Growth, Yield and Quality of Sweet Pepper Fruits Fertilized with Polyphosphates in Hydroponic Cultivation with LED Lighting

Anna Sobczak,Waldemar Kowalczyk,Monika Niedzińska,Katarzyna Kowalczyk,Janina Gajc-Wolska

doi:10.3390/agronomy10101560

Anna Sobczak, Waldemar Kowalczyk + Show 3 more

Open Access

https://doi.org/10.3390/agronomy10101560

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Journal: Agronomy	Publication Date: Oct 13, 2020
Citations: 15	License type: CC BY 4.0

Affiliation: Instytut Ogrodnictwa, Warsaw University of Life Sciences

Abstract

The aim of this study was to investigate the effect of phosphorus application in the form of polyphosphates on the yield and quality of sweet pepper fruits grown with LED (light-emitting diodes) assimilation lighting. Phosphorus is absorbed by the root system of plants mainly in the form of orthophosphates ions. The availability of phosphorus depends, among other things, on the pH of the substrate and the temperature. Two cultivars of sweet pepper with red fruits were tested in hydroponic cultivation on a mineral wool substrate. The plants were fertilized with one of three schedules, each of the same concentration of components, but differing only in the form of the applied phosphorus: polyphosphates (PP) and orthophosphates (OP). In the experiment, stem length extensions and number of leaves, chlorophyll concentration in leaves and fluorescence of the chlorophyll in a leaf were measured. The number and weight of fruits in total as well as marketable and non-commercial fruits with symptoms of dry rot (BER—blossom end rot) were studied. The concentration of dry matter and selected chemical components in fruits were examined and the sensory quality of fruits was evaluated using the QDA (Quantitative Description Analysis) method. The nutrient status of the pepper plants was also examined. Polyphosphates used in the medium increase the activity of photosynthetic apparatus of leaves and have a positive effect on the share of marketable yield of the total yield in the cultivar susceptible to BER. Fertigation in hydroponic cultivation with medium containing 30% phosphorus in the form of polyphosphates increased the uptake of calcium in pepper plants growing with LED lighting. The pepper cultivars tested differ in, among other things, the susceptibility to BER and the quality attributes of the fruit.

Highlights

Sweet pepper (Capsicum annuum L.) is a plant with a long growing period and requires good quality soil or substrate and adequate light, temperature and water [1,2]
The results of biometric measurements showed no effect of polyphosphates used in the nutrient solution for pepper fertigation in hydroponic cultivation with LED lighting on plant height, weekly shoot growth on the length and number of leaves in both studied pepper cultivars
Our results showed that higher values of pepper leaves’ chlorophyll a fluorescence parameters in plants fertilized with polyphosphates indicate an increased yield of pepper photosynthetic apparatus in the case of pepper cultivar more susceptible to been associated with fruit calcium deficiency (BER)

Summary

Introduction

Sweet pepper (Capsicum annuum L.) is a plant with a long growing period and requires good quality soil or substrate and adequate light, temperature and water [1,2]. The pepper fruit is highly valued for its taste and health-promoting qualities. Sweet pepper fruit provides vitamin C and vitamin. A, flavonoids and antioxidants as well [3,4,5]. The demand for the fruit is high all year round. Growing plants in year-round greenhouses requires effective assimilation lighting. Light is an important environmental factor with a significant role in plant life processes [6]

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