Alternative soilless media using olive-mill and paper waste for growing ornamental plants

Abstract

Peat-based growing media are not ecologically sustainable and peat extraction threatens sensitive peatland ecosystem. In this study, olive-stone waste (OSW) and paper waste (PW) were used in different ratios-as growing media-for ornamental crop production, as peat (P) substitutes. Marigold (Calendula officinalis L.), petunia (Petunia x hybrita L.) and matthiola (Matthiola incana L.) plants were grown in (1) P (100%), (2) P:OSW (90%:10%), (3) P:OSW (70%:30%), and (4) P:OSW:PW (60%:20%:20%). The physicochemical properties of these substrates and the effects on plant growth were determined. The addition of 10-30% OSW into the substrate increased marigold height compared to plants grown in 100% peat. No differences in plant size, plant biomass (leaves and flowers), and dry matter content were found. Adding PW, in combination with OSW, maintained marigold height and total number of flowers produced to similar levels as in plants grown in 100% peat. In matthiola, adding 30% OSW into the substrate reduced plant size and fresh weight, but not plant height. No differences were observed when plants grew in lower OSW (i.e., 10%) content. Petunia's height, its total number of flowers and flower earliness (flower opening) were increased in the presence of OSW compared to the plants grown in 100% peat. The addition of OSW did not affect petunia's size and fresh weight among treatments. The addition of PW suppressed several plant growth-related parameters for both matthiola and petunia. The insertion of OSW did not change leaf chlorophyll content whereas the presence of PW decreased chlorophylls for marigold, petunia, and matthiola. Both OSW and PW altered the content of total phenolics and antioxidant capacity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) in leaves and flowers for marigold and petunia. Both 30% OSW and PW increased antioxidative enzyme metabolism due to the increased damage index and lipid peroxidation observed in plants. Leaf N and P content decreased in PW-based media, while matthiola displayed visual phytotoxicity symptoms when PW was added into the substrate. The present work indicates that up to 30% of OSW can replace peat for marigold and petunia growing and only up to 10% of OSW for matthiola, while the addition of PW on top of OSW is not recommended, so further research is needed.

Cotton and cardoon byproducts as potential growing media components for Cichorium spinosum L. commercial cultivation

“…These contrasting results could be attributed to the different growth substrates and growing systems implemented in these studies, as well as to the severity of salinity stress which was higher in the study of Klados and Tzortzakis (2014). Higher values of total phenolic compounds content were also reported for parsley and dill plants grown in Germany soil in comparison to peat-based substrates by Saleh et al (2019), while Chrysargyris et al (2018a) demonstrated the effect of using paper in growth substrate blends on total phenols content of ornamental plants. In contrast, Dannehl et al (2015) reported no significant differences in total phenolic compounds in fruit of tomato plants grown in peat moss, rock wool, sheep wool and hemp which indicates that there is also a species depended response to growth substrate.…”

“…Biochar is also a candidate substrate for soilless cultivation of leafy vegetables since research studies demonstrated that its use increased plant growth and mineral composition and decreased the undesirable growth of algae in nutrient solution (Awad et al, 2017). Other potential peat substitutes include composts from distillery wastes (Bustamante et al, 2008), mixtures of vegetable waste, manure and sawdust (Gavilanes-Ter an et al, 2016), paper waste (Chrysargyris et al, 2018a), hazelnut husks (Dede et al, 2011), and sawdust (Marinou et al, 2013) among others.…”

Biochar or Biochar-Compost Amendment to a Peat-Based Substrate Improves Growth of Syngonium podophyllum

“…The scavenging of ROS is then directly linked to the activity of antioxidant enzymes, such as SOD, POD, and CAT. The activities of these enzymes generally increase with the increase in stress severity [9,60,61]. Furthermore, reducing power was also not altered significantly in response to either BC or BioComp amendment (Table 7).…”

“…In Europe, the volume of organic substrate used for the nursery sector amounts to 34.6 million m 3 per annum, of which 27 million m 3 is composed of peat [7]. The use of peat as growing media, however, has caused ecological concerns [8] because peat is a non-renewable resource, and peatland is a sink of carbon dioxide [9,10]. As a result, peat has become costlier for commercial use [5,11], and there is an increasing need for alternative organic materials to replace or partially replace peat for the production of container plants [5,12,13].…”

“…Compost is another alternative to peat for formulation of substrates, which has been extensively studied [9,22,23]. Recent studies show that mixtures of BC with compost appear to have synergistic effects on container plant growth [1].…”