Amended and composted log yard fines as a growth medium for crimson clover and red top grass

Abstract

Log yard residues (LYR) a bark and soil waste material produced during log handling, could find use as a growth medium for plants. In this study, log yard fines (LYF), a screened fraction of the LYR (<1.3 cm), were either not amended or amended with a N‐S fertilizer mixture (LYF + F) or with cow manure (LYF + M) and then composted outdoors in insulated, aerated tanks for 18–22 weeks. The resulting substrates were then evaluated as growth media for ‘Chief crimson clover (Trifolium incarnatum L.) and ‘Streaker’ red top (Agrostis alba L.). Plants were fertilized (0 or 78 kg N/ha) and grown in a growth chamber.

Temperatures in the LYF and LYF + F piles were similar to ambient conditions over the 5–6 month treatment period, whereas the manure‐amended pile reached a maximum of 34°C after two weeks and then cooled to ambient after two additional weeks. The final C/N ratio of the nonamended LYF was 85 as compared to 36 for LYF + M and 44 for LYF + F. Clover and red top grew best (height and biomass) in LYF + F and poorest in LYF + M, regardless of fertilization regime. Red top grew poorly in the nonamended, unfertilized LYF presumably due to the high C/N ratio of this medium. In summary, this study suggested that LYF could be either amended with fertilizer and aged in piles or directly land applied with supplemental fertilization to support plant growth.