AUTHOR=Kechasov Dmitry , Verheul Michel J. , Paponov Martina , Panosyan Anush , Paponov Ivan A. 

TITLE=Organic Waste-Based Fertilizer in Hydroponics Increases Tomato Fruit Size but Reduces Fruit Quality

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 12 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.680030

DOI=10.3389/fpls.2021.680030

ISSN=1664-462X

ABSTRACT=In regions with intensive agricultural production, large amounts of organic waste are produced by livestock animals. Liquid digestate from manure-based biogas production could potentially serve as fertilizer if integrated with closed horticultural irrigation systems. The aim of the present experiment was to investigate how fertilizer based on liquid biogas by-products of pig manure digestion can affect the growth and production of tomato plants. Integration of a nitrification bioreactor presume a significantly lower concentration of nutrient solutions and a higher level of oxygenation than in classical mineral cultivation; therefore, additional controls were included. We compared plant growth and fruit quality traits of tomato plants grown in a hydroponic solution with organic fertilizer with two levels of mineral fertilizer.
The tomatoes grown on organic waste-based liquid fertilizer showed reduced growth rates but increased mean fruit size, resulting in no significant change in total yield compared to high-mineral cultivation. The growth rate was similarly reduced in plant cultivated in low-mineral fertilizer. Plants cultivated on organic waste-based fertilizer had high Cl- concentration in xylem sap, leaves, and ultimately the fruits. The leaves of plants cultivated on organic waste-based fertilizer contained higher concentrations of starch and soluble carbohydrate and low concentrations of P and S. The plants grown in organic waste-based or low-mineral medium showed significantly poorer fruit quality than the plants cultivated in the high-mineral solution. The low-mineral treatment increased the xylem sap contribution to fruit weight due to the higher root power. The organic waste-based fertilization did not change the root power but increased the fruit size. In conclusion, organic waste-based cultivation is a possible solution for sustainable plant production in greenhouses; however, additional adjustment of nutrient supply is required to improve fruit quality.