Growth and yield of tomato cultivated on composted duck excreta enriched wood shavings and source-separated municipal solid waste

Abstract

A greenhouse experiment was conducted to evaluate the use of growth substrates, made with duck excreta enriched wood shaving compost (DMC) and the organic fraction of source-separated municipal solid waste (MSW) compost, on the growth and yield of tomato (Lycopersicum esculentum Mill. cv. Campbell 1327). Substrate A consisted of 3:2 (W/W) proportion of DMC and MSW composts. Substrates B and C were the same as A but contained 15% (W/W ratio) of brick dust and shredded plastic, respectively. Three control substrates consisted of the commercially available peat-based substrate (Pr), an in-house sphagnum peat-based substrate (Gs), and black earth mixed with sandy loam soil (BE/S) in a 1:4 (W/W) ratio. Substrates (A, B, C) and controls received nitrogen (N), phosphate (P) and potassium (K) at equivalent rates of 780 mg/pot, 625 mg/pot, and 625 mg/pot, respectively, or were used without mineral fertilizers. Compared to the controls (Pr, Gs and BE/S), tomato plants grown on A, B, and C produced a greater total number and dry mass of fruits, with no significant differences between them. On average, total plant dry-matter biomass in substrate A, B, and C was 19% lower than that produced on Pr, but 28% greater than biomass obtained for plant grown, on Gs and BE/S. Plant height, stem diameter and chlorophyll concentrations indicate that substrates A, B, and C were particularly suitable for plant growth. Although the presence of excess N in composted substrates favoured vegetative rather than reproductive growth, the continuous supply of nutrients throughout the growing cycle, as well as the high water retention capacity that resulted in a reduced watering by 50%, suggest that substrates A, B, and C were suitable growing mixes, offering environmental and agronomic advantages.