Non-composted and blended agro-industrial by-products an as alternative soilless substrate affect potted zonal geranium (Pelargonium x hortorum) and murva (Murraya paniculata) production

Abstract

Due to their hiking prices and import restrictions, peat moss and coco coir are not readily available in many developing countries including Pakistan. Therefore, it is necessary to explore alternative soilless substrates having low cost and comparable physico-chemical properties with peat moss and coco coir for local and global market. For this purpose, indigenous agro-industrial by-products, viz., sesame straw, date palm coir, sugarcane pressmud, sugar beet waste and pine bark were collected, cleaned, crushed (where needed) and blended for physico-chemical analyses. Zonal geranium ‘Pinto White’ and murva (Murraya paniculata Kaneh.) were used to evaluate the efficacy of various combinations of substrates on plant growth and production. Three experiments were conducted with six treatments of each experiment replicated three times. Blending of sesame straw with sugarcane pressmud and pine bark (4:4:2 by volume) yielded best results and marketable plants were produced with tallest height (35.8 cm), canopy diameter (20.8 cm), leaf area (29.2 cm2), leaf total chlorophyll contents (62.1 SPAD) and flowers per plant (5.0 No.) along with shortest production time (103 days). Same results were recorded when murva plants were grown in 4:4:2 blending of sesame straw, sugarcane pressmud and pine bark. Zonal geranium and murva plants did not perform well when sesame straw was blended with date palm coir and sugar beet waste. Blending of sesame straw with sugarcane pressmud and pine bark had low pH (7.0), electrical conductivity (1.37 mS cm-1), bulk density (0.29 g cm-3) while high water retention (34.7 %) as compared to other blended substrates. However, shrinkage of substrates in containers was highest (7.7 %) when sesame straw was blended with sugarcane pressmud and pine bark in 5:3:2 followed by 4:4:2. pH value of all blended substrates decreased at termination except when sesame straw, sugarcane pressmud and pine bark were blended in 4:4:2 and 5:2:3, which was increased from 7.0 to 7.1. Electrical conductivity of all blended substrates was decreased at termination of the experiments. It can be concluded that blending of sesame straw, sugarcane pressmud and pine bark in 4:4:2 (v/v/v) significantly improved physico-chemical characteristics of substrates as well as plant growth and production attributes of zonal geranium and murva. Therefore, this indigenous soilless substrate, which is cheaper and readily available to nurserymen can be used as alternative of peat moss and coco coir for containerized plant production.