Compost and vermicompost as nursery pot components: effects on tomato plant growth and morphology

C Lazcano,A Tato,J Domínguez,J Arnold,J.G Zaller

doi:10.5424/sjar/2009074-1107

Abstract

Post transplant success after nursery stage is strongly influenced by plant morphology. Cultural practices strongly shape plant morphology, and substrate choice is one of the most determining factors. Peat is the most often used amendment in commercial potting substrates, involving the exploitation of non-renewable resources and the degradation of highly valuable peatland ecosystems and therefore alternative substrates are required. Here the feasibility of replacing peat by compost or vermicompost for the production of tomato plants in nurseries was investigated through the study of the effect of increasing proportions of these substrates (0%, 10%, 20%, 50%, 75% and 100%) in target plant growth and morphological features, indicators of adequate post-transplant growth and yield. Compost and vermicompost showed to be adequate substrates for tomato plant growth. Total replacement of peat by vermicompost was possible while doses of compost higher than 50% caused plant mortality. Low doses of compost (10 and 20%) and high doses of vermicompost produced significant increases in aerial and root biomass of the tomato plants. In addition these treatments improved significantly plant morphology (higher number of leaves and leaf area, and increased root volume and branching). The use of compost and vermicompost constitute an attractive alternative to the use of peat in plant nurseries due to the environmental benefits involved but also due to the observed improvement in plant quality.

Highlights

The main goal of horticultural nurseries is to produce quality seedlings with target morphological and physiological features that guarantee crop success after transplanting
Total replacement of peat was only possible when vermicompost was used, while doses of compost higher than 50% caused prompt plant mortality
Plant mortality after compost introduction in the potting media has already been reported in previous studies and it has been attributed to the change in the physical properties of the substrate (Papafotiou et al, 2005), to the increase in substrate salinity in the case of tomato plants (García-Gómez et al, 2002; Castillo et al, 2004; Herrera et al, 2008) and to the presence of excessively high concentrations of certain ions (Hashemimajd et al, 2004)

Summary

Introduction

The main goal of horticultural nurseries is to produce quality seedlings with target morphological and physiological features that guarantee crop success after transplanting. Nursery stock is produced in containers due to market demands and numerous production advantages including greater production per surface unit, faster plant growth, higher plant quality, and lack of dependence on arable land. In many countries several restrictions have been established for the use of this material due to environmental concerns and, as a consequence, peat has become a rather scarce and expensive potting substrate. The parallel increasing concern in waste recycling has lead to the proposal of some organic materials such compost-like substrates (Ostos et al, 2008), as partial substitutes of peat. As a product of thermophilic processes of organic waste degradation, and vermicompost, as a mesophilic biodegradation product resulting from interactions between earthworms and microorganisms are humus-like materials which could act as suitable substitutes of peat. The higher nutrient content of compost and vermicompost as compared to peat could allow the reduction of the mineral fertilizers used reducing the expenses of the nursery operations

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Conclusion