Utilisation of by-products of food industry for development of a liquid biodegradable mulch film to control weeds in row crop production

A circular bio-economy has been an ambition for national and international governments. Utilization of by-products form Norwegian food processing industry towards value-added applications and innovation of new products will contribute to the Norwegian bio-economy. Our research goal was to develop the sprayable mulch film formulations from the by-products of food processing industry to protect against row crops from weed growth. Agricultural, low value co-streams (non-food grade) like potato peel (BAMA) and feathers (NORILIA) were investigated as main raw materials for the production of sprayable mulch film formulations. The project consortium was composed of the research institutes NIBIO, Norner Research AS, Technical Research Centre of Finland (VTT) and University of Nebraska-Lincoln, USA and the industry partners Gartnerhallen SA, Bama Gruppen AS, Norilia AS, Tommen Gram Folie AS (including Tommen Gram Agri). Film formulation development and testing has been carried-out at Norner and at University of Nebrasca-Lincoln. Efficiency of different film formulations against weed growth on the soil was evaluated in pot trials in greenhouse and research fields at NIBIO, and farmers? fields (Tommen Gram Agri and NIBIO). The lab studies at Norner and University of Nebraska-Lincoln were performed by spraying the film formulations on glass and then removing the film from the glass after drying. Later, the films were tested for mechanical properties. Testing of the film formulations on the soil (sandy soil and clay soil) was involved counting the number of germinating seeds on mulch film sprayed soils in comparison to non-treated or control soil. Development of film formulations has involved evaluating the influence of various components, such as plasticizers (e.g., water, glycerol), cross-linking agents (e.g., citric acid, formaldehyde), film forming additives (e.g. polyvinyl alcohol) and fillers (e.g. clays, cellulose). A range of optimal film formulations with good film forming ability, where potato peel is a major component, was made. The film samples produced in the laboratory from optimal formulations were strong and flexible. Black coloured films were developed by inclusion of carbon black into the potato peel film formulations. Film formulation development from chicken feather hydrolysate was carried-out at University of Nebraska. Results from the field tests showed that all the formulations were possible to spray on to the soil and had good soil covering properties. Unfortunately, during the days and weeks after spraying, all the film formulations tended to soften in contact with water and did not provide the sufficient weed protection properties. For some of the formulations cracks were formed after watering and re-drying. A tendency of phytotoxicity on plants was seen with film formulations containing borax as a cross binding agent. Phytotoxic symptoms were not observed with other formulations. To develop film formulations with good resistance to water absorption and cracking, and good weed protection, more research and product development is needed. As the project intended to build competence in the utilization of by-products of food processing industry, the consortium has acquired good knowledge in developing spray-able film forming recipes from potato peel and chicken feathers. Film forming recipes have been successfully developed and tested in the laboratory. It was seen that the developed film formulations could be effectively applied on to the soil surface by spraying with agricultural sprayers. However, the film formulations developed in the project were not sufficiently effective in the field trials to inhibit weed germination. The developed films suffer from drawbacks such as cracking, getting soft in contact with water (due to hydrophilicity) and hence ineffective for weed control when tested on the soils. The consortium was not able to achieve optimal film formulations and specify optimal field types of their application within the period of the project. There is a need for further optimisation and development of the film formulations to have water resistant and strong weed inhibitor films.

The proposed project is intend to utilize the low-value side-streams of Norwegian food industry in developing a biodegradable sprayable mulch film to protect the row crops from germinating weeds. An important aspect of the proposed project in addition to adding value to bio-waste, developing a potential environmental friendly substitute for herbicides as well as petroleum-based polymer much films which are not environmental friendly. There has been a large amount of knowledge generated within the fiel d of biodegradable films from high-value biological components for other applications. The focus of the current project is to build knowledge and competence in development and characterisation of films based on products like polysaccharides (starch) from potato, gelatin and protein from animal or fish as well as chicken feathers. The challenges associated in the proposed project are to identify and evaluate suitable components of co-streams of food industry for biodegradable soil film (WP1), developing re cipe formulations for film and evaluating film for mulching applications (WP2). The suitability and ability of the developed films will be evaluated in agricultural field against germinating weeds (WP3). The food industry partners BAMA and Norilia will have benefit from this project according to utilisation of their low cost bio-waste streams. The environmental and labour efficient method for weed protection of crops will reduce production costs and herbicide use for the farmers represented by Gartnerha llen.