Evaluation of spent pig litter compost as a peat substitute in soilless growth media

This study was conducted to investigate the feasibility of using litter compost from a pig-on-litter system in the nursery and growth of vegetables to replace part of peat in substrates containing peat, vermiculite and perlite. The main physical and chemical characteristics of substrates with different proportions of spent pig litter compost (SPLC), peat, vermiculite and perlite were analysed, and the performance of plants grown in these substrates were recorded. A commercially available peat product referred as Peat was used as the control. The total porosity and air porosity of the studied substrates tended to decrease with increasing SPLC proportions. The pH (6.99–7.63) and EC values (3.80–5.75) increased with SPLC addition and were above the range for ideal substrates. The plant height, stem diameter and weight of the tomato seedlings were the highest in substrates containing 30% and 40% SPLC, which were similar to those in Peat and were significantly higher than in substrates containing 50% and 60% SPLC. The results suggested that SPLC could be used as a nutrient source to replace up to 40% of peat without negative effect on tomato seedlings, when also vermiculite and perlite were added in the substrate. The Chinese cabbage grown in substrates containing 30% SPLC had significantly higher yield and quality than those grown in Peat and in substrates containing 50% SPLC. The peat addition could be cut down to 20% without apparently affecting the plant growth in the substrates with 30% SPLC, when also vermiculite and perlite were added in the substrates.