Anaerobic Digestion of Three Microalgae Biomasses and Assessment of Digestates as Biofertilizer for Plant Growth

Anaerobic digestion of organic wastes produces solid residues known as digestates, which have potential as a fertilizer and soil amendment. The majority of research on digestate focuses on their fertilizer value. However, there is a lack of information about additional effects they may have on plant growth, both positive and negative. Understanding the effects of digestate on plant growth is essential to optimizing their use in agriculture and helping close the loop of material and energy balances. This greenhouse study evaluated the effects of two different digestates, a food waste digestate (FWD) and a lignocellulosic biomass digestate (LBD); a liquid fertilizer; and various combinations of fertilizer and digestates on plant growth, nutrient uptake and nutrient use efficiency (NUE) of Brassica juncea (kai choy) plants. It also evaluated potential negative attributes of the digestates, including salinity and possible biohazards. Combinations of LBD and fertilizer performed as well or slightly better than the fertilizer control for most parameters, including aboveground biomass and root length. These same combinations had significantly higher nitrogen use efficiency than the fertilizer control. Inhibitory effects were observed in 100% LBD treatments, likely due to the high electrical conductivity of the media from digestate application. Based on this research, LBD could partially replace mineral fertilizers for kai choy at up to 50% of the target nitrogen rate and may lead to increased plant growth beyond mineral fertilizers. FWD could replace up to 100% of the target nitrogen application, without causing significant negative effects on plant growth. Increasing the use of digestates in agriculture will provide additional incentives for the anaerobic digestion process, as it produces two valuable products: biogas for energy and digestate for fertilizer.

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Comparative fertilizer properties of digestates from mesophilic and thermophilic anaerobic digestion of dairy manure: focusing on plant growth promoting bacteria (PGPB) and environmental risk

Journal of Material Cycles and Waste Management ◽

10.1007/s10163-018-0708-7 ◽

2018 ◽

Vol 20 (3) ◽

pp. 1448-1457 ◽

Cited By ~ 13

Author(s):

Guangdou Qi ◽

Zhifei Pan ◽

Yasuha Sugawa ◽

Fetra J. Andriamanohiarisoamanana ◽

Takaki Yamashiro ◽

...

Keyword(s):

Anaerobic Digestion ◽

Plant Growth ◽

Environmental Risk ◽

Dairy Manure ◽

Plant Growth Promoting Bacteria ◽

Thermophilic Anaerobic Digestion ◽

Plant Growth Promoting ◽

Growth Promoting

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The survival of pathogenic bacteria and plant growth promoting bacteria during mesophilic anaerobic digestion in full‐scale biogas plants

Animal Science Journal ◽

10.1111/asj.13137 ◽

2018 ◽

Vol 90 (2) ◽

pp. 297-303 ◽

Cited By ~ 4

Author(s):

Guangdou Qi ◽

Zhifei Pan ◽

Yuki Yamamoto ◽

Fetra Jules Andriamanohiarisoamanana ◽

Takaki Yamashiro ◽

...

Keyword(s):

Anaerobic Digestion ◽

Plant Growth ◽

Pathogenic Bacteria ◽

Full Scale ◽

Plant Growth Promoting Bacteria ◽

Plant Growth Promoting ◽

Biogas Plants ◽

Growth Promoting

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Processing methods of organic liquid fertilizers affect nutrient availability and yield of greenhouse grown parsley

Renewable Agriculture and Food Systems ◽

10.1017/s1742170517000771 ◽

2018 ◽

Vol 34 (5) ◽

pp. 430-438 ◽

Cited By ~ 1

Author(s):

Bhaniswor Pokhrel ◽

Jorn Nygaard Sorensen ◽

Henrik Bjarne Moller ◽

Karen Koefoed Petersen

Keyword(s):

Anaerobic Digestion ◽

Plant Growth ◽

Root Zone ◽

Organic Liquid ◽

Red Clover ◽

Organic Fertilizers ◽

Chicken Manure ◽

Nutrient Concentrations ◽

Limiting Factor ◽

Liquid Fertilizer

AbstractThe demand for organic foods is increasing globally, but a key limiting factor to the production of organic greenhouse produce is the lack of certified liquid fertilizers. In this experiment, four organic fertilizers were produced using either acidic extraction, anaerobic digestion or both of ensiled biomass of organic red clover and white mustard. The resulting fertilizers were applied to greenhouse-grown parsley either alone, or in combination with nitrogen (N)-enriched water produced by flushing acidic water with ammonia, to determine their effect on plant growth and the nutrient concentrations of parsley. Six combinations of fertilizer treatments were included in the greenhouse experiment. Three treatments received either fertilizers derived from acidic extraction, anaerobic digestion or both and three treatments received fertilizers derived from acidic extraction combined with N-enriched water. Conventional inorganic liquid fertilizer, chicken manure extract and no liquid fertilizer (only water) were added as control treatments. A higher N-min (ammonium and nitrate) to potassium (K) ratio was found in fertilizers after anaerobic digestion compared to acidic extraction. All organic fertigation treatments resulted in high pH, high K and chloride concentrations and high NH4/NO3 ratios in the root zone. In addition, high electrical conductivity (EC), P, K and Mg concentrations were found when only acidic extracted fertilizers were applied. Application of plant-based organic fertilizers without amending with N-enriched water resulted in biomass yields that were 21–26% lower than the inorganic fertigation control. However, fertigation with chicken manure extract, or a combination of fertilizer derived from acidic extraction and N-enriched water, resulted in similar plant growth as inorganic fertilizer. The lower yield from fertilizer derived from acidic extraction was due to elevated EC levels in the growing medium. Our results suggest that yield of greenhouse-grown parsley using either organic fertilizers combined with N-enriched water or chicken manure extract is similar to conventional fertilizer.

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Mechanisms of ethylene biosynthesis and response in plants

Essays in Biochemistry ◽

10.1042/bse0580061 ◽

2015 ◽

Vol 58 ◽

pp. 61-70 ◽

Cited By ~ 11

Author(s):

Paul B. Larsen

Keyword(s):

Plant Growth ◽

Growth And Development ◽

Ethylene Biosynthesis ◽

Unsaturated Hydrocarbon ◽

Flower Senescence ◽

Detailed Knowledge ◽

Plant Growth And Development ◽

Step Process ◽

Ethylene Response ◽

Ethylene Signalling

Ethylene is the simplest unsaturated hydrocarbon, yet it has profound effects on plant growth and development, including many agriculturally important phenomena. Analysis of the mechanisms underlying ethylene biosynthesis and signalling have resulted in the elucidation of multistep mechanisms which at first glance appear simple, but in fact represent several levels of control to tightly regulate the level of production and response. Ethylene biosynthesis represents a two-step process that is regulated at both the transcriptional and post-translational levels, thus enabling plants to control the amount of ethylene produced with regard to promotion of responses such as climacteric flower senescence and fruit ripening. Ethylene production subsequently results in activation of the ethylene response, as ethylene accumulation will trigger the ethylene signalling pathway to activate ethylene-dependent transcription for promotion of the response and for resetting the pathway. A more detailed knowledge of the mechanisms underlying biosynthesis and the ethylene response will ultimately enable new approaches to be developed for control of the initiation and progression of ethylene-dependent developmental processes, many of which are of horticultural significance.

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