The effect of foliar micronutrient applications on nutrient use efficiency in tomatoes

Date
2024-03
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : Stellenbosch University
Abstract
ENGLISH ABSTRACT: Plant nutrient management through the application of a balanced nutrient solution is critical for the success of crops in intensive production systems. Over-application or unbalanced applications however can result in wasted resources and environmental pollution. This study explores the impact of micronutrient foliar applications of silicon (Si) and boron (B) on the post-harvest yield and quality of two tomato varieties in a fertigation system where the calcium (Ca²⁺) and potassium (K⁺) application ratio is adjusted. Using these fertigation systems, the objective is to determine whether the nutrient use efficiency (NUE) can be improved for tomato production systems with the respective treatments. The study was conducted in a greenhouse on the Welgevallen Experimental Farm in Stellenbosch, Western Cape. Two varieties of tomatoes were used, Floradade and Solarino RZ F1 (72-150). Seedlings were planted into 20 L bags with coconut peat as the growing medium. The trial comprised of four treatments with an open-hydroponic system where a foliar feed of Si, B, or a combination of the two was applied in conjunction with a fertigation solution where the Ca²⁺ % was adjusted or followed standard recommendations. This adjusted solution maintained an EC of 2mS.cm⁻¹ where the Ca:K and Ca:Mg ratios were changed with reduced Ca²⁺ and increased K⁺ and Mg²⁺, whereas the standard solution had ratios according to the Steiner solution concentrations. Analysis of the data collected during the trial, both developmental and post-harvest, was done using R (R Core Team, 2023) and STATISTICA Version 13.3 (TIBCO Soft Inc. 2016) for statistical software. A full nutrient analysis was also conducted on the fruits. Standard fertigation treatments, specifically treatment 2 with the added Si foliar feed had the most significant effect on the vegetative growth parameters. The reduced fertigation treatments had a less significant impact on these parameters, although the rate of Ca²⁺ supplied to tomatoes can be reduced if managed correctly, and if amendments of B and Si are given. The adjusted Ca²⁺ % reported an 18% increase in NUE for the marketable weight of the harvested product, and an 8% increase for the marketable weight of all the treatments combined, allowing growers to receive a larger percentage of marketable product at the same input cost and volume of nutrients compared to the standard fertigation treatments. It is confirmed that the NUE can be improved in hydroponic tomato production where Si and B are applied as foliar feed substitutes for Ca²⁺ without compromising the quality and post-harvest shelf- life of tomatoes. The reduction of Ca²⁺ % in the fertigation and the addition of Si and B did not compete with standard fertigation treatments. This reduction of the input, however, allowed for an increase in the NUE of these treatments, allowing growers to receive a larger percentage of marketable product for the input cost and volume of nutrients compared to standard fertigation treatments.
AFRIKAANSE OPSOMMING: Die bestuur van plantvoeding, deur die toepassing van 'n gebalanseerde voedingsoplossing, is van kritieke belang vir die suksesvolle groei van gewasse in intensiewe produksiestelsels. Oortoediening, of ongebalanseerde toedienings, kan egter lei tot onnodige gebruik van hulpbronne en bydra tot die besoedeling van die omgewing en ekostelsel. Hierdie studie ondersoek die impak van mikronutriëntblaartoedienings van silikon (Si) en boor (B) op die na-oes opbrengs en kwaliteit van twee tamatievariëteite in 'n bemestingstelsel waar die kalsium (Ca²⁺) en kalium (K⁺) toedieningsverhouding aangepas word. Deur hierdie bemestingstelsels te gebruik, is die doel om te bepaal of die nutriëntgebruiks-doeltreffendheid (NUE) verbeter kan word vir tamatie- produksiestelsels met die bogenoemde behandelings. Die studie is uitgevoer in 'n kweekhuis op die Welgevallen-proefplaas in Stellenbosch, Wes-Kaap. Twee variëteite tamaties is gebruik, Floradade en Solarino RZ F1 (72-150). Saailinge is in 20 L-sakke geplant met klapperturf as die groei-medium. Die proef het bestaan uit vier behandelings met 'n oop-hidroponiese stelsel waar 'n blaarvoeding van Si, B, of 'n kombinasie van die twee toegedien is tesame met 'n bemestingsoplossing waar die Ca²⁺ % aangepas is of standaard aanbevelings gevolg het. Hierdie aangepaste oplossing het 'n EC van 2mS.cm⁻¹ gehandhaaf waar die Ca:K en Ca:Mg verhoudings verander is met verminderde Ca²⁺ en verhoogde K⁺ en Mg²⁺, terwyl die standaard oplossing verhoudings gehad het volgends die Steiner oplossing konsentrasies. Ontleding van die data wat tydens die proef ingesamel is, beide ontwikkelings- en na-oes, is gedoen deur gebruik te maak van R (R Core Team, 2023) en STATISTICA Weergawe 13.3 (TIBCO Soft Inc. 2016) vir statistiese sagteware. 'n Volledige voedingstofontleding is ook op die vrugte uitgevoer. Standaard bemestingsbehandelings, spesifiek behandeling 2 met die bygevoegde Si-blaarvoer het die mees betekenisvolle effek op die vegetatiewe groeiparameters gehad. Die verminderde bemestingsbehandelings het 'n minder betekenisvolle impak op hierdie parameters gehad, alhoewel die hoeveelheid Ca²⁺ wat aan tamaties verskaf word, verminder kan word indien dit korrek bestuur word, en indien wysigings van B en Si gegee word. Die aangepaste Ca²⁺ % het 'n 18% verhoging in NUE gerapporteer vir die bemarkbare gewig van die geoesde produk, en 'n 8% verhoging vir die bemarkbare gewig van al die behandelings saaam. Dit stel produsente in staat om 'n groter persentasie bemarkbare produk teen dieselfde insetkoste en volume voedingstowwe in vergelyking met die standard bemestingsbehandelings.te ontvang. Dit word bevestig dat die NUE verbeter kan word in hidroponiese tamatieproduksie waar Si en B as blaarvoer plaasvervangers vir Ca²⁺ toegedien word sonder om die kwaliteit en na-oes raklewe van tamaties in te boet. Die vermindering van Ca²⁺ % in die bemesting en die byvoeging van Si en B het nie met standaard bemestingsbehandelings gekompeteer nie. Hierdie vermindering van die inset het egter 'n toename in die NUE van hierdie behandelings moontlik gemaak, wat produsente in staat gestel het om 'n groter persentasie bemarkbare produk te ontvang vir die insetkoste en volume van voedingstowwe in vergelyking met standaardbemestingsbehandelings.
Description
Thesis (MScAgric)--Stellenbosch University, 2024.
Keywords
Citation