Liquid Organic Fertilizer Effects on Growth and Biomass of Lettuce Grown in a Soilless Production System

Abstract

Demand for locally produced, organically grown leafy greens is increasing throughout the United States. However, due to lack of efficient organic fertilizers (OFs) for soilless substrates, organic greenhouse production of leafy greens may be challenging. Therefore, a greenhouse study was conducted to analyze the effects of six liquid OFs on growth and development of lettuce in a soilless system. Two experiments were conducted using a randomized block design, and treatments included six fish- or plant-based OFs: OF1 (5N–1P–1K), OF2 (2N–5P–1K), OF3 (3N–1P–1K), OF4 (2N–2P–2K), OF5 (4N–1P–1K), and OF6 (3N–3P–2K); one inorganic fertilizer treatment (IF, 24N–8P–16K); and one unfertilized control treatment. Fertilizer solutions were prepared at 2 dS⋅m–1 and applied at 100 mL/plant. In Expt. 1, fresh biomass for IF-treated plants was 12% to 38% greater than OF treatments, whereas this difference ranged from 25% to 57% in Expt. 2. Similarly, leaf area values of IF-treated plants were 5% to 40% greater than OF treatments in Expt. 1, and the difference ranged from 28% to 90% in Expt. 2. A possible explanation could be greater availability of nutrients in the IF treatment compared with OF treatments. There was no significant difference among fertilized treatments for number of leaves and stem diameter. Based on the index-based ranking, fish-based (OF1) and fish- and plant-based (OF2 and OF6) performed well among different liquid OFs used in the study. Although the yield under OFs was less compared with that under IF, there is potential to reduce this yield gap by optimized fertility management of these fertilizers. Future research is needed to investigate the impact of optimized rate, timing, different placement, and additional nitrogen (N) sources of OFs on the soilless production of lettuce.

Influence of Arbuscular Mycorrhizal Fungi on Physiology and Yield of Eggplant in Organic Soilless Production System

“…Further, El-Shinawy and Gawish (2006) showed that there was no significant difference in Chl of lettuce fertilized with different OFs and IFs in a hydroponic system. Shaik et al (2022) reported that lettuce plants fertilized with different OFs derived from different plant and animal sources resulted in no significant difference in Chl of lettuce compared with IF. In our study, most of the cases, the eggplant fertilized with different OFs and IFs resulted in similar Chl, which could be because these OFs were composed of different plant and animal sources with an adequate N content.…”

“…compared with IF. Results from the greenhouse experiment conducted by Shaik et al (2022) reported 18% to 30% reduction in lettuce yield while using various OFs compared with IFs. The authors concluded that the yield reduction in OF treatments was due to lower nutrient availability in OFs compared with IF.…”

“…Moreover, specific compounds like chitin, humic and fulvic acids, and other biopolymers in LOFs can act as biostimulants to plants (Canellas et al, 2015;Du Jardin, 2015;Ji et al, 2017;Sharp, 2013;Tang et al, 2014). However, lesser nutrient availability from OFs results in 5% to 34% lower yields in the organic system than the conventional inorganic production system (Pokhrel et al, 2019;Seufert et al, 2012;Shaik et al, 2022). Further, lack of beneficial microorganisms in soilless media may reduce rate of microbe-mediated mineralization, which eventually reduces the nutrient availability to plant growth.…”

“…Various studies have shown that several vegetables, including eggplant, provide high yields and good quality of produce when cultivated in a greenhouse soilless system using inorganic fertilization (Miceli et al, 2003;Moncada et al, 2021;Settanni et al, 2012). However, there is little research aiming at fruit vegetable production with a combination of fertilization (Shaik et al, 2022;Treadwell et al, 2011), especially LOF and AMF inoculation in the soilless production system. For this reason, the objective of the present work was to assess the potential of different LOFs and AMF in improving the growth, gaseous exchange, and yield attributes of eggplant in a soilless production system under greenhouse conditions.…”

GREENBOX Technology I - Technical Feasibility and Performance in Warehouse Environment

“…The FAO estimates that annual world agricultural production needs to increase by 70% between 2005 and 2050 to feed the growing population (Conforti et al, 2011). In response to the current challenges facing feeding the populous urban residents, sustainable food production systems have emerged in urban areas (Shaik et al, 2022). Controlled Environment Agriculture (CEA) is defined as high-yield agriculture protected from the external environment (Armanda et al, 2019;Orsini et al, 2020), and can serve as an excellent solution for feeding the cities of the future (Thomaier et al, 2015).…”