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

Abstract

The 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.

Efficiency of a novel “Food to waste to food” system including anaerobic digestion of food waste and cultivation of vegetables on digestate in a bubble-insulated greenhouse

“…One approach is to combine liquid organic suspensions with mineral nutrients to produce a balanced solution (dos Santos et al, 2013;Pokhrel et al, 2019;Wang et al, 2019). Some also investigate the performance of inorganic, but waste-derived, compounds, such as ammonium compounds from stripping/scrubbing processes and struvite from wastewaters (Sigurnjak, Ivona et al, 2016;Sigurnjak, I. et al, 2019).…”

Organic fertigation system in saline‐sodic soils: A new paradigm for the restoration of soil health

“…Pokhrel et al. (2019) reported a similar response of parsley [ Petroselinum crispum (Mill.) Nyman ex A.W.…”

“…The above discussions indicate that the combined treatments of organic manures, biofertilizers, and liquid organic manures improve biochemical compounds like carbohydrate, soluble sugar, starch, amino acids, and protein in the hybrid seeds of maize and other corns and sequester organic C in soils (Aslani & Souri, 2018; Carr et al., 2020; de Lima et al., 2020; Pokhrel et al., 2019). In addition, phosphatase, dehydrogenase, α‐amylase, glutamine synthetase, gibberellins, and abscisic acid activities increase.…”

“…The global market for organic food and beverages is about US$200 billion and is increasing at a rate of 16% per annum under organic fields. Presently organic foods are in high demand due to human health benefits, and producers need additional liquid organic fertilizers to meet organic market demands (Pokhrel et al., 2019).…”

Expression of N‐cycling genes of root microbiomes provides insights for sustaining oilseed crop production

“…4 and Tables S3 and S4). This may indicate that nitrification and denitrification in the soil were negatively associated with yield but positively associated with oilseed plant biomass because the conversion of NH 4 + to NO 3 − (nitrification) can reduce the availability of nitrogen to the plants and affect yield (Pokhrel et al ., 2019). Plant ammonium uptake is passive and does not require energy for the plants (Wang et al ., 1993) while plant nitrate uptake is an active process that requires energy (Haynes and Goh, 1978), and nitrate needs to be transformed back to ammonia before entering in the protein metabolism, resulting in supplementary energy expenses for plants using nitrate (Moreau et al ., 2019).…”