Decomposition of peat substrates in relation to physical properties and growth of Skimmia

Severe shrinking of the potting compost and poor plant growth are problems that may arise in nursery crops that have a relatively long culture period or are irrigated with ebb/flow systems. Research conducted on the factors expected to be responsible for the physical changes to the potting compost and that influence the growth of the crop Skimmia japonica 'Rubinetta' examined the type of peat (its provenance/degree of decomposition: 4 levels), flow depth (3 levels) in ebb/flow systems and pH (2 levels). Stable Irish peat was found to contain a smaller volume % of easily available water than peat moss and sphagnum moss. It also had the greatest volume % air at pF-1(-10 cm pressure head), followed by Irish moss peat and then sphagnum peat moss. A decrease in the volume % air in the substrate resulted in poorer ratings of root quality, reduced dry matter production and greater shrinkage. The provenance of the peat appeared to be very influential, and the flow depth and pH appeared to contribute importantly to peat shrinkage and crop production.