, economy or social benefits in the decision-making process. Model outputs suggest that the current governmental policy should yield favorable environmental benefits, energy production and waste valorization. The projections stemming from the current policy action plan approach the benefits gained by another scenario emphasizing the environmental aspects in the decision-making process. As expected, without the current policy and action plan in place, or business as usual, little improvements are expected in waste management compared to current trends, and strictly emphasizing economic imperatives does not favor sustainable organic waste management.

Glyphosate-Dependent Inhibition of Photosynthesis in Willow.

We studied the physiological mechanisms involved in the deleterious effects of a glyphosate-based herbicide (Factor® 540) on photosynthesis and related physiological processes of willow (Salix miyabeana cultivar SX64) plants. Sixty-day-old plants grown under greenhouse conditions were sprayed with different rates (0, 1.4, 2.1, and 2.8 kg a.e ha-1) of the commercial glyphosate formulated salt Factor® 540. Evaluations were performed at 0, 6, 24, 48, and 72 h after herbicide exposure. We established that the herbicide decreases chlorophyll, carotenoid and plastoquinone contents, and promotes changes in the photosynthetic apparatus leading to decreased photochemistry which results in hydrogen peroxide (H2O2) accumulation. H2O2 accumulation triggers proline production which can be associated with oxidative protection, NADP+ recovery and shikimate pathway stimulation. Ascorbate peroxidase and glutathione peroxidase appeared to be the main peroxidases involved in the H2O2 scavenging. In addition to promoting decreases of the activity of the antioxidant enzymes, the herbicide induced decreases in ascorbate pool. For the first time, a glyphosate-based herbicide mode of action interconnecting its effects on shikimate pathway, photosynthetic process and oxidative events in plants were presented.

Persistence of Escherichia coli in batch and continuous vermicomposting systems.

Vermicomposting is a biooxidation process in which epigeicearthworms act in synergy with microbial populations to degrade organic matter. Vermicomposting does not go through a thermophilic stage as required by North American legislations for pathogen eradication. We examined the survival of a Green Fluorescent Protein (GFP) labeled Escherichia coli MG1655 as a model for the survival of pathogenic bacteria in both small-scale batch and medium-scale continuously-operated systems to discern the influence of the earthworm Eisenia fetida, nutrient content and the indigenous vermicompost microbial community on pathogen abundance. In batch systems, the microbial community had the greatest influence on the rapid decline of E. coli populations, and the effect of earthworms was only visible in microbially-impoverishedvermicomposts. No significant earthworm density-dependent relationship was observed on E. coli survival under continuous operation. E. coli numbers decreased below the US EPA compost sanitation guidelines of 10(3)Colony Forming Units (CFU)/g (dry weight) within 18-21days for both the small-scale batch and medium-scale continuous systems, but it took up to 51days without earthworms and with an impoverished microbial community to reach the legal limit. Nutrient replenishment (i.e. organic carbon) provided by continuous feed input did not appear to extend E. coli survival. In fact, longer survival of E. coli was noticed in treatments where less total and labile sugars were available, suggesting that sugars may support potentially antagonist bacteria in the vermicompost. Total N, pH and humidity did not appear to affect E. coli survival. Several opportunistic human pathogens may be found in vermicompost, and their populations are likely kept in check by antagonists.

Alteration of plant physiology by glyphosate and its by-product aminomethylphosphonic acid: an overview.

It is generally claimed that glyphosate kills undesired plants by affecting the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) enzyme, disturbing the shikimate pathway. However, the mechanisms leading to plant death may also be related to secondary or indirect effects of glyphosate on plant physiology. Moreover, some plants can metabolize glyphosate to aminomethylphosphonic acid (AMPA) or be exposed to AMPA from different environmental matrices. AMPA is a recognized phytotoxin, and its co-occurrence with glyphosate could modify the effects of glyphosate on plant physiology. The present review provides an overall picture of alterations of plant physiology caused by environmental exposure to glyphosate and its metabolite AMPA, and summarizes their effects on several physiological processes. It particularly focuses on photosynthesis, from photochemical events to C assimilation and translocation, as well as oxidative stress. The effects of glyphosate and AMPA on several plant physiological processes have been linked, with the aim of better understanding their phytotoxicity and glyphosate herbicidal effects.