Articles
Analysis of nutrient composition of liquid organic fertilizer for optimizing fertilizer dosing for hydroponic crop production
Article number
1428_3
Pages
19 – 26
Language
English
Abstract
Environmental awareness and economic benefits are encouraging growers in controlled environment agriculture (CEA) to adopt organic growing media and fertilizers.
However, few studies have been conducted regarding the application of liquid organic fertilizer for hydroponic crop cultivation.
The current study aimed to survey and select commercial liquid organic fertilizers and analyze their nutrient composition for optimizing nutrient dosing.
First, liquid organic fertilizers certified by the organic materials review institute (OMRI) were identified based on the listed nutrient profile and reports of other studies.
The selected liquid organic fertilizers (i.e., Grow Big, Espartan, Caos, Bombardier, Tomato & Veg formula, Pre-Empt) were diluted according to the manufacturer’s recommended rate.
Physical changes, such as biofilm accumulation or sedimentation, and chemical composition were checked at two-week intervals after preparation.
Synthetic fertilizers for hydroponic substrate-based and liquid cultures were considered as the control.
The identified nutrient composition was compared to the standard synthetic fertilizer recipe to assess the nutrient dosing for organic leafy greens and high-wire crop production.
The concentration (ppm) of macronutrients (N, P, K, Ca, Mg, S), total nitrogen (TN), and organic carbon (OC) of each sample were measured.
After two weeks of dilution, biofilm accumulation, sedimentation, and fermentation were observed in some liquid organic fertilizers, which might be solved by sanitization or aeration.
The electrical conductivity (EC) of the diluted fertilizers was within the range of 1.5 to 2.0 mS cm‑1, except for Espartan (0.69) and Bombardier (0.88). The pH was between 5.3 to 6.8, except for Caos (7.3). The total nitrogen concentration was above 100 ppm in Grow Big, Bombardier, and Pre-Empt and below in Espartan, Caos, and Tomato & Veg formula.
A comparison of nutrient components between synthetic and organic fertilizers indicated that no liquid organic fertilizer matched the exact ratio of nutrient ions in standard synthetic fertilizer recipes.
However, Grow Big, Espartan, and Pre-Empt had the closest composition to synthetic fertilizer used for leafy greens and high-wire crop production.
This research will help growers select fertilizers and prepare target concentrations of liquid organic fertilizers from the tank-mixing stage to dosing.
However, few studies have been conducted regarding the application of liquid organic fertilizer for hydroponic crop cultivation.
The current study aimed to survey and select commercial liquid organic fertilizers and analyze their nutrient composition for optimizing nutrient dosing.
First, liquid organic fertilizers certified by the organic materials review institute (OMRI) were identified based on the listed nutrient profile and reports of other studies.
The selected liquid organic fertilizers (i.e., Grow Big, Espartan, Caos, Bombardier, Tomato & Veg formula, Pre-Empt) were diluted according to the manufacturer’s recommended rate.
Physical changes, such as biofilm accumulation or sedimentation, and chemical composition were checked at two-week intervals after preparation.
Synthetic fertilizers for hydroponic substrate-based and liquid cultures were considered as the control.
The identified nutrient composition was compared to the standard synthetic fertilizer recipe to assess the nutrient dosing for organic leafy greens and high-wire crop production.
The concentration (ppm) of macronutrients (N, P, K, Ca, Mg, S), total nitrogen (TN), and organic carbon (OC) of each sample were measured.
After two weeks of dilution, biofilm accumulation, sedimentation, and fermentation were observed in some liquid organic fertilizers, which might be solved by sanitization or aeration.
The electrical conductivity (EC) of the diluted fertilizers was within the range of 1.5 to 2.0 mS cm‑1, except for Espartan (0.69) and Bombardier (0.88). The pH was between 5.3 to 6.8, except for Caos (7.3). The total nitrogen concentration was above 100 ppm in Grow Big, Bombardier, and Pre-Empt and below in Espartan, Caos, and Tomato & Veg formula.
A comparison of nutrient components between synthetic and organic fertilizers indicated that no liquid organic fertilizer matched the exact ratio of nutrient ions in standard synthetic fertilizer recipes.
However, Grow Big, Espartan, and Pre-Empt had the closest composition to synthetic fertilizer used for leafy greens and high-wire crop production.
This research will help growers select fertilizers and prepare target concentrations of liquid organic fertilizers from the tank-mixing stage to dosing.
Authors
M. Chowdhury, U. Samarakoon, J.E. Altland
Keywords
controlled environment agriculture, soilless cultivation, liquid organic fertilizer, nutrient ions, nutrient dosing
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